File: xterm.faq.html

package info (click to toggle)
xterm 398-1
links: PTS, VCS
area: main
in suites: trixie
size: 8,280 kB
sloc: ansic: 86,716; perl: 9,623; sh: 5,488; makefile: 843; xml: 46; sed: 11
file content (10907 lines) | stat: -rw-r--r-- 453,415 bytes
<!--
 *****************************************************************************
 * Copyright 1997-2024,2025 by Thomas E. Dickey                              *
 * All Rights Reserved.                                                      *
 *                                                                           *
 * Permission to use, copy, modify, and distribute this software and its     *
 * documentation for any purpose and without fee is hereby granted, provided *
 * that the above copyright notice appear in all copies and that both that   *
 * copyright notice and this permission notice appear in supporting          *
 * documentation, and that the name of the above listed copyright holder(s)  *
 * not be used in advertising or publicity pertaining to distribution of the *
 * software without specific, written prior permission.                      *
 *                                                                           *
 * THE ABOVE LISTED COPYRIGHT HOLDER(S) DISCLAIM ALL WARRANTIES WITH REGARD  *
 * TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND *
 * FITNESS, IN NO EVENT SHALL THE ABOVE LISTED COPYRIGHT HOLDER(S) BE LIABLE *
 * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES         *
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN     *
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF   *
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.            *
 *****************************************************************************
  $XTermId: xterm.faq.html,v 1.432 2025/04/07 07:44:19 tom Exp $
  -->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
  <meta name="generator" content=
  "HTML Tidy for HTML5 for Linux version 5.6.0">
  <title>XTerm &ndash; Frequently Asked Questions (FAQ)</title>
  <link rel="author" href="mailto:dickey@invisible-island.net">
  <meta http-equiv="Content-Type" content=
  "text/html; charset=us-ascii">
  <meta name="keywords" content=
  "xterm, terminal, vt220, vt420, 256-colors, UTF-8">
  <meta name="description" content=
  "xterm is the standard terminal emulator for the X Window System. This page gives some background and pointers to xterm resources.">
  <link rel="SHORTCUT ICON" href="/img/icons/xterm.ico" type=
  "image/x-icon">
  <link rel="stylesheet" href="/css/simplestyle.css" type=
  "text/css">
  <link rel="stylesheet" href="/css/inline-code.css" type=
  "text/css">
  <link rel="stylesheet" href="/css/xterm-icons.css" type=
  "text/css">
  <style type="text/css">
  @import "/css/simplenavXX.css" all;
  </style>
  <meta name="viewport" content=
  "width=device-width, initial-scale=1">
</head>
<body>
  <hr>

  <p><a href="/">http://invisible-island.net/</a><a href=
  "./">xterm/</a><br>
  Copyright &copy; 1997-2024,2025 by Thomas E. Dickey</p>

  <hr>

  <p><a href=
  "http://invisible-island.net/xterm/xterm.faq.html">Here</a> is
  the latest version of this file.</p>

  <h1 class="no-header">XTerm &ndash; Frequently Asked Questions
  (FAQ)</h1>

  <div class="nav">
    <ul>
      <li class="nav-top"><a href="/xterm/xterm.faq.html">(top)</a></li>

      <li><a href="#what_is_it">What is <strong>XTerm</strong>?</a></li>

      <li><a href="#who_did_it">Who wrote
      <strong>XTerm</strong>?</a></li>

      <li><a href="#what_is_vt220">What is a VT220?</a></li>

      <li><a href="#what_platforms">What platforms does it run
      on?</a></li>

      <li><a href="#latest_version">What is the latest version?</a></li>

      <li><a href="#other_versions">What versions are
      available?</a></li>

      <li><a href="#compare_versions">Comparing versions, by
      counting controls</a></li>

      <li><a href="#how_do_i">How do I ...</a></li>

      <li><a href="#frequent_problems">Frequent problems</a></li>

      <li><a href="#known_bugs">Known Bugs in
      <strong>XTerm</strong> and Look&ndash;alikes</a></li>

      <li><a href="#building_it">How do I build
      <strong>XTerm</strong>?</a></li>

      <li><a href="#report_bugs">How do I report bugs?</a></li>

      <li><a href="#more_info">Additional Information</a></li>

      <li><a href="#future_work">Ongoing/future work</a></li>
    </ul>
  </div>

  <h2 id="what_is_it-id"><a name="what_is_it" id="what_is_it">What
  is <strong>XTerm</strong>?</a></h2>

  <p>From the manual page:</p>

  <blockquote class="code-block">
    <p>The xterm program is a terminal emulator for the X Window
    System. It provides DEC VT102/VT220 and selected features from
    higher-level terminals such as VT320/VT420/VT520 (VTxxx). It
    also provides Tektronix 4014 emulation for programs that cannot
    use the window system directly. If the underlying operating
    system supports terminal resizing capabilities (for example,
    the SIGWINCH signal in systems derived from 4.3bsd), xterm will
    use the facilities to notify programs running in the window
    whenever it is resized.</p>
  </blockquote>

  <p>That is, xterm (pronounced "<em>eks</em>-term") is a
  <em>specific</em> program, not a generic item. It is the standard
  X terminal emulator program.</p>

  <p>This FAQ presents various useful bits of information for both
  the specific program as well as other programs that imitate
  it.</p>

  <p>As a stylistic convention, the capitalized form is
  <em>&ldquo;XTerm&rdquo;</em>, which corresponds to the X resource
  class name. Similarly, <em>uxterm</em> becomes
  <em>&ldquo;UXTerm&rdquo;</em>.</p>

  <h2 id="who_did_it-id"><a name="who_did_it" id="who_did_it">Who
  wrote <strong>XTerm</strong>?</a></h2>

  <p>I've been working on xterm since early 1996 (see my <a href=
  "xterm.log.html">changelog</a> for details).</p>

  <p>But the program is much older than that:</p>

  <ul>
    <li>
      <p><a href="#prehistory">A Prehistory Perspective</a></p>
    </li>

    <li>
      <p><a href="#some_digging">Looking for more perspective</a></p>
    </li>

    <li>
      <p><a href="#my_history">My involvement</a></p>
    </li>

    <li>
      <p><a href="#forward_history">Focus of this FAQ</a></p>
    </li>
  </ul>

  <h3 id="pre_history-id"><a href="#who_did_it" name="prehistory"
  id="prehistory">A Prehistory Perspective</a></h3>

  <p>A lot of people, cited at the bottom of the manual page wrote
  the original xterm program, maintained by the X Consortium (later
  part of The Open Group &ndash; I'm well aware of the distinction,
  but am citing when the work was done, not who the current owner
  may be). There is no changelog, and it is not clear who did what.
  Email from Jim Gettys (September 1998) provides some
  background:</p>

  <blockquote class="code-block">
    <p>Cast of thousands...</p>

    <p>To give a bit of history, xterm predates X!</p>

    <p>It was originally written as a stand-alone terminal emulator
    for the VS100 by Mark Vandevoorde, as my coop student the
    summer that X started.</p>

    <p>Part way through the summer, it became clear that X was more
    useful than trying to do a stand alone program, so I had him
    retarget it to X. Part of why xterm's internals are so
    horrifying is that it was originally intended that a single
    process be able to drive multiple VS100 displays. Don't hold
    this against Mark; it isn't his fault.</p>

    <p>I then did a lot of hacking on it, and merged several
    improved versions from others back in.</p>

    <p>Notable improvements include the proper ANSI parser, that
    Bob McNamara did.</p>

    <p>The Tek 4010 support came from a guy at Smithsonian
    Astrophysical Observatory whose name slips my mind at the
    moment.</p>

    <p>Ported to X11 by Loretta Guarino.</p>

    <p>Then hacked on at the X Consortium by uncounted people.</p>
  </blockquote>

  <p>Email from Doug Mink (October 1999) provides more
  background:</p>

  <blockquote class="code-block">
    <p>I was checking out the newly revised AltaVista search engine
    to see what was on the net about xterm, and I found your pages.
    I can add to the FAQ in that I was the "guy at the Smithsonian
    Astrophysical Observatory" Jim Gettys refers to. I am listed at
    the end of the man page under authors. What happened was that I
    was hired by SAO (after leaving the research staff at MIT) in
    October 1985 to write analysis software for the Spacelab 2
    Infrared Telescope which was to fly on the Space Shuttle in
    1985 less than six months after I was hired. I came with a tar
    tape full of software I had written for Unix and Tektronix
    terminals, but I was presented with a VS100 terminal which had
    an early version (X6 or so) of xterm, with no graphics
    capabilities. SAO is at Harvard, across Cambridge from MIT,
    where Jim Gettys was detailed from DEC to the X project, and
    Jim had connections with SAO, having worked here after college
    (MIT, where we had both worked at the observatory at various
    times); he was still sharing an apartment with an SAO colleague
    of mine, too. Anyway, everyone decided that since I knew
    Tektronix commands pretty well, and our group desparately
    needed the graphics capabilities, it would be a good use of my
    time to implement a Tektronix terminal emulator under X. So I
    set to work learning more C--I had only written a couple of
    wrappers to C I/O routines so I could use them with my Fortran
    software--and wrote a Tektronix emulator. The only X
    documentation at the time was the code itself. While I was at
    it, I wrote an improved Tektronix emulator for our Imagen laser
    printer which used the full resolution of that 300 dpi printer
    instead of the effective 100 dpi (i.e. jaggy) emultator
    distributed with the printer. The original xterm Tek emulator
    shared a window with the VT100 emulator, much like on the VT240
    terminals which I had been using at MIT before I came to
    Harvard. With a VAX 750 running several VS100's, window
    creation was sloowww, so sharing a window was the quickest way
    to do things, and all of my software was written for that mode
    of operation, anyway. While I wrote the emulator so that my
    software would work on it, it was tested by the X group against
    a BBN graphics package, the name of which slips my mind right
    now.</p>

    <p>Anyway, 15 years later, I am still using xterm and some of
    the same mapping software I wrote the emulator for. And I am
    still at the Smithsonian Astrophysical Observatory.</p>
  </blockquote>

  <h3><a href="#who_did_it" name="some_digging" id=
  "some_digging">Looking for more perspective</a></h3>

  <p>VS100 refers to the VAXstation 100, introduced by DEC in 1984
  (see <a href=
  "http://www.bitsavers.org/pdf/dec/vax/vaxstation100/AA-N660A-TE_VAXstation_100_Users_Guide_Jun84.pdf">
  manual</a>).</p>

  <p>There is a git repository <a href=
  "http://cgit.freedesktop.org/~alanc/xc-historical/log/xc/programs/xterm/">
  here</a> which gives some more of xterm's prehistory. But it has
  no usable data for X10 (see initial revisions in <a href=
  "https://cgit.freedesktop.org/~alanc/xc-historical/log/?ofs=25700">
  1985/1986</a>). The X developers did not really start checking in
  their code until 1987.</p>

  <p>The earliest version of xterm which is available is from
  X10R3. According to the xc-historical repository, that was
  <a href=
  "https://cgit.freedesktop.org/~alanc/xc-historical/commit/?id=49c79082577b5ef39c456c03a047e07d8c702e9f">
  February 1, 1986</a> (a change to the <tt>rgb.c</tt> file). Even
  that date is suspect because the X10R3 tarball contains xterm
  files later than that date:</p>

  <blockquote>
    <pre class="code-block">
  17024 May 17 1986    xterm/util.c
  31545 May 17 1986    xterm/main.c
   1377 Feb 10 1986    xterm/Makefile
  10804 Feb  3 1986    man/xterm.1
    660 Feb  2 1986    xterm/terminfo
    606 Feb  2 1986    xterm/termcap
   1178 Feb  2 1986    xterm/tabs.c
  10525 Feb  2 1986    xterm/screen.c
   2907 Feb  2 1986    xterm/resize.c
   6699 Feb  2 1986    xterm/ptyx.h
   2720 Feb  2 1986    xterm/input.c
   2959 Feb  2 1986    xterm/esctable.h
   4482 Feb  2 1986    xterm/cursor.c
   7661 Feb  2 1986    xterm/chartable.h
  23543 Feb  2 1986    xterm/charproc.c
  13990 Feb  2 1986    xterm/button.c
   1122 Feb  2 1986    xterm/buf.c
   3932 Feb  2 1986    xterm/ansi.c
  15662 Feb  2 1986    xterm/Tplot.c
   2382 Feb  2 1986    xterm/README
    234 Feb  2 1986    cursors/xterm_mask.cursor
    234 Feb  2 1986    include/X/cursors/xterm_mask.cursor
    261 Feb  2 1986    cursors/xterm.cursor
    261 Feb  2 1986    include/X/cursors/xterm.cursor
   1335 Dec 21 1985    xterm/icon.ic
   1350 Dec 21 1985    xterm/icon_mask.ic
</pre>
  </blockquote>

  <p>But since the X10R3 tarball contains only 10
  &ldquo;later&rdquo; files out of 974, the 3-4 xterm files are
  just some after-the-fact correction whose reason is long
  lost.</p>

  <p>A posting by Andreas Motl to <a href=
  "https://web.archive.org/web/20151102155441/http://www.netfrag.org/webnews/article.php?id=1064&amp;group=nfo.links.computing">
  <em>nfo.links.computing</em></a> in March 2003 recapitulates the
  content of a page <a href=
  "https://web.archive.org/web/20030618125926/http://www.robotwisdom.com/linux/desktops.html">
  <em>Linux desktops (GUIs, widgets, window managers, etc)</em></a>
  (Jorn Barger, November 2002). That mentions X10 (e.g., &ldquo;X
  v10&rdquo;):</p>

  <blockquote>
    <pre class="code-block">
1985: Sep: X v9 distributed as free [cite] cf Andrew [Gettys]
1985: X/Open Portability Guide [cite]
1985: Oct: Amiga 1.0 [info]
1985: 20Nov: Windows 1.0 ships [tour]
1985: Dec: Clayton Elwell's Portable User Interface Library project [GooJa]

1985: Dec: X v10r2 [annc]

  "X is a portable network transparent window system for bitmap displays.
Applications can be run from any machine in a local area network via stream
connections (currently TCP and Unix domain are supported). X is a fully
hierarchic window system intended to be very flexible. Manipulation of existing
windows is done with an external window manager; if you don't like ours, write
your own. Applications include a terminal emulator (~VT102 and Tek 4010), load
monitor, clock, imagen previewer, and several window managers among other
things."

no-date: Windows 2.0 clones Mac interface; withdrawn and tweaked to avoid
lawsuit? [cite]

1986: Jan: DEC announces VAXstation with X
1986: Feb: X v10r3 [annc]
</pre>
  </blockquote>

  <p>September 1985 might be accurate for X version 9. However, the
  first line of the xterm manual page from X10R3 says</p>

  <blockquote>
    <pre class="code-block">
.TH XTERM 1 "1 January 1985" "X Version 10"
</pre>
  </blockquote>

  <p>Jim Gettys might be able to explain that. Several of the files
  in that version of xterm have copyright dates from 1984, making
  that the likely beginning of development for xterm. Other parts
  of the X10R3 source tree have similar clues. For example, Xlib
  may have begun development in 1984, but since it was unreleased
  until the end of 1985, the actual date is indeterminate.</p>

  <p>A comment by Jim Fulton on <a href=
  "https://tech.slashdot.org/comments.pl?sid=7262&amp;cid=830314">slashdot
  in 2000</a> gives more details on the early versions of X:</p>

  <blockquote>
    <p class="code-block">There weren't really ten full releases
    prior to X11R1, however there were 10 incompatible revs of the
    protocol. Most of the early versions were primarily used within
    MIT (Athena and LCS) and friendly commercial R&amp;D labs.
    Here's some of the pre-history based on cryptic notes and
    blurry memory: X1 - summer 1984 - the first version, based on a
    substantial rearchitecting of the UNIX port of the W Window
    System (originally developed for the V Kernel). X3 - fall 1984
    - used internally at MIT as the initial basis of various
    plotting packages for coursework. X6 - spring 1985 - first
    version licensed by MIT to various companies (including
    Cognition, MASSCOMP, and Digital) for use in commercial
    products. It cost $100 and if you wanted you could stop off at
    the (very small) licensing office to pick up your own magtape.
    X8/X9 - fall 1985 - added color (X8 lasted all of about a week;
    X9 was quickly released to fix a protocol alignment problem
    that impacted ports on the IBM PC/RT). Many organizations began
    developing ports (including a version to the Lexidata 9000
    display card for VAXen that was used at the Autofact tradeshow
    in late 1985 to show a prototype of the first 3rd party
    application: a mechanical engineering design system). X.V10R1 -
    spring 1986 - first version released by MIT that did not
    require signing a license agreement. Also the first version to
    have a DOS Xserver developed. X.V10R[234] - fall 1986 &amp;
    spring 1987 - an explosion of ports done on a variety of
    platforms. X.V11R1 - Sep 15, 1987 - major overall done in
    collaboration with folks from Digital, Sun, IBM, and other
    companies. Formed the basis of core protocol used today.
    Companies and organizations releasing X-based products used
    this release as a starting port for incorporating into their
    own distributions. X.V11R2 - March 1, 1988 - first version
    released under the auspices of the newly-formed MIT X
    Consortium. The MIT X Consortium continued to put out releases
    of X11 for a number of years. Then in the mid-90s, it was spun
    off into a separate not-for-profit organization (simple the X
    Consortium). As has been noted, that eventually folded into
    various organizations that became X.ORG. The rest is history.
    :) Jim Fulton</p>
  </blockquote>

  <h3 id="my_history-id"><a href="#who_did_it" name="my_history"
  id="my_history">My Involvement</a></h3>

  <p>My involvement with <strong>xterm</strong> through XFree86
  began at the <a href="/xterm/xterm.html#history">end of 1995</a>.
  This website has been &ldquo;here&rdquo; since 2001/6/5,
  replacing my ClarkNet page. I started the ClarkNet page
  1996/12/31, as a followup to the <a href=
  "/ncurses/ncurses-license.html#patch_961224">release of ncurses
  4.0</a>) which featured xterm as one of the 16 programs I was
  involved with. From the outset, the page provided a link to a
  snapshot of the current source. Copies of patches which I sent to
  XFree86 were available on the ftp area.</p>

  <p>XFree86 had its sources in CVS, but (like others in that era),
  were not directly visible to random developers. That came later.
  I started by downloading the sources (30Mb of compressed
  tar-files on a 56Kb phone connection took about 6 hours) and
  updating them with patches from the XFree86 mailing list.</p>

  <p>Like the other programs that I worked on with others (<a href=
  "/vile/vile.html">vile</a>, <a href="/tin/tin.html">tin</a>,
  <a href="/lynx/lynx.html">lynx</a>), I set up an RCS archive to
  track my changes locally before sending patches to the
  development list. As the XFree86 developers issued new patches, I
  would re-synchronize my archive. Later, XFree86 provided CVS
  (initially readonly). I was granted commit privileges on this
  <a href="/ansification/ansify-xfs-cve.html#xfree86_work">in
  November 2000</a>, and stopped mailing patches after <a href=
  "xterm.log.html#xterm_149">#149</a>.</p>

  <p>Throughout this period, my work on <strong>xterm</strong> was
  released as part of XFree86. It was rare for a separate package
  to be provided. That was due to the potential conflict between
  the install procedures. Users of the downloads from my web/ftp
  site were predominantly individual developers.</p>

  <p>There were exceptions. Christian Weisgerber proposed a package
  for FreeBSD ports later in 1999 (<a href=
  "https://web.archive.org/web/20130801223050/http://www.mavetju.org/mail/view_message.php?list=freebsd-ports&amp;id=578273">ports/15545:
  new port: x11/xterm</a>, followup in <a href=
  "http://marc.info/?t=102422536300028&amp;r=l&amp;=2">March
  2000</a>). However, that was an exception. None of the Linux
  distributions provided a separate package before 2003 (when Mike
  Harris created a package of <a href=
  "xterm.log.html#xterm_177">patch #177</a> for Red Hat). Again
  that is more of an exception than a rule:</p>

  <ul>
    <li>
      <p>SuSE's package began October 23, 2004 with <a href=
      "xterm.log.html#xterm_196">patch #196</a>.</p>
    </li>

    <li>
      <p>Mandriva's package began October 22, 2005 with <a href=
      "xterm.log.html#xterm_205">patch #205</a>.</p>
    </li>

    <li>
      <p>The Debian package for xterm began in January 6, 2006 with
      <a href="/xterm/xterm.log.html#xterm_204">patch #204</a>.</p>
    </li>
  </ul>

  <p>Given that context (sources distributed via XFree86 CVS,
  releases via XFree86), the statement made by an Xorg hacker
  <a href=
  "http://lists.freedesktop.org/archives/xorg/2005-January/005847.html">
  early in 2005</a> asserting that &ldquo;It has not been
  maintained by anyone within the XFree86 or X.org trees for many
  years&rdquo; was at best misleading.</p>

  <p>After the &ldquo;<a href=
  "xterm.faq.html#xterm-xorg">fork</a>&rdquo;&nbsp;(sic) of Xorg in
  2004, I continued to commit changes for xterm in <a href=
  "http://cvsweb.xfree86.org/cvsweb/xc/programs/xterm/">XFree86
  CVS</a> until <a href="/xterm/xterm.log.html#xterm_216">patch
  #216</a> in mid-2006. I stopped at that point because it was not
  possible to incorporate changes into xterm which were not sent to
  me first. I still send patch announcements to both the XFree86
  and Xorg mailing lists, of course.</p>

  <p>At that point (mid-2006), the XFree86 CVS was no longer the
  primary development repository for xterm. My RCS archive filled
  that need. Later (starting in 2016), I provided <a href=
  "/personal/git-exports.html">Git snapshots</a> using the RCS
  labels which I make in development:</p>

  <ul>
    <li>
      <p><a href="/xterm/old-xterm-patches/">Old xterm patches</a>,
      from patch #1 through patch #149.</p>
    </li>

    <li>
      <p><a href=
      "https://github.com/ThomasDickey/xterm-snapshots">Git
      snapshots</a>, starting from xterm patch #41</p>
    </li>
  </ul>

  <h3 id="forward_history-id"><a href="#who_did_it" name=
  "forward_history" id="forward_history">Focus of this FAQ</a></h3>

  <p>This FAQ is oriented toward the version of xterm originally
  distributed with XFree86 (more commonly known as modern, or "new
  xterm", with a corresponding terminal description "xterm-new"),
  which was based on the X11R6.3 xterm, with the addition of ANSI
  color and VT220 controls.</p>

  <h2 id="what_is_vt220-id"><a name="what_is_vt220" id=
  "what_is_vt220">What is a VT220?</a></h2>

  <ul>
    <li>
      <p><a href="#what_vt220">Why a VT220?</a></p>
    </li>

    <li>
      <p><a href="#whatis_state_table">What is a State Table?</a></p>
    </li>

    <li>
      <p><a href="#why_not_vt320">Why not emulate VT320?</a></p>
    </li>

    <li>
      <p><a href="#why_vt420">Why emulate VT420?</a></p>
    </li>

    <li>
      <p><a href="#why_not_vt520">Why not emulate VT520?</a></p>
    </li>
  </ul>

  <h3 id="why_vt220-id"><a name="what_vt220" id="what_vt220">Why a
  VT220?</a></h3>

  <p>The manual page mentions a VT220. Most terminal emulators
  documentation talk about VT100. But a VT100 is a rather limited
  subset of what people expect:</p>

  <ul>
    <li>
      <p>VT100s have no function keys. Arguably, PF1-PF4 are
      function keys. My keyboard has 12 function keys.</p>
    </li>

    <li>
      <p>VT100s do not do <a href=
      "/ncurses/ncurses.faq.html#vt100_color">color</a>.</p>
    </li>
  </ul>

  <p>Initially, I was only interested in making colors workable for
  curses programs.</p>

  <p>Later, I noticed that xterm had some support for what would
  now be termed as ISO-2022. That was a VT220 feature which
  preceded ISO-2022 called <em>National Replacement Character</em>
  sets. In any case, it was not a VT100 feature. There were some
  missing pieces. So I decided to fill in those pieces and make
  xterm a VT220 emulator. (VT220s do not do ANSI color
  either&mdash;the missing pieces were in other areas).</p>

  <p><strong>XTerm</strong> also provides features that are in
  neither VT100 nor VT220, which are used by other programs as
  "xterm emulation".</p>

  <ul>
    <li>
      <p>set (and retrieve) window- and icon-labels using escape
      sequences.</p>
    </li>

    <li>
      <p>interpret mouse clicks as escape sequences that can be
      read by a program.</p>
    </li>
  </ul>

  <p>By the way, the control string used for setting the titles was
  not in a standard format:</p>

  <ul>
    <li>
      <p>In X10 (1988), the string was simply terminated by any
      nonprinting character.</p>
    </li>

    <li>
      <p>X11R4 (1989) modified that to ensure that the nonprinting
      character is an ASCII BEL (control/G).</p>
    </li>

    <li>
      <p>There is no explanation in the (sketchy) notes distributed
      with the X11R4 xterm; in retrospect it seems that the most
      likely explanation for the choice is that it was simpler to
      implement in shell scripts than <code>ESC&nbsp;\</code>.</p>
    </li>
  </ul>

  <p>ECMA-48 (the standard) does not describe this particular
  control, but prescribes its format (an <a href=
  "ctlseqs/ctlseqs.html#h2-Operating-System-Commands">operating
  system command</a>). It does not use a
  <strong><code>BEL</code></strong>.</p>

  <p>I revised that area <a href=
  "/xterm/xterm.log.html#xterm_24">starting in 1996</a>,</p>

  <ul>
    <li>
      <p>first to use xterm's state table for handling the input,
      and then</p>
    </li>

    <li>
      <p>to accept the standard string terminator as well.</p>
    </li>
  </ul>

  <p>In addition to implementing the VT220's <em>National
  Replacement Character</em> sets (see vttest <a href=
  "/vttest/vttest-nrcs.html">screenshots</a>), I added other
  features to emulate the successive models of DEC terminals. The
  <a href=
  "manpage/xterm.html#VT100-Widget-Resources:decTerminalID"><code>decTerminalID</code></a>
  resource (in <a href="xterm.log.html#xterm_29">1996</a>) lets
  users select the emulation to use. Because many of my changes
  were <em>extensions</em> (features not in any of DEC's terminals)
  and because well-behaved VT100 applications would not use
  features from higher-level terminals it was not initially
  important to prevent use of those by applications which assumed
  they were using just a VT100. Knowledgable users could easily
  configure xterm to emulate a VT220. In <a href=
  "xterm.log.html#xterm_280">2012</a>, I changed the default from
  VT100 to VT420.</p>

  <h3 id="whatis_state_table-id"><a name="whatis_state_table" id=
  "whatis_state_table">What is a State Table?</a></h3>

  <p>That was mentioned regarding the title strings.
  <strong>XTerm</strong> uses a state machine to handle incoming
  characters. That is essentially what a real terminal does. Other
  &ldquo;xterm&rdquo; terminal emulators typically do not do this,
  which makes them not do well with <a href=
  "/vttest/vttest.html">vttest</a>.</p>

  <h3 id="why_not_vt320-id"><a name="why_not_vt320" id=
  "why_not_vt320">Why not emulate VT320?</a></h3>

  <p>You could do that (by changing <code>decTerminalID</code>, but
  the results were not that interesting). In retrospect, the VT320
  was a stopgap implementation designed to bridge between the VT200
  series and the VT420. It provided a standard codepage (for ISO
  Latin-1).</p>

  <p>While it had other features not found in the VT200-series,
  most of those are less useful in a terminal emulator. I did adapt
  the ECMA-48 <em>scrolling</em> operations which the VT320
  interpreted as <em>panning</em> the visible display in the
  terminal's memory. Expect some difference there (if you can find
  an application on VMS which used the feature).</p>

  <p>The VT320 was popular with developers of commercial terminal
  emulators, whose literature referred to it as supporting ANSI
  color. It did not do this.</p>

  <h3 id="why_vt420-id"><a name="why_vt420" id="why_vt420">Why
  emulate VT420?</a></h3>

  <p>The VT420 was interesting because it provided two features
  that could be useful:</p>

  <ul>
    <li>
      <p>rectangles</p>
    </li>

    <li>
      <p>left/right margins (like the top/bottom scrolling
      margins)</p>
    </li>
  </ul>

  <p>A VT420, of course, supports all of the features in VT320, in
  turn all of the features in VT220, and in turn VT100. Users would
  not lose features by changing the default emulation to VT420. By
  changing the default emulation, most users would automatically be
  able to use applications (such as <code>tmux</code>) that could
  perform better if the left/right margin feature is available. I
  changed the emulation to VT420 in 2012 for this reason.</p>

  <p>XTerm does not emulate some esoteric features (such as dual
  sessions) because those require hosts using special software, and
  no publicly-available documentation was available.</p>

  <h3 id="why_not_vt520-id"><a name="why_not_vt520" id=
  "why_not_vt520">Why not emulate VT520?</a></h3>

  <p>Again, the VT500-series is less interesting because most of
  the features which are not hardware-specific (such as reporting
  transmission rate) are less useful.</p>

  <p>However:</p>

  <ul>
    <li>
      <p>the VT500-series provides additional codepages (like the
      VT320). XTerm does that.</p>
    </li>

    <li>
      <p>the VT500-series supports some of the ECMA-48
      cursor-movement operations which had been overlooked in the
      previous terminals. XTerm does that (based on ECMA-48 itself,
      and later on DEC's documentation).</p>
    </li>
  </ul>

  <p>As for the other features, most are not useful in emulation
  (since they are hardware-specific). Additionally, these less-used
  features are not documented precisely and since the only point of
  providing them would be for successful interoperability with
  legacy applications, some reverse-engineering would be needed to
  provide a faithful emulation. To date there are no known terminal
  emulators which do that.</p>

  <h2 id="what_platforms-id"><a name="what_platforms" id=
  "what_platforms">What platforms does it run on?</a></h2>

  <p><strong>XTerm</strong> runs in all of the implementations of
  X11. As of 2000, I had built and run these since I started
  working on xterm in 1996:</p>

  <ul>
    <li>AIX 3.2.5, 4.1, 4.3 (cc)</li>

    <li>Digital Unix 3.2, 4.0, 5.0 (cc)</li>

    <li>FreeBSD 2.2.6 to 6.0 (gcc 2.8)</li>

    <li>HP-UX 9.05 to 11.23 (gcc 2.7.2 to 3.4)</li>

    <li>IRIX 5.2, 6.2 (cc, gcc 2.7.2, gcc 2.8)</li>

    <li>Linux 2.0.0 to 2.6.26 (gcc 2.7.2 to 4.3)</li>

    <li>SCO OpenServer 5 (cc, gcc).</li>

    <li>Solaris 2.4, 2.5, 2.5.1, 2.6, 7, 8 (cc, gcc 2.7.2)</li>

    <li>SunOS 4.1.1, 4.1.3 (gcc 2.7.2)</li>
  </ul>

  <p>The older configurations have X11R5 libraries. Only minor
  changes are needed to make xterm work on those systems. However,
  X11R6 provided better locale support, as well as new features
  such as the active icon. X11R7... not much to say there.</p>

  <p>Since 2000, there have been many changes (including new
  platforms such as MacOS, NetBSD, OpenBSD, etc., as well as QNX,
  Cygwin, and Minix).</p>

  <h2 id="latest_version-id"><a name="latest_version" id=
  "latest_version">What is the latest version?</a></h2>

  <p>The most recent (and well supported) version of xterm is the
  one that I maintain:</p>

  <ul>
    <li>
      <p><a href="/datafiles/release/xterm.tar.gz">source</a></p>
    </li>

    <li>
      <p><a href="/archives/xterm/">archives</a></p>
    </li>
  </ul>

  <h2 id="other_versions-id"><a name="other_versions" id=
  "other_versions">What versions are available?</a></h2>

  <p>There are several other versions of xterm, based on xterm's
  source. These include</p>

  <ul>
    <li>
      <p><a href="#bug_ansi_xterm">ansi_xterm</a></p>
    </li>

    <li>
      <p><a href="xterm.faq.html#bug_color_xterm">color_xterm</a></p>
    </li>

    <li>
      <p><a href="#bug_cxterm">cxterm</a> (Chinese)</p>
    </li>

    <li>
      <p><a href="#bug_hanterm">hanterm</a> (Korean)</p>
    </li>

    <li>
      <p><a href="#bug_mxterm">mxterm</a></p>
    </li>

    <li>
      <p><a href="#bug_nxterm">nxterm</a></p>
    </li>

    <li>
      <p><a href="#bug_kterm">kterm</a> (Japanese)</p>
    </li>

    <li>
      <p><a href="#bug_xterm_r6">xterm</a> (from X Consortium)</p>
    </li>
  </ul>

  <p>There are similar programs not based on xterm's source, which
  are compatible to different degrees. These include</p>

  <ul>
    <li>
      <p><a href="#bug_dtterm">dtterm</a></p>
    </li>

    <li>
      <p><a href="#bug_emu">emu</a> (from X Consortium)</p>
    </li>

    <li>
      <p><a href="#bug_eterm">Eterm</a></p>
    </li>

    <li>
      <p><a href="#bug_gnometerm">GNOME Terminal</a></p>
    </li>

    <li>
      <p><a href="#bug_multignome">Multi GNOME Terminal (MGT)</a></p>
    </li>

    <li>
      <p><a href="#bug_mterm">mterm</a></p>
    </li>

    <li>
      <p><a href="#bug_konsole">konsole</a></p>
    </li>

    <li>
      <p><a href="#bug_mlterm">mlterm</a> (Multi Lingual)</p>
    </li>

    <li>
      <p><a href="#bug_osso_xterm">osso-xterm</a></p>
    </li>

    <li>
      <p><a href="#bug_roxterm">roxterm</a></p>
    </li>

    <li>
      <p><a href="#bug_rxvt">rxvt</a></p>
    </li>

    <li>
      <p><a href="#bug_st">st</a></p>
    </li>

    <li>
      <p><a href="#bug_xfce_term">xfce-term</a></p>
    </li>

    <li>
      <p><a href="#bug_xgterm">xgterm</a></p>
    </li>

    <li>
      <p><a href="#bug_xiterm">xiterm</a></p>
    </li>
  </ul>

  <p>Some of these use the <a href="#vte_widget">VTE widget</a>.
  Since that supplies most of the terminal emulation, the remaining
  differences between programs using VTE tend to be at the level of
  the window manager (menus, borders, etc.). Other (older) programs
  which are based on reusable widgets include <a href=
  "#bug_dtterm">dtterm</a> and <a href=
  "xterm.faq.html#bug_emu">emu</a>.</p>

  <p>(I am aware of a few others, such as <strong>xcterm</strong>,
  but have not seen a working version of these).</p>

  <p>Finally of course, there are a multitude of programs which set
  TERM to &ldquo;xterm&rdquo;, in the hope that applications will
  treat them the same as xterm. For example,</p>

  <ul>
    <li>
      <p>PuTTY does this (see its FAQ <a href=
      "http://www.chiark.greenend.org.uk/~sgtatham/putty/faq.html#faq-term">
      <em>A.5.1 What terminal type does PuTTY use?</em></a>). But
      its wrapping behavior is incompatible with xterm (and any
      vt100 emulator). You can see this in the first menu entry for
      <a href="/vttest/vttest.html">vttest</a>.</p>
    </li>

    <li>
      <p>VTE does this. But consider the list of problems with
      <a href=
      "https://bugzilla.gnome.org/buglist.cgi?quicksearch=vte">VTE</a>
      and with <a href=
      "https://bugzilla.gnome.org/buglist.cgi?quicksearch=gnome+terminal">
      GNOME Terminal</a>. The attitude of the developers is that by
      copying from xterm, they are <em>entitled</em> to do this
      whether or not the program actually matches xterm's terminal
      description. This is unchanged since the mid-2000s (see
      Debian <a href=
      "https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=368916">#368916</a>
      for example).</p>
    </li>

    <li>
      <p>Konsole does this as well&mdash;intentionally as shown in
      <a href="https://bugs.kde.org/show_bug.cgi?id=145977"><em>KDE
      #145977 &ndash; Konsole has a terminfo entry of its own;
      please change default $TERM</em></a>. The reasoning expressed
      there is that Konsole &ldquo;should&rdquo; match xterm.
      Incidentally, one of the comments (about xterm's support for
      mouse) cited as proof a <a href=
      "http://www.linuxjournal.com/article/1136">page about Gpm</a>
      from Linux Journal which was more than 12 years old.</p>
    </li>
  </ul>

  <p>Each of the programs noted here which are well-established and
  which are known to differ markedly from xterm have their own
  terminal descriptions in ncurses, to which TERM should be set.
  Otherwise, bug-reports are misdirected to <a href=
  "/ncurses/ncurses.html#download_database">ncurses</a> which
  should have been addressed by the respective developers of these
  programs. These include</p>

  <ul>
    <li>
      <p><a href="/ncurses/terminfo.src.html#tic-_Eterm">Eterm</a></p>
    </li>

    <li>
      <p><a href="/ncurses/terminfo.src.html#tic-gnome">gnome</a>
      (obsolete)</p>
    </li>

    <li>
      <p><a href=
      "/ncurses/terminfo.src.html#tic-konsole">konsole</a></p>
    </li>

    <li>
      <p><a href="/ncurses/terminfo.src.html#tic-mlterm">mlterm</a></p>
    </li>

    <li>
      <p><a href="/ncurses/terminfo.src.html#tic-mrxvt">mrxvt</a></p>
    </li>

    <li>
      <p><a href="/ncurses/terminfo.src.html#tic-putty">putty</a></p>
    </li>

    <li>
      <p><a href="/ncurses/terminfo.src.html#tic-rxvt">rxvt</a></p>
    </li>

    <li>
      <p><a href="/ncurses/terminfo.src.html#tic-st">st</a></p>
    </li>

    <li>
      <p><a href="/ncurses/terminfo.src.html#tic-vte">vte</a>
      (preferred)</p>
    </li>
  </ul>

  <h2 id="compare_versions-id"><a name="compare_versions" id=
  "compare_versions">Comparing versions, by counting controls</a></h2>

  <p>Several of these programs are claimed (either by their
  developers, or their users) to emulate &ldquo;most&rdquo; of
  xterm. To me, &ldquo;most&rdquo; would be something quantifiable,
  e.g., 80 percent. To satisfy my curiousity, I wrote a script to
  extract the control sequence information from <a href=
  "xterm.faq.html#ctlseqs_ms">ctlseqs.txt</a>. This counts each
  control sequence, as well as the variations such as setting bold,
  color, inverse video. Then I (laboriously) inspected these
  terminal implementations:</p>

  <ul>
    <li>xterm patch #266 ("xterm-new")</li>

    <li>X11R6.3 xterm (xterm-r6)</li>

    <li>DEC vt220</li>

    <li>DEC vt102</li>

    <li>rxvt 2.7.10</li>

    <li>rxvt-unicode 9.09 (urxvt)</li>

    <li>konsole 2.5.3</li>

    <li>VTE 0.25.91 (vte), used in GNOME-Terminal and kindred.</li>
  </ul>

  <p>As of mid-November 2010, these were the latest
  implementations. I included data for the vt220 and vt102 to be
  able to contrast the various terminal <em>emulators</em> against
  those as well as xterm. There were:</p>

  <ul>
    <li>
      <p>498 control sequences listed in the corresponding file for
      xterm patch #266.</p>
    </li>

    <li>
      <p>192 of those are &ldquo;primary&rdquo;, e.g., disregarding
      parameters such as those distinguishing bold from color.</p>
    </li>

    <li>
      <p>37 of the primary control sequences have secondary
      sequences.</p>
    </li>
  </ul>

  <p>For each control, there are three possibilities:</p>

  <ol>
    <li>
      <p>&ldquo;yes&rdquo; &mdash; the terminal implements it,
      matching xterm. If xterm implements it, and it is a feature
      of vt220 or vt102, then in turn xterm's behavior must match
      vt220 or vt102.</p>
    </li>

    <li>
      <p>&ldquo;partial&rdquo; &mdash; the terminal implements it,
      but its behavior does not match the reference noted
      above.</p>
    </li>

    <li>
      <p>&ldquo;no&rdquo; &mdash; the terminal does not implement
      the control.</p>
    </li>
  </ol>

  <p>The <a href="ctlseqs/ctlseqs.html">control sequences</a>
  document lists a few controls which xterm does not (completely)
  implement, e.g.,</p>

  <ul>
    <li>
      <p><a href=
      "ctlseqs/ctlseqs.html#h4-Functions-using-CSI-_-ordered-by-the-final-character-lparen-s-rparen:CSI-?-Pm-h:Ps-=-8.1E68">
      key-repeat</a></p>
    </li>

    <li>
      <p><a href=
      "ctlseqs/ctlseqs.html#h4-Functions-using-CSI-_-ordered-by-the-final-character-lparen-s-rparen:CSI-Ps-q.1CB1">
      enabling LEDs</a> other than scroll-lock</p>
    </li>
  </ul>

  <p>Those are not implemented in xterm because all X applications
  share the same keyboard (see <a href=
  "manpage/xterm.html#h2-EMULATIONS">manpage</a>), and <a href=
  "https://www.x.org/releases/current/doc/man/man1/xset.1.xhtml">xset</a>
  is the proper tool for changing auto-repeat. The <a href=
  "https://github.com/ThomasDickey/old-xterm/blob/d448c6d7373c3bc3df4c75e815baa1e645462893/charproc.c#L1048">
  X10R4</a> xterm did implement key-repeat, but the feature was
  removed in <a href=
  "https://github.com/ThomasDickey/old-xterm/blob/6bf1714f13b7811c3e28d186bfc9942d971edd9b/charproc.c#L1048">
  X11R1</a>. None of the other terminal emulators implements those
  either.</p>

  <table border="1" summary=
  "Comparing against the control sequences document">
    <caption>
      Comparing against the control sequences document
    </caption>

    <colgroup>
      <col width="15%">
      <col width="15%">
      <col width="15%">
      <col width="35%">
    </colgroup>

    <tr>
      <th>yes</th>
      <th>partial</th>
      <th>no</th>
      <th>program</th>
    </tr>

    <tr>
      <td>488</td>
      <td>4</td>
      <td>6</td>
      <td>xterm-new</td>
    </tr>

    <tr>
      <td>154</td>
      <td>6</td>
      <td>338</td>
      <td>xterm-r6</td>
    </tr>

    <tr>
      <td>188</td>
      <td>5</td>
      <td>305</td>
      <td>vt220</td>
    </tr>

    <tr>
      <td>104</td>
      <td>0</td>
      <td>394</td>
      <td>vt102</td>
    </tr>

    <tr>
      <td>204</td>
      <td>3</td>
      <td>291</td>
      <td>rxvt</td>
    </tr>

    <tr>
      <td>219</td>
      <td>3</td>
      <td>276</td>
      <td>urxvt</td>
    </tr>

    <tr>
      <td>191</td>
      <td>2</td>
      <td>305</td>
      <td>putty</td>
    </tr>

    <tr>
      <td>170</td>
      <td>3</td>
      <td>325</td>
      <td>konsole</td>
    </tr>

    <tr>
      <td>184</td>
      <td>6</td>
      <td>308</td>
      <td>vte</td>
    </tr>
  </table>

  <p>Modern xterm implements 188 primary controls. In this table,
  vte ranks lower than PuTTY because it does not support vt52
  emulation. This is not unusual, since the rxvt-based emulators do
  not, either. However, all vt100's provide this feature; programs
  lacking this are not really a vt100 emulator. On the other hand,
  PuTTY (which is not a vt100 emulator due to its incompatible
  wrapping behavior) supports this feature.</p>

  <p>Aside from that, the various emulators implement much the same
  features from xterm. None implements as many as half of xterm's
  controls.</p>

  <table border="1" summary="Comparing against xterm">
    <caption>
      Comparing against xterm
    </caption>

    <colgroup>
      <col width="15%">
      <col width="15%">
      <col width="15%">
      <col width="35%">
    </colgroup>

    <tr>
      <th>yes</th>
      <th>partial</th>
      <th>no</th>
      <th>program</th>
    </tr>

    <tr>
      <td>488</td>
      <td>0</td>
      <td>0</td>
      <td>xterm-new</td>
    </tr>

    <tr>
      <td>154</td>
      <td>6</td>
      <td>328</td>
      <td>xterm-r6</td>
    </tr>

    <tr>
      <td>182</td>
      <td>2</td>
      <td>304</td>
      <td>vt220</td>
    </tr>

    <tr>
      <td>98</td>
      <td>0</td>
      <td>390</td>
      <td>vt102</td>
    </tr>

    <tr>
      <td>204</td>
      <td>3</td>
      <td>281</td>
      <td>rxvt</td>
    </tr>

    <tr>
      <td>219</td>
      <td>3</td>
      <td>266</td>
      <td>urxvt</td>
    </tr>

    <tr>
      <td>189</td>
      <td>2</td>
      <td>297</td>
      <td>putty</td>
    </tr>

    <tr>
      <td>170</td>
      <td>3</td>
      <td>315</td>
      <td>konsole</td>
    </tr>

    <tr>
      <td>184</td>
      <td>6</td>
      <td>298</td>
      <td>vte</td>
    </tr>
  </table>

  <p>DEC VT220 implements 96 primary controls. Modern xterm (as
  documented), implements most of the VT220. VTE implements fewer
  than half. The others are a little better. None of the others
  could be used as a real VT220.</p>

  <table border="1" summary="Comparing against vt220">
    <caption>
      Comparing against vt220
    </caption>

    <colgroup>
      <col width="15%">
      <col width="15%">
      <col width="15%">
      <col width="35%">
    </colgroup>

    <tr>
      <th>yes</th>
      <th>partial</th>
      <th>no</th>
      <th>program</th>
    </tr>

    <tr>
      <td>182</td>
      <td>0</td>
      <td>6</td>
      <td>xterm-new</td>
    </tr>

    <tr>
      <td>78</td>
      <td>6</td>
      <td>104</td>
      <td>xterm-r6</td>
    </tr>

    <tr>
      <td>188</td>
      <td>0</td>
      <td>0</td>
      <td>vt220</td>
    </tr>

    <tr>
      <td>104</td>
      <td>0</td>
      <td>84</td>
      <td>vt102</td>
    </tr>

    <tr>
      <td>101</td>
      <td>3</td>
      <td>84</td>
      <td>rxvt</td>
    </tr>

    <tr>
      <td>106</td>
      <td>3</td>
      <td>79</td>
      <td>urxvt</td>
    </tr>

    <tr>
      <td>107</td>
      <td>2</td>
      <td>79</td>
      <td>putty</td>
    </tr>

    <tr>
      <td>100</td>
      <td>3</td>
      <td>85</td>
      <td>konsole</td>
    </tr>

    <tr>
      <td>88</td>
      <td>6</td>
      <td>94</td>
      <td>vte</td>
    </tr>
  </table>

  <p>DEC VT102 (the actual flavor used for &ldquo;vt100&rdquo; in
  most cases), implements 68 primary controls. Again, VTE fares
  worst, and the others a little better.</p>

  <table border="1" summary="Comparing against vt102">
    <caption>
      Comparing against vt102
    </caption>

    <colgroup>
      <col width="15%">
      <col width="15%">
      <col width="15%">
      <col width="35%">
    </colgroup>

    <tr>
      <th>yes</th>
      <th>partial</th>
      <th>no</th>
      <th>program</th>
    </tr>

    <tr>
      <td>98</td>
      <td>0</td>
      <td>6</td>
      <td>xterm-new</td>
    </tr>

    <tr>
      <td>70</td>
      <td>6</td>
      <td>28</td>
      <td>xterm-r6</td>
    </tr>

    <tr>
      <td>104</td>
      <td>0</td>
      <td>0</td>
      <td>vt220</td>
    </tr>

    <tr>
      <td>104</td>
      <td>0</td>
      <td>0</td>
      <td>vt102</td>
    </tr>

    <tr>
      <td>79</td>
      <td>2</td>
      <td>23</td>
      <td>rxvt</td>
    </tr>

    <tr>
      <td>81</td>
      <td>2</td>
      <td>21</td>
      <td>urxvt</td>
    </tr>

    <tr>
      <td>86</td>
      <td>2</td>
      <td>16</td>
      <td>putty</td>
    </tr>

    <tr>
      <td>85</td>
      <td>3</td>
      <td>16</td>
      <td>konsole</td>
    </tr>

    <tr>
      <td>60</td>
      <td>1</td>
      <td>43</td>
      <td>vte</td>
    </tr>
  </table>

  <p>I have continued to add features to xterm:</p>

  <ul>
    <li>
      <p>as of September 2013, it implemented 546 of 556 documented
      controls</p>
    </li>

    <li>
      <p>as of October 2019, xterm implemented 713 of 723
      documented controls.</p>
    </li>
  </ul>

  <p>The other programs change far more slowly. As a result they
  implement a smaller fraction of xterm's repertoire in 2019 than
  in 2010. Even for cases where they implement a function, it may
  not work properly (see for example the screenshot of VTE in the
  <a href="/vttest/vttest-nrcs.html">vttest NRCS</a> examples).</p>

  <p>In summary, none of the other terminal emulators emulates
  &ldquo;most&rdquo; of xterm. Instead, they implement the most
  commonly-used control sequences, and there are differences
  between them.</p>

  <h2 id="how_do_i-id"><a name="how_do_i" id="how_do_i">How do I
  ...</a></h2>

  <p>Not really problems, but frequently asked questions (the point
  of this, after all):</p>

  <ul>
    <li>
      <p><a href="#how2_fsize">How do I change the font size?</a></p>
    </li>

    <li>
      <p><a href="#how2_print">How do I print the screen?</a></p>
    </li>

    <li>
      <p><a href="#how2_fkeys">How do I set up function keys?</a></p>
    </li>

    <li>
      <p><a href="#how2_title">How do I set the title?</a></p>
    </li>

    <li>
      <p><a href="#how2_blink">How do I make the cursor blink?</a></p>
    </li>
  </ul>

  <h3 id="how2_fsize-id"><a name="how2_fsize" id="how2_fsize">How
  do I change the font size?</a></h3>

  <p><strong>XTerm</strong> uses fonts given as resource settings.
  You can switch between these fonts at runtime, using a menu. This
  is documented in the manpage, in the <a href=
  "/xterm/manpage/xterm.html#h2-MENUS">MENUS</a> section.</p>

  <p>X Consortium xterm provides popup menus, by pressing the
  control key together with the mouse button. Control right mouse
  button pops up the <em>VT FONTS</em> menu, from which you can
  select fonts that are specified in xterm's resources. Usually
  these are in increasing order of size.</p>

  <p>Modern xterm provides the menu, plus a feature adapted from
  rxvt: pressing the shifted keypad plus or minus keys steps
  through the font menu selections, in order of their size.</p>

  <p><strong>XTerm</strong>'s manpage does not document the syntax
  for X resources; it is done in the X documentation. If you are
  instead asking about a <a href=
  "xterm.faq.html#utf8_fonts">problem displaying a given font</a>,
  it may be due to a problem with your resource settings.</p>

  <h3 id="how2_print-id"><a name="how2_print" id="how2_print">How
  do I print the screen?</a></h3>

  <p>That depends on why you want to print it.</p>

  <p>If you want a trace of an interactive session, you should use
  the <em>script</em> program. It records every character sent to
  the screen, recording them in a file <code>typescript</code>.
  There are two drawbacks to this approach:</p>

  <ul>
    <li>
      <p>Every character is recorded. Even cursor movement, if you
      run an editor.</p>
    </li>

    <li>
      <p>You must start a new shell to capture the
      <code>typescript</code> file.</p>
    </li>
  </ul>

  <p>Well, what about logging? Some versions of xterm support
  logging to a file. In fact modern xterm does. Logging was dropped
  from X Consortium xterm during X11R5 due to security concerns.
  Those were addressed, but logging was not reinstated (in fact
  there is a related <a href="#bug_xterm_r6">bug</a> in xterm).
  Some people prefer this, because it is convenient: you can start
  and stop logging a popup menu entry. However</p>

  <ul>
    <li>
      <p>Every character is recorded. Even cursor movement, if you
      run an editor.</p>
    </li>

    <li>
      <p>Line drawing characters are translated to control
      characters, i.e., codes 0-31 (this may be fixed sometime, it
      is a problem inherited from X Consortium xterm).</p>
    </li>
  </ul>

  <p>Both <em>script</em> and logging are useful for recording, but
  they require interpretation to make sense of the trace. You
  probably would not send that trace to a printer (not twice,
  anyway).</p>

  <p>If you want to print the contents of the screen, modern xterm
  implements, as part of the VT100 emulation, an
  &ldquo;attached&rdquo; printer.</p>

  <ul>
    <li>
      <p>The printer is really a pipe command, to which xterm
      writes.</p>
    </li>

    <li>
      <p>You can print the current line, page, or continuously with
      the corresponding control sequences. That takes an
      application program which knows how to print the screen.</p>
    </li>

    <li>
      <p>If you do not have an application, xterm has a popup menu
      entry to print the window.</p>
    </li>
  </ul>

  <p>There are limitations and tradeoffs using the
  &ldquo;attached&rdquo; printer, because it is an emulation:</p>

  <ul>
    <li>
      <p>The emulation is based on detailed documentation for a
      VT320. This states that control sequences are sent in each
      line to reset bold, underlining and other printable
      attributes, and to set them as needed. Your printer probably
      does not understand this sort of input. Use the xterm
      resource <code>printAttributes</code> to get more easily
      printed output.</p>
    </li>

    <li>
      <p>The printer may hang. Not really, but it seems that way.
      If you use the &ldquo;attached&rdquo; printer from an
      application designed for the VT100 terminal, it is written
      with the assumption that the printer is a dedicated piece of
      hardware, printing onto a continuous form. Use the
      <code>printerAutoClose</code> resource to change xterm's
      behavior to close the printer pipe whenever the terminal is
      told to switch the printer offline.</p>
    </li>
  </ul>

  <p>If you use the popup menu to print the screen, this will close
  the printer pipe unless it was already opened by the application
  running in xterm.</p>

  <h3 id="how2_fkeys-id"><a name="how2_fkeys" id="how2_fkeys">How
  do I set up function keys?</a></h3>

  <p>With modern xterm, this is relatively simple. So I'll answer
  that first.</p>

  <p>With X Consortium xterm, you had partial support for DEC VTxxx
  function keys. Function keys F1 to F12 correspond to DEC's F1 to
  F12 (sort of). Actually, DEC's VT220 terminals do not have codes
  for F1 through F5. They are reserved for local functions. And the
  VT220 (and up) terminals have 20 function keys. So you cannot do
  anything with the F13 through F20 (i.e., DO, HELP and SELECT).
  Finally, though xterm is reputed to be VT100-compatible, it has
  no support for the VT100 keypad (PF1 to PF4, and the ","
  key).</p>

  <p>Modern (XFree86) xterm changed the X Consortium codes for F1
  to F4 to match the VT100 PF1 to PF4, except when the emulation
  level is VT220 and up. In this case, it generates the same F1 to
  F4 codes as X Consortium xterm. Moreover, it adds a new resource
  <code>sunKeyboard</code>, which tells the program whether it has
  only 12 function keys (i.e., a Sun or PC keyboard). If so (this
  is selectable from the popup menu), you can use the control key
  with F1 to F12 to get F13 to F24, and use the "+" key on the
  keypad as an alias for "," (comma).</p>

  <p>The emulation level for modern xterm is set via the resource
  <code>decTerminalID</code>, e.g., to 220 for a VT220. Once set,
  applications can set the emulation level up or down within that
  limit. DEC's terminals are configured in much the same way by a
  setup option.</p>

  <p>That is the simple way, using a couple of new resources. The
  traditional way to get function keys involves translations. I
  have seen a few postings on the newsgroups that do this. Here is
  one from Bruce Momjian &lt;root@candle.pha.pa.us&gt; for a
  VT220:</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    xterm&nbsp;<span class=
    "ident2">$XTERMFLAGS</span>&nbsp;+rw&nbsp;+sb&nbsp;+ls&nbsp;<span class="ident2">$@</span>&nbsp;-tm&nbsp;<span class="literal">'erase&nbsp;^?&nbsp;intr&nbsp;^c'</span>&nbsp;\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-name&nbsp;vt220&nbsp;-title&nbsp;vt220&nbsp;-tn&nbsp;xterm-220&nbsp;<span class="literal">"$@"</span>&nbsp;&amp;<br>

    <!--atr2html}}--></p>
  </blockquote>

  <p>with the corresponding resources:</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">translations</span>:<span class=
    "literal">&nbsp;#override&nbsp;\n\<br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Home:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("[</span><span class="number">3</span><span class="literal">~")&nbsp;\n&nbsp;\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">End:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("[</span><span class="number">4</span><span class="literal">~")&nbsp;\n</span><br>

    <span class="ident2">vt220</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">translations</span>:<span class=
    "literal">&nbsp;#override&nbsp;\n\<br>
    ~Shift&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F1:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("OP")&nbsp;\n&nbsp;\<br>
    ~Shift&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F2:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("OQ")&nbsp;\n&nbsp;\<br>
    ~Shift&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F3:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("OR")&nbsp;\n&nbsp;\<br>
    ~Shift&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F4:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("OS")&nbsp;\n&nbsp;\<br>
    ~Shift&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F5:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">16</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    ~Shift&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F6:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">17</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    ~Shift&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F7:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">18</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    ~Shift&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F8:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">19</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    ~Shift&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F9:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">20</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    ~Shift&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F10:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">21</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    ~Shift&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F11:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">28</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    ~Shift&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F12:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">29</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    Shift&nbsp;&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F1:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">23</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    Shift&nbsp;&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F2:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">24</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    Shift&nbsp;&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F3:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">25</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    Shift&nbsp;&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F4:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">26</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    Shift&nbsp;&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F5:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[K~")&nbsp;\n&nbsp;\<br>
    Shift&nbsp;&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F6:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">31</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    Shift&nbsp;&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F7:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">31</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    Shift&nbsp;&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F8:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">32</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    Shift&nbsp;&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F9:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">33</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    Shift&nbsp;&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F10:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">34</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    Shift&nbsp;&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F11:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">28</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    Shift&nbsp;&nbsp;&nbsp;</span><span class=
    "keyword">&lt;Key&gt;</span><span class=
    "literal">F12:&nbsp;string(</span><span class=
    "number">0x1b</span><span class=
    "literal">)&nbsp;string("[</span><span class=
    "number">29</span><span class="literal">~")&nbsp;\n&nbsp;\<br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Print:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("[</span><span class="number">32</span><span class="literal">~")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Cancel:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("[</span><span class="number">33</span><span class="literal">~")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Pause:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("[</span><span class="number">34</span><span class="literal">~")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Insert:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("[</span><span class="number">2</span><span class="literal">~")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Delete:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("[</span><span class="number">3</span><span class="literal">~")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Home:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("[</span><span class="number">1</span><span class="literal">~")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">End:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("[</span><span class="number">4</span><span class="literal">~")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Prior:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("[</span><span class="number">5</span><span class="literal">~")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Next:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("[</span><span class="number">6</span><span class="literal">~")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">BackSpace:&nbsp;string(</span><span class="number">0x7f</span><span class="literal">)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Num_Lock:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("OP")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_Divide:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("Ol")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_Multiply:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("Om")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_Subtract:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("OS")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_Add:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("OM")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_Enter:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("OM")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_Decimal:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("On")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_0:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("Op")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_1:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("Oq")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_2:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("Or")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_3:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("Os")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_4:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("Ot")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_5:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("Ou")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_6:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("Ov")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_7:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("Ow")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_8:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("Ox")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_9:&nbsp;string(</span><span class="number">0x1b</span><span class="literal">)&nbsp;string("Oy")&nbsp;\n</span><br>

    &nbsp;<br>
    <span class=
    "comment">!&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;Up:&nbsp;string(0x1b)&nbsp;string("[A")&nbsp;\n\<br>
    </span> <span class=
    "comment">!&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;Down:&nbsp;string(0x1b)&nbsp;string("[B")&nbsp;\n\<br>
    </span> <span class=
    "comment">!&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;Right:&nbsp;string(0x1b)&nbsp;string("[C")&nbsp;\n\<br>
    </span> <span class=
    "comment">!&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;Left:&nbsp;string(0x1b)&nbsp;string("[D")&nbsp;\n\<br>
    </span> &nbsp;<br>
    *<span class="ident2">visualBell</span>:<span class=
    "literal">&nbsp;&nbsp;&nbsp;&nbsp;</span><span class=
    "keyword">true</span><br>
    *<span class="ident2">saveLines</span>:<span class=
    "literal">&nbsp;&nbsp;&nbsp;&nbsp;</span><span class=
    "number">1000</span><br>
    *<span class="ident2">cursesemul</span>:<span class=
    "literal">&nbsp;&nbsp;&nbsp;&nbsp;</span><span class=
    "keyword">true</span><br>
    *<span class="ident2">scrollKey</span>:<span class=
    "literal">&nbsp;</span><span class="keyword">true</span><br>
    *<span class="ident2">scrollBar</span>:<span class=
    "literal">&nbsp;</span><span class="keyword">true</span><br>
    <!--atr2html}}--></p>
  </blockquote>

  <p>Note that real VT220 terminals use shifted function keys to
  mean something different: the user-programmable keys (i.e.,
  DECUDK). Modern xterm supports this, but the translations do not
  (they're using shift to select F13 to F20).</p>

  <p>Here's another one, from Robert Ess
  &lt;ress@spd.dsccc.com&gt;:</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    <span class="comment">#!/bin/sh</span><br>
    &nbsp;<br>
    <span class=
    "comment">#&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;vax</span><br>

    <span class=
    "comment">#&nbsp;09-17-96&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Bob&nbsp;Ess&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-&nbsp;initial&nbsp;creation</span><br>

    <span class=
    "comment">#&nbsp;09-26-96&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shig&nbsp;Katada&nbsp;&nbsp;-&nbsp;Additional&nbsp;keybindings</span><br>

    <span class="comment">#</span><br>
    <span class=
    "comment">#&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Script&nbsp;file&nbsp;to&nbsp;incorporate&nbsp;keybindings&nbsp;and&nbsp;command&nbsp;line</span><br>

    <span class=
    "comment">#&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;options&nbsp;for&nbsp;connecting&nbsp;to&nbsp;a&nbsp;VAX&nbsp;node</span><br>

    &nbsp;<br>
    <span class="comment">#&nbsp;Usage&nbsp;statement</span><br>
    Usage()<span class="keyword2">{</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;Usage&nbsp;&nbsp;:&nbsp;vax&nbsp;-options"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;Options:&nbsp;-80&nbsp;&nbsp;&nbsp;for&nbsp;80&nbsp;column&nbsp;terminal"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-132&nbsp;&nbsp;for&nbsp;132&nbsp;column&nbsp;terminal"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-fg&nbsp;colorname"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-bg&nbsp;colorname"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-fn&nbsp;fontname"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-fb&nbsp;bold&nbsp;fontname"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-host&nbsp;[altair]&nbsp;[devel]&nbsp;[leonis]&nbsp;[castor]"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class="literal">""</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;Example:&nbsp;</span><span class=
    "keyword2">\</span><span class=
    "literal">"vax&nbsp;-80&nbsp;-fg&nbsp;white&nbsp;-bg&nbsp;black&nbsp;-fn&nbsp;9x15&nbsp;-fb&nbsp;9x15b&nbsp;-host&nbsp;castor</span><span class="keyword2">\</span><span class="literal">""</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Starts&nbsp;a&nbsp;VAX&nbsp;session&nbsp;with&nbsp;an&nbsp;80&nbsp;column&nbsp;terminal"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;with&nbsp;a&nbsp;black&nbsp;background,&nbsp;white&nbsp;foreground,&nbsp;a&nbsp;normal"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;font&nbsp;of&nbsp;9x15&nbsp;and&nbsp;a&nbsp;bold&nbsp;font&nbsp;of&nbsp;9x15b,&nbsp;and&nbsp;connects"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;to&nbsp;the&nbsp;node&nbsp;'castor'"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;If&nbsp;you&nbsp;need&nbsp;additional&nbsp;help,&nbsp;please&nbsp;call&nbsp;Workstation"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Services&nbsp;at&nbsp;x92396."</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">exit</span>&nbsp;<span class="number">1</span><br>
    <span class="keyword2">}</span><br>
    &nbsp;<br>
    <span class=
    "comment">#&nbsp;Default&nbsp;to&nbsp;a&nbsp;black&nbsp;foreground&nbsp;with&nbsp;a&nbsp;white&nbsp;background.</span><br>

    <span class=
    "comment">#&nbsp;Use&nbsp;the&nbsp;9x15&nbsp;and&nbsp;9x15bold&nbsp;fonts.&nbsp;Connect&nbsp;to&nbsp;castor&nbsp;by&nbsp;default.</span><br>

    <span class="comment">#</span><br>
    <span class="ident2">FG</span>=black<br>
    <span class="ident2">BG</span>=white<br>
    <span class="ident2">HOST</span>=castor<br>
    <span class="ident2">FONT</span>=<span class=
    "number">9</span>x15<br>
    <span class="ident2">BFONT</span>=<span class=
    "number">9</span>x15bold<br>
    <span class="ident2">COLS</span>=<span class=
    "number">80</span><br>
    &nbsp;<br>
    <span class=
    "comment">#&nbsp;Parse&nbsp;the&nbsp;command&nbsp;line&nbsp;arguments</span><br>

    <span class="comment">#</span><br>
    <span class="keyword">while</span>&nbsp;[&nbsp;<span class=
    "ident2">$#</span>&nbsp;!=&nbsp;<span class=
    "number">0</span>&nbsp;];<br>
    <span class="keyword">do</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">case</span>&nbsp;<span class=
    "ident2">$1</span>&nbsp;<span class="keyword">in</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="number">-80</span>)&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">COLS</span>=<span class="number">80</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">FONT</span>=spc12x24c<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">BFONT</span>=spc12x24b<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;;;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="number">-132</span>)&nbsp;&nbsp;&nbsp;<span class="ident2">COLS</span>=<span class="number">132</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">FONT</span>=<span class="number">9</span>x15<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">BFONT</span>=<span class="number">9</span>x15b<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;;;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-fg)&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">FG</span>=<span class="ident2">$1</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span>;;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-bg)&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">BG</span>=<span class="ident2">$1</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span>;;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-fn)&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">FONT</span>=<span class="ident2">$1</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span>;;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-fb)&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">BFONT</span>=<span class="ident2">$1</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span>;;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-host)&nbsp;&nbsp;<span class="keyword">shift</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">HOST</span>=<span class="ident2">$1</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span>;;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-help)&nbsp;&nbsp;Usage;;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;*)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Usage;;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">esac</span><br>
    <span class="keyword">done</span><br>
    &nbsp;<br>
    xterm&nbsp;&nbsp;-title&nbsp;<span class=
    "literal">"VAX"</span>&nbsp;-sb&nbsp;-sl&nbsp;<span class=
    "number">1200</span>&nbsp;-geo&nbsp;<span class=
    "ident2">${COLS}</span>x24&nbsp;-fg&nbsp;<span class=
    "ident2">${FG}</span>&nbsp;-bg&nbsp;<span class=
    "ident2">${BG}</span>&nbsp;\<br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-cr&nbsp;red&nbsp;-fn&nbsp;<span class="ident2">${FONT}</span>&nbsp;-fb&nbsp;<span class="ident2">${BFONT}</span>&nbsp;-xrm&nbsp;\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "literal">'XTerm*VT100.translations:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;#override&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;Insert:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(\001)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&lt;Key&gt;Up:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;scroll-back(1,lines)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&lt;Key&gt;Down:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;scroll-forw(1,lines)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&lt;Key&gt;Right:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("f")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&lt;Key&gt;Left:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("b")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&lt;Key&gt;Delete:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string(0x08)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&lt;Key&gt;Tab:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("*")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;0x1000FF0D:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;scroll-back(1,page)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;0x1000FF0E:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;scroll-forw(1,page)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;0x1000FF09:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(\010)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;0x1000FF0A:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(\005)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;BackSpace:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0xff)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;Select:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;select-start()&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;0x1000FF02:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;select-end(PRIMARY,CUT_BUFFER0)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Meta&nbsp;&lt;Key&gt;0x1000FF02:&nbsp;&nbsp;&nbsp;select-end(CLIPBOARD)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;0x1000FF04:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;insert-selection(PRIMARY,CUT_BUFFER0)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Meta&nbsp;&lt;Key&gt;0x1000FF04:&nbsp;&nbsp;&nbsp;insert-selection(CLIPBOARD)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;F1:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("OP")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;F2:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("OQ")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;F3:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("OR")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;F4:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("OS")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;F5:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("OA")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;F11:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("[23~")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;F12:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("[24~")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_0:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("Op")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_1:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("Oq")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_2:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("Or")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_3:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("Os")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_4:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("Ot")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_5:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("Ou")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_Divide:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("OP")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_Multiply:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("[29~")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_Enter:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("OM")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_Subtract:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("Om")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_Add:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("Ol")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_Decimal:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;string("On")&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Btn1Down&gt;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;select-start()&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Btn1Motion&gt;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;select-extend()&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Btn1Up&gt;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;select-end(PRIMARY,CUT_BUFFER0)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Button1&lt;Btn2Down&gt;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;select-end(CLIPBOARD)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Button1&lt;Btn2Up&gt;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;ignore()'</span>&nbsp;\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-e&nbsp;telnet&nbsp;<span class="ident2">$HOST</span>&nbsp;&amp;<br>

    <!--atr2html}}--></p>
  </blockquote>

  <p>Finally (for the moment) is a further modification of Robert
  Ess's script by <a href=
  "https://web.archive.org/web/20110411233005/http://www-personal.une.edu.au/~oahlefel/vmsterm.htm">
  Erik Ahlefeldt</a>, &lt;oahlefel@metz.une.edu.au&gt;. From his
  readme file, for vmsterm:</p>

  <blockquote>
    <p>This script is for people who wish to connect from a Linux
    or Unix computer to a VMS computer using telnet and get a good
    VT100 or VT220 emulation. The key mappings have been
    specifically designed to emulate the VT terminal auxiliary
    numeric keypad, so that you can use VMS EDT and TPU editors, as
    well as the many VMS applications use keys PF1 to PF4. The
    script should work with any recent version of Xterm using a
    standard extended IBM PC keyboard or a Sun keyboard.</p>

    <p>About the keymappings. First the auxiliary numeric keypad.
    My prime objective with these mappings was to produce a setup
    that I could use with the EDT and TPU editors which make
    extensive use of the numeric keypad. The top row of keys PC
    numeric keypad (Num Lock, Divide, Multiply, Subtract) are where
    you find PF1, PF2, PF3, PF4 on a VT keyboard, so I have mapped
    them to PF1 thru PF4. The PC numeric keypad Add key (+) takes
    up the space of two keys which are Minus and Comma on the VT
    keyboard &ndash; I have mapped it to Comma (Delete Character in
    the EDT editor). I have then used the PC Pause key to map to VT
    key Minus (Delete Word in the EDT editor). The remaining keys
    on the auxiliary numeric keypad are the same for PC and VT.</p>

    <p>The six keys between the main and numeric keypads on the PC
    (Insert, Home, Page Up, Delete End, Page Down) are usually
    mapped to the VT keys by either position or by (approximate)
    function. As I rarely use these keys I have mapped them by
    function as follows: PC key Insert to VT Insert Here, PC Home
    to VT Find, PC Page Up to VT Prev, PC Delete to VT Remove, PC
    End to VT Select, PC Page Down to VT Next.</p>

    <dl>
      <dt>Function keys.</dt>

      <dd>
        There are 12 function keys on the PC keyboard and 20 on the
        VT keyboard, so I map PC F1 thru F12 to VT F1 thru F12
        (except for F1 thru F5 as noted below) and PC Shift F1 thru
        Shift F10 to VT F11 thru F20.
        <p>The VT keys F1 thru F5 are local hardware function keys
        so there is nothing to emulate, however some PC to VT
        emulations in the past have mapped PF1 thru PF4 here, so I
        have done that too, even though they are already mapped on
        the auxiliary numeric keypad.</p>
      </dd>

      <dt>Xterm functionality.</dt>

      <dd>You lose some xterm functions when you remap the
      keyboard, however this script implements a scroll back buffer
      of 1000 lines which you scroll through using Shift and Up
      (a.k.a. Up Arrow or Cursor Up key) or Shift and Down.</dd>
    </dl>
  </blockquote>

  <p>a summary of the keyboard mapping:</p>

  <blockquote>
    <pre class="code-block">
PC Key     maps to   VT Key.
------               ------
F1                   PF1
F2                   PF2
F3                   PF3
F4                   PF4
F5                   unused
F6                   F6
F7                   F7
F8                   F8
F9                   F9
F10                  F10
F11                  F11
F12                  F12
Shift F1             F11
Shift F2             F12
Shift F3             F13
Shift F4             F14
Shift F5             F15 (Help)
Shift F6             F16 (Do)
Shift F7             F17
Shift F8             F18
Shift F9             F19
Shift F10            F20
Shift F11            F11
Shift F12            F12
Print                Help (F15)
Cancel               Do   (F16)
Pause                Keypad Minus

Insert               Insert Here
Delete               Remove
Home                 Find
End                  Select
Prior                Prev
Next                 Next
BackSpace            BackSpace (sends DEL - ascii 127)

Num_Lock             PF1
KP_Divide            PF2
KP_Multiply          PF3
KP_Subtract          PF4
KP_Add               Keypad Comma
KP_Enter             Enter
KP_Decimal           Period
KP_0                 Keypad 0
KP_1                 Keypad 1
KP_2                 Keypad 2
KP_3                 Keypad 3
KP_4                 Keypad 4
KP_5                 Keypad 5
KP_6                 Keypad 6
KP_7                 Keypad 7
KP_8                 Keypad 8
KP_9                 Keypad 9
Up                   Up
Shift Up             Scroll Back
Down                 Down
Shift Down           Scroll Forward
Right                Right
Left                 Left
</pre>
  </blockquote>

  <p>and the script:</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    <span class="comment">#!/bin/sh</span><br>
    <span class=
    "comment">#&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;vmsterm</span><br>

    <span class=
    "comment">#&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;from&nbsp;an&nbsp;original&nbsp;script&nbsp;by&nbsp;Bob&nbsp;Ess</span><br>

    <span class=
    "comment">#&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;key&nbsp;translations&nbsp;by&nbsp;Erik&nbsp;Ahlefeldt&nbsp;</span><br>

    <span class="comment">#</span><br>
    <span class=
    "comment">#&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Script&nbsp;file&nbsp;using&nbsp;Xterm&nbsp;and&nbsp;telnet&nbsp;to&nbsp;connect&nbsp;to&nbsp;a&nbsp;VMS&nbsp;host</span><br>

    <span class=
    "comment">#&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;and&nbsp;give&nbsp;a&nbsp;decent&nbsp;vt220&nbsp;emulation.</span><br>

    <span class="comment">#</span><br>
    <span class="comment">#&nbsp;Usage&nbsp;statement</span><br>
    Usage()<strong><em><span class=
    "comment">{</span></em></strong><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;Usage&nbsp;&nbsp;:&nbsp;vmsterm&nbsp;-options"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;Options:&nbsp;-80&nbsp;&nbsp;&nbsp;for&nbsp;80&nbsp;column&nbsp;terminal"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-132&nbsp;&nbsp;for&nbsp;132&nbsp;column&nbsp;terminal"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-bg&nbsp;colorname"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-fg&nbsp;colorname"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-fn&nbsp;fontname"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-fb&nbsp;bold&nbsp;fontname"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-host&nbsp;[crusher.saltmine.com]&nbsp;[earth]&nbsp;[192.168.7.7]"</span>&nbsp;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class="literal">""</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;Example:&nbsp;</span><strong><em><span class=
    "comment">\</span></em></strong><span class=
    "literal">"vmsterm&nbsp;-80&nbsp;-fg&nbsp;white&nbsp;-bg&nbsp;black&nbsp;-fn&nbsp;9x15&nbsp;-fb&nbsp;9x15b&nbsp;-host&nbsp;earth</span><strong><em><span class="comment">\</span></em></strong><span class="literal">""</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Starts&nbsp;a&nbsp;VMS&nbsp;session&nbsp;with&nbsp;an&nbsp;80&nbsp;column&nbsp;terminal"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;with&nbsp;a&nbsp;black&nbsp;background,&nbsp;white&nbsp;foreground,&nbsp;a&nbsp;normal"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;font&nbsp;of&nbsp;9x15&nbsp;and&nbsp;a&nbsp;bold&nbsp;font&nbsp;of&nbsp;9x15b,&nbsp;and&nbsp;connects"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;to&nbsp;the&nbsp;node&nbsp;'earth'"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class="literal">""</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;Example:&nbsp;</span><strong><em><span class=
    "comment">\</span></em></strong><span class=
    "literal">"vmsterm&nbsp;-host&nbsp;earth</span><strong><em><span class="comment">\</span></em></strong><span class="literal">""</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Starts&nbsp;a&nbsp;VMS&nbsp;session&nbsp;with&nbsp;default&nbsp;terminal&nbsp;settings&nbsp;"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class="literal">""</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;Example:&nbsp;</span><strong><em><span class=
    "comment">\</span></em></strong><span class=
    "literal">"vmsterm&nbsp;-help</span><strong><em><span class=
    "comment">\</span></em></strong><span class=
    "literal">""</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Displays&nbsp;vmsterm&nbsp;options&nbsp;"</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">echo</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">exit</span>&nbsp;<span class="number">1</span><br>
    <strong><em><span class="comment">}</span></em></strong><br>
    &nbsp;<br>
    <span class=
    "comment">#&nbsp;Default&nbsp;to&nbsp;a&nbsp;black&nbsp;foreground&nbsp;with&nbsp;a&nbsp;white&nbsp;background.</span><br>

    <span class=
    "comment">#&nbsp;Use&nbsp;the&nbsp;9x15&nbsp;and&nbsp;9x15bold&nbsp;fonts.&nbsp;Connect&nbsp;to&nbsp;192.168.3.3&nbsp;by&nbsp;default.</span><br>

    <span class="comment">#</span><br>
    <span class="ident2">FG</span>=black<br>
    <span class="ident2">BG</span>=white<br>
    <span class="ident2">HOST</span>=192.168.3.3<br>
    <span class="ident2">FONT</span>=9x15<br>
    <span class="ident2">BFONT</span>=9x15bold<br>
    <span class="ident2">COLS</span>=<span class=
    "number">80</span><br>
    &nbsp;<br>
    <span class=
    "comment">#&nbsp;Parse&nbsp;the&nbsp;command&nbsp;line&nbsp;arguments</span><br>

    <span class="comment">#</span><br>
    <span class="keyword">while</span>&nbsp;[&nbsp;<span class=
    "ident2">$#</span>&nbsp;!=&nbsp;<span class=
    "number">0</span>&nbsp;];<br>
    <span class="keyword">do</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">case</span>&nbsp;<span class=
    "ident2">$1</span>&nbsp;<span class="keyword">in</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="number">-80</span>)&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">COLS</span>=<span class="number">80</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">FONT</span>=spc12x24c<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">BFONT</span>=spc12x24b<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;;;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="number">-132</span>)&nbsp;&nbsp;&nbsp;<span class="ident2">COLS</span>=<span class="number">132</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">FONT</span>=9x15<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">BFONT</span>=9x15b<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;;;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-fg)&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">FG</span>=<span class="ident2">$1</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span>;;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-bg)&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">BG</span>=<span class="ident2">$1</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span>;;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-fn)&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">FONT</span>=<span class="ident2">$1</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span>;;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-fb)&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">BFONT</span>=<span class="ident2">$1</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span>;;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-host)&nbsp;&nbsp;<span class="keyword">shift</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="ident2">HOST</span>=<span class="ident2">$1</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">shift</span>;;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-help)&nbsp;&nbsp;Usage;;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;*)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Usage;;<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "keyword">esac</span><br>
    <span class="keyword">done</span><br>
    &nbsp;<br>
    xterm&nbsp;&nbsp;&nbsp;-title&nbsp;<span class=
    "literal">"VMSTERM"</span>&nbsp;-sb&nbsp;-sl&nbsp;<span class=
    "number">1000</span>&nbsp;-geo&nbsp;<span class=
    "ident2">${COLS}</span>x24&nbsp;-fg&nbsp;<span class=
    "ident2">${FG}</span>&nbsp;-bg&nbsp;<span class=
    "ident2">${BG}</span>&nbsp;\<br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-cr&nbsp;blue&nbsp;-fn&nbsp;<span class="ident2">${FONT}</span>&nbsp;-fb&nbsp;<span class="ident2">${BFONT}</span>&nbsp;-xrm&nbsp;\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "literal">"XTerm*vt100.translations:&nbsp;#override&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift&nbsp;&nbsp;&lt;Key&gt;F1:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>OP<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift&nbsp;&nbsp;&lt;Key&gt;F2:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>OQ<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift&nbsp;&nbsp;&lt;Key&gt;F3:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>OR<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift&nbsp;&nbsp;&lt;Key&gt;F4:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>OS<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift&nbsp;&nbsp;&lt;Key&gt;F5:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string("</span>Break<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift&nbsp;&nbsp;&lt;Key&gt;F6:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">17</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift&nbsp;&nbsp;&lt;Key&gt;F7:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">18</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift&nbsp;&nbsp;&lt;Key&gt;F8:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">19</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift&nbsp;&nbsp;&lt;Key&gt;F9:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">20</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift&nbsp;&nbsp;&lt;Key&gt;F10:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">21</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift&nbsp;&nbsp;&lt;Key&gt;F11:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">23</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift&nbsp;&nbsp;&lt;Key&gt;F12:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">24</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&nbsp;&nbsp;&lt;Key&gt;F1:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">23</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&nbsp;&nbsp;&lt;Key&gt;F2:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">24</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&nbsp;&nbsp;&lt;Key&gt;F3:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">25</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&nbsp;&nbsp;&lt;Key&gt;F4:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">26</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&nbsp;&nbsp;&lt;Key&gt;F5:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">28</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&nbsp;&nbsp;&lt;Key&gt;F6:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">29</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&nbsp;&nbsp;&lt;Key&gt;F7:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">31</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&nbsp;&nbsp;&lt;Key&gt;F8:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">32</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&nbsp;&nbsp;&lt;Key&gt;F9:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">33</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&nbsp;&nbsp;&lt;Key&gt;F10:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">34</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&nbsp;&nbsp;&lt;Key&gt;F11:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">28</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&nbsp;&nbsp;&lt;Key&gt;F12:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">29</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;Print:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">28</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;Cancel:&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">29</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;Pause:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>Om<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;Insert:&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">2</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;Delete:&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">3</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;Home:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">1</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;End:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">4</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;Prior:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">5</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;Next:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[<span class="number">6</span>~<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;BackSpace:&nbsp;string(0x7f)&nbsp;&nbsp;&nbsp;&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;Num_Lock:&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>OP<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_Divide:&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>OQ<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_Multiply:&nbsp;string(0x1b)&nbsp;&nbsp;string("</span>OR<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_Subtract:&nbsp;string(0x1b)&nbsp;&nbsp;string("</span>OS<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_Add:&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>Ol<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_Enter:&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>OM<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_Decimal:&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;string("</span>On<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_0:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>Op<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_1:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>Oq<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_2:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>Or<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_3:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>Os<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_4:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>Ot<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_5:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>Ou<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_6:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>Ov<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_7:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>Ow<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_8:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>Ox<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;KP_9:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>Oy<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift&nbsp;&nbsp;&lt;Key&gt;Up:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[A<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&nbsp;&nbsp;&lt;Key&gt;Up:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;scroll-back(1,lines)&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift&nbsp;&nbsp;&lt;Key&gt;Down:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[B<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;&nbsp;&nbsp;&lt;Key&gt;Down:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;scroll-forw(1,lines)&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;Right:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[C<span class="literal">")&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal">n&nbsp;</span><strong><em><span class="comment">\</span></em></strong><span class="literal"><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;Left:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;string(0x1b)&nbsp;&nbsp;&nbsp;&nbsp;string("</span>[D<span class="literal">")"</span>&nbsp;\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-e&nbsp;telnet&nbsp;<span class="ident2">$HOST</span>&nbsp;<br>

    <!--atr2html}}--></p>
  </blockquote>

  <h3 id="how2_title-id"><a name="how2_title" id="how2_title">How
  do I set the title?</a></h3>

  <p>The control sequences for doing this are documented in
  <a href="#ctlseqs_ms">ctlseqs.ms</a>.</p>

  <p>The usual context for this question is setting the title
  according to the current working directory. People post answers
  to this periodically on the newsgroups. Here is one that I have
  seen, from Roy Wright &lt;nobody@roystoy.dseg.ti.com&gt;. In your
  /etc/profile after:</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    <span class="keyword">if</span>&nbsp;[&nbsp;<span class=
    "literal">"</span><span class=
    "ident2">$SHELL</span><span class="literal">"</span>&nbsp;=&nbsp;<span class="literal">"/bin/pdksh"</span>&nbsp;-o&nbsp;<span class="literal">"</span><span class="ident2">$SHELL</span><span class="literal">"</span>&nbsp;=&nbsp;<span class="literal">"/bin/ksh"</span>&nbsp;];&nbsp;<span class="keyword">then</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "ident2">PS1</span>=<span class=
    "literal">"!&nbsp;$&nbsp;"</span><br>
    <span class="keyword">elif</span>&nbsp;[&nbsp;<span class=
    "literal">"</span><span class=
    "ident2">$SHELL</span><span class="literal">"</span>&nbsp;=&nbsp;<span class="literal">"/bin/zsh"</span>&nbsp;];&nbsp;<span class="keyword">then</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "ident2">PS1</span>=<span class=
    "literal">"%m:%~%#&nbsp;"</span><br>
    <span class="keyword">elif</span>&nbsp;[&nbsp;<span class=
    "literal">"</span><span class=
    "ident2">$SHELL</span><span class="literal">"</span>&nbsp;=&nbsp;<span class="literal">"/bin/ash"</span>&nbsp;];&nbsp;<span class="keyword">then</span><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "ident2">PS1</span>=<span class="literal">"$&nbsp;"</span><br>
    <span class="keyword">else</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "ident2">PS1</span>=<span class=
    "literal">'\u@\h:\w\$&nbsp;'</span><br>
    <span class="keyword">fi</span><br>
    <!--atr2html}}--></p>
  </blockquote>

  <p>add:</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    <span class="keyword">if</span>&nbsp;[&nbsp;<span class=
    "literal">"</span><span class="ident2">$TERM</span><span class=
    "literal">"</span>&nbsp;=&nbsp;<span class=
    "literal">"xterm"</span>&nbsp;];&nbsp;<span class=
    "keyword">then</span><br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class=
    "ident2">PS1</span>=<span class="literal">"</span><span class=
    "keyword2">\</span><span class=
    "literal">033]2;</span><span class=
    "keyword2">\</span><span class="literal">u@</span><span class=
    "keyword2">\</span><span class="literal">h:</span><span class=
    "keyword2">\</span><span class="literal">w</span><span class=
    "keyword2">\</span><span class=
    "literal">007bash$&nbsp;"</span><br>
    <span class="keyword">fi</span><br>
    <!--atr2html}}--></p>
  </blockquote>

  <p>The terminator "\007" is a problem area.
  <strong>XTerm</strong> historically uses this character, though
  it is non-ANSI. The &ldquo;correct&rdquo; character should be a
  "\233" string terminator, or "\033\\", which is the 7-bit
  equivalent. Modern xterm recognizes either (the "\007" or string
  terminator); waiting for the first of these.</p>

  <p>You may have resource or environment problems that prevent you
  from setting the title at all. Newer xterms (starting somewhere
  in X11R5) use the $LANG variable. If your locale is incorrectly
  installed, you will be unable to set the xterm's title. As noted
  by Mikhail Teterin &lt;mi@rtfm.ziplink.net&gt;: Make sure that
  the locale (LANG and/or LOCALE environment variable) is known to
  X Window System. Check ${X11ROOT}/lib/X11/locale.* for it. If it
  is not listed in either one of the files, find the nearest match
  and add an alias to it. Restart X if you have made changes.</p>

  <p>On a related note, some people want to know how to read the
  title from an xterm. This works for modern xterm and dtterm, but
  not for other variations:</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    <span class="comment">#!/bin/ksh</span><br>
    <span class=
    "comment">#&nbsp;Echo&nbsp;the&nbsp;current&nbsp;X&nbsp;term&nbsp;title&nbsp;bar&nbsp;to&nbsp;standard&nbsp;output.</span><br>

    <span class=
    "comment">#&nbsp;Written&nbsp;by&nbsp;Icarus&nbsp;Sparry&nbsp;&lt;icarus@bath.ac.uk&gt;&nbsp;11&nbsp;Apr&nbsp;1997</span><br>

    <span class="comment">#</span><br>
    <span class="keyword">exec</span>&nbsp;&lt;/dev/tty<br>
    <span class="ident2">old</span>=<span class=
    "keyword2">$(</span>stty&nbsp;-g<span class=
    "keyword2">)</span><br>
    stty&nbsp;raw&nbsp;-echo&nbsp;min&nbsp;<span class=
    "number">0</span>&nbsp;&nbsp;<span class=
    "keyword">time</span>&nbsp;<span class=
    "ident2">${1</span><span class=
    "keyword2">-</span>10<span class="ident2">}</span><br>
    <span class="keyword">print</span>&nbsp;<span class=
    "literal">"</span><span class="keyword2">\</span><span class=
    "literal">033[21t</span><span class=
    "keyword2">\</span><span class=
    "literal">c"</span>&nbsp;&gt;&nbsp;/dev/tty<br>
    <span class="ident2">IFS</span>=<span class=
    "literal">''</span>&nbsp;<span class=
    "keyword">read</span>&nbsp;-r&nbsp;a<br>
    stty&nbsp;<span class="ident2">$old</span><br>
    <span class="ident2">b</span>=<span class=
    "ident2">${a</span><span class=
    "keyword2">#</span>???<span class="ident2">}</span><br>
    <span class="keyword">print</span>&nbsp;-R&nbsp;<span class=
    "literal">"</span><span class="ident2">${b</span><span class=
    "keyword2">%</span>??<span class="ident2">}</span><span class=
    "literal">"</span><br>
    <!--atr2html}}--></p>
  </blockquote>

  <p>But it is possible to avoid escape sequences altogether (from
  Hemant Shah &lt;shah@typhoon.xnet.com&gt;):</p>

  <blockquote>
    <pre class="code-block">
$ xprop -id $WINDOWID | grep WM_NAME
WM_NAME(STRING) = "this is my title"
current_title=$(xprop -id $WINDOWID | grep WM_NAME | cut -d= -f2)
</pre>
  </blockquote>

  <p>Here's another source of information: <a href=
  "http://tldp.org/HOWTO/Xterm-Title.html">Xterm-Title
  HowTo</a></p>

  <h3 id="how2_blink-id"><a name="how2_blink" id="how2_blink">How
  do I make the cursor blink?</a></h3>

  <p>Standard xterm does not implement a blinking cursor. Some of
  the variations do: dtterm, GNOME Terminal, and modern xterm (from
  mid 1999, <a href="/xterm/xterm.log.html#xterm_107">patch
  107</a>).</p>

  <h2 id="frequent_problems-id"><a name="frequent_problems" id=
  "frequent_problems">Frequent problems</a></h2>

  <ul>
    <li>
      <a href="#problems_starting">Starting xterm, or not</a>
      <ul>
        <li>
          <p><a href="#no_ptys">Xterm does not run (no available
          pty's)</a></p>
        </li>

        <li>
          <p><a href="#no_termcap">I need /etc/termcap</a></p>
        </li>

        <li>
          <p><a href="#no_libpath">Why does $LD_LIBRARY_PATH get
          reset?</a></p>
        </li>

        <li>
          <p><a href="#no_ls_and_e">Why do the -e and -ls options
          not work together?</a></p>
        </li>

        <li>
          <p><a href="#setup_resize">Why is my screen size not
          set?</a></p>
        </li>

        <li>
          <p><a href="#tiny_menus">Why are the menus tiny?</a></p>
        </li>
      </ul>
    </li>

    <li>
      <a href="#problems_fonts">Font problems</a>
      <ul>
        <li>
          <p><a href="#no_altchar">My terminal doesn't show box
          characters</a></p>
        </li>

        <li>
          <p><a href="#scaled_font">The bold font is ugly</a></p>
        </li>

        <li>
          <p><a href="#little_dot">I see little dots on the
          screen</a></p>
        </li>

        <li>
          <p><a href="#no_russian">My terminal doesn't display
          Cyrillic characters</a></p>
        </li>

        <li>
          <p><a href="#utf8_fonts">I see boxes instead of
          characters in uxterm</a></p>
        </li>

        <li>
          <p><a href="#utf8_badcode">I see question-marks instead
          of characters in uxterm</a></p>
        </li>

        <li>
          <p><a href="#slow_menus">The first popup menu is very
          slow</a></p>
        </li>
      </ul>
    </li>

    <li>
      <a href="#problems_keyboard">Keyboard problems</a>
      <ul>
        <li>
          <p><a href="#xterm_8bits">Why can't I input 8-bit
          characters?</a></p>
        </li>

        <li>
          <p><a href="#xterm_erase">Why doesn't my delete key
          work?</a></p>
        </li>

        <li>
          <p><a href="#xterm_erased">Why did my delete key stop
          working?</a></p>
        </li>

        <li>
          <p><a href="#xterm_xmodmap">Well, how can I set my delete
          key?</a></p>
        </li>

        <li>
          <p><a href="#xterm_keypad">Why doesn't my keypad
          work?</a></p>
        </li>

        <li>
          <p><a href="#xterm_modother">How can my program
          distinguish control-I from tab?</a></p>
        </li>

        <li>
          <p><a href="#xterm_pageup">Why can't I use the
          pageup/pagedown keys?</a></p>
        </li>

        <li>
          <p><a href="#xterm_pc_style">Why can't I use the home/end
          keys?</a></p>
        </li>

        <li>
          <p><a href="#xterm_arrows">Why can't I use the cursor
          keys in (whatever) shell?</a></p>
        </li>

        <li>
          <p><a href="#bash_meta_mode">Alt-keys do not work in
          bash</a></p>
        </li>
      </ul>
    </li>

    <li>
      <a href="#problems_colors">Colors and other graphic
      rendition</a>
      <ul>
        <li>
          <p><a href="#no_color">My terminal doesn't recognize
          color</a></p>
        </li>

        <li>
          <p><a href="#xterm_terminfo">What $TERM should I use?</a></p>
        </li>

        <li>
          <p><a href="#xterm_hilite">Reverse video is not reset</a></p>
        </li>

        <li>
          <p><a href="#vim_16colors">My colors changed in vim</a></p>
        </li>

        <li>
          <p><a href="#bold_vs_16colors">Aren't bright colors the
          same as bold?</a></p>
        </li>

        <li>
          <p><a href="#color_by_number">Can I set a color by its
          number?</a></p>
        </li>

        <li>
          <p><a href="#dont_like_blue">I don't like that shade of
          blue</a></p>
        </li>

        <li>
          <p><a href="#what_256colors">What is the 256-color
          palette?</a></p>
        </li>

        <li>
          <p><a href="#why_no_italics">Why doesn't xterm support
          italics?</a></p>
        </li>

        <li>
          <p><a href="#grep_colors">"grep --color" does not show
          the right output</a></p>
        </li>

        <li>
          <p><a href="#vt100_wrapping">That description of wrapping
          is odd, say more?</a></p>
        </li>

        <li>
          <p><a href="#bce_oddness">That color scheme is odd, say
          more?</a></p>
        </li>
      </ul>
    </li>

    <li>
      <a href="#problems_weird">Odd behavior</a>
      <ul>
        <li>
          <p><a href="#xterm_paste">Why can't I select/paste in
          xterm?</a></p>
        </li>

        <li>
          <p><a href="#xterm_select_clipboard">Why can't I
          select/paste to/from other programs?</a></p>
        </li>

        <li>
          <p><a href="#xterm_tabs">Why can't I select
          tab-characters in xterm?</a></p>
        </li>

        <li>
          <p><a href="#xterm_paste_nl">Can bracketed-paste solve my
          problems?</a></p>
        </li>

        <li>
          <p><a href="#xterm_resize">FVWM does weird things when I
          try to resize xterm</a></p>
        </li>

        <li>
          <p><a href="#xterm_tite">Why doesn't the screen clear
          when running vi?</a></p>
        </li>

        <li>
          <p><a href="#xterm_form_feed">Why doesn't the screen
          clear when I type control/L?</a></p>
        </li>

        <li>
          <p><a href="#xterm_vite">Why is the cursor misplaced
          after running vi?</a></p>
        </li>

        <li>
          <p><a href="#narrowproto">Why doesn't the scrollbar
          work?</a></p>
        </li>

        <li>
          <p><a href="#xaw_scrollbars">Can I improve the
          scrollbars?</a></p>
        </li>

        <li>
          <p><a href="#scroll_speed">Can I improve the scrolling
          speed?</a></p>
        </li>

        <li>
          <p><a href="#window_ops">Why can't my program read the
          window title?</a></p>
        </li>

        <li>
          <p><a href="#window_ops2">Why can't my program set the
          window size?</a></p>
        </li>

        <li>
          <p><a href="#compiz_bugs">Why is the text in the wrong
          place?</a></p>
        </li>
      </ul>
    </li>

    <li>
      <p><a href="#my_xdefaults">Sample .Xdefaults Color-Settings
      for XTerm</a></p>
    </li>

    <li>
      <p><a href="#warning_msg">What is this warning message?</a></p>
    </li>
  </ul>

  <h3 id="problems_starting-id"><a name="problems_starting" id=
  "problems_starting">Starting xterm, or not</a></h3>

  <h4 id="no_ptys-id"><a name="no_ptys" id=
  "no_ptys"><strong>XTerm</strong> does not run (no available
  pty's)</a></h4>

  <p>Your copy of xterm may not have enough permissions to use
  existing pty's:</p>

  <ul>
    <li>
      <p>you may have to make xterm run setuid to root (though
      newer systems have wrappers that make this unnecessary).</p>
    </li>

    <li>
      <p>the pty's permissions may be restrictive (that is ok, but
      you have to make xterm agree with it). Usually this is done
      by making the group ownership of the pty's &ldquo;tty&rdquo;,
      and requiring that xterm run setgid to &ldquo;tty&rdquo;.
      This is done rather than make xterm run setuid to root, since
      that presents problems with security.</p>
    </li>

    <li>
      <p>newer systems (with Unix98 pty's) have a single entry
      under /dev which has to have the right permissions. For
      example:</p>

      <blockquote>
        <pre class="code-block">
# ls -l /dev/ptmx
crw-rw----    1 root     tty        5,   2 Aug 21 20:19 /dev/ptmx
</pre>
      </blockquote>
    </li>
  </ul>

  <p>Perhaps your system does not have enough pty's, or (problems
  reported with newer Linux kernels supporting Unix98 pty's,
  beginning with RedHat 6.0) the major device numbers of the pty's
  may have changed during a kernel upgrade. (This is described in
  <code>/usr/src/linux/Documentation</code>).</p>

  <p>See also the MAKEDEV script, which usually exists under
  /dev.</p>

  <h4 id="no_termcap-id"><a name="no_termcap" id="no_termcap">I
  need /etc/termcap</a></h4>

  <p>If you have a termcap version of xterm on a system with no
  termcap libraries, you may also be missing /etc/termcap.</p>

  <p>A workaround is to copy /usr/X11R6/lib/X11/etc/xterm.termcap
  to /etc/termcap.</p>

  <p>This is fixed another way starting with XFree86 3.3.1. If
  xterm cannot find the terminal description, it will accept that,
  though it will print a warning. If xterm does not find the
  termcap entry, it will not set the $TERMCAP variable.</p>

  <h4 id="no_libpath-id"><a name="no_libpath" id="no_libpath">Why
  does $LD_LIBRARY_PATH get reset?</a></h4>

  <p>If xterm is running setuid (which is needed on some systems
  which have no wrappers for opening pty's and updating utmp),
  newer systems automatically set or reset environment variables
  which are considered security problems. These include
  <code>$PATH</code> and <code>$LD_LIBRARY_PATH</code>, since they
  affect the choice of which programs are run if not specified via
  a full pathname.</p>

  <p>This means, for example, that if you attempt to run</p>

  <blockquote>
    <pre class="code-block">
xterm -e foo
</pre>
  </blockquote>

  <p>where <code>foo</code> is a program that uses shared libraries
  in <code>/usr/local/lib</code>, then the command will fail,
  because <code>/usr/local/lib</code> is not considered part of
  <code>root</code>'s environment.</p>

  <p>Modern Unix systems (such as recent Solaris and HPUX versions)
  do not require you to run xterm setuid. Some will result in odd
  malfunctions if you do this.</p>

  <h4 id="no_ls_and_e-id"><a name="no_ls_and_e" id=
  "no_ls_and_e">Why do the -e and -ls options not work
  together?</a></h4>

  <p><strong>XTerm</strong> has two useful options for controlling
  the shell that is run:</p>

  <dl>
    <dt>-e</dt>

    <dd>tells xterm to execute a command using the remaining
    parameters after this option.</dd>

    <dt>-ls</dt>

    <dd>tells xterm to invoke a login shell, making it read your
    <code>.login</code> file, for instance.</dd>
  </dl>

  <p>The two are not compatible. If you specify both, xterm uses
  <code>-e</code>, and if that fails for whatever reason will fall
  through to the <code>-ls</code> option. It cannot (in general)
  combine the two, since some shells permit this (e.g., bash), and
  others do not (e.g., tcsh).</p>

  <h4 id="setup_resize-id"><a name="setup_resize" id=
  "setup_resize">Why is my screen size not set?</a></h4>

  <p>Well, it may be set, but not correctly. You may notice these
  symptoms:</p>

  <ul>
    <li>
      <p>When editing with vi, you cannot see the beginning of the
      file, or</p>
    </li>

    <li>
      <p>Running</p>

      <blockquote>
        <pre class="code-block">
stty -a
</pre>
      </blockquote>

      <p>shows the rows and/or columns values as 0, or some other
      value (such as 65) which has nothing to do with the actual
      window size.</p>
    </li>
  </ul>

  <p><strong>XTerm</strong> knows how big the screen is (of
  course), and tries to tell your applications (e.g., by invoking
  ioctl's and sending SIGWINCH). But sometimes it cannot:</p>

  <ul>
    <li>
      <p><strong>XTerm</strong> itself may have been built
      incorrectly (the #ifdef's that make the logic work are
      inactive).</p>
    </li>

    <li>
      <p>You may be running xterm via a remote connection which
      refuses to pass that information. This can happen even on
      &ldquo;modern&rdquo; networks where the connection crosses
      domain boundaries.</p>
    </li>

    <li>
      <p>You may be running su'd to another account. SIGWINCH is
      just another signal; signals do not propagate for security
      reasons.</p>
    </li>
  </ul>

  <p>Most full-screen applications such as vi are designed to use
  the ioctl calls that return the screen size. When they fail, the
  applications use the size defined in the terminal's terminfo or
  termcap description.</p>

  <p>You may be able to use the <em>resize</em> program to issue
  the ioctl's that will notify your application of the actual
  screen size. This does not always work for the reasons just
  mentioned. Newer versions of stty let you specify the screen
  size, though it will not be updated if you resize the xterm
  window:</p>

  <blockquote>
    <pre class="code-block">
stty rows 24 columns 80
</pre>
  </blockquote>

  <p>Most full-screen applications also check if the $LINES and
  $COLUMNS variables are set, using those values to override the
  terminal description:</p>

  <blockquote>
    <pre class="code-block">
setenv LINES 24
setenv COLUMNS 80
</pre>
  </blockquote>

  <p>Why 65 lines? The standard xterm terminfo description
  specifies 65 lines, perhaps because someone liked it that way.
  Real VT100's are 24 lines. I once used (and wrote applications
  for) a Bitgraph terminal, which emulated VT100, but displayed 65
  lines.</p>

  <h4 id="tiny_menus-id"><a name="tiny_menus" id="tiny_menus">Why
  are the menus tiny?</a></h4>

  <p>Everything seems to work, except that the xterm menus (VT
  options, fonts, etc.) do not display properly; the menus pop up,
  but only with a tiny display area in which none of the options
  are visible (and only part of the menu title is visible).</p>

  <p>You have specified the geometry for xterm too high in the
  hierarchy, and that 24x80 (or whatever the -geometry parameter
  happens to be) is applying to the menus in pixels. This resource
  makes the geometry apply to the menus as well as the VT100
  widget:</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    <span class="keyword">XTerm</span>*<span class=
    "ident2">geometry</span>:<span class=
    "literal">&nbsp;80x24</span><br>
    <!--atr2html}}--></p>
  </blockquote>

  <p>while this applies only to the VT100 widget (which is probably
  what you intended):</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    <span class="keyword">XTerm</span>.<span class=
    "keyword">VT100</span>.<span class=
    "ident2">geometry</span>:<span class=
    "literal">&nbsp;80x24</span><br>
    <!--atr2html}}--></p>
  </blockquote>

  <p>or better yet (to allow for the toolbar option, which uses a
  level of widget hierarchy):</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">geometry</span>:<span class=
    "literal">&nbsp;80x24</span><br>
    <!--atr2html}}--></p>
  </blockquote>

  <h3 id="problems_fonts-id"><a name="problems_fonts" id=
  "problems_fonts">Font problems</a></h3>

  <h4 id="no_altchar-id"><a name="no_altchar" id="no_altchar">My
  terminal doesn't show box characters</a></h4>

  <p><strong>XTerm</strong> displays the 7-bit ASCII and VT100
  graphic characters (including box corners) using specially
  arranged fixed-pitch fonts. The first 32 glyph positions (which
  would correspond to nonprinting control characters) are used to
  hold the VT100 graphic characters. Some fonts that otherwise look
  fine (such as courier) do not have glyphs defined for these
  positions. So they display as blanks. Use <em>xfd</em> to display
  the font.</p>

  <p>Modern xterm can form its own line-drawing characters (see
  <a href="/xterm/xterm.log.html#xterm_90">patch 90</a>, for
  example). It does not draw all of the graphic characters, only
  those that may be done with straight lines. But those are the
  most used, making most of the fixed-pitch fonts useful for
  xterm.</p>

  <p>You may also have a problem with the terminfo description. As
  distributed, the X11R6 terminfo for xterm does not have the
  <em>acsc</em> string defined, so most implementations of curses
  do not try to use the alternate character set.</p>

  <p>Finally, some people confuse the VT100 graphic characters with
  the VT220 support for DEC technical character set. These are
  distinct (7-bit) character sets. Xterm currently does not support
  this.</p>

  <h4 id="scaled_font-id"><a name="scaled_font" id=
  "scaled_font">The bold font is ugly</a></h4>

  <p><strong>XTerm</strong> lets you directly specify one bold
  font, which is assumed to correspond to the default font. Older
  versions of xterm make a fake bold font for the other choices via
  the fonts menu by drawing the characters offset by one pixel. I
  modified xterm to ask the font server for a bold font that
  corresponds to each font (other than the default one). Usually
  that works well. However, sometimes the font server gives a poor
  match. Xterm checks for differences in the alignment and size,
  but the font server may give incorrect information about the font
  size. The scaled bitmap font feature gives poor results for the
  smaller fonts. In your X server configuration file, that can be
  fixed by disabling the feature, e.g., by appending ":unscaled" to
  the path:</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    FontPath&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"<span class="literal">/usr/lib/X11/fonts/100dpi/:unscaled</span>"<br>

    FontPath&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"<span class="literal">/usr/lib/X11/fonts/75dpi/:unscaled</span>"<br>

    FontPath&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"<span class="literal">/usr/lib/X11/fonts/misc/:unscaled</span>"<br>

    <!--atr2html}}--></p>
  </blockquote>

  <p>You can suppress xterm's overstriking for bold fonts using the
  <code>alwaysBoldMode</code> and related resources. However,
  rendering ugly bold fonts is a "feature" of the font server. In
  particular, the TrueType interface provides less ability to the
  client for determining if a particular font supports a bold
  form.</p>

  <h4 id="little_dot-id"><a name="little_dot" id="little_dot">I see
  little dots on the screen</a></h4>

  <p>Well, I do. Perhaps you do not. It depends on the fonts you
  choose, and how you use them.</p>

  <p>Standard xterm has a &ldquo;normal&rdquo; font for which a
  bold font can be chosen, and several alternative fonts, useful
  for changing the font size. The alternative fonts do not have
  corresponding bold fonts. Xterm simulates bold fonts in this case
  by overstriking the character one pixel offset. That can make an
  bold character extend into the area that another character
  occupies. When erasing a bold character from the screen, xterm
  does not erase the extra pixel. This is corrected in modern
  xterm, subject to the available fonts (from late 1998, <a href=
  "xterm.log.html#xterm_85">patch 85</a>). For each font, it asks
  the font server for a corresponding bold font. Your font server
  may not have the bold font (or it may incorrectly report that it
  does). But it usually works.</p>

  <h4 id="no_russian-id"><a name="no_russian" id="no_russian">My
  terminal doesn't display Cyrillic characters</a></h4>

  <p>Cyrillic encodings typically use characters in the range
  128-159. For a VT220 (or any terminal that follows ISO 6429),
  those are treated as control characters. Still, some people want
  to use KOI8-R, etc. I modified xterm in <a href=
  "xterm.log.html#xterm_175">patch 175</a> to add an option
  (<code>-k8</code>) and corresponding resource settings to allow
  them to customize their environment. Here is a <a href=
  "/archives/xterm/koi8-term">sample script</a> and <a href=
  "/archives/xterm/KOI8Term">resource file</a> which I use for
  testing this configuration.</p>

  <h4 id="utf8_fonts-id"><a name="utf8_fonts" id="utf8_fonts">I see
  boxes instead of characters in uxterm</a></h4>

  <p><strong>XTerm</strong> may show boxes instead of characters if
  the font that you have selected does not contain those
  characters. Normally you can fix most of that using the UTF-8
  feature, with <code>uxterm</code>. However, your X resource
  settings may be the source of the problem.</p>

  <p>One pitfall to setting X resources is that they allow you to
  specify wildcards, e.g., the "*" character. When you give a
  wildcard, the X resource matches any number of levels in the
  widget hierarchy.</p>

  <p><strong>XTerm</strong> has more than one widget matching
  &ldquo;font&rdquo; at different levels of the hierarchy. There
  are the popup menus, and there are the fonts used for
  <code>uxterm</code>. The latter is where an overbroad pattern can
  cause xterm to use a different font than you expect.</p>

  <p>Suppose your resource setting includes this pattern</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    *<span class="keyword">VT100</span>*<span class=
    "ident2">font</span>:<span class=
    "literal">&nbsp;fixed</span><br>
    <!--atr2html}}--></p>
  </blockquote>

  <p>It could be interpreted as this:</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    *<span class="keyword">VT100</span>.<span class=
    "ident2">font</span>:<span class=
    "literal">&nbsp;fixed</span><br>
    *<span class="keyword">VT100</span>.<span class=
    "ident2">utf8Fonts</span>.<span class=
    "ident2">font</span>:<span class=
    "literal">&nbsp;fixed</span><br>
    <!--atr2html}}--></p>
  </blockquote>

  <p><strong>XTerm</strong> uses the <code>utf8Fonts</code>
  subresources to provide runtime-switchable fonts between
  IS0-8859-1 (Latin-1) and ISO-10646 (Unicode). Modifying the
  Unicode font to &ldquo;fixed&rdquo; will make most of the
  characters unavailable (i.e., shown as boxes). If instead your
  resource looks like</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    *<span class="keyword">VT100</span>.<span class=
    "ident2">font</span>:<span class=
    "literal">&nbsp;fixed</span><br>
    <!--atr2html}}--></p>
  </blockquote>

  <p>it would be unambiguous, and not modify the
  <code>utf8Fonts</code> value.</p>

  <h4><a name="utf8_badcode" id="utf8_badcode">I see question-marks
  instead of characters in uxterm</a></h4>

  <p>You may be seeing a question mark in a black diamond, like
  this:</p>

  <blockquote>
    <p>&#65533;</p>
  </blockquote>

  <p>That is called the Unicode <em>replacement character</em>. It
  is used when a program is told to display a character which is
  not in the Unicode system. The program <em>replaces</em> the
  illegal/invalid character with this symbol. That is different
  from <em>boxes</em>, which xterm displays when it has nothing in
  the current font for a valid Unicode character.</p>

  <p>Unicode's rules are oriented toward handling <em>input</em> in
  different encodings, and <em>displaying</em> the corresponding
  Unicode value. Although Unicode has rules and a definition for
  the valid characters, different programs may handle invalid input
  in different ways. <a href="bad-utf8/">This page</a> gives an
  overview of how xterm may differ from other programs in that
  regard.</p>

  <h4 id="slow_menus-id"><a name="slow_menus" id="slow_menus">The
  first popup menu is very slow</a></h4>

  <p>Some users report that when starting xterm, it is very slow,
  that their computer's CPU time increases, etc.</p>

  <p>This is a longstanding bug in the X libraries. There is a
  workaround using a resource setting for xterm.</p>

  <h5 id="slow_menus_details-id">Details</h5>

  <p><strong>XTerm</strong> uses the Athena (Xaw) widgets to
  display popup menus. In the normal case, those are initialized
  one-by-one as they are first used. If you have configured xterm
  to use its toolbar configuration, they are all initialized on
  startup. In the latter, performance problems are more
  noticeable.</p>

  <p>The Athena widgets <code>XawInitializeWidgetSet</code>
  function goes through several levels down to the X library
  <code>_XlcAddUtf8LocaleConverters</code> function to call
  <code>create_tocs_conv</code> and related functions to make a
  list of character sets from the locale, which is used in menus to
  get all possible fonts needed for a fontset.</p>

  <p>If your current locale uses <em>UTF-8</em> encoding, this will
  read a long list of bitmap fonts&mdash;everything whose
  <em>encoding</em> might be useful for displaying the menus. For
  example, this list (from <code>lcUTF8.c</code>) which dates from
  around 2000 is the core of the problem:</p>

  <blockquote class="code-block">
    <p>ISO10646-1, ISO8859-1, ISO8859-2, ISO8859-3, ISO8859-4,
    ISO8859-5, ISO8859-6, ISO8859-7, ISO8859-8, ISO8859-9,
    ISO8859-10, ISO8859-11, ISO8859-13, ISO8859-14, ISO8859-15,
    ISO8859-16, JISX0201.1976-0, TIS620-0, GB2312.1980-0,
    JISX0208.1983-0, JISX0208.1990-0, JISX0212.1990-0,
    KSC5601.1987-0, KOI8-R, KOI8-U, KOI8-C, TATAR-CYR, ARMSCII-8,
    IBM-CP1133, MULELAO-1, VISCII1.1-1, TCVN-5712,
    GEORGIAN-ACADEMY, GEORGIAN-PS, ISO8859-9E, MICROSOFT-CP1251,
    MICROSOFT-CP1255, MICROSOFT-CP1256, BIG5-0, BIG5-E0, BIG5-E1,
    ISO10646-1, ISO10646-1</p>
  </blockquote>

  <p>However, xterm is going to use only the characters shown in
  the popup menus. It is unlikely that you need Chinese fonts for
  that.</p>

  <h5 id="slow_menus_solution-id">Solution</h5>

  <p><strong>XTerm</strong>'s <code>menuLocale</code> resource can
  be set to an explicit value, e.g., &ldquo;C&rdquo; to override
  the current locale as seen by this initialization debacle.</p>

  <h5 id="slow_menus_limits-id">Limitations</h5>

  <p>The workaround does not prevent some hacker from
  &ldquo;improving&rdquo; the X libraries still further.</p>

  <h3 id="problems_keyboard-id"><a name="problems_keyboard" id=
  "problems_keyboard">Keyboard problems</a></h3>

  <h4 id="xterm_8bits-id"><a name="xterm_8bits" id=
  "xterm_8bits">Why can't I input 8-bit characters?</a></h4>

  <p>You must have the <code>eightBitInput</code> resource set to
  do this.</p>

  <h4 id="xterm_erase-id"><a name="xterm_erase" id=
  "xterm_erase">Why doesn't my delete key work?</a></h4>

  <p>This seems to have begun as a problem with the older XFree86
  release (3.1.2). I have picked up pieces of the story (xterm and
  the keyboard work as designed under XFree86 3.2 and up).</p>

  <p>The underlying problem is that we've accumulated three things
  that are being equated as &ldquo;Delete&rdquo;:</p>

  <blockquote>
    <pre class="code-block">
ASCII BS (backspace, code 8)
ASCII DEL (delete. code 127)
VT220 "remove" aka "delete" (ESC [ 3 ~)
</pre>
  </blockquote>

  <p>You are probably talking about the <strong>backarrow</strong>
  key (on my keyboard, at the upper right of the QWERTY block), or
  the key labeled <strong>delete</strong> which is on the 6-key
  "editing keypad". Since xterm is emulating a VT100/VT220, the
  backarrow key should generate a 127 (often displayed as
  <code>^?</code>). You would use a control/H to obtain a backspace
  on a real VT220.</p>

  <p>The reason why <code>BS</code> and <code>DEL</code> are of
  special interest is that on Unix, the <code>stty</code> command
  and the underlying termios/termio system calls allow only
  single-byte codes to be assigned to special functions such as
  <code>erase</code>. For instance, you could see something like
  this on your terminal:</p>

  <blockquote>
    <pre class="code-block">
$ stty -a
speed 38400 baud; rows 40; columns 80; line = 0;
intr = ^C; quit = ^\; erase = ^H; kill = ^U; eof = ^D; eol = &lt;undef&gt;;
eol2 = &lt;undef&gt;; swtch = &lt;undef&gt;; start = &lt;undef&gt;; stop = &lt;undef&gt;; susp = &lt;undef&gt;;
rprnt = ^R; werase = ^W; lnext = ^V; flush = ^O; min = 1; time = 0;
-parenb -parodd cs8 -hupcl -cstopb cread -clocal -crtscts
-ignbrk brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr -icrnl ixon -ixoff
-iuclc -ixany -imaxbel -iutf8
-opost -olcuc -ocrnl -onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
isig -icanon -iexten -echo -echoe -echok -echonl -noflsh -xcase -tostop -echoprt
-echoctl -echoke
</pre>
  </blockquote>

  <p>Tastes differ. On Unix, people expect the backarrow key to
  generate a backspace (or not). As I understand it, at one point,
  XFree86 picked up the sense of the erase character during
  initialization, so that xterm would in effect use the same erase
  character as the console. The current scheme (X11R6) uses
  keyboard mapping tables that are independent of the
  environment.</p>

  <p>Modern xterm (since <a href=
  "/xterm/xterm.log.html#xterm_83">patch #83</a> in 1998) provides
  a resource toggle <em>backarrowKey</em> (and an escape sequence
  from VT320) that changes this key between the two styles
  (backspace or delete).</p>

  <p>With modern xterm <a href=
  "/xterm/xterm.log.html#xterm_95">patch 95</a> (also in the stable
  version as &ldquo;88c&rdquo;), you may have an xterm which can
  automatically initialize the backarrow key to backspace or delete
  depending on the pseudo terminal's sense, or based on the termcap
  setting of <em>kbs</em> (backspace key). This feature is
  controlled by the resource setting <em>ptyInitialErase</em>.</p>

  <h4 id="xterm_erased-id"><a name="xterm_erased" id=
  "xterm_erased">Why did my delete key stop working?</a></h4>

  <p>Well, something changed. You have to determine what did.</p>

  <p>This may be because an upgrade introduced different X resource
  settings, or because you are using the newer xterm with the
  <em>ptyInitialErase</em> resource (or perhaps both). Use</p>

  <blockquote>
    <pre class="code-block">
appres XTerm
</pre>
  </blockquote>

  <p>to see the X resources that you are using, in particular the
  <code>translation</code> (or <code>Translation</code>) resource
  for the vt100 widget.</p>

  <p>One unexpected scenario came out of hiding when I was
  implementing the <em>ptyInitialErase</em> resource. When xterm is
  (by default) built to support this, it sets the pty's erase
  character to match the termcap entry. Xterm also sets the
  $TERMCAP environment variable to match. So everything is
  consistent, and everything defined. The <code>stty erase</code>
  character is either backspace (^H) or delete (^?).</p>

  <p>The problem arises because there are two things called
  &ldquo;delete&rdquo;, which were not well-defined: ASCII delete
  (127) and the PC-style adaptation of VT220 <kbd>remove</kbd>
  assigned to the key Delete.</p>

  <p>However, the <em>screen</em> program prefers to make the
  termcap delete (<code>kD</code>) an &lt;escape&gt;[3~, which
  corresponds to the VT220 <kbd>remove</kbd> key. If $TERMCAP is
  set when starting <em>screen</em>, it will translate stty's erase
  character into the &lt;escape&gt;[3~, making most curses and
  termcap applications work. But stty still has the original erase
  character. So low-level applications which check stty will not
  work. I found that unsetting $TERMCAP before running would work,
  but this was not a good solution. Someone pointed out (see
  <a href="/xterm/xterm.log.html#xterm_129">patch 129</a>), that
  the problem really was because termcap <code>kD</code> should
  delete the character at the current position. So it cannot be the
  same as <code>stty erase</code>.</p>

  <p>As a matter of fact, <code>stty erase</code> has to be a
  single character, so &lt;escape&gt;[3~ would not work anyway.</p>

  <h4 id="xterm_xmodmap-id"><a name="xterm_xmodmap" id=
  "xterm_xmodmap">Well, how can I set my delete key?</a></h4>

  <p>When people first started asking this question in 1995-1996,
  it appeared in the context of making Netscape work. Netscape's
  use of the delete key running in X did not match user's
  expectations when compared to that other platform. They were
  commonly advised to use <em>xmodmap</em>, e.g.,</p>

  <blockquote>
    <pre class="code-block">
keysym BackSpace = Delete
</pre>
  </blockquote>

  <p>or</p>

  <blockquote>
    <pre class="code-block">
keycode 22 = 0xff08
</pre>
  </blockquote>

  <p>Either way is a bad technical solution &ndash; it works for
  some people but not others (on my keyboard at work, keycode 22 is
  the numeric keypad '9').</p>

  <p>Alternatively, you can set resources. This works reasonably
  well for environments where you have different versions of xterm,
  e.g.,</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">translations</span>:<span class=
    "literal">&nbsp;#override&nbsp;\n\<br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Key&gt;Delete:&nbsp;string(</span><span class="number">0x7f</span><span class="literal">)</span><br>

    <!--atr2html}}--></p>
  </blockquote>

  <p>I do not do that either, because it is not flexible. Not all
  programs use the same sense of <code>stty erase</code>; some use
  termcap or terminfo, and some are hardcoded. So I prefer to be
  able to switch the xterm's keyboard at runtime. You cannot do
  that with resources. (Or not really &ndash; xterm has a
  <code>keymap()</code> action which could support this if you
  provided a rather complex resource settings, but the X library
  support for that is broken in X11R6). Instead, I have added to
  xterm a set of resources (and popup menu entries) to allow simple
  switching between the different styles of keyboard, in particular
  for the backspace/delete issues. See the manual page for
  <code>backarrowKey</code> <code>backarrowKeyIsErase</code> and
  <code>deleteIsDEL</code> as well as <code>sunKeyboard</code>.</p>

  <h4 id="xterm_keypad-id"><a name="xterm_keypad" id=
  "xterm_keypad">Why doesn't my keypad work?</a></h4>

  <p>A few people have commented that the keypad does not work
  properly. Aside from bugs (I have fixed a few), the most common
  problem seems to be misconception.</p>

  <p>Here's a picture of the VT100 numeric keypad:</p>

  <blockquote>
    <pre class="code-block">
+-----+-----+-----+-----+
| PF1 | PF2 | PF3 | PF4 |
+-----+-----+-----+-----+
|  7  |  8  |  9  |  -  |
+-----+-----+-----+-----+
|  4  |  5  |  6  |  ,  |
+-----+-----+-----+-----+
|  1  |  2  |  3  |     |
+-----+-----+-----+ ENT +
|     0     |  .  |     |
+-----+-----+-----+-----+
</pre>
  </blockquote>

  <p>and the similar Sun and PC keypads:</p>

  <blockquote>
    <pre class="code-block">
+-----+-----+-----+-----+
| NUM |  /  |  *  |  -  |
+-----+-----+-----+-----+
|  7  |  8  |  9  |     |
+-----+-----+-----+  +  +
|  4  |  5  |  6  |     |
+-----+-----+-----+-----+
|  1  |  2  |  3  |     |
+-----+-----+-----+ ENT +
|     0     |  .  |     |
+-----+-----+-----+-----+
</pre>
  </blockquote>

  <p>Working in X11, the NUM (NumLock) key has better uses than an
  alias for PF1 (and is sometimes reserved). I use the F1 through
  F4 on the keyboard to implement PF1 through PF4, alias the keypad
  "+" to "," and use the existing "-" key.</p>

  <p>VT220 emulation uses the VT100 numeric keypad as well as a
  6-key editing keypad. Here's a picture of the VT220 editing
  keypad:</p>

  <blockquote>
    <pre class="code-block">
+--------+--------+--------+
| Find   | Insert | Remove |
+--------+--------+--------+
| Select | Prev   | Next   |
+--------+--------+--------+
</pre>
  </blockquote>

  <p>and the similar Sun and PC keypads:</p>

  <blockquote>
    <pre class="code-block">
+--------+--------+--------+
| Insert | Home   | PageUp |
+--------+--------+--------+
| Delete | End    | PageDn |
+--------+--------+--------+
</pre>
  </blockquote>

  <p>I chose to use keys that are mnemonic rather than in the
  &ldquo;same&rdquo; positions, though some emulators (e.g., Tera
  Term) use the same positions:</p>

  <blockquote>
    <pre class="code-block">
+--------+--------+--------+
| Insert | Find   | Prev   |
+--------+--------+--------+
| Remove | Select | Next   |
+--------+--------+--------+
</pre>
  </blockquote>

  <p>I test the keyboard (for VT52/VT100/VT220) using <a href=
  "/vttest/vttest.html">vttest</a>. If you find (or think that you
  have found) a problem with the keyboard handling of xterm, please
  test it with vttest first.</p>

  <p>Other arrangements of the keyboard are possible of course. If
  you prefer to use the top row of the numeric keypad as PF1
  through PF4, you should do this using xterm's X resources.</p>

  <p>In 2014, I noticed <a href=
  "http://www.neilvandyke.org/racket-charterm/">a comment</a>,
  which relates to the PF1-PF4 assignment, but also to the use of
  function-key modifiers.<br>
  Because that is a digression, I have expanded it in a <a href=
  "/xterm/xterm-function-keys.html">separate page</a>.</p>

  <h4 id="xterm_modother-id"><a name="xterm_modother" id=
  "xterm_modother">How can my program distinguish control-I from
  tab?</a></h4>

  <p>Your program can use xterm's <a href=
  "manpage/xterm.html#VT100-Widget-Resources:modifyOtherKeys">modifyOtherKeys</a>
  feature, e.g., using a <a name=
  "h4-Functions-using-CSI-_-ordered-by-the-final-character-lparen-s-rparen:CSI-gt-Pp;Pv-m.1EB3"
  id=
  "h4-Functions-using-CSI-_-ordered-by-the-final-character-lparen-s-rparen:CSI-gt-Pp;Pv-m.1EB3">
  control sequence</a> such as</p>

  <blockquote>
    <pre class="code-block">
\033 [ &gt; 4 ; 2 m
</pre>
  </blockquote>

  <p>to temporarily switch into a mode where shift, alt, control
  and meta modifiers applied to a key tell xterm to send an escape
  sequence which encodes all of that information. The <tt>tab</tt>
  key would send a <em>tab</em>, but
  <em>control-<strong>i</strong></em> would send</p>

  <blockquote>
    <pre class="code-block">
\033 [ 2 7 ; 5 ; 1 0 5 ~
</pre>
  </blockquote>

  <p>while <em>control-shift-<strong>i</strong></em> would send</p>

  <blockquote>
    <pre class="code-block">
\033 [ 2 7 ; 6 ; 7 3 ~
</pre>
  </blockquote>

  <p>Your program should turn that off when it is not needed; it is
  a real nuisance when you cannot type control-characters as they
  were meant to be used:</p>

  <blockquote>
    <pre class="code-block">
\033 [ &gt; 4 m
</pre>
  </blockquote>

  <p>In 2019, Bram Moolenaar asked for more details about modifying
  <em>other keys</em>; I have expanded that in a <a href=
  "/xterm/modified-keys.html">separate page</a>.</p>

  <h4 id="xterm_pageup-id"><a name="xterm_pageup" id=
  "xterm_pageup">Why can't I use the pageup/pagedown keys?</a></h4>

  <p>Some vendors, e.g,. Sun, added key translations which make the
  pageup and pagedown keys talk to the xterm's scrollbar instead of
  your application. They did the same thing for the home and end
  keys, thereby obscuring a bug in <a href=
  "xterm.faq.html#bug_xterm_r6">xterm</a>.</p>

  <p>You can override this by specifying your own translations in
  your resource file. The issue was first noted with Solaris 2.5,
  with the file given in two locations:</p>

  <blockquote>
    <pre class="code-block">
/usr/lib/X11/app-defaults/XTerm
/usr/openwin/lib/app-defaults
</pre>
  </blockquote>

  <p>using a symbolic link to relate the two. Later releases of
  Solaris, e.g., 8-10 omitted the former location.<br>
  Solaris 11 provides modern xterm (<a href=
  "/xterm/xterm.log.html#xterm_271">patch #271</a>), and does not
  have this problem.</p>

  <p>As of February 2014, I was able to verify that AIX and HPUX
  have updated to modern xterm, e.g.,</p>

  <ul>
    <li>
      <p><a href="/xterm/xterm.log.html#xterm_180">patch #180</a>
      on HPUX 11.31,</p>
    </li>

    <li>
      <p><a href="/xterm/xterm.log.html#xterm_222">patch #222</a>
      on AIX 6.1 and 7.1,</p>
    </li>
  </ul>

  <p>Older AIX and HPUX releases distributed the X Consortium
  (1994) app-defaults file.</p>

  <blockquote>
    <p style="font-variant:small-caps">In updating this question in
    February 2014, I noticed that IBM added their copyright notice
    in AIX's copy of the app-defaults file in</p>

    <blockquote>
      <pre class="code-block">
/usr/lpp/X11/lib/X11/app-defaults
</pre>
    </blockquote>

    <p style="font-variant:small-caps">There were no other changes
    to the file. Someone at IBM blundered.<br>
    In patch #252, I ensured that my copyright notice is on those
    files (I am the sole author, and can do that).</p>
  </blockquote>

  <p>Use the translations in the system's app-defaults file as a
  guide. The relevant section of the app-default file looks
  like</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    *<span class="keyword">VT100</span>.<span class=
    "ident2">translations</span>:<span class=
    "literal">&nbsp;&nbsp;&nbsp;&nbsp;#override&nbsp;\<br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Num_Lock</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_0:&nbsp;string(</span><span class="number">0</span><span class="literal">)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Num_Lock</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_1:&nbsp;string(</span><span class="number">1</span><span class="literal">)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Num_Lock</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_2:&nbsp;string(</span><span class="number">2</span><span class="literal">)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Num_Lock</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_3:&nbsp;string(</span><span class="number">3</span><span class="literal">)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Num_Lock</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_4:&nbsp;string(</span><span class="number">4</span><span class="literal">)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Num_Lock</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_5:&nbsp;string(</span><span class="number">5</span><span class="literal">)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Num_Lock</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_6:&nbsp;string(</span><span class="number">6</span><span class="literal">)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Num_Lock</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_7:&nbsp;string(</span><span class="number">7</span><span class="literal">)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Num_Lock</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_8:&nbsp;string(</span><span class="number">8</span><span class="literal">)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Num_Lock</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_9:&nbsp;string(</span><span class="number">9</span><span class="literal">)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Num_Lock</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_Add:&nbsp;string(+)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Num_Lock</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_Decimal:&nbsp;string(.)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Num_Lock</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_Divide:&nbsp;string(/)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Num_Lock</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_Enter:&nbsp;string(\015)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Num_Lock</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_Equal:&nbsp;string(=)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Num_Lock</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_Multiply:&nbsp;string(*)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;@Num_Lock</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_Subtract:&nbsp;string(-)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Prior:scroll-back(</span><span class="number">1</span><span class="literal">,page)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Next:scroll-forw(</span><span class="number">1</span><span class="literal">,page)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">F16:&nbsp;start-extend()&nbsp;select-end(PRIMARY,&nbsp;CUT_BUFFER0,&nbsp;CLIPBOARD)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">F18:&nbsp;insert-selection(PRIMARY,&nbsp;CLIPBOARD)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">F27:&nbsp;scroll-back(</span><span class="number">100</span><span class="literal">,page)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">R13:&nbsp;scroll-forw(</span><span class="number">100</span><span class="literal">,page)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Home:&nbsp;scroll-back(</span><span class="number">100</span><span class="literal">,page)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">End:&nbsp;scroll-forw(</span><span class="number">100</span><span class="literal">,page)&nbsp;\n</span><br>

    <!--atr2html}}--></p>
  </blockquote>

  <p>For example, a more-specific pattern for the resource name
  lets you override:</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">translations</span>:<span class=
    "literal">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;#override&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Home:&nbsp;&nbsp;string(\033[</span><span class="number">1</span><span class="literal">~)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift</span><span class="keyword">&lt;Key&gt;</span><span class="literal">End:&nbsp;&nbsp;&nbsp;string(\033[</span><span class="number">4</span><span class="literal">~)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Prior:&nbsp;string(\033[</span><span class="number">5</span><span class="literal">~)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Next:&nbsp;&nbsp;string(\033[</span><span class="number">6</span><span class="literal">~)\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Prior:&nbsp;&nbsp;scroll-back(</span><span class="number">1</span><span class="literal">,page)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Next:&nbsp;&nbsp;&nbsp;scroll-forw(</span><span class="number">1</span><span class="literal">,page)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift</span><span class="keyword">&lt;Key&gt;</span><span class="literal">Home:&nbsp;&nbsp;&nbsp;scroll-back(</span><span class="number">100</span><span class="literal">,page)&nbsp;\n\<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift</span><span class="keyword">&lt;Key&gt;</span><span class="literal">End:&nbsp;&nbsp;&nbsp;&nbsp;scroll-forw(</span><span class="number">100</span><span class="literal">,page)&nbsp;\n</span><br>

    <!--atr2html}}--></p>
  </blockquote>

  <p>makes the home/end and pageup/pagedown keys usable by your
  editor, while leaving their shifted equivalents available for the
  scrollbar.</p>

  <h4 id="xterm_pc_style-id"><a name="xterm_pc_style" id=
  "xterm_pc_style">Why can't I use the home/end keys?</a></h4>

  <p>This is a long story, unless you are referring to X Consortium
  <a href="#bug_xterm_r6">xterm</a>. That program is simply broken
  in this respect.</p>

  <p>At the beginning, when the home/end keys were fixed for modern
  xterm (in early 1996), there was some discussion regarding what
  the escape sequences should be for those keys (for the 6-key
  editing keypad). Those were chosen as "PC-style" codes (like SCO
  &ldquo;ansi&rdquo;), i.e.,</p>

  <blockquote>
    <pre class="code-block">
ESC [ H
ESC [ F
</pre>
  </blockquote>

  <p>for normal mode, and</p>

  <blockquote>
    <pre class="code-block">
ESC O H
ESC O F
</pre>
  </blockquote>

  <p>for cursor application mode.</p>

  <p>That style of coding fit easily into the existing logic of
  xterm. It was not my change, and (because xterm should be based
  upon standards), I did question this, and asked the opinion of
  the person who was at that time developing rxvt. He had chosen a
  layout based on DEC's VT220 terminals, though the key labels on
  the typical PC keyboard did not <a href=
  "xterm.faq.html#xterm_keypad">match</a>. At that point, neither
  of us knew enough to make a good case for this.</p>

  <p>Somewhat later I could see that xterm had a number of
  undocumented extensions to support the VT220-style (pre-ISO 2022)
  character sets. I decided to complete the functionality by making
  xterm a VT220 emulator. This would require that it provide the
  same escape sequences for the editing and numeric keypads. I
  could not simply change the escape sequences from "PC-style" to
  "VT220-style", since a number of users &ldquo;knew&rdquo; that
  the keypad "ought to" send home, end, cursor keys, etc., because
  they had labels indicating that use. To retain compatibility (but
  allow easy reconfiguration to make a VT220 emulator), I added
  popup-menu items to switch between the modes. With minor
  refinements, this was the approach for about two years,
  culminating with the <a href=
  "/xterm/xterm.log.html#xterm_88">&ldquo;stable&rdquo; patch
  #88</a>, which is essentially the version distributed with
  XFree86 3.3.x.</p>

  <dl>
    <dt><em>NOTE</em>:</dt>

    <dd>
      the terminfo distributed with xterm patch #88 is incorrect:
      the escape sequences given for home/end keys are the
      VT220-style, rather than the default PC-style. Too accustomed
      to switching modes on the fly, I overlooked a line in my
      .Xdefaults file:
      <blockquote class="code-block">
        <!--{{atr2html-->

        <p style="font-family: monospace; font-size: 10pt;">
        *<span class="ident2">sunKeyboard</span>:<span class=
        "literal">&nbsp;</span><span class=
        "keyword">true</span><br>
        <!--atr2html}}--></p>
      </blockquote>

      <p>Downstream packagers (when they noticed this) accommodated
      the bug by modifying the VT100 translations resource which is
      not a good technical solution since it interferes with the
      users' ability to modify that resource. For example, Red Hat
      bug <a href=
      "https://bugzilla.redhat.com/show_bug.cgi?id=100695">#100695</a>
      quoted a suggested <a href=
      "https://bugzilla.redhat.com/attachment.cgi?id=93107&amp;action=diff">
      patch</a> which shows that the package had overridden the
      xterm behavior for shifted function keys. See <a href=
      "xterm.faq.html#xterm_xmodmap">this</a> for more
      discussion.</p>
    </dd>
  </dl>

  <p>But xterm continues to evolve past the stable patch #88. The
  keyboard support was still unsatisfactory for two reasons:</p>

  <ul>
    <li>
      <p>some users wanted to be able to use applications that
      detected whether the control key was pressed (e.g.,
      control/F1).</p>
    </li>

    <li>
      <p>the compromises made for <code>xkb</code> with X11R6
      interfered with xterm's use of the NumLock key for the
      numeric keypad.</p>
    </li>
  </ul>

  <p>The former could be addressed by expanding the escape
  sequences sent by the PC-style function keys, while the latter
  was a VT100/VT220 design issue. I decided to redesign
  function-key support to separate the two styles of function keys
  better, but leaving the choice still controlled by the
  <code>sunKeyboard</code> resource. Partway through that, I was
  asked to do similar cleanup and redesign of the backspace and
  delete key handling, e.g., the <a href=
  "xterm.faq.html#xterm_erased">ptyInitialErase</a> resource.
  Because it is a redesign, I chose to not make the keyboard
  differences between the old and new xterms completely compatible.
  If you were to run both on the same system, one or the other
  would have some problems with the editing keypad or the
  backspace/delete keys which would be addressed by the popup-menu
  selections.</p>

  <p>For example, at this time (2001/9/4):</p>

  <ul>
    <li>
      <p>Debian stable is xterm-88c, which should be identical to
      the XFree86 3.3.6 version, but is not (there are some label
      differences in the resource-file, but nothing interesting
      relative to home/end keys). And of course, Debian changes the
      terminfo <code>kbs</code> from <code>^H</code> to
      <code>^?</code>. As noted, the terminfo I wrote for XFree86
      3.3.x has an error. Setting</p>

      <blockquote class="code-block">
        <!--{{atr2html-->

        <p style="font-family: monospace; font-size: 10pt;">
        *<span class="ident2">sunKeyboard</span>:<span class=
        "literal">&nbsp;</span><span class=
        "keyword">true</span><br>
        <!--atr2html}}--></p>
      </blockquote>

      <p>in the app-defaults file fixes the problem with xterm-88,
      which was that I documented in the terminfo the behavior
      <em>with</em> that resource set. Similarly, setting</p>

      <blockquote class="code-block">
        <!--{{atr2html-->

        <p style="font-family: monospace; font-size: 10pt;">
        *<span class="ident2">backarrowKey</span>:<span class=
        "literal">&nbsp;</span><span class=
        "keyword">false</span><br>
        <!--atr2html}}--></p>
      </blockquote>

      <p>is one way to address Debian's change to
      <code>kbs</code>.</p>
    </li>

    <li>
      <p>Debian unstable is xterm-149. Other than omitting the
      color resources from the app-defaults file, I see that it
      sets</p>

      <blockquote class="code-block">
        <!--{{atr2html-->

        <p style="font-family: monospace; font-size: 10pt;">
        *<span class=
        "ident2">backarrowKeyIsErase</span>:<span class=
        "literal">&nbsp;</span><span class=
        "keyword">true</span><br>
        <!--atr2html}}--></p>
      </blockquote>

      <p>which would not affect the home/end keys. (The color
      resources are redundant, so that is not a problem
      either).</p>
    </li>
  </ul>

  <p><a href="/xterm/XTerm-debian-88c">Here is a resource file</a>
  which I tested with xterm-88c, xterm-149 and xterm-158, using
  $TERM set to xterm-debian:</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    <span class="comment">!&nbsp;$Id: xterm.faq.html,v 1.169
    2012/02/05 11:58:56 tom Exp $<br></span><span class=
    "comment">!&nbsp;Settings&nbsp;to&nbsp;make&nbsp;xterm-88c&nbsp;work&nbsp;as&nbsp;expected&nbsp;for&nbsp;Debian.<br>
    </span> <span class="comment">!<br></span><span class=
    "comment">!&nbsp;Patch&nbsp;#88&nbsp;was&nbsp;the&nbsp;basis&nbsp;for&nbsp;XFree86&nbsp;3.3.1&nbsp;xterm.&nbsp;&nbsp;There&nbsp;were&nbsp;a&nbsp;few&nbsp;additions<br>
    </span> <span class=
    "comment">!&nbsp;through&nbsp;patch&nbsp;88c,&nbsp;to&nbsp;incorporate&nbsp;the&nbsp;ptyInitialErase&nbsp;resource.&nbsp;&nbsp;Debian&nbsp;uses<br>
    </span> <span class=
    "comment">!&nbsp;the&nbsp;VT220-style&nbsp;keyboard,&nbsp;which&nbsp;at&nbsp;#88&nbsp;was&nbsp;the&nbsp;xterm-xfree86&nbsp;terminfo&nbsp;entry,<br>
    </span> <span class=
    "comment">!&nbsp;with&nbsp;one&nbsp;change:&nbsp;kbs&nbsp;changed&nbsp;from&nbsp;^H&nbsp;to&nbsp;^?.<br>
    </span> <span class="comment">!<br></span><span class=
    "comment">!&nbsp;After&nbsp;patch&nbsp;88,&nbsp;I&nbsp;started&nbsp;work&nbsp;on&nbsp;keyboard&nbsp;changes.&nbsp;&nbsp;The&nbsp;result&nbsp;was&nbsp;that&nbsp;the<br>
    </span> <span class=
    "comment">!&nbsp;xterm-xfree86&nbsp;terminfo&nbsp;entry&nbsp;was&nbsp;set&nbsp;to&nbsp;the&nbsp;PC-style&nbsp;keyboard,&nbsp;and&nbsp;I&nbsp;added<br>
    </span> <span class=
    "comment">!&nbsp;xterm-vt220,&nbsp;which&nbsp;corresponded&nbsp;mostly&nbsp;to&nbsp;the&nbsp;older&nbsp;(patch-88)&nbsp;version&nbsp;of&nbsp;the<br>
    </span> <span class=
    "comment">!&nbsp;xterm-xfree86&nbsp;terminfo&nbsp;entry.<br></span>&nbsp;<br>

    <span class=
    "comment">!&nbsp;The&nbsp;terminfo&nbsp;with&nbsp;patch&nbsp;#88&nbsp;assumed&nbsp;sunKeyboard&nbsp;was&nbsp;set&nbsp;(actually&nbsp;a&nbsp;bug,&nbsp;but<br>
    </span> <span class=
    "comment">!&nbsp;also&nbsp;assumed&nbsp;in&nbsp;Debian).<br></span><span class="comment">!<br>
    </span> <span class=
    "comment">!&nbsp;A&nbsp;different&nbsp;problem&nbsp;(addressed&nbsp;after&nbsp;patch&nbsp;#88)&nbsp;is&nbsp;that&nbsp;if&nbsp;you&nbsp;wanted&nbsp;to&nbsp;use<br>
    </span> <span class=
    "comment">!&nbsp;a&nbsp;VT100/VT220-style&nbsp;numeric&nbsp;keypad's&nbsp;escape&nbsp;sequences,&nbsp;you&nbsp;had&nbsp;to&nbsp;have<br>
    </span> <span class=
    "comment">!&nbsp;NumLock&nbsp;set.&nbsp;&nbsp;Otherwise,&nbsp;in&nbsp;keypad&nbsp;application&nbsp;mode,&nbsp;the&nbsp;keys&nbsp;would&nbsp;transmit<br>
    </span> <span class=
    "comment">!&nbsp;only&nbsp;the&nbsp;PC-style&nbsp;escape&nbsp;sequences&nbsp;corresponding&nbsp;to&nbsp;the&nbsp;key&nbsp;labels,&nbsp;e.g.,&nbsp;the<br>
    </span> <span class=
    "comment">!&nbsp;page-up&nbsp;string&nbsp;rather&nbsp;than&nbsp;the&nbsp;escape&nbsp;sequence&nbsp;for&nbsp;keypad-9.<br>
    </span> <span class="keyword">XTerm</span>*<span class=
    "ident2">sunKeyboard</span>:<span class=
    "literal">&nbsp;</span><span class="keyword">true</span><br>
    &nbsp;<br>
    <span class=
    "comment">!&nbsp;These&nbsp;settings&nbsp;overlap&nbsp;to&nbsp;some&nbsp;extent&nbsp;(backarrowKeys&nbsp;says&nbsp;to&nbsp;send&nbsp;a&nbsp;127&nbsp;for<br>
    </span> <span class=
    "comment">!&nbsp;the&nbsp;"backspace"&nbsp;key,&nbsp;and&nbsp;ptyInitialErase&nbsp;says&nbsp;to&nbsp;use&nbsp;the&nbsp;pty's&nbsp;initial&nbsp;sense<br>
    </span> <span class=
    "comment">!&nbsp;of&nbsp;the&nbsp;erase&nbsp;character,&nbsp;which&nbsp;is&nbsp;reported&nbsp;to&nbsp;be&nbsp;the&nbsp;same&nbsp;on&nbsp;Linux).<br>
    </span> <span class="keyword">XTerm</span>*<span class=
    "ident2">backarrowKey</span>:<span class=
    "literal">&nbsp;</span><span class="keyword">false</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "ident2">ptyInitialErase</span>:<span class=
    "literal">&nbsp;</span><span class="keyword">true</span><br>
    <!--atr2html}}--></p>
  </blockquote>

  <h4 id="xterm_arrows-id"><a name="xterm_arrows" id=
  "xterm_arrows">Why can't I use the cursor keys in (whatever)
  shell?</a></h4>

  <p>VTxxx (VT100 and up) terminals may send different escape
  sequences for the cursor (arrow) keys depending on how they are
  set up. The choices are referred to as the normal and application
  modes. Initially, the terminal is in normal mode.</p>

  <p>VTxxx terminals are usually set up so that full-screen
  applications will use the cursor application mode strings. This
  is good for full-screen applications, including legacy
  applications which may have hard-coded behavior, but bad for
  interactive shells (e.g., ksh, tcsh, bash) which use arrow keys
  to scroll through a history of command strings.</p>

  <p>To see the difference between normal/application modes,
  consider this example:</p>

  <ul>
    <li>
      <p>In normal (non-application) mode, the terminal transmits a
      down-arrow as \E[C, which happens to echo as a
      down-arrow.</p>
    </li>

    <li>
      <p>In application mode the terminal transmits \EOC, which
      echoes as C. That is because the \EO is the SS3 control,
      which says to use the character from the G3 character set for
      the next cell.</p>
    </li>
  </ul>

  <p>Since termcaps and terminfo descriptions are written for
  full-screen applications, shells and similar programs often rely
  on built-in tables of escape sequences which they use instead.
  Defining keys in terms of the termcap/terminfo entry (e.g., by
  capturing the string sent by tputs) is apt to confuse the
  shell.</p>

  <p>Depending on the terminal type, the keypad(s) on the keyboard
  may switch modes along with the cursor keys, or have their own
  independent modes. The control sequences for these are
  independent of the ones used for cursor-addressing, but are
  grouped together, e.g., as the terminfo <code>smkx</code> and
  <code>rmkx</code> capabilities. Terminfo entries are written
  assuming that the application has initialized the terminal using
  the <code>smkx</code> string before it is able to match the codes
  given for the cursor or keypad keys.</p>

  <h4 id="bash_meta_mode-id"><a name="bash_meta_mode" id=
  "bash_meta_mode">Alt-keys do not work in bash</a></h4>

  <p>See <a href=
  "/ncurses/ncurses.faq.html#bash_meta_mode">Alt-keys do not work
  in bash</a>.</p>

  <h3 id="problems_colors-id"><a name="problems_colors" id=
  "problems_colors">Colors and other graphic rendition</a></h3>

  <h4 id="no_color-id"><a name="no_color" id="no_color">My terminal
  doesn't recognize color</a></h4>

  <p>First, ensure that you have set up xterm to render color.
  Modern xterm renders color only if you have set resources to do
  this; the default behavior is monochrome to maintain
  compatibility with older applications. The manual page describes
  these resources. I set them in my <a href=
  "xterm.faq.html#my_xdefaults">.Xdefaults</a> file.</p>

  <p>Even if you set the resources properly, there may be another
  application running which prevents xterm from allocating the
  colors you have specified. But you should see a <a href=
  "xterm.faq.html#alloc_color">warning message</a> for this.</p>

  <p>Check the terminal description, to see if it is installed
  properly, e.g., for <a href=
  "/ncurses/ncurses.faq.html#no_color">ncurses</a>, which uses
  terminfo.</p>

  <p>Finally, some applications (that do not interface properly
  with terminfo or termcap) may need the environment variable
  <a href="/ncurses/ncurses.faq.html#no_colorterm">$COLORTERM</a>
  to be set.</p>

  <h4 id="xterm_terminfo-id"><a name="xterm_terminfo" id=
  "xterm_terminfo">What $TERM should I use?</a></h4>

  <p><strong>XTerm</strong> provides in its sources both <a href=
  "terminfo.html">terminfo</a> and <a href=
  "termcap.html">termcap</a> files. They are designed to allow
  scripting to override the most common choices, e.g., the
  backspace key.</p>

  <p>The <code>xterm-color</code> value for $TERM is a bad choice
  for modern xterm because it is commonly used for a terminfo entry
  which happens to not support <code>bce</code>. Complicating
  matters, FreeBSD (after dithering for a few years on the matter)
  introduced a bastardized version which implies the opposite sense
  of <code>bce</code>, (because it uses SGR 39 and 49), but does
  not set it. After lengthy discussion, FreeBSD began using the
  terminal descriptions which I've written.</p>

  <p>The most recent XFree86 version's terminal description
  corresponds to <code>xterm-xfree86</code> (also distributed with
  ncurses). I have continued to make changes; the most recent
  version is simply named <code>xterm-new</code> (also distributed
  with ncurses).</p>

  <p>The term "<code>bce</code>" stands for "back color erase".
  Terminals such as modern xterm and rxvt implement back color
  erase, others such as dtterm do not. (Roughly half of the
  emulators that I know about implement bce). When an application
  clears the screen, a terminal that implements back color erase
  will retain the last-set background color. A terminal that does
  not implement back color erase will reset the background color to
  the default or initial colors. Applications that paint most of
  the screen in a single color are more efficient on terminals that
  support back color erase. Inevitably, there are tradeoffs and
  issues with standardization of the feature as noted in the
  <a href="/ncurses/ncurses.faq.html#bce_mismatches">ncurses
  FAQ</a>. Unsurprisingly, ncurses supports xterm's behavior.</p>

  <p>Curses libraries that support color know about
  <code>bce</code> and do the right thing &ndash; provided that you
  tell them what the terminal does. That is the whole point of
  setting $TERM. The "xterm-color" description distributed with
  ncurses does not list <code>bce</code>, because it was applied
  originally to a terminal type which does not implement back color
  erase. It will &ldquo;work&rdquo; for modern xterm, though less
  efficient. Some other applications such as the slang library have
  hardcoded support for terminals that implement back color erase.
  Given the "xterm-color" description, those will be efficient
  &ndash; and fortuitously work. However, slang (through version
  1.4.0) did not work properly for the terminals that xterm-color
  was designed for. See this <a href=
  "/lynx/lynx-ncurses.html">page</a> for an example of (n)curses
  and slang running on dtterm. That bug in slang is reported to be
  fixed for succeeding versions, though your application may
  require changes to use this fix. (The demo which comes with slang
  to illustrate the use of <code>bce</code> does not work properly,
  for instance).</p>

  <p>The <code>xterm-color</code> value for $TERM is also (for the
  same reason) a bad choice for rxvt, but &ldquo;works&rdquo; due
  to the large number of hard-coded applications that override
  this.</p>

  <p>Some people recommend using <a href=
  "/ncurses/terminfo.src.html#tic-xtermc"><code>xtermc</code></a>.
  That is installed on Solaris. However, it does not match any
  xterm in current use. (Apparently it was written for an obsolete
  version on Unixware). The colors work, true, but the mouse will
  not, nor will the function keys.</p>

  <h4 id="xterm_hilite-id"><a name="xterm_hilite" id=
  "xterm_hilite">Reverse video is not reset</a></h4>

  <p>When running <em>less</em> or other programs that do
  highlighting, you see the highlighting not turned off
  properly.</p>

  <p>This may be due to incompatible terminal descriptions for
  xterm. With XFree86 3.2, I modified the terminal description for
  XFree86 xterm to use the VT220 (aka ISO 6429) controls that allow
  an application to turn off highlighting (or bold, underline)
  without modifying the other attributes. The X Consortium xterm
  does not recognize these controls.</p>

  <p>If, for example, you are running an older xterm and rlogin to
  a system where the newer xterm has been installed, you will have
  this problem, because both programs default to $TERM set to
  xterm. The solution for mixed systems is to install the newer
  terminal description as as a different name (e.g.,
  <code>xterm-color</code>) and set the <code>termName</code>
  resource accordingly in the app-defaults file for the system
  which has the newer xterm.</p>

  <p>However &ndash; see <a href=
  "xterm.faq.html#xterm_terminfo">above</a>.</p>

  <h4 id="vim_16colors-id"><a name="vim_16colors" id=
  "vim_16colors">My colors changed in vim</a></h4>

  <p>Some <code>vim</code> users may notice their colors change
  after updating to <a href="/xterm/xterm.log.html#xterm_238">patch
  238</a>. Before, some text would display in a dark color using a
  bold font. Now, it displays in a bright color and normal
  font.</p>

  <p>This is not a bug, but the result of a feature
  <em>tcap-query</em> which was added for vim in 2000. Several vim
  users requested that it be enabled by default in the configure
  script. It allows vim to ask what characters the different
  function keys actually send, eliminating the chance that the
  termcap does not match.</p>

  <p>Vim also asks how many colors the terminal supports. Since
  <a href="/xterm/xterm.log.html#xterm_148">patch 148</a>, xterm
  has responded with the number of distinct colors that it can
  display. By default, that is 16 (8 ANSI colors with bright
  counterparts for displaying PC-style &ldquo;bold&rdquo;
  text).</p>

  <p>The interpretation of this depends on the application:
  termcaps do not tell how to display more than 8 colors. But vim
  understands how to tell xterm to display using 16 colors. It
  makes a difference when displaying bright colors. Vim has a table
  of 16 color names ("dos-colors"), which one can use to define
  parts of the color scheme. If the terminal supports only 8 colors
  (colors 0-7), vim uses the bold attribute to simulate colors
  8-15.</p>

  <p>Changing the color scheme to use bold where it is wanted will
  make the colors work as before &ndash; and work consistently with
  other terminals.</p>

  <h4 id="bold_vs_16colors-id"><a name="bold_vs_16colors" id=
  "bold_vs_16colors">Aren't bright colors the same as bold?</a></h4>

  <p>No.</p>

  <p>Actually, &ldquo;bold&rdquo; happens to be whatever the
  terminal shows when it is sent the control-string that says "show
  bold".</p>

  <p>The standard (ANSI aka ISO-6429 or ECMA-48) says no more than
  that. ANSI specified eight (8) colors. In fact, ANSI did not
  specify the appearance. That is an implementation detail.</p>

  <p>XTerm can be configured to use colors 8-15 for displaying bold
  text. Or it can be configured to use those colors as part of a
  16-color scheme (a feature of aixterm). They use different
  control strings. When xterm is configured to use the 16-color
  scheme, it displays bold text by relying on the font to show
  &ldquo;bold&rdquo; (usually thicker characters).</p>

  <p>By default, colors 8-15 are brighter versions of colors 0-7
  (with some special handling for blue). But again, xterm is
  configurable and you can use anything that you like for the
  numbered colors.</p>

  <h4 id="color_by_number-id"><a name="color_by_number" id=
  "color_by_number">Can I set a color by its number?</a></h4>

  <p>Well, yes: you can set a color in several ways:</p>

  <ul>
    <li>
      <p>using the color <em>name</em></p>
    </li>

    <li>
      <p>using an RGB <em>value</em></p>
    </li>

    <li>
      <p>selecting an <em>index</em> from the color palette</p>
    </li>
  </ul>

  <p>That last (an <em>index</em>) is what some people think of as
  the <em>color number</em>. The short answer is that you can find
  on the web tables of colors and match them up to the &ldquo;color
  number&rdquo;. But the number itself has no meaning.</p>

  <p>In my reply to <em><a href=
  "http://unix.stackexchange.com/questions/269077/tput-setaf-color-table-how-to-determine-color-codes">
  tput setaf color table? How to determine color codes?</a></em>, I
  noted</p>

  <blockquote>
    <p>You may find this question/answer helpful as well:
    <em><a href=
    "https://stackoverflow.com/questions/27159322/rgb-values-of-the-colors-in-the-ansi-extended-colors-index-17-255">
    RGB values of the colors in the Ansi extended colors index
    (17-255)</a></em></p>
  </blockquote>

  <p>although both question and answer raise additional questions.
  This FAQ is the logical place to answer those questions.</p>

  <p>Presumably you are reading this to better understand how xterm
  works. But you may be interested in the way in which other
  terminals emulate xterm. If so, this explanation may help as
  well.</p>

  <p>The long answer is that the correct mapping depends on the
  terminal &mdash; other terminals do not necessarily match
  xterm.</p>

  <p>From a shell script, you might use <a href=
  "/ncurses/man/tput.1.html">tput</a> with a parameter to an escape
  sequence referred to as <code>setaf</code> in the terminal
  description. <code>tput</code> attaches no particular meaning to
  the number. That actually depends upon the particular terminal
  emulator.</p>

  <p>A while back, ANSI defined codes for 8 colors, and there were
  two schemes for numbering those. The two are seen in some
  terminal descriptions as the pairs <code>setf/setb</code> or
  <code>setaf/setab</code>. Since the latter has the connotation of
  "ANSI colors", you will see that used more often. The former
  (<code>setf/setb</code>) switched the order for red/blue as noted
  in <em><a href=
  "/ncurses/ncurses.faq.html#interchanged_colors">Why are red/blue
  interchanged?</a></em>, but in either case, the scheme was
  established for just numbering the colors. There is no predefined
  relationship between those numbers and RGB content.</p>

  <p>For specific terminal emulators, there are predefined color
  palettes which can be enumerated easily enough &mdash; and can be
  programmed using these escape sequences. There are no relevant
  standards, and you will see differences between terminal
  emulators, as noted in <em><a href="#dont_like_blue">I don't like
  that shade of blue</a></em>.</p>

  <p>However, convention is often confused with standards. Because
  xterm has been around a while, it is regarded as a standard by
  some.</p>

  <p>XTerm had color support before I began working on it at the
  <a href="/xterm/xterm.html#history">end of 1995</a>. Some of this
  was mentioned in XFree86's changelog:</p>

  <blockquote>
    <pre class="code-block">
XFree86 3.1.2Be (10 January 1996)
203. Major xterm cleanup (including prototyping), and fixes to the colour
     code (Thomas E. Dickey).
XFree86 3.1.2a (23 September 1995)
 14. Colour support for xterm (David Wexelblat).
 13. Fix usage of $LINES and $COLUMNS by xterm on SVR4 (David Wexelblat).
</pre>
  </blockquote>

  <p>and some was not:</p>

  <ul>
    <li>
      <p>The &ldquo;dynamic colors&rdquo; feature came from a patch
      written by Erik Fortune (at SGI). Someone applied this to the
      XFree86 sources (probably early 1995).</p>

      <p>Since X11R4, xterm had colors for foreground and
      background in the VT100 and Tek4014 widgets, as well as
      cursor- and mouse-colors which could be set via resources.
      But those were <em>static</em>. The <em>dynamic colors</em>
      feature allowed those colors to be set via escape
      sequences.</p>
    </li>

    <li>
      <p>&ldquo;Colour support&rdquo; was a set of changes for ANSI
      color. It might have been based on a patch (said to be of
      unknown authorship) for X11R5 xterm incorporated into a
      program called <em>color_xterm</em>. Raymond's <a href=
      "/ncurses/terminfo.src.html#tic-color_xterm">comment</a> in
      terminfo.src implies that this program was distributed
      earlier; however the copy of <code>color_xterm-alpha4</code>
      which I have at hand has file modification dates starting in
      December 1995. Wexelblat's commit is an earlier
      <em>non-patch</em> use of the feature for xterm.</p>

      <p>Both were probably due to Tom Weinstein (also at SGI) in
      1992, which you can find in the <a href=
      "http://www.ibiblio.org/pub/historic-linux/ftp-archives/tsx-11.mit.edu/Oct-07-1996/sources/usr.bin.X11/">
      historic Linux</a> archive. The <code>README.color</code>
      file in this earlier <a href=
      "http://www.ibiblio.org/pub/historic-linux/ftp-archives/tsx-11.mit.edu/Oct-07-1996/sources/usr.bin.X11/color_xterm.tar.gz">
      color_xterm</a> says</p>

      <blockquote>
        <pre class="code-block">
2) Added ISO 6429 support for color text.  You can set the foreground
   and background color for text using SGR.  For example, to make the
   foreground red, you do:  "^[[31m".  The values from 30 to 37 set
   foreground, those from 40 to 47 set background.  The default colors
   are:
        0) black   1) red   2) green  3) yellow  4) blue  5) magenta
        6) cyan    7) white

   These are settable with the resources "color0" to "color1"
</pre>
      </blockquote>

      <p>Aside from <code>README.color</code>, there was no
      documentation. The terminal description was unmodified.</p>
    </li>
  </ul>

  <p>Thus, from the start there were two types of color support in
  xterm. ANSI colors treats the available colors as an array (its
  palette) which can be programmed, while dynamic colors applies a
  single color to a feature.</p>

  <p id="ANSI_colors_before_and_now">There have been some changes
  since the <em>color_xterm</em> in 1992:</p>

  <blockquote>
    <table border="1" summary="ANSI colors before and now">
      <tr>
        <th>Resource</th>
        <th>1992</th>
        <th>1995</th>
        <th>2016</th>
      </tr>

      <tr>
        <td><code>color0</code>
        </td>
        <td><code>Black</code>
        </td>
        <td><code>black</code>
        </td>
        <td><code>black</code>
        </td>
      </tr>

      <tr>
        <td><code>color1</code>
        </td>
        <td><code>Red</code>
        </td>
        <td><code>red3</code>
        </td>
        <td><code>red3</code>
        </td>
      </tr>

      <tr>
        <td><code>color2</code>
        </td>
        <td><code>Green</code>
        </td>
        <td><code>green3</code>
        </td>
        <td><code>green3</code>
        </td>
      </tr>

      <tr>
        <td><code>color3</code>
        </td>
        <td><code>Yellow</code>
        </td>
        <td><code>yellow3</code>
        </td>
        <td><code>yellow3</code>
        </td>
      </tr>

      <tr>
        <td><code>color4</code>
        </td>
        <td><code>Blue</code>
        </td>
        <td><code>blue3</code>
        </td>
        <td><code>blue2</code>
        </td>
      </tr>

      <tr>
        <td><code>color5</code>
        </td>
        <td><code>Magenta</code>
        </td>
        <td><code>magenta3</code>
        </td>
        <td><code>magenta3</code>
        </td>
      </tr>

      <tr>
        <td><code>color6</code>
        </td>
        <td><code>Cyan</code>
        </td>
        <td><code>cyan3</code>
        </td>
        <td><code>cyan3</code>
        </td>
      </tr>

      <tr>
        <td><code>color7</code>
        </td>
        <td><code>White</code>
        </td>
        <td><code>gray90</code>
        </td>
        <td><code>gray90</code>
        </td>
      </tr>

      <tr>
        <td><code>color8</code>
        </td>
        <td>&nbsp;</td>
        <td><code>gray30</code>
        </td>
        <td><code>gray50</code>
        </td>
      </tr>

      <tr>
        <td><code>color9</code>
        </td>
        <td>&nbsp;</td>
        <td><code>red</code>
        </td>
        <td><code>red</code>
        </td>
      </tr>

      <tr>
        <td><code>color10</code>
        </td>
        <td>&nbsp;</td>
        <td><code>green</code>
        </td>
        <td><code>green</code>
        </td>
      </tr>

      <tr>
        <td><code>color11</code>
        </td>
        <td>&nbsp;</td>
        <td><code>yellow</code>
        </td>
        <td><code>yellow</code>
        </td>
      </tr>

      <tr>
        <td><code>color12</code>
        </td>
        <td>&nbsp;</td>
        <td><code>blue</code>
        </td>
        <td><code>rgb:5c/5c/ff</code>
        </td>
      </tr>

      <tr>
        <td><code>color13</code>
        </td>
        <td>&nbsp;</td>
        <td><code>magenta</code>
        </td>
        <td><code>magenta</code>
        </td>
      </tr>

      <tr>
        <td><code>color14</code>
        </td>
        <td>&nbsp;</td>
        <td><code>cyan</code>
        </td>
        <td><code>cyan</code>
        </td>
      </tr>

      <tr>
        <td><code>color15</code>
        </td>
        <td>&nbsp;</td>
        <td><code>white</code>
        </td>
        <td><code>white</code>
        </td>
      </tr>

      <tr>
        <td><code>colorUL</code>
        </td>
        <td>&nbsp;</td>
        <td><code>yellow</code>
        </td>
        <td><code>foreground</code>
        </td>
      </tr>

      <tr>
        <td><code>colorBD</code>
        </td>
        <td>&nbsp;</td>
        <td><code>white</code>
        </td>
        <td><code>foreground</code>
        </td>
      </tr>

      <tr>
        <td><code>colorRV</code>
        </td>
        <td>&nbsp;</td>
        <td>&nbsp;</td>
        <td><code>foreground</code>
        </td>
      </tr>

      <tr>
        <td><code>colorIT</code>
        </td>
        <td>&nbsp;</td>
        <td>&nbsp;</td>
        <td><code>foreground</code>
        </td>
      </tr>
    </table>
  </blockquote>

  <p>In development of xterm over the past 20 years, we</p>

  <ul>
    <li>
      <p>incorporated ANSI (8) colors,</p>
    </li>

    <li>
      <p>adapted the aixterm feature (16) colors,</p>
    </li>

    <li>
      <p>added extensions for 88- and 256-colors.</p>
    </li>
  </ul>

  <p>Much of that has been adopted by other developers for
  different terminal emulators. That is summarized in <a href=
  "/ncurses/ncurses.faq.html#xterm_256color">Why not make
  &ldquo;xterm&rdquo; equated to
  &ldquo;xterm-256color&rdquo;?</a>.</p>

  <p>As hinted by the table, the 16-color extension was partly
  implemented in xterm by late 1995, using the scheme of Linux
  console: <em>bold</em> fonts are shown as <em>brighter</em>
  equivalents of the ANSI 8 colors. Unlike the Linux console, xterm
  can use bold fonts and (aside from providing similar appearance
  to the Linux console for programs such as <a href=
  "/dialog/dialog.html">dialog</a>) there was no reason to pretend
  that <a href="#bold_vs_16colors">bold and bright were
  synonymous</a>.</p>

  <p>The <code>colorUL</code> and <code>colorBD</code> features are
  part of this discussion because I incorporated those into the
  indexing scheme for colors. More on that later.</p>

  <p>First, deal with the 256- and 88-color extensions.</p>

  <p>The reason for <em>256</em> colors is that the index would fit
  in a byte. Larason's scheme was simple enough:</p>

  <ul>
    <li>
      <p>the existing 16 colors</p>
    </li>

    <li>
      <p>a color cube (6x6x6 is 216, which is the largest cube no
      larger than 256).</p>
    </li>

    <li>
      <p>a grayscale &ldquo;ramp&rdquo;, using the remaining 24
      entries.</p>
    </li>
  </ul>

  <p>The xterm source-code includes scripts for demonstrating the
  colors, e.g., using the same escape sequences that
  <code>tput</code> would use:</p>

  <ul>
    <li>
      <p><a href="/xterm/xterm.log.html#xterm_94">patch #94</a>
      (1999/03/27) added <code>8colors.sh, 16colors.sh</code></p>
    </li>

    <li>
      <p><a href="/xterm/xterm.log.html#xterm_111">patch #111</a>
      (1999/07/10) added <code>256colors.pl and
      256colors2.pl</code></p>
    </li>

    <li>
      <p><a href="/xterm/xterm.log.html#xterm_115">patch #115</a>
      (1999/07/18) added <code>88colors.pl and
      88colors2.pl</code></p>
    </li>
  </ul>

  <p>I added the scripts in patch #94 because of some user comments
  that there were scripts of that sort available, that there were
  some deficiencies in those, and and it would be nice to have some
  good examples in xterm's source. Coincidentally, that gave Todd
  Larason and Stephen P Wall a starting point for the changes to
  support 256- and 88-colors.</p>

  <p>The 256-color extension came first. 88-colors (using the same
  control sequence) came next, to reduce the amount of memory
  needed. XTerm stores both foreground and background color indexes
  for each cell on the screen. That is two bytes, which doubled the
  amount of memory used by xterm for the scrollback. More
  important, however, was the number of entries in the
  <em>colormap</em>. With 256 colors, 65536 entries might be used,
  but 88 colors use at most 7744 entries. In the late 1990s,
  inexpensive displays were far less capable, requiring workarounds
  to get acceptable performance.</p>

  <p id="Allocation_of_colors_for_88/157/256_schemes">The 256- and
  88-color schemes (a 16-color table of <em>ANSI</em> (or
  <em>aixterm</em>) colors, followed by a cube and then a grayscale
  &ldquo;ramp&rdquo;) are similar. An intermediate <a href=
  "https://lists.gnu.org/archive/html/bug-ncurses/2020-03/msg00025.html">
  157-color scheme</a> could have been provided,</p>

  <table border="1" summary=
  "Allocation of colors for 88/157/256 schemes">
    <tr>
      <th>88</th>
      <th>157</th>
      <th>256</th>
      <th>Usage</th>
    </tr>

    <tr>
      <td align="right">16</td>
      <td align="right">16</td>
      <td align="right">16</td>
      <td>ANSI/AIX</td>
    </tr>

    <tr>
      <td align="right">64</td>
      <td align="right">125</td>
      <td align="right">216</td>
      <td>cube</td>
    </tr>

    <tr>
      <td align="right">8</td>
      <td align="right">16</td>
      <td align="right">24</td>
      <td>grayscale "ramp"</td>
    </tr>
  </table>

  <p>but the savings in the colormap would be less compelling:</p>

  <table border="1" summary=
  "Size of colormap for 88/157/256 schemes">
    <tr>
      <th>Colors</th>
      <th>Size</th>
      <th>Bits</th>
    </tr>

    <tr>
      <td align="right">88</td>
      <td align="right">7744</td>
      <td align="right">13</td>
    </tr>

    <tr>
      <td align="right">157</td>
      <td align="right">24649</td>
      <td align="right">15</td>
    </tr>

    <tr>
      <td align="right">256</td>
      <td align="right">65536</td>
      <td align="right">16</td>
    </tr>
  </table>

  <p id="semicolon_vs_colon">Like the aixterm 16-color extension,
  these colors are stored in an array. Unlike aixterm (whose
  developers invented a new set of escape sequences not found in
  ANSI or ECMA-48), we used sequences found in ECMA-48: SGR codes
  38 and 48. However, the feature evolved:</p>

  <ul>
    <li>
      <p>The default color palette for xterm uses header-files
      generated using scripts similar to the ones provided for
      demonstrations (<a href=
      "/xterm/xterm.log.html#xterm_112">patch #112</a>).</p>

      <p>The first 16 colors (except for blue) use names in the X
      <code>rgb.txt</code>.</p>
    </li>

    <li>
      <p>The X libraries cannot handle enough resources to specify
      all of the 256 colors as well as other features in xterm.</p>

      <p>Starting with <a href=
      "/xterm/xterm.log.html#xterm_129">patch #129</a>, I made the
      <em>resource</em> settings for colors past the first 16 a
      compile-time option. If you prefer to have the colors as X
      resource values, you lose UTF-8. Since xterm accepted escape
      sequences for setting the palette, this was not a
      problem.</p>
    </li>

    <li>
      <p>Steve Wall modified the palette in 2002 (<a href=
      "/xterm/xterm.log.html#xterm_166">patch #166</a>), making it
      a little brighter.</p>
    </li>

    <li>
      <p>We used semicolon (like other SGR parameters) for
      separating the R/G/B values in the escape sequence, since a
      copy of ITU T.416 (ISO-8613-6) which presumably clarified the
      use of colon for this feature was costly.</p>

      <p>Using semicolon was incorrect because some applications
      could expect their parameters to be order-independent. As
      used for the R/G/B values, that <em>was</em> order-dependent.
      The relevant information, by the way, is part of ECMA-48 (not
      ITU T.416, as mentioned in <a href=
      "/ncurses/ncurses.faq.html#xterm_16MegaColors"><em>Why only
      16 (or 256) colors?</em></a>). Quoting from <a href=
      "https://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf">
      section 5.4.2 of ECMA-48, page 12</a>, and adding emphasis
      (not in the standard):</p>

      <blockquote>
        <p class="code-block">Each parameter sub-string consists of
        one or more bit combinations from 03/00 to
        <strong>03/10</strong>; the bit combinations from 03/00 to
        03/09 represent the digits <em>ZERO</em> to <em>NINE</em>;
        bit combination <strong>03/10</strong> may be used as a
        separator in a <em>parameter sub-string</em>, for example,
        to separate the fractional part of a decimal number from
        the integer part of that number.</p>
      </blockquote>

      <p>and later on page 78, in 8.3.117 <em>SGR &ndash; SELECT
      GRAPHIC RENDITION</em>, the description of SGR 38:</p>

      <blockquote>
        <p class="code-block">(reserved for future standardization;
        intended for setting character foreground colour as
        specified in ISO 8613-6 [CCITT Recommendation T.416])</p>
      </blockquote>

      <p>Of course you will immediately recognize that
      <strong><tt>03/10</tt></strong> is ASCII <em>colon</em>, and
      that ISO 8613-6 necessarily refers to the encoding in a
      <em>parameter sub-string</em>. Or perhaps you will not.</p>

      <p>It took several years for this to become an issue. The
      developers of other terminal emulators were not the ones who
      first complained about it. In fact, though the
      order-dependence was mentioned, no one pointed to a specific
      program which was affected. Still, it was a known
      problem.</p>

      <p>Later, in 2012 (<a href="/xterm/xterm.log.html">patch
      #282</a>), I extended the parser to accommodate the
      <em>corrected</em> syntax. The original remains, simply
      because of its widespread use. As before, it took a few years
      for other terminal developers to notice and start
      incorporating the improvement. As of March 2016, not all had
      finished noticing.</p>

      <p>On releasing <a href="/ncurses/announce-6.1.html">ncurses
      6.1</a> in 2018, I used the corrected syntax in the <a href=
      "/ncurses/terminfo.src.html#tic-xterm-direct"><em>xterm-direct</em></a>
      terminal description, and also provided working examples for
      the other terminals which supported the <em>direct color</em>
      feature. Some of those still did not support the standard
      syntax for the control sequences:</p>

      <ul>
        <li>
          <p><a href=
          "/ncurses/terminfo.src.html#tic-xterm_direct">xterm+direct</a>
          is the building-block for standard terminals</p>
        </li>

        <li>
          <p><a href=
          "/ncurses/terminfo.src.html#tic-xterm_indirect">xterm+indirect</a>
          is a building-block for nonstandard terminals</p>
        </li>
      </ul>

      <p>Still later, in 2020, a user's request prompted review of
      this area:</p>

      <ul>
        <li>
          <p>One of the other terminal developers had implemented a
          new feature using xterm's original semicolon
          delimiters.</p>
        </li>

        <li>
          <p>That created a problem for this user because the same
          string sent to both terminals would color text on the
          other terminal, but reset colors on xterm.</p>
        </li>

        <li>
          <p>That happens because (unless xterm were specially
          modified), xterm cannot tell that the new feature has
          subparameters which are supposed to be used for setting
          colors.</p>
        </li>

        <li>
          <p>The feature itself is nonstandard, using a code marked
          in ECMA-48 for future standardization, so there is no
          reason to modify xterm.</p>
        </li>

        <li>
          <p>As noted in the ncurses FAQ <a href=
          "/ncurses/ncurses.faq.html#xterm_generic"><em>Why not
          just use TERM set to &ldquo;xterm&rdquo;?</em></a>,
          sometimes xterm's terminal description uses features not
          supported by other terminals.</p>
        </li>

        <li>
          <p>ncurses has correct terminal descriptions for xterm
          and other terminals (such as the one with the nonstandard
          feature).</p>
        </li>

        <li>
          <p>Providing a terminal description using the nonstandard
          semicolon for delimiting subparameters encourages users
          to stumble into this problem.</p>
        </li>

        <li>
          <p>Going forward (e.g., xterm patch #357), these terminfo
          building blocks are used in ncurses:</p>

          <ul>
            <li>
              <p><a href=
              "/ncurses/terminfo.src.html#tic-xterm_256color2">xterm+256color<strong>2</strong></a>
              is the building-block for standard terminals</p>
            </li>

            <li>
              <p><a href=
              "/ncurses/terminfo.src.html#tic-xterm_256color">xterm+256color</a>
              is a building-block for nonstandard terminals</p>
            </li>
          </ul>
        </li>
      </ul>
    </li>
  </ul>

  <p id="changing_256color_palette">As others incorporated the
  xterm 256-color feature, the ability to <em>set</em> the palette
  was usually not done before announcing that a program had the
  256-color feature. Others acquired the ability to set the palette
  after a lapse of years. As an exception, Geoff Wing (rxvt
  developer) implemented the complete feature in August 2002
  (release 2.7.9). Any xterm-<em>compatible</em> implementation
  with support for 256-colors automatically supports 88-colors,
  since the palette is modifiable, which makes comments such as
  <a href=
  "http://unix.stackexchange.com/questions/269077/tput-setaf-color-table-how-to-determine-color-codes">
  this</a> at best badly informed.</p>

  <p>A few non-xterm applications may support the feature,
  e.g.,</p>

  <ul>
    <li>
      <p><a href="/ncurses/terminfo.src.html#tic-putty">PuTTY</a>
      (Windows)</p>
    </li>

    <li>
      <p><a href="/ncurses/terminfo.src.html#tic-iterm2">iTerm2</a>
      (MacOS)</p>
    </li>

    <li>
      <p><a href="/ncurses/terminfo.src.html#tic-teken">teken</a>
      (FreeBSD)</p>
    </li>
  </ul>

  <p>though the results may not be satisfactory. Here are
  screenshots for 88- and 256-colors which I made in <a href=
  "https://lists.freebsd.org/pipermail/freebsd-arch/2014-February/015081.html">
  February 2014</a> while discussing deficiencies of the FreeBSD
  console emulator:</p>

  <blockquote>
    <p><a href="/xterm/images/teken-88colors.png"><img width="450"
    src="images/teken-88colors.png" alt="teken with 88-colors"></a></p>

    <p><a href="/xterm/images/teken-256colors.png"><img width="450"
    src="images/teken-256colors.png" alt=
    "teken with 256-colors"></a></p>
  </blockquote>

  <p>XTerm stores the colors for <code>colorUL</code>, etc., at the
  end of the color array used for ANSI, 16-, 88- and 256-colors. An
  application can <em>modify</em> the colors using
  <code>OSC&nbsp;4</code>, which does not reduce the range
  available for the <code>SGR&nbsp;38/48</code> index used for
  <em>selecting</em> colors (underline, bold, reverse &mdash; and
  italics &mdash; all have their place in the video attribute
  fields). Like dynamic colors, this was a feature found in XFree86
  but not in X11R5 or X11R6. According to David Dawes, some people
  liked the feature. <a href="http://olesenm.github.io/about/">Mark
  J Olesen</a> incorporated the same into rxvt mid-1996, and I
  added the other two attributes. However, it was mainly popular
  with Red Hat users who wanted to color their manpages. After
  Werner Lemberg changed groff behavior <a href=
  "https://lists.gnu.org/archive/html/groff/2001-10/msg00055.html">in
  2001</a> to color manpages, this feature is not that well
  known.</p>

  <p>Finally, there are the <em>default</em> foreground and
  background colors set using <code>SGR&nbsp;39/49</code>.</p>

  <p>If one wants to enumerate the colors which can be set by index
  in xterm, there are multiple indices that are needed:</p>

  <ul>
    <li>
      <p>SGR number (for the 8 ANSI colors, the extra 8 aixterm
      colors and the default colors)</p>
    </li>

    <li>
      <p>SGR 38/48 with (index) parameter (for the 88-colors and
      the 256-colors, keeping in mind that those include the first
      16 ANSI and aixterm colors)</p>
    </li>

    <li>
      <p>OSC 4 with (index) parameter (colored video
      attributes)</p>
    </li>

    <li>
      <p>OSC numbers 10-19 (dynamic colors)</p>
    </li>
  </ul>

  <p>The sample scripts in xterm's sources demonstrate these
  features. Some are written in POSIX shell, the remainder are in
  Perl.</p>

  <h4 id="dont_like_blue-id"><a name="dont_like_blue" id=
  "dont_like_blue">I don't like that shade of blue</a></h4>

  <p>Nobody does. But there are no universal solutions.</p>

  <p>If your terminal (or the application running in it has a dark
  background, then darker blues are hard to see. With a light
  background, yellows are hard to see.</p>

  <p>The available standards do not help: there <em>are</em> no
  standards for terminal colors. Here is an illustration which I
  made in reply to a <a href=
  "http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=241717">bug
  report</a>, contrasting different choices for blue, against some
  of the other terminals which (were said to) provide "standard
  vt100 colors":</p>

  <blockquote class="code-block">
    <p><a href="/xterm/images/contrast.jpg"><img width="450" src=
    "images/contrast.jpg" alt=
    "Contrasting blue in terminal emulators"></a></p>
  </blockquote>

  <p>Of course, anyone <em>developing</em> a terminal emulator
  already knew that <a href=
  "/ncurses/ncurses.faq.html#vt100_color">vt100's never did do
  colors</a>.</p>

  <p>Ultimately it is up to the application running in a terminal
  to enforce the colors it needs. XTerm merely provides the best
  compromise on default visibility that I and my users have
  found.</p>

  <h4 id="what_256colors-id"><a name="what_256colors" id=
  "what_256colors">What is the 256-color palette?</a></h4>

  <p>The 256-color palette is a collection of red, green and blue
  color values. Todd Larason's original proposal for this feature
  in <a href="/xterm/xterm.log.html#xterm_111">1999</a> included a
  sample script (see <a href=
  "https://github.com/ThomasDickey/xterm-snapshots/blob/c6542a40c0ca62feb56961fffc67b6ef3e8a12aa/vttests/256colors2.pl">
  link</a>). Here is a screenshot:</p>

  <blockquote>
    <p><a href="/xterm/images/256colors-1999.png"><img width="450"
    src="images/256colors-1999.png" alt=
    "original 256color demo"></a></p>
  </blockquote>

  <p>I adapted Larason's script to create definitions which can be
  compiled into xterm, initially as resource settings. Steve Wall
  modified the colors in <a href=
  "/xterm/xterm.log.html#xterm_166">2002</a> (see <a href=
  "https://github.com/ThomasDickey/xterm-snapshots/blob/ebedc23345c9e786d4458aebccf932f39b792036/vttests/256colors2.pl">
  link</a>). Here is a screenshot:</p>

  <blockquote>
    <p><a href="/xterm/images/256colors-2002.png"><img width="450"
    src="images/256colors-2002.png" alt=
    "updated 256color demo"></a></p>
  </blockquote>

  <p>Both of those scripts ignore the first sixteen colors, which
  are set using <a href=
  "/xterm/manpage/xterm.html#VT100-Widget-Resources:color0">resource
  values</a>. A script to show the red, green and blue components
  for all 256 colors is complicated by the changes I made for the
  colors 4 and 12 (blue) in <a href=
  "/xterm/xterm.log.html#xterm_192">2004</a>. This python script
  prints the color values which xterm uses by default:</p>

  <blockquote class="code-block100">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    <span class="comment">#&nbsp;print&nbsp;a&nbsp;list&nbsp;of&nbsp;the&nbsp;256-color&nbsp;red/green/blue&nbsp;values&nbsp;used&nbsp;by&nbsp;xterm.<br>
    </span> <span class="comment">#<br></span> <span class=
    "comment">#&nbsp;reference:<br></span> <span class=
    "comment">#&nbsp;<a href=
    "https://github.com/ThomasDickey/ncurses-snapshots/blob/master/test/xterm-16color.dat">https://github.com/ThomasDickey/ncurses-snapshots/blob/master/test/xterm-16color.dat</a><br>
    </span> <span class="comment">#&nbsp;<a href=
    "https://github.com/ThomasDickey/xterm-snapshots/blob/master/XTerm-col.ad">https://github.com/ThomasDickey/xterm-snapshots/blob/master/XTerm-col.ad</a><br>
    </span> <span class="comment">#&nbsp;<a href=
    "https://github.com/ThomasDickey/xterm-snapshots/blob/master/256colres.pl">https://github.com/ThomasDickey/xterm-snapshots/blob/master/256colres.pl</a><br>
    </span> &nbsp;<br>
    <strong><span class=
    "keyword">print</span></strong>(<span class="literal">"colors&nbsp;0-16&nbsp;correspond&nbsp;to&nbsp;the&nbsp;ANSI&nbsp;and&nbsp;aixterm&nbsp;naming"</span>)<br>

    <strong><span class=
    "keyword">for</span></strong>&nbsp;code&nbsp;<strong><span class="keyword">in</span></strong>&nbsp;<span class="ident2">range</span>(<strong><span class="number">0</span></strong>,&nbsp;<strong><span class="number">16</span></strong>):<br>

    &nbsp;&nbsp;&nbsp;&nbsp;<strong><span class=
    "keyword">if</span></strong>&nbsp;code&nbsp;&gt;&nbsp;<strong><span class="number">8</span></strong>:<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;level&nbsp;=&nbsp;<strong><span class="number">255</span></strong><br>

    &nbsp;&nbsp;&nbsp;&nbsp;<strong><span class=
    "keyword">elif</span></strong>&nbsp;code&nbsp;==&nbsp;<strong><span class="number">7</span></strong>:<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;level&nbsp;=&nbsp;<strong><span class="number">229</span></strong><br>

    &nbsp;&nbsp;&nbsp;&nbsp;<strong><span class=
    "keyword">else</span></strong>:<br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;level&nbsp;=&nbsp;<strong><span class="number">205</span></strong><br>

    &nbsp;&nbsp;&nbsp;&nbsp;r&nbsp;=&nbsp;<strong><span class=
    "number">127</span></strong>&nbsp;<strong><span class=
    "keyword">if</span></strong>&nbsp;code&nbsp;==&nbsp;<strong><span class="number">8</span></strong>&nbsp;<strong><span class="keyword">else</span></strong>&nbsp;level&nbsp;<strong><span class="keyword">if</span></strong>&nbsp;(code&nbsp;&amp;&nbsp;<strong><span class="number">1</span></strong>)&nbsp;!=&nbsp;<strong><span class="number">0</span></strong>&nbsp;<strong><span class="keyword">else</span></strong>&nbsp;<strong><span class="number">92</span></strong>&nbsp;<strong><span class="keyword">if</span></strong>&nbsp;code&nbsp;==&nbsp;<strong><span class="number">12</span></strong>&nbsp;<strong><span class="keyword">else</span></strong>&nbsp;<strong><span class="number">0</span></strong><br>

    &nbsp;&nbsp;&nbsp;&nbsp;g&nbsp;=&nbsp;<strong><span class=
    "number">127</span></strong>&nbsp;<strong><span class=
    "keyword">if</span></strong>&nbsp;code&nbsp;==&nbsp;<strong><span class="number">8</span></strong>&nbsp;<strong><span class="keyword">else</span></strong>&nbsp;level&nbsp;<strong><span class="keyword">if</span></strong>&nbsp;(code&nbsp;&amp;&nbsp;<strong><span class="number">2</span></strong>)&nbsp;!=&nbsp;<strong><span class="number">0</span></strong>&nbsp;<strong><span class="keyword">else</span></strong>&nbsp;<strong><span class="number">92</span></strong>&nbsp;<strong><span class="keyword">if</span></strong>&nbsp;code&nbsp;==&nbsp;<strong><span class="number">12</span></strong>&nbsp;<strong><span class="keyword">else</span></strong>&nbsp;<strong><span class="number">0</span></strong><br>

    &nbsp;&nbsp;&nbsp;&nbsp;b&nbsp;=&nbsp;<strong><span class=
    "number">127</span></strong>&nbsp;<strong><span class=
    "keyword">if</span></strong>&nbsp;code&nbsp;==&nbsp;<strong><span class="number">8</span></strong>&nbsp;<strong><span class="keyword">else</span></strong>&nbsp;<strong><span class="number">238</span></strong>&nbsp;<strong><span class="keyword">if</span></strong>&nbsp;code&nbsp;==&nbsp;<strong><span class="number">4</span></strong>&nbsp;<strong><span class="keyword">else</span></strong>&nbsp;level&nbsp;<strong><span class="keyword">if</span></strong>&nbsp;(code&nbsp;&amp;&nbsp;<strong><span class="number">4</span></strong>)&nbsp;!=&nbsp;<strong><span class="number">0</span></strong>&nbsp;<strong><span class="keyword">else</span></strong>&nbsp;<strong><span class="number">0</span></strong><br>

    &nbsp;&nbsp;&nbsp;&nbsp;<strong><span class=
    "keyword">print</span></strong>(f<span class=
    "literal">"{code:3d}:&nbsp;{r:02X}&nbsp;{g:02X}&nbsp;{b:02X}"</span>)<br>

    &nbsp;<br>
    <strong><span class=
    "keyword">print</span></strong>(<span class="literal">"colors&nbsp;16-231&nbsp;are&nbsp;a&nbsp;6x6x6&nbsp;color&nbsp;cube"</span>)<br>

    <strong><span class=
    "keyword">for</span></strong>&nbsp;red&nbsp;<strong><span class="keyword">in</span></strong>&nbsp;<span class="ident2">range</span>(<strong><span class="number">0</span></strong>,&nbsp;<strong><span class="number">6</span></strong>):<br>

    &nbsp;&nbsp;&nbsp;&nbsp;<strong><span class=
    "keyword">for</span></strong>&nbsp;green&nbsp;<strong><span class="keyword">in</span></strong>&nbsp;<span class="ident2">range</span>(<strong><span class="number">0</span></strong>,&nbsp;<strong><span class="number">6</span></strong>):<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<strong><span class="keyword">for</span></strong>&nbsp;blue&nbsp;<strong><span class="keyword">in</span></strong>&nbsp;<span class="ident2">range</span>(<strong><span class="number">0</span></strong>,&nbsp;<strong><span class="number">6</span></strong>):<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;code&nbsp;=&nbsp;<strong><span class="number">16</span></strong>&nbsp;+&nbsp;(red&nbsp;*&nbsp;<strong><span class="number">36</span></strong>)&nbsp;+&nbsp;(green&nbsp;*&nbsp;<strong><span class="number">6</span></strong>)&nbsp;+&nbsp;blue<br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;r&nbsp;=&nbsp;red&nbsp;&nbsp;&nbsp;*&nbsp;<strong><span class="number">40</span></strong>&nbsp;+&nbsp;<strong><span class="number">55</span></strong>&nbsp;<strong><span class="keyword">if</span></strong>&nbsp;red&nbsp;&nbsp;&nbsp;!=&nbsp;<strong><span class="number">0</span></strong>&nbsp;<strong><span class="keyword">else</span></strong>&nbsp;<strong><span class="number">0</span></strong><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;g&nbsp;=&nbsp;green&nbsp;*&nbsp;<strong><span class="number">40</span></strong>&nbsp;+&nbsp;<strong><span class="number">55</span></strong>&nbsp;<strong><span class="keyword">if</span></strong>&nbsp;green&nbsp;!=&nbsp;<strong><span class="number">0</span></strong>&nbsp;<strong><span class="keyword">else</span></strong>&nbsp;<strong><span class="number">0</span></strong><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;b&nbsp;=&nbsp;blue&nbsp;&nbsp;*&nbsp;<strong><span class="number">40</span></strong>&nbsp;+&nbsp;<strong><span class="number">55</span></strong>&nbsp;<strong><span class="keyword">if</span></strong>&nbsp;blue&nbsp;&nbsp;!=&nbsp;<strong><span class="number">0</span></strong>&nbsp;<strong><span class="keyword">else</span></strong>&nbsp;<strong><span class="number">0</span></strong><br>

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<strong><span class="keyword">print</span></strong>(f<span class="literal">"{code:3d}:&nbsp;{r:02X}&nbsp;{g:02X}&nbsp;{b:02X}"</span>)<br>

    &nbsp;<br>
    <strong><span class=
    "keyword">print</span></strong>(<span class="literal">"colors&nbsp;232-255&nbsp;are&nbsp;a&nbsp;grayscale&nbsp;ramp,&nbsp;intentionally&nbsp;leaving&nbsp;out&nbsp;black&nbsp;and&nbsp;white"</span>)<br>

    code&nbsp;=&nbsp;<strong><span class=
    "number">232</span></strong><br>
    <strong><span class=
    "keyword">for</span></strong>&nbsp;gray&nbsp;<strong><span class="keyword">in</span></strong>&nbsp;<span class="ident2">range</span>(<strong><span class="number">0</span></strong>,&nbsp;<strong><span class="number">24</span></strong>):<br>

    &nbsp;&nbsp;&nbsp;&nbsp;level&nbsp;=&nbsp;gray&nbsp;*&nbsp;<strong><span class="number">10</span></strong>&nbsp;+&nbsp;<strong><span class="number">8</span></strong><br>

    &nbsp;&nbsp;&nbsp;&nbsp;code&nbsp;=&nbsp;<strong><span class=
    "number">232</span></strong>&nbsp;+&nbsp;gray<br>
    &nbsp;&nbsp;&nbsp;&nbsp;<strong><span class=
    "keyword">print</span></strong>(f<span class=
    "literal">"{code:3d}:&nbsp;{level:02X}&nbsp;{level:02X}&nbsp;{level:02X}"</span>)<br>

    <!--atr2html}}--></p>
  </blockquote>

  <h4 id="why_no_italics-id"><a name="why_no_italics" id=
  "why_no_italics">Why doesn't xterm support italics?</a></h4>

  <p>Well, actually it does and it doesn't.</p>

  <p>You can display &ldquo;any&rdquo; font using xterm (though
  proportional fonts may be disappointing).</p>

  <p>But xterm has specific types of graphic rendition that it will
  do. If you want italics, then xterm has an option
  (<code>italicULMode</code>) to use that rendition instead of
  underlining. That is the usual typographic alternative, though of
  course some people want both at the same time.</p>

  <p>However, standard curses does not support italics. Few
  terminals do this reliably, so it was disregarded long ago, never
  was supported except for low-level applications (in terminfo). No
  bit was reserved in the curses header for adding italics for
  high-level applications. (As a special case, ncurses was modified
  to provide <a href="/ncurses/NEWS.html#t20130831">partial
  support</a>, but programs using this feature will not work with
  other implementations).</p>

  <p>XTerm stores each cell of the display in fixed-size
  structures. One byte stores the graphic rendition. XTerm is using
  all of the bits in this byte for its VT220 emulation:</p>

  <table border="1" summary="Bits for XTerm's graphic rendition">
    <tr>
      <th>Mnemonic</th>
      <th>Bit</th>
      <th>Description</th>
    </tr>

    <tr>
      <td>INVERSE</td>
      <td>0</td>
      <td>show cell reverse-video</td>
    </tr>

    <tr>
      <td>UNDERLINE</td>
      <td>1</td>
      <td>show cell underlined</td>
    </tr>

    <tr>
      <td>BOLD</td>
      <td>2</td>
      <td>show cell as bold</td>
    </tr>

    <tr>
      <td>BLINK</td>
      <td>3</td>
      <td>show cell as blinking</td>
    </tr>

    <tr>
      <td>BG_COLOR</td>
      <td>4</td>
      <td>use background color</td>
    </tr>

    <tr>
      <td>FG_COLOR</td>
      <td>5</td>
      <td>use foreground color</td>
    </tr>

    <tr>
      <td>PROTECTED</td>
      <td>6</td>
      <td>character cannot be erased</td>
    </tr>

    <tr>
      <td>CHARDRAWN</td>
      <td>7</td>
      <td>character has been drawn here on the screen</td>
    </tr>
  </table>

  <p>While additional bytes could be added to each cell, the cost
  to the typical user has so far not been in line with the
  usefulness of the feature.</p>

  <p>For those who are not constrained by cost, since <a href=
  "xterm.log.html#xterm_305">patch #305</a> xterm provides a
  compile-time option to support italics. The main reason for
  implementing this is to be able to test the italics feature added
  in ncurses (patch <a href=
  "/ncurses/NEWS.html#t20130831">5.9.20130831</a>):</p>

  <ul>
    <li>
      <p>this increases the size of the attributes data.</p>
    </li>

    <li>
      <p>the feature requires some overhead for font-switching
      (treating italics as &ldquo;rare&rdquo;)</p>
    </li>
  </ul>

  <p>The increase in size is not entirely wasted. The SGR
  attributes for <em>dim</em>, <em>strike-out</em>, and
  <em>double-underscore</em> also are implemented. However, the
  last two are not in the portable terminfo definition (from
  X/Open), and are not supported in the higher-level curses
  interface (there is no <code>A_STRIKE</code> for that
  reason).</p>

  <p>Here are screenshots showing the ncurses test-program
  displaying video attributes (including italics). The first uses
  bitmap fonts:</p>

  <blockquote>
    <p><a href=
    "/ncurses/images/ncurses6-bitmap-italics.png"><img width="300"
    src="/ncurses/images/ncurses6-bitmap-italics.png" alt=
    "ncurses &ndash; video attributes with bitmap-font"></a></p>
  </blockquote>

  <p>and the second uses a (same size) TrueType font:</p>

  <blockquote>
    <p><a href=
    "/ncurses/images/ncurses6-truetype-italics.png"><img width=
    "300" src="/ncurses/images/ncurses6-truetype-italics.png" alt=
    "ncurses &ndash; video attributes with TrueType font"></a></p>
  </blockquote>

  <h4 id="grep_colors-id"><a name="grep_colors" id=
  "grep_colors">"grep --color" does not show the right output</a></h4>

  <p>GNU grep (version 2.5) introduced a <code>--color</code>
  option.</p>

  <p>It does this for each highlighted match:</p>

  <ol>
    <li>
      <p>it writes the text up to (not including the match)</p>
    </li>

    <li>
      <p>it writes an ANSI color control control sequence</p>
    </li>

    <li>
      <p>it writes the matched text</p>
    </li>

    <li>
      <p>it writes a control sequence to clear to the end of the
      line</p>
    </li>

    <li>
      <p>it writes an ANSI control sequence to reset graphic
      rendition.</p>
    </li>

    <li>
      <p>repeat this process until the entire line is written.</p>
    </li>
  </ol>

  <p>One problem is in the second and fourth steps. If the
  preceding text brought us up to the last column, then xterm (and
  any VT100-compatible terminal) is waiting for graphic text to
  wrap to the next line. Any controls would take effect on the
  current column position. Newlines are ignored while in this
  state.</p>

  <p>However, if xterm gets a control sequence while waiting to
  wrap to the next line, it will update the screen according to
  that control. Then it is ready to accept more data. But at this
  point, it is no longer waiting to wrap; the special case is for
  newline versus graphic characters. For instance, backspacing
  clears the state (<a href="/vttest/vttest.html">vttest</a>
  illustrates this). So the data starts to write at the current
  column (the last one on the line), rather than at the beginning
  of the next line. In that case, grep's output will not look
  right.</p>

  <p>Here are some relevant bug reports:</p>

  <ul>
    <li>
      <p><a href=
      "https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=456943">Debian
      #456943 - grep: incorrect display with color and wrapping in
      some terminals</a></p>
    </li>

    <li>
      <p><a href=
      "https://bugzilla.redhat.com/show_bug.cgi?id=1006310">Fedora
      #1006310 - xterm does not print a character if the character
      is last on a row and a color-change ANSI sequence follows</a></p>
    </li>

    <li>
      <p><a href=
      "https://bugzilla.novell.com/show_bug.cgi?id=148844">Novell
      #148844 - terminal text wrapping bug</a></p>
    </li>
  </ul>

  <h4 id="vt100_wrapping-id"><a name="vt100_wrapping" id=
  "vt100_wrapping">That description of wrapping is odd, say
  more?</a></h4>

  <p>This is one of the aspects of the so-called "vt100 glitch", as
  mentioned in the terminfo manpage:</p>

  <blockquote class="code-block">
    <p>Terminals which ignore a line-feed immediately after an am
    wrap, such as the Concept and vt100, should indicate xenl.</p>
  </blockquote>

  <p>When the terminal reaches the right margin, it is in a special
  state where it ignores tab characters and other formatting
  controls (carriage return and newline), and in effect is
  expecting only printable characters to wrap to the next line.</p>

  <p>Without it, it is misleading to refer to a terminal as a vt100
  emulator. After all, it is a well-known feature named for the
  VT100. The applicable standards (ISO-6429, ECMA-48) do not go
  into enough detail to address this sort of behavior, so the other
  terminal emulators can be referred to most accurately as ANSI
  terminals (if they obey the other guidelines).</p>

  <p><a href="/vttest/CHANGES">In 2004</a>, I added a test-screen
  to vttest to demonstrate this. It was in response to someone who
  insisted that xterm was wrong and one of those other terminal
  emulators was &ldquo;right&rdquo;. I investigated, found that the
  behavior had not changed in xterm at least since the early 1990s,
  and that it matched the description of behavior from the DEC
  manuals. One of my users verified the correctness of the test on
  a VT520.</p>

  <p>Reviewing the results with xterm-alikes or less ambitious
  "vt100 emulators" in mid-2013:</p>

  <ul>
    <li>
      <p>xterm, kterm, mlterm, some operating system consoles are
      consistent with the VT100 behavior.</p>
    </li>

    <li>
      <p>rxvt, screen, putty (pterm), konsole, vte (gnome-terminal,
      xfce4-terminal) are not consistent with VT100 (and behave
      differently compared to each other).</p>

      <p>I included screen here because it claims to be a vt100
      emulator, and putty since it claims to be an xterm emulator.
      I did not include tmux, because it does not make either
      claim.</p>
    </li>

    <li>
      <p>mrxvt does not get to that screen; it resizes its window
      to a single line.</p>
    </li>
  </ul>

  <p>In the <a href="/vttest/vttest-wrap.html">vttest</a> page, I
  have provided screenshots to illustrate these points.</p>

  <p>Since 2013, Mattias Engdeg&aring;rd created a test program to
  explore this area, citing DEC's internal standard document for
  terminals (<a href=
  "http://www.bitsavers.org/pdf/dec/standards/EL-SM070-00_DEC_STD_070_Video_Systems_Reference_Manual_Dec91.pdf"><em>DEC
  STD 070 Video Systems Reference Manual</em></a>). That document
  refers to this as the <em>last column flag</em>.</p>

  <p>Revisiting this in 2019, no improvement has been observed in
  the problematic programs from 2013. A VTE user gave this
  example</p>

  <blockquote>
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    <span class="comment">#!/bin/bash</span><br>
    <strong><span class=
    "keyword">echo</span></strong>&nbsp;-e&nbsp;<span class=
    "literal">"</span><strong><em><span class=
    "keyword2">\</span></em></strong><span class=
    "literal">e[2J"</span><br>
    <strong><span class=
    "keyword">echo</span></strong>&nbsp;-e&nbsp;<span class=
    "literal">"</span><strong><em><span class=
    "keyword2">\</span></em></strong><span class=
    "literal">e[1;79Hx</span><strong><em><span class=
    "keyword2">\</span></em></strong><span class=
    "literal">b</span><strong><em><span class=
    "keyword2">\</span></em></strong><span class=
    "literal">vx</span><strong><em><span class=
    "keyword2">\</span></em></strong><span class=
    "literal">b</span><strong><em><span class=
    "keyword2">\</span></em></strong><span class=
    "literal">vx</span><strong><em><span class=
    "keyword2">\</span></em></strong><span class=
    "literal">n"</span><br>
    <strong><span class=
    "keyword">echo</span></strong>&nbsp;-e&nbsp;<span class=
    "literal">"</span><strong><em><span class=
    "keyword2">\</span></em></strong><span class=
    "literal">e[5;80Hx</span><strong><em><span class=
    "keyword2">\</span></em></strong><span class=
    "literal">b</span><strong><em><span class=
    "keyword2">\</span></em></strong><span class=
    "literal">vx</span><strong><em><span class=
    "keyword2">\</span></em></strong><span class=
    "literal">b</span><strong><em><span class=
    "keyword2">\</span></em></strong><span class=
    "literal">vx</span><strong><em><span class=
    "keyword2">\</span></em></strong><span class=
    "literal">n"</span><br>
    <!--atr2html}}--></p>
  </blockquote>

  <p>In this case, DEC's documentation for the <em>last column
  flag</em> mentions that cursor-positioning resets the flag.
  Because <strong>xterm</strong> takes that into account (while the
  others from 2013 do not), the example will show different
  results. Markus Schmidt provided a screenshot which demonstrates
  that DEC's documentation is correct and that some terminal
  emulators (e.g., <strong>xterm</strong>, <em>zoc</em>, MacOS
  <em>Terminal</em>, <em>st</em>) implement this detail in the same
  way that the hardware terminal did:</p>

  <blockquote>
    <p><a href="images/LCF-versus-CUP.jpg"><img width="200" src=
    "images/LCF-versus-CUP.jpg" alt=
    "screenshot of last column flag with cursor positioning"></a></p>
  </blockquote>

  <h4><a id="bce_oddness" name="bce_oddness">That color scheme is
  odd, say more?</a></h4>

  <p>Occasionally someone questions the behavior of the
  <strong>bce</strong> (<em>background color erase</em>) feature in
  <strong>xterm</strong>, and mentions that some DEC terminal did
  not behave that way with ANSI colors.</p>

  <p>First off:</p>

  <ul>
    <li>
      <p>Aside from the VT525, DEC terminals had no support for
      ANSI colors.</p>
    </li>

    <li>
      <p>Likely, they were thinking of a terminal <em>emulator</em>
      which supported colors. A while back, there was more than one
      which said they were a &ldquo;VT340&rdquo; and the
      misconceptions began. Not all of those behaved the same.</p>

      <p>Some developers were aware of this, others were not. The
      <em>comp.os.vms</em> newsgroup thread <a href=
      "https://groups.google.com/forum/#!topic/comp.os.vms/U0kbnWP4dMU">
      <em>How to setting color in code for a VT terminal</em></a>
      shows both.</p>
    </li>

    <li>
      <p>From the outset, <em>modern xterm</em> was a VT100 or
      VT220 <em>with</em> ANSI colors. No technical manual was
      available for a VT525 at the time. Lacking a technical
      manual, information about a VT525 was no more reliable than
      the statements about a VT340.</p>
    </li>
  </ul>

  <p>The design used for <strong>xterm</strong> imitated Linux
  console, which itself came about from different people (see
  <a href="/ncurses/ncurses-slang.html#cause_bce">this page</a> for
  some background).</p>

  <p>The VT525 programmer's reference manual is vague on the
  details (ANSI color is mentioned in a fraction of one percent of
  the manual), but the DEC standard for terminals is clear that it
  would not implement <em>bce</em>: any <em>erase</em> command will
  reset the video attributes. It documents ANSI color in the
  section on video attributes without mentioning a special case.
  Color would be reset as well.</p>

  <h3 id="problems_weird-id"><a name="problems_weird" id=
  "problems_weird">Odd behavior</a></h3>

  <h4 id="xterm_paste-id"><a name="xterm_paste" id=
  "xterm_paste">Why can't I select/paste in xterm?</a></h4>

  <p>When an application sets xterm to any of its <a href=
  "ctlseqs/ctlseqs.html#h2-Mouse-Tracking">mouse tracking
  modes</a>, it reserves the <em>unshifted</em> mouse button clicks
  for the application's use. Unless you have modified the treatment
  of the shifted mouse button events (e.g., with your window
  manager), you can always do select/paste by pressing the
  <em>shift</em> key while clicking with the mouse.</p>

  <p>This is all done using the <em>translations</em> resource (see
  the <a href=
  "manpage/xterm.html#h3-Default-Key-Bindings"><em>Default Key
  Bindings</em></a> section in the manual page).</p>

  <h4><a name="xterm_select_clipboard" id=
  "xterm_select_clipboard">Why can't I select/paste to/from other
  programs?</a></h4>

  <p>Whether you select text in xterm and paste into another
  window, or the reverse, the X client in which you have
  <em>selected</em> text may provide the data in different
  <em>formats</em> and different <em>containers</em>:</p>

  <blockquote>
    <dl>
      <dt><em>formats</em>
      </dt>

      <dd>
        <p>Originally (and by default) xterm made the selected data
        available with ISO-8859-1 encoding (Latin-1). Since
        <a href="xterm.log.html#xterm_101">patch #101 (1999)</a>,
        it has provided it also in UTF-8.</p>

        <p>Regarding the type of data:</p>

        <ul>
          <li>
            <p>X11R4's ICCM documented &ldquo;string&rdquo;
            selection data with ISO-8859-1, while</p>
          </li>

          <li>
            <p>X11R6 documented "compound text" (another name for
            multibyte encoding, without specifying <em>what</em>
            encoding).</p>
          </li>

          <li>
            <p>Selection data using UTF-8 was an extension by
            XFree86.</p>
          </li>
        </ul>

        <p>The client holding the selection advertises the formats
        that it can provide, and other client(s) ask for it using
        one of those formats.</p>

        <p>Xterm can ask for UTF-8 even if it is not configured to
        use UTF-8. In that case, it converts (a small number of)
        useful characters to their ASCII or VT100 line-graphics
        equivalents, and uses a "#" character for those which
        cannot be converted.</p>
      </dd>

      <dt><em>containers</em>
      </dt>

      <dd>
        <p>By default, xterm follows the <a href=
        "https://tronche.com/gui/x/icccm/"><em>Inter-Client
        Communication Conventions Manual</em></a> (ICCM). That
        dates back to X11R4 in 1989, with minor updates in 1996 for
        X11R6. The copyright for ICCM 1.0 is 1988/1989, making it
        slightly older than Microsoft Windows.</p>

        <p>The ICCM specifies <a href=
        "https://tronche.com/gui/x/icccm/sec-2.html#s-2.6"><em>"selection
        atoms"</em></a> which are maintained by the X server.
        According to the ICCM:</p>

        <blockquote>
          <p>The selection named by the atom <em>PRIMARY</em> is
          used for all commands that take only a single argument
          and is the principal means of communication between
          clients that use the selection mechanism.</p>
        </blockquote>

        <p>and</p>

        <blockquote>
          <p>The selection named by the atom <em>CLIPBOARD</em> is
          used to hold data that is being transferred between
          clients, that is, data that usually is being cut or
          copied, and then pasted.</p>
        </blockquote>

        <p>xterm uses PRIMARY by default. The default translations
        also update something called CUT_BUFFER0 (also <a href=
        "https://tronche.com/gui/x/icccm/sec-3.html#s-3">part of
        the ICCM</a>).</p>

        <p>Unlike the PRIMARY selection, a cut buffer can hold only
        "type STRING and format 8" (which happens to be
        ISO-8859-1). That sounds like a drawback, but on the other
        hand, cut buffers are <em>persistent</em>, while the
        PRIMARY selection is <em>not</em>. An X client can provide
        data using the PRIMARY selection only as long as it
        <em>holds</em> the selection.</p>
      </dd>
    </dl>
  </blockquote>

  <p>If xterm does not own the selection, it cannot supply the data
  (and you cannot select/paste). Initially, xterm held the PRIMARY
  selection only as long as the text was highlighted. Another
  application could assert the selection, but generally losing the
  PRIMARY selection in xterm was the same as losing highlighting.
  That has been improved, e.g., using the
  <code>keepSelection</code> resource in <a href=
  "xterm.log.html#xterm_230">patch #230</a> (2007), as well as
  refinements to retain highlighting when it updates other parts of
  the window.</p>

  <p>A more likely reason for failing to select/paste is that the
  other application may not use the same <em>selection atom</em>
  (container). In the mid-1990s, Netscape set out to compete with
  Internet Explorer. Part of that involved copying many aspects of
  the way Internet Explorer worked, including the way it worked
  with the Microsoft Windows clipboard. Netscape on non-Windows
  platforms, "of course" assumed the clipboard was the way to do
  things, and used the X11 clipboard rather following the ICCM.
  (The way it used the X11 clipboard was also not in line with the
  ICCM, but it was &ldquo;close&rdquo;).</p>

  <p>Not all applications followed Netscape and its descendents,
  making it a nuisance if one wanted to select/paste text to/from
  the web browser.</p>

  <p>Since <a href="xterm.log.html#xterm_209">patch #209</a>
  (2006), xterm has provided a workaround: a menu entry (and
  resource <code>selectToClipboard</code>) which changes xterm's
  behavior for a special token <em>SELECT</em> in its default
  translations. If the resource is true (or the menu item enabled),
  xterm provides its selection to the <em>CLIPBOARD</em>. A menu
  item is provided, of course, since many applications follow the
  ICCM. In the default translations, these lines use
  <em>SELECT</em>:</p>

  <blockquote>
    <pre class="code-block">
Shift &lt;KeyPress&gt; Select:select-cursor-start() \
                           select-cursor-end(SELECT, CUT_BUFFER0) \n\
Shift &lt;KeyPress&gt; Insert:insert-selection(SELECT, CUT_BUFFER0) \n\
</pre>
  </blockquote>

  <h4 id="xterm_tabs-id"><a name="xterm_tabs" id="xterm_tabs">Why
  can't I select tabs in xterm?</a></h4>

  <p>This issue was noted early on, <a href=
  "xterm.faq.html#known_bugs">here</a> in 1997.</p>

  <p><strong>XTerm</strong> is copying from the screen, which
  stores only printable characters. That includes spaces and
  line-drawing characters. But tabs are special; they are used for
  more than one purpose.</p>

  <p>If the screen is cleared in some part, that stores nulls.
  Cursor addressing does not fill in nulls as it jumps around,
  though xterm does supply blanks for the most useful cases,
  especially when getting data for a selection.</p>

  <p>Full-screen programs such as text-editors tend to write in
  random fashion, and generally do not print nulls to the screen.
  Curses on the other hand, may supply tabs where you thought there
  were none. Also, the terminal driver can expand tabs (and often
  is set to do this by default).</p>

  <p>So the whole thing is unreliable: unless you make special
  arrangements for each of the programs running inside xterm, you
  would often get a tab when you expect, and vice versa.</p>

  <p>For the special case where your expectations would match the
  available data, it is solvable. There are basically two ways it
  could be done:</p>

  <ul>
    <li>
      <p>set a bit in each cell's data which says it was skipped
      over via a tab. The complication is that xterm is using all
      of the flag bits in each cell.</p>
    </li>

    <li>
      <p>store literal tabs and nulls to be interpreted later
      &ndash; both by the display and the selection logic.</p>
    </li>
  </ul>

  <p>As of 2010, a few other terminals did implement this feature.
  But the reason that it's been low-priority is that it's of very
  limited usefulness when copying between terminal sessions (and
  for that matter, from other clients).</p>

  <h4><a name="xterm_paste_nl" id="xterm_paste_nl">Can
  bracketed-paste solve my problems?</a></h4>

  <p>That depends. Bracketed-paste only gives an application a
  <em>clue</em> that the input from the keyboard is being pasted
  rather than typed. It was intended to help with the
  <em>autoindent</em> feature in text editors. But not all programs
  recognize the feature (see <a href="xterm-paste64.html">this
  page</a> for more information).</p>

  <h4 id="xterm_resize-id"><a name="xterm_resize" id=
  "xterm_resize">FVWM does weird things when I try to resize
  xterm</a></h4>

  <p>I have an old (3.1.2G) bug report for xterm which may be
  related to the second (3.9s) problem:</p>

  <ul>
    <li>
      <p>Steven Lang &lt;tiger@ecis.com&gt; reports a problem with
      extra resize events for xterm.</p>

      <p>When I change font size often I will get the
      double-refresh, and when that happens the text program gets 2
      resize events.. Running a quick test, I got this: Going to a
      bigger font, it got a 53x20 resize, then a 80x24 resize.
      Going to a smaller font, it got a 120x27 resize, then a 80x24
      resize.</p>

      <p>Earlier I made a mention of changing font size in rxvt
      (And xterm does it to) causing 2 resize events. Well I just
      happened to do it in fvwm (Instead of fvwm 95) and found it
      seems to be a 'feature' of fvwm95, not XFree86 as I'd
      initially assumed.</p>
    </li>

    <li>
      <p>Stephen Marley &lt;stephen@memex.com&gt; reports a problem
      with the active icon (from X11R6.3 xterm):</p>

      <p>Using the XFree86 xterm-53 with the active icon feature
      on, I get some problems resizing where the xterm window
      shrinks as small as possible and won't stay at whatever size
      you set it thereafter.</p>

      <p>Comment out the PixmapPath and IconPath from your .fvwmrc
      file to disable the fvwm icons and restart the WM. Start an
      xterm. Iconify xterm and maximize it again. Use resize button
      or corners to resize the xterm.</p>

      <p>The xterm now shrinks to a tiny size and attempts to
      resize it result in it shrinking again.</p>

      <p>I've tried this with fvwm 1.23 and fvwm 2.0.46 with the
      same results. Olvm, olvwm and twm all behave correctly so it
      may be a fvwm problem.</p>
    </li>
  </ul>

  <p>I have not observed the first, but have reproduced the
  second.</p>

  <h4 id="xterm_tite-id"><a name="xterm_tite" id="xterm_tite">Why
  doesn't the screen clear when running vi?</a></h4>

  <p>This refers to the "alternate screen" feature, which has been
  used in its termcap file since 1988. On various systems, this
  feature may have been removed, although it has always been in the
  xterm sources.</p>

  <p>The feature is controllable (it can be enabled or disabled).
  However, as it was originally conceived, that ability to control
  it applies only to programs using termcap.</p>

  <p>Under SunOS 4.x, the termcap description for xterm embeds in
  the <code>ti</code> and <code>te</code> capabilities a command to
  switch to xterm's alternate screen (e.g., while running
  <code>vi</code>), and return to the normal screen on exit. This
  has the effect of clearing the screen. The corresponding terminfo
  symbols for <code>ti</code> and <code>te</code> are
  <code>smcup</code> and <code>rmcup</code>, respectively.</p>

  <p>Beginning with Solaris 2.x, the terminfo description did not
  use the alternate screen (it is a matter of preference after
  all), so that the text from vi remains on the screen after exit.
  Sun patched the X11R5 terminfo description to omit the
  <code>smcup</code> and <code>rmcup</code> capabilities. However,
  Sun began distributing modern xterm on the <em>freeware
  companion</em> (a CDROM) beginning with Solaris 8. In Solaris 10
  for instance, the ncurses 5.6 package provided a usable terminal
  description for xterm which uses the alternate screen. Solaris 11
  distributes modern xterm (though perhaps oddly) using an
  old&mdash;unpatched&mdash;terminal description.</p>

  <p>Because it is in the terminal description, the feature is
  configurable...</p>

  <p>For example (from Bjorn Helgaas &lt;helgaas@dhc.net&gt;) this
  procedure adds these capabilities to the &ldquo;xterm&rdquo;
  terminfo definition on HP-UX 10.20:</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    cp&nbsp;/usr/lib/terminfo/x/xterm&nbsp;/usr/lib/terminfo/x/xterm.orig<br>

    untic&nbsp;xterm&nbsp;&gt;&nbsp;/tmp/xterm.src<br>
    <span class="keyword">echo</span>&nbsp;<span class=
    "literal">"&nbsp;smcup=</span><span class=
    "keyword2">\</span><span class="literal">E7</span><span class=
    "keyword2">\</span><span class=
    "literal">E[?47h,&nbsp;rmcup=</span><span class=
    "keyword2">\</span><span class=
    "literal">E[2J</span><span class="keyword2">\</span><span class="literal">E[?47l</span><span class="keyword2">\</span><span class="literal">E8,"</span>&nbsp;&gt;&gt;&nbsp;/tmp/xterm.src<br>

    tic&nbsp;/tmp/xterm.src<br>
    <!--atr2html}}--></p>
  </blockquote>

  <p>In this example, the terminfo strings are a series of
  operations:</p>

  <blockquote>
    <dl>
      <dt><code>smcup</code>
      </dt>

      <dd><code>\E7</code> saves the cursor's position</dd>

      <dd><code>\E[?47h</code> switches to the alternate
      screen</dd>

      <dt><code>rmcup</code>
      </dt>

      <dd><code>\E[2J</code> clears the screen (assumed to be the
      alternate screen)</dd>

      <dd><code>\E[?47l</code> switches back to the normal
      screen</dd>

      <dd><code>\E8</code> restores the cursor's position.</dd>
    </dl>
  </blockquote>

  <p>However, xterms that are linked with termcap are more flexible
  in this area than those linked with terminfo libraries. The xterm
  program supports a resource <code>titeInhibit</code> which
  manipulates the $TERMCAP variable to accomplish this. It sets the
  $TERMCAP variable for the client with the <code>ti</code> and
  <code>te</code> capabilities suppressed. Systems that use
  terminfo cannot do this. If you are running terminfo with the
  alternate screen controls in the terminal description, then you
  can suppress the switching to the alternate screen by the
  <code>titeInhibit</code>, but not the associated cursor
  save/restore and clear-screen operations.</p>

  <p><a href="/xterm/xterm.log.html#xterm_54">XFree86 3.9s</a>
  xterm implemented a different set of controls (private setmodes
  1047, 1048 and 1049) which address this (in addition to the older
  set of controls, for compatibility). The new set of controls
  implements the entire <code>ti</code> sequence (save cursor,
  switch to alternate screen, clear screen) and <code>te</code>
  (switch to normal screen, restore cursor) as two control
  sequences that can be disabled by <code>titeInhibit</code>.</p>

  <p>The 1049 code is a refinement of 1047 and 1048, clearing the
  alternate screen before switching to it rather than after
  switching back to the normal screen. Since <a href=
  "xterm.log.html#xterm_90">patch #90 in 1998</a> xterm allows you
  (with a popup menu entry designed to exploit this behavior) to
  switch the display back to the alternate screen to select text
  from it, to paste into the normal screen. You can also set or
  clear the <code>titeInhibit</code> resource using another popup
  menu entry (<code>Enable Alternate Screen Switching</code>).</p>

  <p>Most other terminal emulators implement only half of the
  feature. They recognize the control sequence, but do not provide
  the ability to change it at runtime, e.g., using a menu entry.
  Like any other half-done implementation, that is a bug which
  should be reported to the developers of those programs.</p>

  <h4 id="xterm_form_feed-id"><a name="xterm_form_feed" id=
  "xterm_form_feed">Why doesn't the screen clear when I type
  control/L?</a></h4>

  <p><em>Control/L</em> is ASCII <em>form-feed</em>. Printers do
  something with form-feed. Terminals do not, as a rule (though I
  agree it would be nice, e.g., <a href=
  "/personal/oldprogs.html#repaginator">this</a>).</p>

  <p>Interpreting form-feed is normally done by your shell, not by
  the terminal emulator. In a quick check:</p>

  <ul>
    <li>
      <p>bash, tcsh, zsh interpret form-feed by clearing the
      screen, while</p>
    </li>

    <li>
      <p>csh, dash, ksh, mksh, yash do not</p>
    </li>
  </ul>

  <p>VT100s did not respond to form-feed. A few terminal emulators
  interpret form-feed (PuTTY and SunOS console), but neither
  matches VT100 behavior.</p>

  <p>Because most people do not see the difference between a
  form-feed which they type (and is presumably echoed as a
  form-feed) versus a form-feed which is sent from an application
  to the terminal, this leads to confusion. <a href=
  "http://www.thecodingforums.com/threads/screen-editing.444014/page-2#post-2480220">
  Several years ago</a>, I pointed this out as one of the errors in
  the <a href="http://c-faq.com/osdep/termcap.html">C FAQ</a>
  (notwithstanding Summit's comment, he did not update the
  FAQ).</p>

  <h4 id="xterm_vite-id"><a name="xterm_vite" id="xterm_vite">Why
  is the cursor misplaced after running vi?</a></h4>

  <p>Vi and other full-screen applications use the termcap
  <code>ti/te</code> (terminfo <code>smcup/rmcup</code>) strings to
  initiate and end cursor addressing mode. As mentioned in the
  discussion of <a href=
  "xterm.faq.html#xterm_tite">titeInhibit</a>, full-screen
  applications can expect the initialization string to save the
  cursor's position, and the end-string to restore it.</p>

  <p>A few applications (reportedly IRIX 5.x and 6.x
  <code>vi</code> incorrectly move the cursor before initializing
  cursor-addressing. This will cause the end-string to restore the
  cursor to its position when it was saved by the initialization
  string (typically at the upper left corner of the screen).</p>

  <p>The usual reason is due to the cursor save/restore controls in
  the <code>ti/te</code> strings. If your application runs a
  subprocess which in turn runs another full-screen application (or
  when reinitializing the screen after the shell process), it will
  save the cursor position again, so the position which is restored
  when finally exiting your program is the last one saved, not the
  first. Modern xterm (from late 1998, <a href=
  "xterm.log.html#xterm_90">patch 90</a>) changes the behavior of
  the cursor save/restore operations so they apply only to the
  current screen. That makes it less likely to misplace your
  cursor.</p>

  <h4 id="narrowproto-id"><a name="narrowproto" id=
  "narrowproto">Why doesn't the scrollbar work?</a></h4>

  <p>Originally xterm was built using imake rather than a configure
  script. One feature of imake that is not possible to guess within
  the configure script is the wide-prototype compile-time
  definition NARROWPROTO. When this is not set properly, the Athena
  widget scrollbars do not work properly. xterm's configure script
  has a fallback case which allows disabling imake. However, this
  is moot with the Xorg &ldquo;modular&rdquo; build, whose compiler
  options are unrelated to imake or older versions of any libraries
  that it may distribute. In this case, the configure script needs
  some help. Use this option to enable or disable NARROW proto (and
  disable imake with the --disable-imake option) to match the whims
  of Xorg hackers.</p>

  <p>For instance</p>

  <blockquote>
    <pre class="code-block">
configure --disable-imake --disable-narrowproto
</pre>
  </blockquote>

  <h4 id="xaw_scrollbars-id"><a name="xaw_scrollbars" id=
  "xaw_scrollbars">Can I improve the scrollbars?</a></h4>

  <p>Is that a problem with the appearance, or the way they
  work?</p>

  <p>The appearance can be modified (though few do this) by linking
  with one of the variants of the Athena widget set (Xaw).</p>

  <p>To illustrate, here are a few screenshots:</p>

  <blockquote>
    <dl>
      <dt>Xaw (default)</dt>

      <dd>
        <p><a href="images/xterm-Xaw.png"><img width="300" src=
        "images/xterm-Xaw.png" alt=
        "xterm &ndash; default scrollbar with Xaw"></a></p>
      </dd>

      <dt>XawPlus</dt>

      <dd>
        <p><a href="images/xterm-XawPlus.png"><img width="300" src=
        "images/xterm-XawPlus.png" alt=
        "xterm &ndash; scrollbar with XawPlus"></a></p>
      </dd>

      <dt>Xaw3d</dt>

      <dd>
        <p><a href="images/xterm-Xaw3d.png"><img width="300" src=
        "images/xterm-Xaw3d.png" alt=
        "xterm &ndash; scrollbar with Xaw3d"></a></p>
      </dd>

      <dt>neXtaw</dt>

      <dd>
        <p><a href="images/xterm-neXtaw.png"><img width="300" src=
        "images/xterm-neXtaw.png" alt=
        "xterm &ndash; scrollbar with neXtaw"></a></p>
      </dd>
    </dl>
  </blockquote>

  <p>Those variants use the same calling interface, so supporting
  them is simple. Adapting to other toolkits would be much more
  difficult. For instance (see the discussion of <a href=
  "#bug_mxterm">mxterm</a>), replacing the scrollbars may require
  replacing other parts from the library to get consistent
  initialization and operation. In the case of Motif, it had
  nothing like the Athena widget set's popup menus.</p>

  <h4 id="scroll_speed-id"><a name="scroll_speed" id=
  "scroll_speed">Can I improve the scrolling speed?</a></h4>

  <p>Several years ago (before 2010) there was a <a href=
  "https://web.archive.org/web/20091210162250/https://martin.ankerl.com/2007/09/01/comprehensive-linux-terminal-performance-comparison/">
  webpage</a> which gave its author's notion of what constituted a
  &ldquo;good&rdquo; terminal emulator:
  <strong><code>cat</code></strong>'ing (sending) a large file to
  the terminal would complete in minimal time. Apparently that was
  the sole interest. Interestingly, its author stated that
  <em>xterm</em> was the slowest although the presented data do not
  show this. Also, although the page says &ldquo;Linux&rdquo; some
  of the data are for programs running on
  <strong><em>Windows</em></strong>. The page spawned a few
  imitators (with no better methodology), none was systematic, none
  did any analysis.</p>

  <p>Of course, developers do not do that in practice. The terminal
  is useful for interactive tasks. Compiling is best done by
  redirecting the build messages to a log file or using a batch
  process. End users have a different outlook.</p>

  <p>There is more than one factor involved in scrolling speed.
  Here are a few:</p>

  <ul>
    <li>
      <p>When <strong>xterm</strong> was first written, machines
      had less memory, and scrolling back a thousand lines seemed
      good enough for users. Internally, <em>xterm</em> stored the
      current screen and saved-lines in a large array. It scrolled
      the array by shifting the entire array by a given number of
      rows. For a thousand lines saved-lines (the scrollback
      region), that works well enough.</p>

      <p>But the <a href=
      "manpage/xterm.html#VT100-Widget-Resources:saveLines"><code>saveLines</code></a>
      resource allows a full <em>integer</em>, and during the
      mid/late-1990s, a few users found that setting the resource
      to a million lines made <em>xterm</em> very slow.</p>

      <p>Still, the graphics display was fast enough. By the way,
      <em>xterm</em> uses the <em>XCopyArea</em> function, and
      normally (attempts to) display all of the updates to the
      screen.</p>
    </li>

    <li>
      <p>Later, <strong>rxvt</strong> came along. It limited the
      number of saved-lines to a signed 16-bit integer, i.e., 32767
      (and some packagers limited it to only a few thousand lines),
      and moved just the pointers to the line data when scrolling
      rather than shifting all of the text. It also uses
      <em>XCopyArea</em>, noting in its features</p>

      <blockquote>
        <pre class="code-block">
/*
 * Define to remove support for XCopyArea() support.  XCopyArea() is useful
 * for scrolling on non-local X displays
 */
/* #define NO_SLOW_LINK_SUPPORT */
</pre>
      </blockquote>

      <p>Unlike <em>xterm</em>, <em>rxvt</em> did not attempt to
      display all updates. If it fell behind, it would discard some
      of the updates, to catch up. Doing that had a greater effect
      on the apparent scrolling speed than its internal memory
      organization, since it was useful for any number of
      saved-lines. One drawback was that ASCII animations were
      somewhat erratic.</p>
    </li>

    <li>
      <p>A few other terminal emulators, such as
      <strong>konsole</strong> copied the <em>rxvt</em> feature.
      Others copied, in turn, from whatever source. As a result,
      one cannot compare the speed of different terminal emulators,
      since they do not follow the same rules.</p>
    </li>

    <li>
      <p>The issue with <em>xterm</em> shifting a large array was a
      problem which was addressed by changing all of the pointers
      to its line data into a <a href=
      "http://www.geeksforgeeks.org/implementation-deque-using-circular-array/">
      <em>circular array</em></a> in 2009 (<a href=
      "xterm.log.html#xterm_244">patch #244</a>).</p>
    </li>

    <li>
      <p>Even after improving the memory performance of scrolling,
      <em>rxvt</em> and its imitators still appeared to scroll
      faster.</p>

      <p>The <a href=
      "manpage/xterm.html#VT100-Widget-Resources:fastScroll"><code>fastScroll</code></a>
      resource added in patch #244 provides a simple implementation
      of the <em>rxvt</em> (mis?)feature for <em>xterm</em>.</p>

      <p>As implemented, it is rather crude (sometimes
      <em>xterm</em> &mdash; like <em>konsole</em> &mdash; appears
      to stop, since it is waiting for a new set of screen updates
      after having discarded some).</p>
    </li>
  </ul>

  <p>Scrolling speed is only one aspect of terminal speed, but it
  is easy to measure. Other aspects (such as the speed with which
  an application can change color, move the cursor around the
  screen, write text in various places) can also be measured. But
  comparing terminals based on that speed can be misleading. When
  the terminal drops updates to keep up with an application's
  speed, the result may be unnoticeable (if the application is fast
  enough), or it may not.</p>

  <p>For example, running the <strong>dots</strong> program from
  the <a href="/ncurses/ncurses-examples.html">ncurses-examples</a>
  shows some interesting misbehavior with <em>gnome-terminal</em>
  and <em>konsole</em>: both &ldquo;choke&rdquo; at times for a few
  seconds. The <em>dots</em> program prints colored cells randomly
  around the screen, pausing briefly 1% of the time. However when
  <em>dots</em> is terminated, it prints the program's notion of
  the output rate. In spite of the pauses, the program saw a fairly
  good rate of output. Some terminal emulators cannot keep up with
  <em>dots</em>; one possible explanation for the discrepancy is
  that the terminal emulator discards output (as in the special
  case of scrolling).</p>

  <p>Seeing that raised the question of what variation to expect
  from different terminal emulators, to point out which might
  discard output to achieve fast scrolling speeds. A simple script
  showing the elapsed time to send <em>ncurses</em>'s <a href=
  "/ncurses/terminfo.src.html"><code>terminfo.src</code></a>
  (1.1Mb) a given number of times to the terminal was used. Here is
  a table illustrating the differences, using the available
  terminal emulators for Fedora 26 and Ubuntu 17 in November
  2017:</p>

  <table border="1" summary="examples of scrolling speed">
    <tr>
      <th rowspan="2" style="width:6em;">Mode</th>
      <th rowspan="2" style="width:10em;">Terminal</th>
      <th colspan="3">Fedora</th>
      <th colspan="3">Ubuntu</th>
    </tr>

    <tr>
      <th style="width:4em;">1</th>
      <th style="width:4em;">10</th>
      <th style="width:4em;">99</th>
      <th style="width:4em;">1</th>
      <th style="width:4em;">10</th>
      <th style="width:4em;">99</th>
    </tr>

    <tr>
      <td rowspan="10" align="center">Remote</td>
      <td>gnome-terminal</td>
      <td>(1)</td>
      <td>(1)</td>
      <td>(1)</td>
      <td>(1)</td>
      <td>(1)</td>
      <td>(1)</td>
    </tr>

    <tr>
      <td>konsole</td>
      <td>0.12</td>
      <td>2.10</td>
      <td>23.2</td>
      <td>0.26</td>
      <td>2.65</td>
      <td>25.7</td>
    </tr>

    <tr>
      <td>mlterm</td>
      <td>(2)</td>
      <td>(2)</td>
      <td>(2)</td>
      <td>0.30</td>
      <td>3.07</td>
      <td>30.4</td>
    </tr>

    <tr>
      <td>pterm / putty</td>
      <td>0.15</td>
      <td>1.42</td>
      <td>14.6</td>
      <td>0.55</td>
      <td>5.66</td>
      <td>56.2</td>
    </tr>

    <tr>
      <td>rxvt (3)</td>
      <td>0.25</td>
      <td>2.97</td>
      <td>29.5</td>
      <td>0.23</td>
      <td>3.03</td>
      <td>29.5</td>
    </tr>

    <tr>
      <td>st / stterm (4)</td>
      <td>0.07</td>
      <td>0.50</td>
      <td>4.40</td>
      <td>0.15</td>
      <td>1.42</td>
      <td>14.4</td>
    </tr>

    <tr>
      <td>terminology</td>
      <td>0.10</td>
      <td>1.00</td>
      <td>10.1</td>
      <td>0.19</td>
      <td>2.01</td>
      <td>19.0</td>
    </tr>

    <tr>
      <td>urxvt</td>
      <td>0.05</td>
      <td>0.38</td>
      <td>3.24</td>
      <td>0.17</td>
      <td>1.60</td>
      <td>15.7</td>
    </tr>

    <tr>
      <td>xterm</td>
      <td>0.31</td>
      <td>3.50</td>
      <td>34.8</td>
      <td>0.47</td>
      <td>4.41</td>
      <td>44.1</td>
    </tr>

    <tr>
      <td>xterm + fastScroll</td>
      <td>0.09</td>
      <td>0.82</td>
      <td>8.36</td>
      <td>0.39</td>
      <td>2.43</td>
      <td>22.9</td>
    </tr>

    <tr>
      <td rowspan="10" align="center">Local</td>
      <td>gnome-terminal</td>
      <td>0.12</td>
      <td>1.16</td>
      <td>11.4</td>
      <td>0.29</td>
      <td>3.14</td>
      <td>30.6</td>
    </tr>

    <tr>
      <td>konsole</td>
      <td>0.11</td>
      <td>0.82</td>
      <td>7.97</td>
      <td>0.22</td>
      <td>2.17</td>
      <td>20.1</td>
    </tr>

    <tr>
      <td>mlterm</td>
      <td>(2)</td>
      <td>(2)</td>
      <td>(2)</td>
      <td>1.01</td>
      <td>7.59</td>
      <td>105.</td>
    </tr>

    <tr>
      <td>pterm / putty</td>
      <td>0.17</td>
      <td>1.52</td>
      <td>14.6</td>
      <td>(5)</td>
      <td>(5)</td>
      <td>(5)</td>
    </tr>

    <tr>
      <td>rxvt</td>
      <td>1.23</td>
      <td>11.9</td>
      <td>118.</td>
      <td>1.75</td>
      <td>16.9</td>
      <td>166.</td>
    </tr>

    <tr>
      <td>st / stterm (4)</td>
      <td>0.08</td>
      <td>0.61</td>
      <td>5.10</td>
      <td>0.21</td>
      <td>1.63</td>
      <td>15.9</td>
    </tr>

    <tr>
      <td>terminology</td>
      <td>0.09</td>
      <td>1.03</td>
      <td>10.1</td>
      <td>0.43</td>
      <td>1.64</td>
      <td>16.0</td>
    </tr>

    <tr>
      <td>urxvt</td>
      <td>0.07</td>
      <td>0.53</td>
      <td>4.52</td>
      <td>0.26</td>
      <td>2.41</td>
      <td>23.7</td>
    </tr>

    <tr>
      <td>xterm</td>
      <td>1.77</td>
      <td>18.5</td>
      <td>178.</td>
      <td>2.70</td>
      <td>26.5</td>
      <td>259.</td>
    </tr>

    <tr>
      <td>xterm + fastScroll</td>
      <td>0.12</td>
      <td>0.96</td>
      <td>9.92</td>
      <td>0.25</td>
      <td>2.36</td>
      <td>22.9</td>
    </tr>
  </table>

  <p><strong>Notes</strong>:</p>

  <ol>
    <li>
      <p>On both systems, <em>gnome-terminal</em> failed to connect
      remotely.</p>
    </li>

    <li>
      <p>Fedora does not have <em>mlterm</em>.</p>
    </li>

    <li>
      <p>On Ubuntu, the <em>urxvt</em> package hijacks the name
      &ldquo;rxvt&rdquo;, so the <em>&ldquo;rxvt&rdquo;</em>
      actually tested was <em>rxvt-xpm</em> from the rxvt 2.7.10
      package.</p>
    </li>

    <li>
      <p>Fedora has <em>st</em> 0.70, while Ubuntu has version
      0.60, which is a couple of years older.</p>
    </li>

    <li>
      <p>Running locally on Ubuntu, <em>pterm</em> 0.70-1 dumped
      core.</p>
    </li>
  </ol>

  <p>Regarding the selection of terminal emulators:</p>

  <ul>
    <li>
      <p>Keeping mind that this is an <em>xterm</em> FAQ, the Linux
      console (and Windows console, and PuTTY running on Windows)
      are off-topic.</p>
    </li>

    <li>
      <p>The table mentions programs which at one time or another
      have set <a href=
      "/ncurses/ncurses.faq.html#xterm_generic"><code>TERM=xterm</code></a>.</p>

      <p>The actual test does not rely upon the terminal
      description, nor in fact on any terminal description. The
      distinction was made for their relevance to this FAQ.</p>
    </li>

    <li>
      <p>Given that, <em>rxvt</em> 2.7.10 is listed, as well as its
      descendent <em>urxvt</em> (rxvt-unicode).</p>

      <p>Other variations of <em>rxvt</em> (such as <em>aterm</em>
      and <em>mrxvt</em>) were considered, but since much of the
      related code is identical, not very interesting.</p>
    </li>

    <li>
      <p>Both systems have several variants of the <em>skins</em>
      for the VTE library, but for both systems, the developers
      have a heavy bias in favor of the GNOME desktop. Comparing
      the performance of the various skins would be pointless,
      since not all are equally supported (due to the GNOME
      developers' practice of making incompatible changes), and
      would make an unbalanced comparison in any case.</p>
    </li>

    <li>
      <p>The Unix port of PuTTY, <em>pterm</em> is listed. It uses
      <em>GDK</em>.</p>
    </li>
  </ul>

  <p>Interestingly, performance is better running remotely. In the
  test, the machines are not identical:</p>

  <ul>
    <li>
      <p>The <em>remote</em> system uses a Mac mini-server.</p>
    </li>

    <li>
      <p>The Fedora system is a virtual machine using
      Parallels.</p>
    </li>

    <li>
      <p>The Ubuntu system is a virtual machine using Vmware
      Fusion.</p>
    </li>
  </ul>

  <p>Possibly displaying on the virtual machines does not perform
  as well as via XQuartz. But that is a lot of difference to
  explain. More likely, the local X server is performing badly on
  some calls.</p>

  <ul>
    <li>
      <p>For a while, <em>XCopyArea</em> was a problem, where the
      Xorg hackers had degraded its performance radically. While
      that might still be the underlying issue, <em>st</em> and
      <em>urxvt</em> do use that function.</p>
    </li>

    <li>
      <p>Another possibility is mentioned in <em><a href=
      "#compiz_bugs">Why is the text in the wrong place?</a></em>
      where the apparent root cause was a server feature which only
      implemented parts of the X protocol.</p>
    </li>
  </ul>

  <p>Using the <em>fastScroll</em> feature made <em>xterm</em>
  performance comparable to the &ldquo;desktop&rdquo; applications.
  But as usual, with performance data, your mileage may vary.</p>

  <h4 id="window_ops-id"><a name="window_ops" id="window_ops">Why
  can't my program read the window title?</a></h4>

  <p>The longstanding control sequence for reading the window title
  is something that can be abused in special conditions. For novice
  (unknowledgable) users, this can be a problem.</p>

  <p><strong>XTerm</strong> provides resource-settings and menu
  entries to allow this and related features to be enabled or
  disabled. See for example <code>allowWindowOps</code> The default
  resource settings in xterm can be overridden by a packager.
  However, a knowledgable user can override those default
  settings.</p>

  <p>It is also possible that an overzealous packager may have
  crippled xterm by removing the functionality altogether. (That
  should be reported as a bug, to me).</p>

  <p>For instance, one of those sent me a "security fix" some years
  ago, which deleted most of the control sequences which return
  data to the host. It broke the <code>resize</code> program, and
  selection, among other uses considered to be benign. In contrast,
  the same features used in other terminal emulators are tolerated
  by the same people, so rather than being a misguided attempt at
  fixing security issues, patches such as that appear to be an
  attempt at harassment.</p>

  <h4 id="window_ops2-id"><a name="window_ops2" id=
  "window_ops2">Why can't my program set the window size?</a></h4>

  <p>Some overzealous packagers, perhaps influenced by the
  demonstration I provided, are protecting you against the
  possibility of your xterm becoming inaccessible. (That's
  unlikely...).</p>

  <p>You should be able to override it, as noted above via resource
  settings or menu entry ("Allow Window Ops").</p>

  <h4><a name="compiz_bugs" id="compiz_bugs">Why is the text in the
  wrong place?</a></h4>

  <p>Are you using Ubuntu? This was a frequently-reported problem
  for Ubuntu users. With other systems, it could occur (as of
  September 2012), but is less frequent. But it was an issue with
  Ubuntu since 2008.</p>

  <p>There ware several related symptoms, e.g.,</p>

  <ul>
    <li>
      <p>text may be the wrong size</p>
    </li>

    <li>
      <p>repainting the screen puts text in the wrong place</p>
    </li>
  </ul>

  <p>Here are some of the corresponding bug reports:</p>

  <ul>
    <li>
      <p><a href=
      "https://bugs.launchpad.net/ubuntu/+source/xterm/+bug/199285">
      Ubuntu #199285 - xterm crashes when compiz is on</a></p>
    </li>

    <li>
      <p><a href=
      "http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=467399">Debian
      #467399 - compiz fails to take control of windows</a></p>
    </li>

    <li>
      <p><a href=
      "https://bugs.launchpad.net/ubuntu/+source/xfce4-terminal/+bug/378668">
      Ubuntu #378668 - Cursor in terminal behaves badly with
      special characters present</a></p>
    </li>

    <li>
      <p><a href=
      "https://bugzilla.novell.com/show_bug.cgi?id=622936">Novell
      #622936 - xterm: font drawing glitch</a></p>
    </li>

    <li>
      <p><a href=
      "https://bugzilla.redhat.com/show_bug.cgi?id=583904">Redhat
      #583904 - gnome-terminal and xterm show garbled fonts with
      compiz enabled (intel graphics)</a></p>
    </li>

    <li>
      <p><a href=
      "https://bugzilla.redhat.com/show_bug.cgi?id=614542">Redhat
      #614542 - xterm graphical corruption when compiz is
      active</a></p>
    </li>

    <li>
      <p><a href=
      "https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/635258">
      Ubuntu #635258 - Garbled chars in xterm</a></p>
    </li>

    <li>
      <p><a href=
      "https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/644943">
      Ubuntu #644943 - xterm fonts get corrupted while typing</a></p>
    </li>

    <li>
      <p><a href=
      "https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/701160">
      Ubuntu #701160 - /usr/bin/xterm is not functional in
      natty</a></p>
    </li>

    <li>
      <p><a href=
      "https://bugs.launchpad.net/ubuntu/+source/xterm/+bug/700477">
      Ubuntu #700477 - Font corruption in xterm under Lucid</a></p>
    </li>

    <li>
      <p><a href=
      "https://bugzilla.novell.com/show_bug.cgi?id=681359">Novell
      #681359 - xterm: no data shown under the screen program</a></p>
    </li>

    <li>
      <p><a href=
      "https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/711894">
      Ubuntu #711894 - iconic option does not work with compiz</a></p>
    </li>

    <li>
      <p><a href=
      "https://bugs.launchpad.net/ubuntu/+source/xterm/+bug/778439">
      Ubuntu #778439 - Typing &ldquo;exit&rdquo; in xterm kills X
      session</a></p>
    </li>

    <li>
      <p><a href=
      "https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/831336">
      Ubuntu #831336 - running 'xterm' crashes X server</a></p>
    </li>

    <li>
      <p><a href=
      "https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/841103">
      Ubuntu #841103 - Text has artifacts when typing something
      else</a></p>
    </li>

    <li>
      <p><a href=
      "https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/844454">
      Ubuntu #844454 - Garbled chars in xterm (Onieric)</a></p>
    </li>

    <li>
      <p><a href=
      "https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/1002972">
      Ubuntu #1002972 - xterm moves to upper left when clicking
      titel bar</a></p>
    </li>

    <li>
      <p><a href=
      "https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/1007722">
      Ubuntu #1007722 - xterm doesn't display all the
      information</a></p>
    </li>
  </ul>

  <p>Since the problem was not in xterm, all I could do is to help
  forward those bug-reports to whatever package owns
  <code>compiz</code>. What these had in common is that someone
  wrote code which was tested against only a small subset of the X
  protocol.</p>

  <p>Looking for solutions (since compiz was not being fixed), it
  was possible to disable compiz. The means for doing this varied
  with time. Aside from pointing to the root cause of the problem,
  there was little advice that was useful.</p>

  <ul>
    <li>
      <p>For instance, <a href=
      "http://force.subcritical.org/xterm_under_compiz/">this
      comment</a> by Eric Williams suggested that the problem could
      be worked around by setting xterm's <code>borderWidth</code>
      resource to zero.</p>
    </li>

    <li>
      <p>other comments suggested turning off the &ldquo;desktop
      effects&rdquo; or &ldquo;animation&rdquo;.</p>
    </li>

    <li>
      <p>On my machines using the default <em>Ubuntu</em> desktop,
      I could see misbehavior easily in Ubuntu 12.04 using <a href=
      "/vttest/vttest.html">vttest</a>. However, Ubuntu 12.04
      provided <em>Ubuntu&nbsp;2D</em>, which did not show those
      problems (and was noticeably faster).</p>
    </li>
  </ul>

  <p>Ubuntu dropped <em>compiz</em> in 2017. Its replacement (GNOME
  shell) has fewer bugs.</p>

  <h3 id="my_xdefaults-id"><a name="my_xdefaults" id=
  "my_xdefaults">Sample .Xdefaults Color-Settings for XTerm</a></h3>

  <p>This example dates from March 1997:</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    <span class="keyword">XTerm</span>*<span class=
    "ident2">internalBorder</span>:<span class=
    "literal">&nbsp;&nbsp;</span><span class="number">10</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "ident2">highlightSelection</span>:<span class=
    "literal">&nbsp;&nbsp;</span><span class=
    "keyword">true</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">colorBDMode</span>:<span class=
    "literal">&nbsp;&nbsp;on</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">colorBD</span>:<span class=
    "literal">&nbsp;&nbsp;blue</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">colorULMode</span>:<span class=
    "literal">&nbsp;&nbsp;on</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">colorUL</span>:<span class=
    "literal">&nbsp;&nbsp;magenta</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">eightBitInput</span>:<span class=
    "literal">&nbsp;&nbsp;</span><span class=
    "keyword">true</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">eightBitOutput</span>:<span class=
    "literal">&nbsp;&nbsp;</span><span class=
    "keyword">true</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "ident2">scrollBar</span>:<span class=
    "literal">&nbsp;&nbsp;</span><span class=
    "keyword">true</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">titeInhibit</span>:<span class=
    "literal">&nbsp;&nbsp;</span><span class=
    "keyword">true</span><br>
    &nbsp;<br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">colorMode</span>:<span class=
    "literal">&nbsp;&nbsp;on</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">dynamicColors</span>:<span class=
    "literal">&nbsp;&nbsp;on</span><br>
    &nbsp;<br>
    <span class=
    "comment">!&nbsp;Uncomment&nbsp;this&nbsp;to&nbsp;use&nbsp;color&nbsp;for&nbsp;underline&nbsp;attribute<br>
    </span> <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">colorULMode</span>:<span class=
    "literal">&nbsp;&nbsp;on</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">underLine</span>:<span class=
    "literal">&nbsp;&nbsp;off</span><br>
    &nbsp;<br>
    <span class=
    "comment">!&nbsp;Uncomment&nbsp;this&nbsp;to&nbsp;use&nbsp;color&nbsp;for&nbsp;the&nbsp;bold&nbsp;attribute<br>
    </span> <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">colorBDMode</span>:<span class=
    "literal">&nbsp;on</span><br>
    &nbsp;<br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">color0</span>:<span class=
    "literal">&nbsp;black</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">color1</span>:<span class=
    "literal">&nbsp;red3</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">color2</span>:<span class=
    "literal">&nbsp;green3</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">color3</span>:<span class=
    "literal">&nbsp;yellow3</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">color4</span>:<span class=
    "literal">&nbsp;blue3</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">color5</span>:<span class=
    "literal">&nbsp;magenta3</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">color6</span>:<span class=
    "literal">&nbsp;cyan3</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">color7</span>:<span class=
    "literal">&nbsp;gray90</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">color8</span>:<span class=
    "literal">&nbsp;gray30</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">color9</span>:<span class=
    "literal">&nbsp;red</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">color10</span>:<span class=
    "literal">&nbsp;green</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">color11</span>:<span class=
    "literal">&nbsp;yellow</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">color12</span>:<span class=
    "literal">&nbsp;blue</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">color13</span>:<span class=
    "literal">&nbsp;magenta</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">color14</span>:<span class=
    "literal">&nbsp;cyan</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">color15</span>:<span class=
    "literal">&nbsp;white</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">colorUL</span>:<span class=
    "literal">&nbsp;yellow</span><br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">colorBD</span>:<span class=
    "literal">&nbsp;white</span><br>
    &nbsp;<br>
    <span class="keyword">XTerm</span>*<span class=
    "keyword">VT100</span>.<span class=
    "ident2">cursorColor</span>:<span class=
    "literal">&nbsp;lime&nbsp;green</span><br>
    <!--atr2html}}--></p>
  </blockquote>

  <p><strong>XTerm</strong> comes with two copies of each resource
  file, one with color only (<code>XTerm-col.ad</code>, which is
  installed as <code>XTerm-color</code>), and the regular one
  (<code>XTerm.ad</code>, installed as <code>XTerm</code>). To use
  the <code>XTerm-color</code> file in conjunction with a separate
  <code>XTerm</code> app-defaults file which does not contain
  color, add the following line to your <code>.Xdefaults</code>
  file:</p>

  <blockquote class="code-block">
    <!--{{atr2html-->

    <p style="font-family: monospace; font-size: 10pt;">
    *<span class="ident2">customization</span>:<span class=
    "literal">&nbsp;-color</span><br>
    <!--atr2html}}--></p>
  </blockquote>

  <p>Since 1997, the resource files grew in size and number.
  Besides <code>XTerm</code> and <code>XTerm-color</code>, there
  are also resource files for <strong>xterm</strong> using
  different <em>class</em> values, together with the
  <code>-color</code> flavors of these. Because the
  <code>-color</code> flavors differ only by an
  <code>#include</code> statement, the makefile generates these
  from <a href=
  "https://github.com/ThomasDickey/xterm-snapshots/blob/master/XTerm-col.ad">
  XTerm-col.ad</a>. Here are the others:</p>

  <blockquote>
    <table border="1" summary="resource files for XTerm">
      <tr>
        <th>Program</th>
        <th>Resource</th>
      </tr>

      <tr>
        <td><a href="#xterm_man">xterm</a>
        </td>
        <td><a href=
        "https://github.com/ThomasDickey/xterm-snapshots/blob/master/XTerm.ad">
        XTerm</a>
        </td>
      </tr>

      <tr>
        <td><a href="#uxterm_man">uxterm</a>
        </td>
        <td><a href=
        "https://github.com/ThomasDickey/xterm-snapshots/blob/master/UXTerm.ad">
        UXTerm</a>
        </td>
      </tr>

      <tr>
        <td><a href="#koi8rxterm_man">koi8rxterm</a>
        </td>
        <td><a href=
        "https://github.com/ThomasDickey/xterm-snapshots/blob/master/KOI8RXTerm.ad">
        KOI8RXTerm</a>
        </td>
      </tr>
    </table>
  </blockquote>

  <p>Besides just adding files, I continued testing more resource
  combinations. Originally (in the 1990s for instance), developers
  could reasonably expect their users to configure resources for
  themselves, rather than use a single prepackaged flavor. That was
  a while ago. After 2000, I developed nicer resource files. Rather
  than modify the installed <code>app-defaults</code> file, I use
  this feature from X:</p>

  <blockquote>
    <p class="code-block">Directories named by the environment
    variable <code>XUSERFILESEARCHPATH</code> or the environment
    variable <strong><code>XAPPLRESDIR</code></strong> (which names
    a single directory and should end with a &lsquo;/&rsquo; on
    POSIX systems), plus directories in a standard place (usually
    under <em><code>/usr/share/X11/</code></em>, but this can be
    overridden with the <em><code>XFILESEARCHPATH</code></em>
    environment variable) are searched for for application-specific
    resources. For example, application default resources are
    usually kept in
    <em><code>/usr/share/X11/app-defaults/</code></em>. See the
    <em>X Toolkit Intrinsics &ndash; C Language Interface</em>
    manual for details.</p>
  </blockquote>

  <p>That is, if you set the <code>XAPPLRESDIR</code> environment
  variable to point to a directory, you can put application
  resource files there, and X will find those before the system
  app-defaults files. That allows more flexibility and better
  control over the various applications than putting everything
  into a single <code>.Xdefaults</code> file.</p>

  <p>On the opposite extreme, some people advise using
  <code>xrdb</code>. Not everyone. Back around 1990 I had an
  informative conversation with one of the developers at the
  Software Productivity Consortium. He was a member of a team
  developing a set of X widgets. The gist of our conversation was
  that</p>

  <ul>
    <li>
      <p>using <code>xrdb</code> prevented you from changing things
      dynamically.</p>
    </li>

    <li>
      <p>it was like using a hammer (nailing things down to prevent
      them from being different).</p>
    </li>

    <li>
      <p>when the only tool you know how to use is a hammer,
      <a href=
      "https://www.google.com/search?q=hammer+nail+problem&amp;tbm=isch&amp;tbo=u&amp;source=univ&amp;sa=X&amp;ved=0ahUKEwigkLaixZLPAhWGWCYKHVD5B0sQsAQIUQ">
      all of the problems look like nails</a>.</p>
    </li>

    <li>
      <p>a good developer knows how to use more than one tool.</p>
    </li>
  </ul>

  <h3 id="warning_msg-id"><a name="warning_msg" id=
  "warning_msg">What is this warning message?</a></h3>

  <dl>
    <dt id="warning_errno">xterm: Error 11, errno 22: permission
    denied</dt>

    <dd>
      Actually, any message like this denotes a failure which
      requires studying the xterm source to determine the exact
      problem.
      <p>You have either found a bug in xterm, or there is
      something wrong with your computer's configuration, e.g., not
      enough pty's, incorrect permissions, etc.</p>

      <p>The first number is an internal code (defined in error.h
      in xterm's source), and the second is the system error number
      (defined in /usr/include/sys/errno.h). The system error
      number is easier to lookup, but the internal error code tells
      you where to look in the source.</p>
    </dd>

    <dt id="warning_preedit">input method doesn't support my
    preedit type</dt>

    <dd>
      Ignore this if you do not know what <em>input method</em> is.
      Input methods are used to enter composite characters (e.g.,
      umlauts, other types of punctuated characters, East Asian
      characters, etc). Your computer's libraries support this, but
      are missing configuration tables, and xterm is warning you.
      <p>If the message bothers you (e.g., if you aren't starting
      xterm from a window manager menu), you can suppress it by
      setting a resource:</p>

      <blockquote class="code-block">
        <!--{{atr2html-->

        <p style="font-family: monospace; font-size: 10pt;">
        <span class="keyword">XTerm</span>*<span class=
        "ident2">openIm</span>:<span class=
        "keyword">false</span><br>
        <!--atr2html}}--></p>
      </blockquote>
    </dd>

    <dt id="warning_action">Warning: Actions not found: ignore,
    "<em>xxx</em>"</dt>

    <dd>
      The action "<em>xxx</em>" (for example "scroll-back") is
      specified in a resource file whose translations match widgets
      that do not support them. For example, this
      <blockquote class="code-block">
        <!--{{atr2html-->

        <p style="font-family: monospace; font-size: 10pt;">
        <span class="keyword">XTerm</span>*<span class=
        "ident2">translations</span>:<span class=
        "literal">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;#override\n\<br>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Leave&gt;</span><span class="literal">,&nbsp;~Ctrl&nbsp;~Meta&nbsp;</span><span class="keyword">&lt;Btn2Up&gt;</span><span class="literal">:&nbsp;ignore()\n\<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_8:&nbsp;scroll-back(</span><span class="number">1</span><span class="literal">,line)\n\<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_2:&nbsp;scroll-forw(</span><span class="number">1</span><span class="literal">,line)\n\<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_8:&nbsp;scroll-back(</span><span class="number">1</span><span class="literal">,halfpage)\n\<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_2:&nbsp;scroll-forw(</span><span class="number">1</span><span class="literal">,halfpage)</span><br>

        <!--atr2html}}--></p>
      </blockquote>

      <p>will produce warnings such as</p>

      <blockquote>
        <pre class="code-block">
Warning: Actions not found: ignore, scroll-back, scroll-forw
Warning: Actions not found: ignore, scroll-back, scroll-forw
Warning: Actions not found: ignore, scroll-back, scroll-forw
</pre>
      </blockquote>

      <p>This is a correct form, assigning the actions to the
      &ldquo;VT100&rdquo; widget.</p>

      <blockquote class="code-block">
        <!--{{atr2html-->

        <p style="font-family: monospace; font-size: 10pt;">
        <span class="keyword">XTerm</span>*<span class=
        "keyword">VT100</span>.<span class=
        "ident2">translations</span>:<span class=
        "literal">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;#override\n\<br>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span class="keyword">&lt;Leave&gt;</span><span class="literal">,&nbsp;~Ctrl&nbsp;~Meta&nbsp;</span><span class="keyword">&lt;Btn2Up&gt;</span><span class="literal">:&nbsp;ignore()\n\<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_8:&nbsp;scroll-back(</span><span class="number">1</span><span class="literal">,line)\n\<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~Shift&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_2:&nbsp;scroll-forw(</span><span class="number">1</span><span class="literal">,line)\n\<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_8:&nbsp;scroll-back(</span><span class="number">1</span><span class="literal">,halfpage)\n\<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Shift&nbsp;</span><span class="keyword">&lt;Key&gt;</span><span class="literal">KP_2:&nbsp;scroll-forw(</span><span class="number">1</span><span class="literal">,halfpage)</span><br>

        <!--atr2html}}--></p>
      </blockquote>
    </dd>

    <dt id="alloc_color-id"><a name="alloc_color" id=
    "alloc_color">Warning: Cannot allocate colormap entry for
    "<em>xxx</em>"</a>
    </dt>

    <dd>
      This comes from the X library. Modern xterm uses the default
      color map. What this means is that if your X server has
      insufficient space to store color information for more than
      one color map, other applications which could use other color
      maps may conflict with xterm. In practice, that is 256 unique
      colors on the screen at a time&mdash;not enough for a fancy
      background or an application such as Netscape.
      <p>During resource initialization, xterm attempts to allocate
      an entry from the color map for each color which it might
      use. If there are not enough free slots in the color map, you
      will see a "Cannot allocate" message for each color that
      xterm failed to allocate. Those colors will be rendered in
      the foreground color, making full-screen color applications
      such as <a href="/dialog/dialog.html">dialog</a>
      unreadable.</p>

      <p>This problem is alleviated with <a href=
      "xterm.log.html#xterm_129">patch 129</a>, which modified
      xterm to delay the most color allocation until the colors are
      first needed. If a color is never needed (xterm allocates 20
      colors in this manner), that reduces the number of slots in
      the color map that are needed. Even with this improvement,
      xterm must still allocate 4 colors during initialization to
      determine how to display the cursor. If none of those colors
      can be allocated, xterm reverts to monochrome.</p>
    </dd>
  </dl>

  <h2 id="known_bugs-id"><a name="known_bugs" id="known_bugs">Known
  Bugs in <strong>XTerm</strong> and Look&ndash;alikes</a></h2>

  <p>These are the known bugs (or limitations) in modern xterm.
  They are also present in the other versions based on the X
  Consortium sources (color_xterm, ansi_xterm, kterm).</p>

  <p>Note that of the emulators that support color, some do not
  support <code>bce</code> (back color erase). The bce capability
  is also called the "new color model", though it has been
  implemented in the IBM PC for quite a while. Technically, not
  implementing <code>bce</code> (or allowing the choice between it
  and its complement) is not a bug, since few hardware terminals
  (with good reason) implemented this feature.</p>

  <ul>
    <li>
      <p>cut/paste does not <a href=
      "xterm.faq.html#xterm_tabs">select tabs</a>; instead spaces
      are selected. This is because the selection works from the
      array of displayed characters, on which tab/space conversion
      has already been performed.</p>
    </li>

    <li>
      <p>does not implement the autorepeat feature of VTxxx
      terminals.</p>
    </li>
  </ul>

  <h3 id="bug_xterm_r6-id"><a name="bug_xterm_r6" id=
  "bug_xterm_r6">X11R6.3 <strong>XTerm</strong></a></h3>

  <p>The X Consortium version of xterm (and versions based on it)
  has additional bugs not in modern xterm:</p>

  <ul>
    <li>
      <p>the program must be run with fixed (nonproportional)
      fonts.</p>
    </li>

    <li>
      <p>the home and end keys do not generate usable escape
      sequences, due to an indexing error. (Note that it is
      possible to work around this using the VT100 translations
      resource, but usually this is not done).</p>
    </li>

    <li>
      <p>the Main Options menu is improperly constructed, due to
      incorrect indices after removing the logging toggle. This
      makes the list of signals off by one.</p>
    </li>

    <li>
      <p>very large screens (e.g., by using nil2 for a font) cause
      core dumps because the program uses a fixed array (200 lines)
      for adjusting pointers.</p>
    </li>

    <li>
      <p>certain types of key translations cause a core dump
      because the program does not check the event class before
      attempting to use events.</p>
    </li>
  </ul>

  <p>(These bugs are also present in the X11R5 version).</p>

  <p id="xterm-xorg-id"><a name="xterm-xorg" id=
  "xterm-xorg"><em>Update 2004/04/08:</em></a><br>
  Complicating this discussion is the "X.Org" xterm (from 2004).
  That is the XFree86 xterm from XFree86 CVS with all visible
  &ldquo;xfree86&rdquo; strings changed to "X.Org" or
  &ldquo;xorg&rdquo;, depending on the use. For example the
  "xterm-xfree86" terminfo entry becomes "xterm-xorg". The change
  history for the related CVS for X.Org shows this. Similarly, the
  release notes for X11R6.7 included my notes for XFree86 4.4.</p>

  <p><em>As of 2009</em>, it was apparent that "X.Org" xterm had
  died a natural death, since none of the people who created it had
  any likelihood of maintaining it. Instead, X.Org defers to my
  version of xterm.</p>

  <p><em>Reviewing in 2014</em>, the major vendors have been using
  modern xterm (different patch levels) for some time. However,
  there are documentation problems with AIX, beyond what is noted
  <a href="#xterm_pageup">here</a>:</p>

  <ul>
    <li>
      <p>AIX provides a copy of <a href="/luit/luit.html">luit</a>,
      and a corresponding <a href=
      "http://publib.boulder.ibm.com/infocenter/aix/v7r1/index.jsp?topic=%2Fcom.ibm.aix.cmds%2Fdoc%2Faixcmds3%2Fluit.htm">
      manpage</a>&mdash;which omits the sections on security, bugs
      and attribution.</p>
    </li>

    <li>
      <p>The <a href=
      "http://publib.boulder.ibm.com/infocenter/aix/v7r1/index.jsp?topic=%2Fcom.ibm.aix.cmds%2Fdoc%2Faixcmds6%2Fxterm.htm">
      xterm</a> manpage provided with AIX says this is X11R6 xterm
      &ldquo;with no functional enhancements.&rdquo; Comparing
      releases X11R5, X11R6.1, X11R6.3 against the AIX page, it
      matches X11R6.1 (December 1995). That is, it includes the
      text of the X11R6.1 xterm manpage plus the control sequences
      document&mdash;again omitting the security, bugs and
      attribution sections from each.</p>
    </li>
  </ul>

  <p>The other vendors provide documentation which is more
  up-to-date.</p>

  <h3 id="bug_color_xterm-id"><a name="bug_color_xterm" id=
  "bug_color_xterm">COLOR_XTERM</a> <a href=
  "ftp://ftp.x.org/contrib/applications/color_xterm-beta1.tar.gz">download</a></h3>

  <p>This is based on the X Consortium X11R5 source, with the same
  bugs.</p>

  <ul>
    <li>
      <p>implements non-bce color model</p>
    </li>

    <li>
      <p>moving the cursor is reported to leave trails of incorrect
      color</p>
    </li>

    <li>
      <p>clearing the screen resets colors (arguably this is a
      limitation).</p>
    </li>
  </ul>

  <p>Not exactly a bug, but it does not build on Linux with
  X11R6.3</p>

  <h3 id="bug_ansi_xterm-id"><a name="bug_ansi_xterm" id=
  "bug_ansi_xterm">ANSI_XTERM</a> <a href=
  "ftp://ftp.x.org/contrib/applications/xterm-R6-sb_right-ansi-3d.tar.gz">
  download</a></h3>

  <p>This is based on the X Consortium source, with the same
  bugs.</p>

  <ul>
    <li>
      <p>implements non-bce color model</p>
    </li>

    <li>
      <p>fails <a href="/vttest/vttest.html">vttest</a> by not
      rendering reverse-video screen</p>
    </li>
  </ul>

  <h3 id="bug_cxterm-id"><a name="bug_cxterm" id=
  "bug_cxterm">CXTERM</a> <a href=
  "ftp://ftp.cuhk.hk/pub/chinese/ifcss/software/x-win/cxterm/">download</a></h3>

  <p>CXterm stands for "Chinese Xterm". This is based on the X
  Consortium source.</p>

  <h3 id="bug_dtterm-id"><a name="bug_dtterm" id=
  "bug_dtterm">DTTERM</a></h3>

  <p>This is distributed with CDE. It implements more of the DEC
  VT220 than the X Consortium xterm, and also adds controls to
  manipulate the window and icon.</p>

  <ul>
    <li>
      <p>implements non-bce color model</p>
    </li>

    <li>
      <p>fails <a href="/vttest/vttest.html">vttest</a> by clearing
      its background to solid white rather than preserving its
      sense in response to ED.</p>
    </li>

    <li>
      <p>under some circumstances, scrolling margins are not
      recognized. For instance, running <a href=
      "/vile/vile.html">vile</a> which uses scrolling margins, we
      see text overwriting the status line.</p>
    </li>
  </ul>

  <h3 id="bug_emu-id"><a name="bug_emu" id="bug_emu">EMU 1.3</a>
  <a href=
  "ftp://ftp.x.org/contrib/applications/emu-1.31.tar.gz">download</a></h3>

  <p>This is not based on the X Consortium source. The authors
  state that it implements VT220 emulation. It is in need of
  maintenance, since it builds with some problems to produce an
  executable that (on Linux and SunOS) does not handle the carriage
  return and newline translations properly. So I am unable to run
  <a href="/vttest/vttest.html">vttest</a> on this emulator.</p>

  <h3 id="bug_eterm-id"><a name="bug_eterm" id=
  "bug_eterm">ETERM</a> <a href=
  "http://www.eterm.org/">link</a></h3>

  <p>Eterm was based on rxvt, though the appearance differs. The
  terminal emulation capabilities appear similar, though I am not
  able to run the full suite of tests in <a href=
  "/vttest/vttest.html">vttest</a> with this emulator (the core
  dump noted for rxvt, as well as hanging while awaiting response
  from one or more control sequences). Oddly, it appears that
  neither Eterm nor rxvt implement CPR (cursor position report).
  Finally, it reserves F1 (function-key) for a popup menu. This
  applies to versions of <em>Eterm</em> through 0.9.</p>

  <h3 id="bug_gnometerm-id"><a name="bug_gnometerm" id=
  "bug_gnometerm">GNOME TERMINAL</a> <a href=
  "http://www.gnome.org/">link</a></h3>

  <p>Unless specifically mentioned, GNOME Terminal and VTE's issues
  generally accumulate, with occasional veering off with skin-deep
  &ldquo;rewrites&rdquo;. Each sighting provides a new episode.</p>

  <p>Starting in 1999 &mdash;</p>

  <p>GNOME Terminal is developed separately from both xterm and
  rxvt, and was originally based on the <a href=
  "http://www.fifi.org/doc/gnome-dev-doc/html/zvt/book1.html">zvt
  (zterm) widget</a>. Like <a href="#bug_kvt">kvt</a>), it appears
  to have been developed imitating other terminal emulators (Linux
  console and xterm) rather than strictly emulating a VT102. The
  documentation is fragmentary (with a comment suggesting that the
  author does not know where to find relevant information), and the
  program fares badly with <a href=
  "/vttest/vttest.html">vttest</a>. Beginning with late 1999,
  reports indicate that it does not properly parse ANSI control
  sequences: the vim editor is using xterm's vt220-style "Send
  Device Attributes" (Secondary DA) control sequence to obtain the
  terminal emulator's version. That is, it sends</p>

  <blockquote>
    <pre class="code-block">
\E[&gt;c
</pre>
  </blockquote>

  <p>expecting a response such as</p>

  <blockquote>
    <pre class="code-block">
\E[&gt;0;138;0c
</pre>
  </blockquote>

  <p>for vt100. The bug report indicates that the &ldquo;c&rdquo;
  sent by vim is echoed rather than interpreted by the
  emulator.</p>

  <p>But it suffices for vi.</p>

  <p>Moving on to 2001 &mdash;</p>

  <p>A more recent GNOME Terminal uses the VTE widget. I observed
  version 1.4.0.4 in late 2001, which mentioned it in the credits
  (although VTE 0.1's ChangeLog mentions no date before February
  2002). It does not implement a complete vt102: it was missing
  several features which can be demonstrated in <a href=
  "/vttest/vttest.html">vttest</a>). Most of the bugs in the Device
  Attributes responses remain, but it works a little better with
  vim. However, there are problems with the alternate screen that
  show up with vim. Again, these can be demonstrated with vttest
  (menu 11.6.3 in the 20011130 snapshot).</p>

  <p>Moving on to 2002 &mdash;</p>

  <p>Rather than evolving from zvt, VTE is largely a new work. It
  does credit zvt in one place. However, its source code uses
  xterm's source code as a resource, accounting for odd (often
  incomplete) chunks. Reviewing 0.9.0 (September 2002):</p>

  <ul>
    <li>
      <p>the termcap file. The last comment in the file is copied
      from xterm's source. The content of course is generated from
      ncurses with a small number of changes.</p>
    </li>

    <li>
      <p>the parser <code>src/vte.c</code> &mdash;a 14,125 line
      file. For example, the chunks related to DEC VT220 keyboard
      queries and DEC private modes contain comments copied from
      xterm's source code.</p>
    </li>
  </ul>

  <p>Jumping to 2010 &mdash;</p>

  <p>Later versions of VTE incorporate more features (and comments,
  symbol names, etc), from xterm's source. In some instances, the
  copied features were disabled by Red Hat's package for xterm.
  <a href=
  "https://bugzilla.redhat.com/show_bug.cgi?id=122815">Here</a> is
  a related bug report, for key bindings.</p>

  <p id="vte:xconsortium">The documentation for GNOME Terminal
  asserts:</p>

  <blockquote class="code-block">
    <p>GNOME Terminal emulates the xterm application developed by
    the X Consortium. In turn, the xterm application emulates the
    DEC VT102 terminal and also supports the DEC VT220 escape
    sequences. An escape sequence is a series of characters that
    starts with the Esc character. GNOME Terminal accepts all of
    the escape sequences that the VT102 and VT220 terminals use for
    functions such as to position the cursor and to clear the
    screen.</p>
  </blockquote>

  <p>That sounds fine, except that it is both inaccurate and
  misleading:</p>

  <blockquote>
    <dl>
      <dt>inaccurate</dt>

      <dd>
        combining the "X Consortium" and "DEC VT220", for example,
        since that was done after the demise of said organization.
        <p>It emulates a <em>subset</em> of VT100, lacks support
        for most of the VT220 control sequences (including some
        used for positioning the cursor) that are not recognized by
        a VT100.</p>

        <p>Even in the subset which it emulates, GNOME Terminal has
        bugs. Many of these are easy to demonstrate with
        vttest.</p>
      </dd>

      <dt>misleading</dt>

      <dd>as noted in <a href="#ctlseqs_ms">Xterm Control
      Sequences</a>, xterm (mostly after "X Consortium") supports
      control sequences which are not VT100/VT220. GNOME Terminal
      implements many of these, but not all.</dd>
    </dl>
  </blockquote>

  <p>Perhaps that was unintentional &ndash; GNOME developers did
  not appear to document what their program <em>does</em> outside
  of that remark. However, an inspection of the changelog for
  libvte (VTE) does show that most of the borrowing from xterm is
  cited in an oblique manner &ndash; not once mentioning XFree86
  for example, leaving the impression (as indicated by "X
  Consortium") that all of the work on xterm was done before
  development of GNOME Terminal commenced.</p>

  <p>Most of this observation was documented between 2000 and 2007.
  Other than maintenance, development of GNOME Terminal appeared to
  have paused in 2005. As of 2009, its maintainer was (of the
  development team), the least knowledgeable about terminal
  emulation. So there was no progress on the large number of bug
  reports related to xterm-compatibility.</p>

  <p>Revisiting in 2018 &mdash;</p>

  <p>Regarding documentation, the situation was not as good as
  reported earlier. The problematic documentation was not even part
  of the &ldquo;official&rdquo; GNOME Terminal, but was an add-on
  by a Debian developer, adapted from GNOME Terminal's online help.
  The developer's relationship was mentioned in a Debian bug
  report:</p>

  <p><a href=
  "https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=127622"><em>#127622:
  ncurses-term: terminfo entry for gnome-terminal swaps
  Backspace/Delete</em></a>:</p>

  <blockquote>
    <pre class="code-block">
&gt;&gt; "TD" == Thomas Dickey &lt;dickey@herndon4.his.com&gt; writes:

&gt; On Sun, Jan 06, 2002 at 06:13:30PM +0100, Christian Marillat wrote:

[...]

&gt;&gt; The upstream author should consider ours Debian changes has official
&gt;&gt; changes ?

&gt; sure - get gnome-terminal's author to make the changes.  (I generally
&gt; don't add customizations to ncurses' terminfo unless I see them incorporated
&gt; intact by more than one other source).

Sorry to say that, but upstream don't care about my patches. I've
forwarded patches since one year, and these patches has never been
included by upstream. Upstream sayd &ldquo;commited&rdquo;, but I never seen any
changes.

Christian
</pre>
  </blockquote>

  <p>The manual page provided as an attachment to GNOME <a href=
  "https://bugzilla.gnome.org/show_bug.cgi?id=311565#c15">#311565</a>
  identifies the author. However, four years later there is still
  no manpage for GNOME Terminal. GNOME <a href=
  "https://bugzilla.gnome.org/show_bug.cgi?id=701691">#701691</a>
  mentions this in conjunction with GNOME Terminal's incompatible
  behavior versus other terminals for the
  &ldquo;<code>-e</code>&rdquo; option:</p>

  <blockquote>
    <pre class="code-block">
 Christian Persch 2013-06-06 11:10:43 UTC

This works as designed. Note that both -x and -e are deprecated; the only supported way to pass the arguments is after -- like this:

$ gnome-terminal -- emacs file
</pre>
  </blockquote>

  <p>and</p>

  <blockquote>
    <pre class="code-block">
 Christian Persch 2013-06-06 16:02:54 UTC

There are no docs for the gnome-terminal command line options.
</pre>
  </blockquote>

  <p>Admittedly, GNOME Terminal has <em>some</em> documentation, in
  its online help pages. As mentioned, the misleading comments
  about <em>X Consortium</em> came from that material, which
  remained for more than ten years before being revised early in
  2013. Here are a few links for that process:</p>

  <ul>
    <li>
      <p><a href=
      "https://git.gnome.org/browse/gnome-terminal/commit/?id=13ece45d6398e0ebe9aa06cc8da2148534ca8af6">
      <em>help: update introduction.page</em></a> (2013-01-10)</p>
    </li>

    <li>
      <p><a href=
      "https://git.gnome.org/browse/gnome-terminal/commit/?id=dd1c5125c785f644954010052ee3e4c7783c08da">
      <em>help: review</em></a> (2013-01-09)</p>
    </li>

    <li>
      <p><a href=
      "https://git.gnome.org/browse/gnome-terminal/commit/?id=317b05f46807ea60fbd6a0ed493824a2269dcc60">
      <em>help: modified help in accordance with last
      review</em></a> (2013-01-09)</p>
    </li>

    <li>
      <p><a href=
      "https://git.gnome.org/browse/gnome-terminal/commit/?id=13ece45d6398e0ebe9aa06cc8da2148534ca8af6">
      <em>help: write instroduction.page</em></a> (2013-01-08)</p>
    </li>

    <li>
      <p><a href=
      "https://git.gnome.org/browse/gnome-terminal/commit/?id=8a4b9e67bc8f6a19e62c58650a635de6178911bd">
      <em>help: start rewrite in Mallard</em></a> (2013-01-08)</p>
    </li>
  </ul>

  <p>The document editors removed this statement</p>

  <blockquote class="code-block">
    <p>Run any application that is designed to run on VT102, VT220,
    and <code>xterm</code> terminals</p>
  </blockquote>

  <p>as well as the extended comment about the <a href=
  "#vte:xconsortium">X Consortium</a>, and replaced it with a less
  specific statement.</p>

  <blockquote class="code-block">
    <p><code>Terminal</code> is a terminal emulator application for
    accessing a UNIX shell environment which can be used to run
    programs available on your system.</p>

    <p><code>Terminal</code> supports escape sequences that control
    cursor position and colors.</p>
  </blockquote>

  <p>The assertion about GNOME-Terminal's support for
  &ldquo;any&rdquo; persisted in its <a href=
  "https://packages.debian.org/sid/gnome-terminal">package
  description</a> in Debian as of 2018:</p>

  <blockquote class="code-block">
    <ul>
      <li>
        <p>Access a UNIX shell in the GNOME environment.</p>
      </li>

      <li>
        <p>Run any application that is designed to run on VT102,
        VT220, and xterm terminals.</p>
      </li>
    </ul>
  </blockquote>

  <p>Whether the revised manual is improved or even helpful is
  debatable. For instance, it tells the reader how to turn the
  scrollbar on and off (using a dialog, of course). But for
  command-line options, it can print only about 45 lines of option
  names and short (less than 10 words) descriptions for each if one
  types</p>

  <blockquote>
    <pre class="code-block">
gnome-terminal --help-all
</pre>
  </blockquote>

  <p>Other programs do the equivalent. In a quick check using
  Debian 8:</p>

  <ul>
    <li>
      <p>85 lines for konsole</p>
    </li>

    <li>
      <p>120 lines for xterm patch #331</p>
    </li>

    <li>
      <p>122 lines for mlterm</p>
    </li>

    <li>
      <p>140 lines for urxvt</p>
    </li>
  </ul>

  <p>Bug <a href=
  "https://bugzilla.gnome.org/show_bug.cgi?id=311565#c15">#311565</a>
  was (writing in 2018) more than four years ago, but still there
  is no manual page, for either the command-line options or the
  control sequences which it supports.</p>

  <h3 id="vte_widget-id"><a name="vte_widget" id="vte_widget">Notes
  on VTE</a></h3>

  <p>VTE is used by developers who provide a <a href=
  "http://best-practice-software-engineering.ifs.tuwien.ac.at/patterns/facade.html">
  facade</a> (also referred to as a &ldquo;<a href=
  "https://techterms.com/definition/skin">skin</a>&rdquo;) for
  simple desktop-oriented terminal emulation. <a href=
  "http://www.calno.com/evilvte">This page</a> gives a number of
  examples with sizes for the skins. The actual program size is far
  larger in each case, making the size of the skin irrelevant.</p>

  <p>For more than <a href=
  "https://git.gnome.org/browse/vte/diff/README?id=4e253be9282829f594c8a55ca08d1299e80e471d">
  ten years</a>, VTE's README file asserted</p>

  <blockquote class="code-block">
    <p>VTE supports Unicode and character set conversion, as well
    as emulating any terminal known to the system's terminfo
    database.</p>
  </blockquote>

  <p>The latter part of that ("emulating any terminal") was
  incorrect. It did have the ability to work with the standard
  function-key definitions which can be defined in a terminfo
  description. That feature was discarded in 2014.</p>

  <p>Notes from 2010 &mdash;</p>

  <p>Some of the function-key logic was adapted from xterm;
  generally refactoring the xterm source-code to make it appear
  different. In places however (naming conventions and comments),
  there was some verbatim copying. The same observation can be made
  of "character set conversion". None of that is reflected in VTE's
  <a href="https://git.gnome.org/browse/vte/log/">git-log</a>.</p>

  <p>As an aside, the credits in GNOME Terminal's
  &ldquo;About&rdquo; box also are inaccurate. For several years
  (according to its change-log), most of the work on VTE (the
  principal part of the program) was done by Nalin Dahyabhai.</p>

  <p>xterm on the other hand, can be told with the <a href=
  "manpage/xterm.html#Application-Resources:tcapFunctionKeys"><code>
  tcapFunctionKeys</code></a> resource setting to use a more
  complete subset, based on the ncurses extended terminal
  descriptions. However, terminal descriptions describe only one
  particular configuration of a terminal. Even xterm's
  terminfo/termcap descriptions do not cover the (literally)
  thousands of keyboard combinations which are available via its
  resource settings.</p>

  <p>Outside of function-keys, VTE provided no ability to emulate
  &ldquo;any terminal&rdquo;. A casual glance at its source code
  revealed the following:</p>

  <ul>
    <li>
      <p>no support for VT220-style protected areas.</p>
    </li>

    <li>
      <p>inconsistent support for modifier keys (the subject of
      several bug reports misdirected toward ncurses).</p>
    </li>

    <li>
      <p>only a subset of the standard terminfo/termcap properties
      is used (5/36 booleans, 3/33 numbers, 125/242 strings other
      than function-keys).</p>
    </li>

    <li>
      <p>a pervasive assumption that the terminal is something like
      xterm, e.g., to provide hardcoded behavior where termcap
      might describe something different.</p>
    </li>

    <li>
      <p>it uses termcap to retrieve data, rather than providing a
      choice between terminfo/termcap, opening up the problem of
      using an obsolete database.</p>
    </li>

    <li>
      <p>using termcap also means that it has no guidance for
      following features which are absent or have
      limited-functionality compared to terminfo, such as setting
      video attributes, colors, etc.</p>
    </li>
  </ul>

  <p>For instance, VTE cannot emulate <a href=
  "xterm.faq.html#bug_dtterm">dtterm</a>, because of differences in
  color behavior. In fact, VTE does not use any of the termcap data
  to support its interpretation of color control sequences.</p>

  <p>After 2014 &mdash;</p>

  <p>Until 2014, VTE used a <em>termcap</em> file, with its own
  <em>reader</em>, presumably under the impression that could be
  used to describe &ldquo;any terminal&rdquo; (although it was
  fairly well known that terminals could support escape sequences
  not found in any terminal description). As a separate file, the
  <em>termcap</em> was a nuisance, whether it was bundled with VTE
  (and inaccessible to users) or not. The developers tried it both
  ways.</p>

  <p>One recurring problem was that VTE's termcap did not match
  xterm's function-keys. Even when VTE's developers modified the
  termcap to match as well as the termcap could, the match was
  still incomplete. None of the <em>modified</em> keys were
  correct, since none of those are described by termcap. That meant
  that a <em><strong>control</strong></em> modifier with a
  cursor-key or function key was likely to be misread by programs
  running in VTE.</p>

  <p>Finally in 2014, the VTE developers decided to change it.
  First, one decided to adapt a chunk of source-code from ncurses,
  perhaps thinking that was the way to get a better
  <em>reader</em>. That did not work well, and finally they
  discarded the whole feature, hardcoding the behavior to match
  xterm's default configuration.</p>

  <p>Here are bug reports which give the story:</p>

  <ul>
    <li>
      <p><a href=
      "https://bugzilla.gnome.org/show_bug.cgi?id=600659">#600659
      &ndash; <em>Home/End generate wrong control
      sequences</em></a>.</p>

      <pre class="code-block">
Escape sequences of the &ldquo;default&rdquo; kbd mode should be okay now.

Removal of non-default kbd modes is continued in bug 730137.
</pre>
    </li>

    <li>
      <p><a href=
      "https://bugzilla.gnome.org/show_bug.cgi?id=169295">#169295
      &ndash; <em>builtin termcap parser not needed</em></a>.</p>

      <pre class="code-block">
all: Use terminfo instead of termcap
</pre>
    </li>

    <li>
      <p><a href=
      "https://bugzilla.gnome.org/show_bug.cgi?id=730137">#730137
      &ndash; <em>Drop (or fix) nondefault fkey modes</em></a>.</p>

      <p class="code-block">Since addressing bug 600659, VTE's
      default mode pretty accurately matches XTerm. VT220 is
      okay-ish, Legacy is so-so, HP and Sun are quite broken.</p>
    </li>

    <li>
      <p><a href=
      "https://bugzilla.gnome.org/show_bug.cgi?id=728900">#728900
      &ndash; <em>use terminfo instead of termcap</em></a>.</p>

      <p class="code-block">Do we want to rely in term{cap,info}
      *at all*? So far vte has used hardwired sequences most of the
      time. Even if we clean up everything and drop all fkey modes
      except the default (request: bug 600659 comment 73) we'd need
      to keep hardwired sequences for numerous reasons. E.g.
      Home/End should generate ^[[H/^[[F which are not present in
      terminfo. Application cursor keys and application keypad mode
      alter some sequences, with AFAICT no terminfo support
      whatsoever. F1..F4 completely change their sequences when a
      modifier is pressed, again probably no support for it in
      terminfo. Terminfo is just able to encode the complexity (app
      keypad mode, app cursor mode, modifiers, numlock) we need.
      Wouldn't life be much simpler with just hardwired
      xterm-compatible sequences? (With probably a way to override
      them from config file or dconf for experts.)</p>
    </li>
  </ul>

  <p>As a minor improvement, those changes removed some of the code
  whose origin was cut/paste from xterm. But that does not mean
  that the VTE developers stopped that practice. For instance, a
  change in late 2017 <a href=
  "https://en.wikipedia.org/w/index.php?title=ANSI_escape_code&amp;type=revision&amp;diff=816842550&amp;oldid=815750533">
  here</a> reminded me to check what VTE does when saving/restoring
  the cursor position. It turns out that it does something similar,
  because (see <a href=
  "https://bugzilla.gnome.org/show_bug.cgi?id=731205">#731205</a>
  and <a href=
  "https://bugzilla.gnome.org/show_bug.cgi?id=741193">#741193</a>)
  the developer studied xterm's source-code and imitated it (see
  <a href=
  "https://git.gnome.org/browse/vte/commit/?id=5a434e6c4457bdfe182a13213396e7a66a08f767">
  source changes</a> and <a href=
  "https://git.gnome.org/browse/vte/commit/?id=e549a0eebc82fde89134c15ead322dc199d99239">
  followup fixes</a>). There's a quirk in the resulting program (it
  pays attention to send/receive and insert modes, which are
  unrelated, while also missing the handling of wrap state), but if
  the developer had read the documentation (DEC's manuals), that
  detail would be missing. In reviewing the documentation, I
  noticed a different aspect which might be used to improve xterm,
  and ultimately appear in VTE (or perhaps not, since it is in an
  area poorly supported by VTE, i.e., the bug which was
  reported).</p>

  <p>VTE developers do more than copy from xterm, of course. There
  are other programs (such as Konsole and Terminal.app) which get
  similar treatment. Because they tend to copy from others rather
  than doing their own solutions, they have not acquired the
  experience to see why features were added or modified (or
  removed), just that it is there. For instance:</p>

  <ul>
    <li>
      <p>In a recent rewrite (early 2018), they introduced a
      skeleton of code from Paul Williams' sample parser. However,
      that is only a skeleton. For the flesh &ndash; the usual
      approach (see above).</p>

      <p>Two thirds of the functions listed in the skeleton are
      no-ops (<a href=
      "https://gitlab.gnome.org/GNOME/vte/blob/86e1d0883b88d4899c9b398d9f0a1c51b9d86e8d/src/parser-cmd.hh#L125">not
      implemented</a>). Some of those listed as implemented do not
      work (see vttest <a href=
      "/vttest/vttest-codepages.html#ISO-Latin-1">screenshot</a>).</p>

      <p>Oddly enough, the developers decided to make the program
      <a href=
      "https://gitlab.gnome.org/GNOME/vte/blob/86e1d0883b88d4899c9b398d9f0a1c51b9d86e8d/src/vteseq.cc#L2316">
      claim that it is a VT525</a>, though the skeleton
      demonstrates that it lacks almost all of features provided by
      the corresponding hardware terminal. In October 2018, the
      listing shows mostly a subset of VT100, with some
      (longstanding) features adapted from xterm, and a few
      inspired by ECMA-48.</p>
    </li>

    <li>
      <p>The latter requires some comment: xterm's
      control-sequences document has mentioned ISO-6429 and ECMA-48
      since its earliest version. VTE's developers used that as a
      reference <a href=
      "https://bugzilla.gnome.org/buglist.cgi?quicksearch=ctlseqs">(see
      bug reports)</a> along with xterm's source-code rather than
      <a href=
      "https://bugzilla.gnome.org/buglist.cgi?quicksearch=ecma-48">ECMA-48</a>
      or DEC's manuals until around the end of 2016.</p>
    </li>

    <li>
      <p>They did (eventually) read documentation referred to by
      xterm's documentation. But that took a while, and they began
      copying from those sources before understanding the tradeoffs
      in those. Late in 2016, they started copying features
      mentioned in ECMA-48. The motivation for that appears to be
      (unsurprisingly) copying from yet another source, e.g.,
      <a href="https://github.com/kovidgoyal/kitty">kitty</a> (yet
      another copyist: see <a href=
      "https://github.com/jwilm/alacritty">alacritty</a>, but also
      see <a href="https://github.com/jwilm/vte">this</a>).</p>
    </li>

    <li>
      <p>Introducing those ECMA-48 features caused additional
      failures for VTE versus <a href=
      "/vttest/vttest.html">vttest</a>, which the VTE developers
      solved by making a copy of vttest, to &ldquo;fix&rdquo; the
      bug. The problematic feature dealt with clearing tab-stops
      (selection 2).</p>

      <p>ECMA-48 specifies the <em>active line</em> in selection 2.
      For an explanation of the term, see ECMA-48 section
      <em><strong>6.1.5</strong> Relationship between active data
      position and active presentation position</em>. This is
      distinct from the feature which DEC's terminals
      supported.</p>

      <p>The VT520 manual is explicit in this case (only selections
      0 and 3 are supported). Per Lindberg's 1985 test demonstrated
      that the unsupported selection 2 was ignored in a VT100.</p>
    </li>

    <li>
      <p>The VT520 did not support the other selection (2) because
      that would have been used to support bi-directional text.
      There is no point in having two differently-worded
      descriptions of the same identical feature.</p>

      <p>At the time the VTE developers copied the feature, they
      had not begun to develop support bi-directional text (see for
      example <a href=
      "https://bugzilla.gnome.org/show_bug.cgi?id=321490"><em>#321490
      (vtebidi)</em></a> and <a href=
      "https://bugzilla.gnome.org/show_bug.cgi?id=767529"><em>#767529
      (vteemoji)</em></a>.</p>

      <p>At this writing (two years later), the developers are
      talking about working on that. The tab-clear operation is
      still <a href=
      "https://gitlab.gnome.org/GNOME/vte/blob/86e1d0883b88d4899c9b398d9f0a1c51b9d86e8d/src/vteseq.cc#L7710">
      identical in VTE</a> for both selections 2 and 3, and does
      not implement any of the features from ECMA-48
      <strong>not</strong> in a DEC terminal.</p>
    </li>
  </ul>

  <p>Other problems with VTE &mdash;</p>

  <p>These are a few of the interesting bugs found in VTE (or GNOME
  Terminal) during 2017:</p>

  <ul>
    <li>
      <p>system crash due to running out of memory<br>
      while running ncurses sample programs <a href=
      "/ncurses/ncurses-slang.html#compare_dots">dots</a> and
      <a href=
      "/ncurses/ncurses-slang.html#compare_picsmap">picsmap</a>.</p>
    </li>

    <li>
      <p>failure to open a remote connection, noticed<br>
      while gathering data for a <a href="#scroll_speed">discussion
      of scrolling performance</a>.</p>
    </li>
  </ul>

  <p>Other uses of VTE &mdash;</p>

  <p>Because of GNOME Terminal's reputation for excessive code
  bloat, developers of every other program based on VTE advertise
  their version as reduced memory usage, faster startup, etc. Here
  are a few of the available ones:</p>

  <ul>
    <li>
      <p><a name="bug_osso_xterm" id=
      "bug_osso_xterm">osso-xterm</a> <a href=
      "http://maemo.org/development/tools/doc/diablo/osso-xterm/">link</a></p>

      <p>Its home page refers to "at least two versions". I recall
      seeing an older version which was apparently not based on
      VTE. There did not appear to be any relevant page (as of
      2009) for that version.</p>
    </li>

    <li>
      <p><a name="bug_roxterm" id="bug_roxterm">roxterm</a>
      <a href="http://roxterm.sourceforge.net/">link</a></p>
    </li>

    <li>
      <p><a name="bug_xfce_term" id="bug_xfce_term">XFCE
      Terminal</a> <a href=
      "http://terminal.os-cillation.com/">link</a></p>
    </li>
  </ul>

  <h3 id="bug_multignome-id"><a name="bug_multignome" id=
  "bug_multignome">MULTI GNOME TERMINAL (MGT)</a> <a href=
  "http://multignometerm.sourceforge.net/">link</a></h3>

  <p>Of particular note, MGT 1.4.0 announcement claims that it
  works properly for all of <a href=
  "/vttest/vttest.html">vttest</a>)'s tests. On the positive side,
  it does do VT52 emulation, but (reading the source code did not
  help) it apparently does not really do VT220 from vttest's
  perspective.</p>

  <h3 id="bug_hanterm-id"><a name="bug_hanterm" id=
  "bug_hanterm">HANTERM</a> <a href=
  "http://www.debian.org/Packages/frozen/x11/hanterm.html">download</a></h3>

  <p>HanTerm stands for "Hangul term" (Korean). This is based on
  the XFree86 source.</p>

  <h3 id="bug_konsole-id"><a name="bug_konsole" id=
  "bug_konsole">KONSOLE</a> <a href=
  "http://www.kde.org/">link</a></h3>

  <p>More than just a rewrite of <a href=
  "xterm.faq.html#bug_kvt">kvt</a> into C++. But there are several
  incompatibilities between konsole (noted with version 1.0.2 in
  late 2001) and xterm:</p>

  <ul>
    <li>
      <p>none of the selections of keyboard mappings match the
      actual behavior of xterm (a few come close, but do so by
      matching the terminfo descriptions rather than the programs).
      In particular, the application keypad does not send
      vt100-style escapes.</p>
    </li>

    <li>
      <p><a href="/vttest/vttest.html">vttest</a>) demonstrates
      that konsole does not properly ignore escape sequences to
      switch character sets that it does not support. Also, the
      developers of konsole did use an old version of vttest, but
      that was to add a bogus Device Attributes response (claimed
      to be for &ldquo;vt220&rdquo;, but not corresponding to any
      that DEC produced). They do not use the newer version of
      vttest (which was available more than a year before
      development of konsole began).</p>
    </li>

    <li>
      <p>konsole implements several features from XFree86 xterm,
      but some are done incorrectly. In particular, the <a href=
      "xterm.faq.html#xterm_tite">private setmode 1049</a> does not
      save and restore the cursor, causing the cursor to be in
      unexpected locations after exiting a fullscreen application
      such as vi.</p>
    </li>
  </ul>

  <p>The problem with setmode 1049 was fixed several weeks later
  (reported here 2001/09/10, fixed upstream 2001/11/01 and packaged
  <a href=
  "https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=121159#20">2001/11/26</a>);
  other issues linger on.</p>

  <p>The original change and the correction bear comment:</p>

  <ul>
    <li>
      <p>The initial change adding the 1049 mode was one of several
      changes where the konsole developer copied features from
      xterm.</p>

      <blockquote class="code-block100">
        <!--{{atr2html-->

        <p style="font-family: monospace; font-size: 10pt;">
        commit&nbsp;<a href=
        "https://invent.kde.org/utilities/konsole/-/commit/ec4314a82cea1396f763da459caa5016cf4ca5e6">ec4314a82cea1396f763da459caa5016cf4ca5e6</a><br>

        Author:&nbsp;Lars&nbsp;Doelle&nbsp;&lt;lars.doelle@on-line.de&gt;<br>

        Date:&nbsp;&nbsp;&nbsp;Sun&nbsp;Jan&nbsp;16&nbsp;04:52:58&nbsp;2000&nbsp;+0000<br>

        &nbsp;<br>
        &nbsp;&nbsp;&nbsp;&nbsp;added&nbsp;1049&nbsp;privacy&nbsp;code.&nbsp;reverted&nbsp;back&nbsp;to&nbsp;TERM=xterm.<br>

        &nbsp;&nbsp;&nbsp;&nbsp;<br>
        &nbsp;&nbsp;&nbsp;&nbsp;svn&nbsp;path=/trunk/kdebase/konsole/;&nbsp;revision=38470<br>

        &nbsp;<br>
        diff&nbsp;--git&nbsp;a/ChangeLog&nbsp;b/ChangeLog<br>
        index&nbsp;5c50f8e1f..9c7a895aa&nbsp;100644<br>
        <strong><span class=
        "number">---</span></strong><span class="ident2">&nbsp;a/ChangeLog<br>
        </span> <strong><span class=
        "number">+++</span></strong><span class=
        "ident2">&nbsp;b/ChangeLog<br></span> <strong><span class=
        "number">@@</span></strong><span class=
        "ident2">&nbsp;-1,3&nbsp;+1,6&nbsp;@@<br></span>
        +<span class="preproc">16&nbsp;Jan&nbsp;2000<br></span>
        +<span class=
        "preproc">-&nbsp;added&nbsp;privacy&nbsp;code&nbsp;1049.<br>
        </span> +<span class=
        "preproc">-&nbsp;reverted&nbsp;to&nbsp;TERM=xterm.<br></span>
        &nbsp;11&nbsp;Jan&nbsp;2000<br>
        &nbsp;-&nbsp;upgraded&nbsp;xterm&nbsp;title&nbsp;hack&nbsp;to&nbsp;unicode.<br>

        &nbsp;-&nbsp;upgraded&nbsp;copy/paste&nbsp;to&nbsp;handle&nbsp;unicode.<br>

        diff&nbsp;--git&nbsp;a/src/TEShell.C&nbsp;b/src/TEShell.C<br>

        index&nbsp;4910f685c..7587ca4f5&nbsp;100644<br>
        <strong><span class=
        "number">---</span></strong><span class="ident2">&nbsp;a/src/TEShell.C<br>
        </span> <strong><span class=
        "number">+++</span></strong><span class=
        "ident2">&nbsp;b/src/TEShell.C<br></span>
        <strong><span class="number">@@</span></strong><span class=
        "ident2">&nbsp;-29,6&nbsp;+29,12&nbsp;@@<br></span>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\par&nbsp;FIXME<br>
        &nbsp;<br>
        +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;NOTE&nbsp;that&nbsp;this&nbsp;module&nbsp;is&nbsp;part&nbsp;of&nbsp;a&nbsp;program&nbsp;and&nbsp;not&nbsp;a&nbsp;dump&nbsp;for<br>
        </span> +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;obsolete&nbsp;tty&nbsp;interfaces.&nbsp;The&nbsp;opening&nbsp;sequence&nbsp;can&nbsp;be&nbsp;reduced&nbsp;to<br>
        </span> +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;three&nbsp;or&nbsp;four&nbsp;lines,&nbsp;and,&nbsp;yes,&nbsp;i'll&nbsp;do&nbsp;this&nbsp;on&nbsp;a&nbsp;regular&nbsp;basis.<br>
        </span> +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;<br></span> +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;\par&nbsp;FIXME<br></span>
        +<span class="preproc"><br></span>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[NOTE:&nbsp;much&nbsp;of&nbsp;the&nbsp;technical&nbsp;stuff&nbsp;below&nbsp;will&nbsp;be&nbsp;replaced&nbsp;by&nbsp;forkpty.]<br>

        &nbsp;<br>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;publish&nbsp;the&nbsp;SIGCHLD&nbsp;signal&nbsp;if&nbsp;not&nbsp;related&nbsp;to&nbsp;an&nbsp;instance.<br>

        <strong><span class="number">@@</span></strong><span class=
        "ident2">&nbsp;-356,11&nbsp;+362,11&nbsp;@@&nbsp;void&nbsp;Shell::makeShell(const&nbsp;char*&nbsp;dev,&nbsp;QStrList&nbsp;&amp;&nbsp;args,&nbsp;const&nbsp;char*&nbsp;term,&nbsp;int&nbsp;lo<br>
        </span> &nbsp;&nbsp;&nbsp;<br>
        &nbsp;&nbsp;&nbsp;if&nbsp;(tt&nbsp;&gt;&nbsp;2)&nbsp;close(tt);<br>

        &nbsp;<br>
        -<span class=
        "comment">&nbsp;&nbsp;//&nbsp;Setup&nbsp;job&nbsp;control<br>
        </span> +<span class=
        "preproc">&nbsp;&nbsp;//&nbsp;Setup&nbsp;job&nbsp;control&nbsp;//////////////////////////////////&nbsp;<br>
        </span> +<span class="preproc"><br></span> +<span class=
        "preproc">&nbsp;&nbsp;//&nbsp;This&nbsp;is&nbsp;pretty&nbsp;obscure&nbsp;stuff&nbsp;which&nbsp;makes&nbsp;the&nbsp;session<br>
        </span> +<span class=
        "preproc">&nbsp;&nbsp;//&nbsp;to&nbsp;be&nbsp;the&nbsp;controlling&nbsp;terminal&nbsp;of&nbsp;a&nbsp;process&nbsp;group.<br>
        </span> &nbsp;<br>
        -<span class=
        "comment">&nbsp;&nbsp;//&nbsp;"There&nbsp;be&nbsp;dragons."<br>
        </span> -<span class=
        "comment">&nbsp;&nbsp;//&nbsp;&nbsp;&nbsp;(Ancient&nbsp;world&nbsp;map)<br>
        </span> -<span class="comment">&nbsp;&nbsp;<br></span>
        &nbsp;&nbsp;&nbsp;if&nbsp;(setsid()&nbsp;&lt;&nbsp;0)&nbsp;perror("failed&nbsp;to&nbsp;set&nbsp;process&nbsp;group");&nbsp;//&nbsp;(vital&nbsp;for&nbsp;bash)<br>

        &nbsp;<br>
        &nbsp;#if&nbsp;defined(TIOCSCTTY)&nbsp;&nbsp;<br>
        diff&nbsp;--git&nbsp;a/src/TEmuVt102.C&nbsp;b/src/TEmuVt102.C<br>

        index&nbsp;3870d086f..68a991110&nbsp;100644<br>
        <strong><span class=
        "number">---</span></strong><span class="ident2">&nbsp;a/src/TEmuVt102.C<br>
        </span> <strong><span class=
        "number">+++</span></strong><span class=
        "ident2">&nbsp;b/src/TEmuVt102.C<br></span>
        <strong><span class="number">@@</span></strong><span class=
        "ident2">&nbsp;-423,6&nbsp;+423,11&nbsp;@@&nbsp;void&nbsp;VT102Emulation::tau(&nbsp;int&nbsp;code,&nbsp;int&nbsp;p,&nbsp;int&nbsp;q&nbsp;)<br>
        </span>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('h',&nbsp;1048)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;saveCursor&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;);&nbsp;break;&nbsp;//XTERM<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('l',&nbsp;1048)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;restoreCursor&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;);&nbsp;break;&nbsp;//XTERM<br>

        &nbsp;<br>
        +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;//FIXME:&nbsp;every&nbsp;once&nbsp;new&nbsp;sequences&nbsp;like&nbsp;this&nbsp;pop&nbsp;up&nbsp;in&nbsp;xterm.<br>
        </span> +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;//&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Here's&nbsp;a&nbsp;guess&nbsp;of&nbsp;what&nbsp;they&nbsp;could&nbsp;mean.<br>
        </span> +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('h',&nbsp;1049)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;setMode&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(MODE_AppScreen);&nbsp;break;&nbsp;//XTERM<br>
        </span> +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('l',&nbsp;1049)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;resetMode&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(MODE_AppScreen);&nbsp;break;&nbsp;//XTERM<br>
        </span> +<span class="preproc"><br></span>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;//FIXME:&nbsp;when&nbsp;changing&nbsp;between&nbsp;vt52&nbsp;and&nbsp;ansi&nbsp;mode&nbsp;evtl&nbsp;do&nbsp;some&nbsp;resetting.<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_VT52__('A'&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;)&nbsp;:&nbsp;scr-&gt;cursorUp&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1);&nbsp;break;&nbsp;//VT52<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_VT52__('B'&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;)&nbsp;:&nbsp;scr-&gt;cursorDown&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1);&nbsp;break;&nbsp;//VT52<br>

        &nbsp;<br>
        <!--atr2html}}--></p>
      </blockquote>
    </li>

    <li>
      <p>Here is the fix:</p>

      <blockquote class="code-block100">
        <!--{{atr2html-->

        <p style="font-family: monospace; font-size: 10pt;">
        commit&nbsp;<a href=
        "https://invent.kde.org/utilities/konsole/-/commit/d221e4719e48c67886b149c3412a52f9a5daf697">d221e4719e48c67886b149c3412a52f9a5daf697</a><br>

        Author:&nbsp;Waldo&nbsp;Bastian&nbsp;&lt;bastian@kde.org&gt;<br>

        Date:&nbsp;&nbsp;&nbsp;Thu&nbsp;Nov&nbsp;1&nbsp;02:50:59&nbsp;2001&nbsp;+0000<br>

        &nbsp;<br>
        &nbsp;&nbsp;&nbsp;&nbsp;Fix&nbsp;"joe"&nbsp;under&nbsp;konsole:<br>

        &nbsp;&nbsp;&nbsp;&nbsp;*&nbsp;Setting&nbsp;a&nbsp;scroll&nbsp;region&nbsp;takes&nbsp;effect&nbsp;on&nbsp;both&nbsp;primary&nbsp;and&nbsp;alternate&nbsp;screen.<br>

        &nbsp;&nbsp;&nbsp;&nbsp;*&nbsp;Some&nbsp;cleanups&nbsp;to&nbsp;make&nbsp;konsole&nbsp;follow&nbsp;xterm&nbsp;behaviour&nbsp;more&nbsp;closely.<br>

        &nbsp;&nbsp;&nbsp;&nbsp;<br>
        &nbsp;&nbsp;&nbsp;&nbsp;svn&nbsp;path=/trunk/kdebase/konsole/;&nbsp;revision=120208<br>

        &nbsp;<br>
        diff&nbsp;--git&nbsp;a/konsole/TEmuVt102.cpp&nbsp;b/konsole/TEmuVt102.cpp<br>

        index&nbsp;5aa088825..0b72224e9&nbsp;100644<br>
        <strong><span class=
        "number">---</span></strong><span class="ident2">&nbsp;a/konsole/TEmuVt102.cpp<br>
        </span> <strong><span class=
        "number">+++</span></strong><span class=
        "ident2">&nbsp;b/konsole/TEmuVt102.cpp<br></span>
        <strong><span class="number">@@</span></strong><span class=
        "ident2">&nbsp;-100,7&nbsp;+100,7&nbsp;@@&nbsp;void&nbsp;TEmuVt102::reset()<br>
        </span>
        &nbsp;&nbsp;&nbsp;//kdDebug(1211)&lt;&lt;"TEmuVt102::reset()&nbsp;resetCharSet()"&lt;&lt;endl;<br>

        &nbsp;&nbsp;&nbsp;resetCharset(1);<br>
        &nbsp;&nbsp;&nbsp;//kdDebug(1211)&lt;&lt;"TEmuVt102::reset()&nbsp;reset&nbsp;screen&nbsp;1"&lt;&lt;endl;<br>

        -<span class=
        "comment">&nbsp;&nbsp;screen[0]-&gt;reset();<br></span>
        +<span class=
        "preproc">&nbsp;&nbsp;screen[1]-&gt;reset();<br></span>
        &nbsp;&nbsp;&nbsp;//kdDebug(1211)&lt;&lt;"TEmuVt102::reset()&nbsp;setCodec()"&lt;&lt;endl;<br>

        &nbsp;&nbsp;&nbsp;setCodec(0);<br>
        &nbsp;&nbsp;&nbsp;//kdDebug(1211)&lt;&lt;"TEmuVt102::reset()&nbsp;done"&lt;&lt;endl;<br>

        <strong><span class="number">@@</span></strong><span class=
        "ident2">&nbsp;-528,7&nbsp;+528,7&nbsp;@@&nbsp;void&nbsp;TEmuVt102::tau(&nbsp;int&nbsp;token,&nbsp;int&nbsp;p,&nbsp;int&nbsp;q&nbsp;)<br>
        </span>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PN('c'&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;reportTerminalType&nbsp;&nbsp;&nbsp;(&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;);&nbsp;break;&nbsp;//VT100<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PN('d'&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;)&nbsp;:&nbsp;scr-&gt;setCursorY&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(p&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;);&nbsp;break;&nbsp;//LINUX<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PN('f'&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;)&nbsp;:&nbsp;scr-&gt;setCursorYX&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(p,&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;q);&nbsp;break;&nbsp;//VT100<br>

        -<span class=
        "comment">&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PN('r'&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;)&nbsp;:&nbsp;scr-&gt;setMargins&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(p,&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;q);&nbsp;break;&nbsp;//VT100<br>
        </span> +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PN('r'&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;setMargins&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(p,&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;q);&nbsp;break;&nbsp;//VT100<br>
        </span>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PN('y'&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;)&nbsp;:&nbsp;/*&nbsp;IGNORED:&nbsp;Confidence&nbsp;test&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;*/&nbsp;break;&nbsp;//VT100<br>

        &nbsp;<br>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('h',&nbsp;&nbsp;&nbsp;&nbsp;1)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;setMode&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(MODE_AppCuKeys);&nbsp;break;&nbsp;//VT100<br>

        <strong><span class="number">@@</span></strong><span class=
        "ident2">&nbsp;-573,6&nbsp;+573,8&nbsp;@@&nbsp;void&nbsp;TEmuVt102::tau(&nbsp;int&nbsp;token,&nbsp;int&nbsp;p,&nbsp;int&nbsp;q&nbsp;)<br>
        </span> &nbsp;<br>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('h',&nbsp;&nbsp;&nbsp;47)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;setMode&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(MODE_AppScreen);&nbsp;break;&nbsp;//VT100<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('l',&nbsp;&nbsp;&nbsp;47)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;resetMode&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(MODE_AppScreen);&nbsp;break;&nbsp;//VT100<br>

        +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('s',&nbsp;&nbsp;&nbsp;47)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;saveMode&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(MODE_AppScreen);&nbsp;break;&nbsp;//XTERM<br>
        </span> +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('r',&nbsp;&nbsp;&nbsp;47)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;restoreMode&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(MODE_AppScreen);&nbsp;break;&nbsp;//XTERM<br>
        </span> &nbsp;<br>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;//&nbsp;XTerm&nbsp;defines&nbsp;the&nbsp;following&nbsp;modes:<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;//&nbsp;SET_VT200_MOUSE&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1000<br>

        <strong><span class="number">@@</span></strong><span class=
        "ident2">&nbsp;-604,16&nbsp;+606,20&nbsp;@@&nbsp;void&nbsp;TEmuVt102::tau(&nbsp;int&nbsp;token,&nbsp;int&nbsp;p,&nbsp;int&nbsp;q&nbsp;)<br>
        </span>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('r',&nbsp;1003)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;restoreMode&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(MODE_Mouse1000);&nbsp;break;&nbsp;//XTERM<br>

        &nbsp;<br>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('h',&nbsp;1047)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;setMode&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(MODE_AppScreen);&nbsp;break;&nbsp;//XTERM<br>

        -<span class=
        "comment">&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('l',&nbsp;1047)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;resetMode&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(MODE_AppScreen);&nbsp;break;&nbsp;//XTERM<br>
        </span> +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('l',&nbsp;1047)&nbsp;:&nbsp;screen[1]-&gt;clearEntireScreen();&nbsp;resetMode(MODE_AppScreen);&nbsp;break;&nbsp;//XTERM<br>
        </span> +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('s',&nbsp;1047)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;saveMode&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(MODE_AppScreen);&nbsp;break;&nbsp;//XTERM<br>
        </span> +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('r',&nbsp;1047)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;restoreMode&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(MODE_AppScreen);&nbsp;break;&nbsp;//XTERM<br>
        </span> &nbsp;<br>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;//FIXME:&nbsp;Unitoken:&nbsp;save&nbsp;translations<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('h',&nbsp;1048)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;saveCursor&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;);&nbsp;break;&nbsp;//XTERM<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('l',&nbsp;1048)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;restoreCursor&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;);&nbsp;break;&nbsp;//XTERM<br>

        +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('s',&nbsp;1048)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;saveCursor&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;);&nbsp;break;&nbsp;//XTERM<br>
        </span> +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('r',&nbsp;1048)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;restoreCursor&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;);&nbsp;break;&nbsp;//XTERM<br>
        </span> &nbsp;<br>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;//FIXME:&nbsp;every&nbsp;once&nbsp;new&nbsp;sequences&nbsp;like&nbsp;this&nbsp;pop&nbsp;up&nbsp;in&nbsp;xterm.<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;//&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Here's&nbsp;a&nbsp;guess&nbsp;of&nbsp;what&nbsp;they&nbsp;could&nbsp;mean.<br>

        -<span class=
        "comment">&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('h',&nbsp;1049)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;setMode&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(MODE_AppScreen);&nbsp;break;&nbsp;//XTERM<br>
        </span> -<span class=
        "comment">&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('l',&nbsp;1049)&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;resetMode&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(MODE_AppScreen);&nbsp;break;&nbsp;//XTERM<br>
        </span> +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('h',&nbsp;1049)&nbsp;:&nbsp;saveCursor();&nbsp;screen[1]-&gt;clearEntireScreen();&nbsp;setMode(MODE_AppScreen);&nbsp;break;&nbsp;//XTERM<br>
        </span> +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_CSI_PR('l',&nbsp;1049)&nbsp;:&nbsp;resetMode(MODE_AppScreen);&nbsp;restoreCursor();&nbsp;break;&nbsp;//XTERM<br>
        </span> &nbsp;<br>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;//FIXME:&nbsp;when&nbsp;changing&nbsp;between&nbsp;vt52&nbsp;and&nbsp;ansi&nbsp;mode&nbsp;evtl&nbsp;do&nbsp;some&nbsp;resetting.<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;TY_VT52__('A'&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;)&nbsp;:&nbsp;scr-&gt;cursorUp&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1);&nbsp;break;&nbsp;//VT52<br>

        <strong><span class="number">@@</span></strong><span class=
        "ident2">&nbsp;-942,6&nbsp;+948,12&nbsp;@@&nbsp;void&nbsp;TEmuVt102::useCharset(int&nbsp;n)<br>
        </span>
        &nbsp;&nbsp;&nbsp;CHARSET.pound&nbsp;&nbsp;&nbsp;=&nbsp;(CHARSET.charset[n&amp;3]&nbsp;==&nbsp;'A');&nbsp;//This&nbsp;mode&nbsp;is&nbsp;obsolete<br>

        &nbsp;}<br>
        &nbsp;<br>
        +<span class=
        "preproc">void&nbsp;TEmuVt102::setMargins(int&nbsp;t,&nbsp;int&nbsp;b)<br>
        </span> +<span class="preproc">{<br></span> +<span class=
        "preproc">&nbsp;&nbsp;screen[0]-&gt;setMargins(t,&nbsp;b);<br>
        </span> +<span class=
        "preproc">&nbsp;&nbsp;screen[1]-&gt;setMargins(t,&nbsp;b);<br>
        </span> +<span class="preproc">}<br></span> +<span class=
        "preproc"><br></span>
        &nbsp;/*!&nbsp;Save&nbsp;the&nbsp;cursor&nbsp;position&nbsp;and&nbsp;the&nbsp;rendition&nbsp;attribute&nbsp;settings.&nbsp;*/<br>

        &nbsp;<br>
        &nbsp;void&nbsp;TEmuVt102::saveCursor()<br>
        <strong><span class="number">@@</span></strong><span class=
        "ident2">&nbsp;-1001,10&nbsp;+1013,10&nbsp;@@&nbsp;void&nbsp;TEmuVt102::setMode(int&nbsp;m)<br>
        </span> &nbsp;&nbsp;&nbsp;{<br>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;MODE_Mouse1000&nbsp;:&nbsp;gui-&gt;setMouseMarks(FALSE);<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;break;<br>
        +<span class="preproc"><br></span>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;MODE_AppScreen&nbsp;:&nbsp;screen[1]-&gt;clearSelection();<br>

        -<span class=
        "comment">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;screen[1]-&gt;clearEntireScreen();<br>
        </span>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;setScreen(1);<br>

        -<span class=
        "comment">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;break;<br>
        </span> +<span class=
        "preproc">&nbsp;&nbsp;&nbsp;&nbsp;break;<br></span>
        &nbsp;&nbsp;&nbsp;}<br>
        &nbsp;&nbsp;&nbsp;if&nbsp;(m&nbsp;&lt;&nbsp;MODES_SCREEN&nbsp;||&nbsp;m&nbsp;==&nbsp;MODE_NewLine)<br>

        &nbsp;&nbsp;&nbsp;{<br>
        <strong><span class="number">@@</span></strong><span class=
        "ident2">&nbsp;-1020,6&nbsp;+1032,7&nbsp;@@&nbsp;void&nbsp;TEmuVt102::resetMode(int&nbsp;m)<br>
        </span> &nbsp;&nbsp;&nbsp;{<br>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;MODE_Mouse1000&nbsp;:&nbsp;gui-&gt;setMouseMarks(TRUE);<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;break;<br>
        +<span class="preproc"><br></span>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case&nbsp;MODE_AppScreen&nbsp;:&nbsp;screen[0]-&gt;clearSelection();<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;setScreen(0);<br>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;break;<br>
        diff&nbsp;--git&nbsp;a/konsole/TEmuVt102.h&nbsp;b/konsole/TEmuVt102.h<br>

        index&nbsp;1ef4b19e0..9291ddb9c&nbsp;100644<br>
        <strong><span class=
        "number">---</span></strong><span class="ident2">&nbsp;a/konsole/TEmuVt102.h<br>
        </span> <strong><span class=
        "number">+++</span></strong><span class=
        "ident2">&nbsp;b/konsole/TEmuVt102.h<br></span>
        <strong><span class="number">@@</span></strong><span class=
        "ident2">&nbsp;-128,6&nbsp;+128,8&nbsp;@@&nbsp;protected:<br>
        </span> &nbsp;&nbsp;&nbsp;void&nbsp;saveCursor();<br>
        &nbsp;&nbsp;&nbsp;void&nbsp;restoreCursor();<br>
        &nbsp;&nbsp;&nbsp;void&nbsp;resetCharset(int&nbsp;scrno);<br>

        +<span class=
        "preproc">&nbsp;&nbsp;void&nbsp;setMargins(int&nbsp;t,&nbsp;int&nbsp;b);<br>
        </span> +<span class="preproc">&nbsp;&nbsp;<br></span>
        &nbsp;&nbsp;&nbsp;CharCodes&nbsp;charset[2];<br>
        &nbsp;<br>
        &nbsp;&nbsp;&nbsp;DECpar&nbsp;currParm;<br>
        &nbsp;<br>
        <!--atr2html}}--></p>
      </blockquote>
    </li>

    <li>
      <p>Possibly the KDE developers had read this FAQ; I began
      this page in April 1997. The control sequences document was
      not a web page at that time. A knowledgeable X11 developer
      would know that <em>ctlseqs.ms</em> was in
      <tt>xc/doc/specs/xterm</tt>. The fix indicates that the
      latter developer had read the documentation while the
      original code demonstrates the reverse.</p>

      <p>At that point in time, the documentation said</p>

      <blockquote>
        <pre class="code-block">
CSI ? <em>Pm</em> h     DEC Private Mode Set (DECSET)
...
                 <em>Ps</em> = 1 0 4 9  &rarr; Save cursor as in DECSC and use Alter&#8208;
               nate Screen Buffer, clearing it first (unless disabled by
               the <strong>titeInhibit</strong> resource)
CSI ? <em>Pm</em> l     DEC Private Mode Reset (DECRST)
...
                 <em>Ps</em> = 1 0 4 9  &rarr; Use Normal Screen Buffer and restore
               cursor as in DECRC (unless disabled by the <strong>titeInhibit</strong>
               resource)
CSI ? <em>Pm</em> r     Restore DEC Private Mode Values.  The value of <em>Ps</em> previ&#8208;
               ously saved is restored.  <em>Ps</em> values are the same as for
               DECSET.
CSI ? <em>Pm</em> s     Save DEC Private Mode Values.  <em>Ps</em> values are the same as
               for DECSET.
</pre>
      </blockquote>
    </li>

    <li>
      <p>The fix did not amend the unnecessary comment, which at
      this time (2025) is still present in the <a href=
      "https://invent.kde.org/utilities/konsole/-/blob/master/src/Vt102Emulation.cpp?ref_type=heads#L2103">
      source code</a>. But then, a lot of the comments in the code
      are inaccurate, such as this, a few lines later:</p>

      <blockquote>
        <pre class="code-block">
// Set Cursor Style (DECSCUSR), VT520, with the extra xterm sequences       
// the first one is a special case, 'ESC[ q', which mimics 'ESC[1 q'        
// Using 0 to reset to default is matching VTE, but not any official standard. 
</pre>
      </blockquote>

      <p>Apparently, in the view of the <a href=
      "https://invent.kde.org/utilities/konsole/-/commit/97f101af8a10b4f273775545ac53e7938b4b5c8e">
      KDE developer</a>, the VT520 reference manual is not an
      official standard.</p>
    </li>
  </ul>

  <p>Like <a href="#bug_gnometerm">GNOME Terminal</a>, konsole's
  documentation is incomplete and inaccurate. This <a href=
  "https://invent.kde.org/utilities/konsole/-/commit/7acfe93e288e6dcf6836dac4727ec3fa481536dc">
  gem</a> from its handbook illustrates the problem:</p>

  <blockquote class="code-block">
    <p>After a decade, Konsole is the first rewrite from the ground
    up. While xterm has definitely been hacked to death (its README
    begins with the words Abandon All Hope, Ye Who Enter Here),
    Konsole offers a fresh start using contemporary technologies
    and understanding of X.</p>
  </blockquote>

  <p>The problem:</p>

  <ul>
    <li>
      <p>the remark was apparently written in 1997. It was
      inaccurate at that time, since it disregards the earlier
      xvt/rxvt applications. Limiting it only to a plain statement
      that konsole was a rewrite of <a href=
      "xterm.faq.html#bug_kvt">kvt</a> would have been more
      accurate. Lacking that context, we find nonfactual articles
      such as <a href=
      "http://everything2.com/index.pl?node=Konsole">this</a> on
      the net.</p>
    </li>

    <li>
      <p>for those lacking a proper education, the README was
      apparently intended to be a humorous reference to Dante's
      <em>Inferno</em>.</p>
    </li>

    <li>
      <p>reading konsole's source code and considering "hacked to
      death" can provide some occasion for humor. Enjoy.</p>
    </li>
  </ul>

  <h3 id="bug_kterm-id"><a name="bug_kterm" id=
  "bug_kterm">KTERM</a> <a href=
  "ftp://ftp.x.org/contrib/applications/kterm-6.2.0.tar.gz">download</a></h3>

  <p>KTerm stands for "Kanji term" (Japanese). This is based on the
  X Consortium source, with the same bugs (though the list of
  original authors has been removed; the modifications that
  comprise kterm is relatively small).</p>

  <ul>
    <li>
      <p>implements non-bce color model</p>
    </li>

    <li>
      <p>implements status line, but uses non-DEC escape sequences
      for this.</p>
    </li>
  </ul>

  <p>There is a variation of xvt (ancestor of rxvt) originally
  known as <a name="bug_kvt" id="bug_kvt"><strong>kvt</strong></a>
  bundled with <a href="http://www.kde.org/">KDE</a> which may be
  referred to as &ldquo;kterm&rdquo;, but I do not find it
  interesting, other than to comment that it was a poor choice of
  name. For more information:</p>

  <ul>
    <li>
      <p><a href=
      "https://invent.kde.org/historical/kde1-kdebase/-/tree/master/kvt?ref_type=heads">
      Source archive</a> starting in April 1997, which includes
      rxvt sources.</p>
    </li>

    <li>
      <p>The <a href=
      "https://invent.kde.org/historical/kde1-kdebase/-/blob/master/kvt/LICENSE.readme?ref_type=heads">
      LICENSE.readme</a> file indicates it was from rxvt version
      2.08, which was released in October 1994.</p>
    </li>

    <li>
      <p>kvt's <a href=
      "https://invent.kde.org/historical/kde1-kdebase/-/blob/master/kvt/README?ref_type=heads">
      README</a> (from <a href=
      "https://invent.kde.org/historical/kde1-kdebase/-/commits/master/kvt/README?ref_type=heads">
      1997</a>) hints that kvt was written by different developers
      than konsole.</p>
    </li>
  </ul>

  <h3 id="bug_mlterm-id"><a name="bug_mlterm" href=
  "http://mlterm.sourceforge.net/" id="bug_mlterm">MLTERM</a></h3>

  <p>Mlterm is not based on xterm or rxvt source, though it
  implements many of their features. It does fairly well with
  <a href="/vttest/vttest.html">vttest</a>, except for some odd
  misbehavior in operations that save/restore the cursor
  position.</p>

  <h3 id="bug_mterm-id"><a name="bug_mterm" id=
  "bug_mterm">MTERM</a></h3>

  <p>There are a few variants of this: the xterm bundled with some
  Motif clients is more common. More interesting, however is one
  (not Motif), attributed to "Der Mouse".</p>

  <blockquote>
    <pre class="code-block">
(mouse@Lightning.McRCIM.McGill.EDU) Available:
larry.mcrcim.mcgill.edu (132.206.1.1) in
/X/mterm.src/mterm.ball-o-wax.
</pre>
  </blockquote>

  <p>I saw only an incomplete version of this while it was
  advertised in the mid-90's. It is available by email from
  &lt;mouse@Rodents.Montreal.QC.CA&gt;. or via <a href=
  "ftp://ftp.rodents.montreal.qc.ca/mouse/X/mterm.src/">ftp</a>.
  This is not a patched version of xterm, though it was apparently
  written, like rxvt, to emulate vt100's. While it does have some
  interesting features (such as blinking characters), overall it
  does not do as well with <a href="/vttest/vttest.html">vttest</a>
  as the more widely known emulators.</p>

  <h3 id="bug_mxterm-id"><a name="bug_mxterm" id=
  "bug_mxterm">MXTERM</a></h3>

  <p>There are several variants on this: xterm adapted for Motif
  libraries. I have seen none that work properly:</p>

  <ul>
    <li>
      <p><a href=
      "https://web.archive.org/web/20110202044334/http://www.cmbi.kun.nl/~schaft/mxterm/mxterm.html">
      MXTERM: a motif Xterm with character attributes color
      rendered</a> I've noticed this one only recently. It is a
      reworking of the earlier patches for color_xterm (credited to
      Erik Fortune at SGI) and the Motif widgets (apparently first
      done by Ivan M. Hajadi at SGI in 1991, but credited in this
      release to Mahesh Neelakanta, for Motif 1.2.4).</p>
    </li>

    <li>
      <a href=
      "http://www.muquit.com/muquit/software/ansi_xterm/ansi_xterm.html">
      ANSI Xterm with Motif Scrollbar</a> Usually seen as the
      ansi-xterm-R6-motif-sb patch, I used this as the starting
      point for changes to my #82 patch of xterm in August 1998.
      <p>The original patch changes only the scrollbars to Motif,
      leaving the popup menus in Athena widgets. That was not what
      I wanted. My motivation for using Motif is not for
      performance or esthetics, of course, but to make it simpler
      to build on hosts that have no Athena widgets installed.</p>

      <p>I set those changes aside, having found (the hard way)
      that the Motif library has hardcoded behavior regarding the
      control right-mouse button. According to the O'Reilly book on
      Motif programming (volume 6), it does a server grab when
      processing menus. Making the menus behave just as in the
      Athena widgets can cause the X server to hang. (I was able to
      do this with both Lesstif and Motif libraries). Given that, I
      decided to restructure the menus entirely, making a toolbar
      which could support at compile-time either widget set.</p>
    </li>

    <li>
      <p><a href=
      "http://web.archive.org/web/*/http://www.fh-wilhelmshaven.de/~akcaagaa/index_mxterm.html">
      mxterm</a> This is a different reworking of the Motif widget
      patch, using a 1993 version (ignoring the more recent 1994
      patches noted above). However, it appears to have the same
      technical defect that I noted above.</p>
    </li>
  </ul>

  <h3 id="bug_nxterm-id"><a name="bug_nxterm" id=
  "bug_nxterm">NXTERM</a></h3>

  <p>Distributed with Redhat 5.2, it is a repackaging of <a href=
  "#bug_ansi_xterm">xterm-sb_right-ansi</a>, to use the Xaw3d
  widget set. This is based on the X Consortium X11R6 source, with
  the same bugs.</p>

  <ul>
    <li>
      <p>implements non-bce color model</p>
    </li>

    <li>
      <p>does not implement SGR 39 and SGR 49, all attributes are
      reset when changing colors.</p>
    </li>

    <li>
      <p>popup menus do not appear to work.</p>
    </li>
  </ul>

  <p>Starting with Redhat 6.0, <em>nxterm</em> is the XFree86 3.3.6
  xterm. Unfortunately Redhat neglected to update their termcap for
  nxterm to match the program.</p>

  <h3 id="bug_rxvt-id"><a name="bug_rxvt" id="bug_rxvt">RXVT</a>
  <a href="http://www.rxvt.org/">link</a></h3>

  <p>Rxvt's manual page states the following unqualified
  comment:</p>

  <blockquote class="code-block">
    <p>rxvt, version 2.6.2, is a colour vt102 terminal emulator
    intended as an xterm(1) replacement for users who do not
    require features such as Tektronix 4014 emulation and
    toolkit-style configurability. As a result, rxvt uses much less
    swap space -- a significant advantage on a machine serving many
    X sessions.</p>
  </blockquote>

  <p>How much is <em>much less</em>? Perhaps not as much as one
  would think from reading that. The Tektronix emulation in xterm
  (which has been optional since late 1997) accounts for about 25kb
  of the code.</p>

  <p>The toolkit-style configurability glibly referenced is the
  ability to redefine keys on the keyboard without recompiling the
  program, i.e., the <a href="#how2_fkeys">translations</a>
  resource. It also is the way mouse events and other actions are
  passed to xterm.</p>

  <p>The toolkit-style configurability accounts for about 300kb,
  which does add up if you happen to be running 50 xterm processes
  (i.e., about 10Mb).</p>

  <p>This comment was topical in December 2001:</p>

  <blockquote class="code-block">
    <p>Compared with something like GNOME Terminal, which takes 2-3
    times, or KDE konsole, which takes 15-20 times as much memory
    to run, xterm and rxvt memory requirements are
    indistinguishable to the normal user.</p>
  </blockquote>

  <p id="rxvt_sizes_2010">In June 2010, the numbers had changed
  somewhat. Here is a table showing the total application and
  library sizes needed for each of the terminal emulators on my
  development machine. All sizes are in kb (1024 bytes).</p>

  <table border="1" summary="Comparing XTerm's size">
    <tr>
      <th>program</th>
      <th>base size</th>
      <th>total size</th>
      <th>libraries</th>
    </tr>

    <tr>
      <td>aterm</td>
      <td>127</td>
      <td>10763</td>
      <td>45</td>
    </tr>

    <tr>
      <td>color_xterm</td>
      <td>142</td>
      <td>3647</td>
      <td>13</td>
    </tr>

    <tr>
      <td>Eterm</td>
      <td>1</td>
      <td>5126</td>
      <td>19</td>
    </tr>

    <tr>
      <td>fbiterm</td>
      <td>6</td>
      <td>2424</td>
      <td>8</td>
    </tr>

    <tr>
      <td>gnome-terminal</td>
      <td>292</td>
      <td>14587</td>
      <td>51</td>
    </tr>

    <tr>
      <td>hpterm</td>
      <td>146</td>
      <td>14386</td>
      <td>31</td>
    </tr>

    <tr>
      <td>konsole</td>
      <td>2</td>
      <td>39815</td>
      <td>71</td>
    </tr>

    <tr>
      <td>kterm</td>
      <td>226</td>
      <td>4194</td>
      <td>17</td>
    </tr>

    <tr>
      <td>mlterm</td>
      <td>316</td>
      <td>6606</td>
      <td>27</td>
    </tr>

    <tr>
      <td>mrxvt</td>
      <td>298</td>
      <td>4515</td>
      <td>19</td>
    </tr>

    <tr>
      <td>multi-aterm</td>
      <td>144</td>
      <td>2821</td>
      <td>7</td>
    </tr>

    <tr>
      <td>pterm</td>
      <td>405</td>
      <td>12817</td>
      <td>42</td>
    </tr>

    <tr>
      <td>rxvt 2.6.4</td>
      <td>108</td>
      <td>2725</td>
      <td>6</td>
    </tr>

    <tr>
      <td>rxvt 2.7.10</td>
      <td>152</td>
      <td>2829</td>
      <td>7</td>
    </tr>

    <tr>
      <td>rxvt-unicode</td>
      <td>1259</td>
      <td>13641</td>
      <td>49</td>
    </tr>

    <tr>
      <td>terminal.app</td>
      <td>211</td>
      <td>15274</td>
      <td>29</td>
    </tr>

    <tr>
      <td>wterm</td>
      <td>110</td>
      <td>2922</td>
      <td>11</td>
    </tr>

    <tr>
      <td>xfce4-terminal</td>
      <td>148</td>
      <td>14059</td>
      <td>48</td>
    </tr>

    <tr>
      <td>xgterm</td>
      <td>953</td>
      <td>4602</td>
      <td>14</td>
    </tr>

    <tr>
      <td>xhpterm</td>
      <td>130</td>
      <td>2748</td>
      <td>6</td>
    </tr>

    <tr>
      <td>xiterm</td>
      <td>12</td>
      <td>3762</td>
      <td>16</td>
    </tr>

    <tr>
      <td>xterm (everything)</td>
      <td>346</td>
      <td>5484</td>
      <td>24</td>
    </tr>

    <tr>
      <td>xterm (minimal)</td>
      <td>186</td>
      <td>4123</td>
      <td>15</td>
    </tr>

    <tr>
      <td>xterm-r5</td>
      <td>135</td>
      <td>4164</td>
      <td>11</td>
    </tr>

    <tr>
      <td>xterm-r6</td>
      <td>140</td>
      <td>4169</td>
      <td>11</td>
    </tr>
  </table>

  <p>Counting the libraries is appropriate, since some programs
  such as xiterm and the VTE-based programs are implemented in
  libraries.</p>

  <p>These comments apply to versions of <em>rxvt</em> through
  2.21:</p>

  <ul>
    <li>
      <p>clearing the screen resets colors</p>
    </li>

    <li>
      <p>does not have a delete key</p>
    </li>

    <li>
      <p>the implementation of <code>ech</code> (erase characters)
      does not follow DEC VT220 (also ISO 6429), causing
      applications using this function to misbehave.</p>
    </li>
  </ul>

  <p>A newer version (upgraded to an beta as of 2.6.PRE3, however,
  since it no longer dumps core in <a href=
  "/vttest/vttest.html">vttest</a>) is reported to fix the
  <code>ech</code> bug. However, it is less VT100-compatible than
  the earlier versions such as 2.21b because it does not render
  reverse video (<code>DECSCNM</code>) properly. All versions do
  not update the screen frequently enough, making animation
  ineffective. See <a href="/vttest/vttest.html">vttest</a>, tests
  1 and 2.</p>

  <p>One longstanding issue with rxvt impacts use of xterm. While
  rxvt does not use the X Toolkit (and corresponding X resource
  matching), it does read your <code>.Xdefaults</code> and
  app-defaults files to extract resource settings. That in itself
  would not be a problem. However, since rxvt also looks for
  resources in the <code>XTerm</code> class (a parasitic
  relationship like setting $TERM to &ldquo;xterm&rdquo; based on
  the presumption that it is a nuisance to install its
  configuration files), there have been several occasions on which
  xterm's app-defaults files have been modified to accommodate
  rxvt's variant usage.</p>

  <p>That comment applies mainly to the resource
  <strong>patterns</strong>. However, even when the pattern is
  reasonably unambiguous, but overbroad, the results can be
  conflicting. For example, some versions of rxvt may accept a
  <code>font</code> resource which does not match the XLFD pattern.
  It accepts a prefix of "xft:". This feature (apparently
  introduced by <a href="#bug_konsole">konsole</a>) tells rxvt to
  interpret the remainder of the string as a TrueType (Xft) font
  rather than a bitmap font. xterm uses the <code>faceName</code>
  resource for these values.</p>

  <h3 id="bug_st-id">st <a name="bug_st" href=
  "http://st.suckless.org" id="bug_st">link</a></h3>

  <p>Rxvt revisited, this program originally depended only on the
  X11 library. Since then, it has grown a lot, though the project
  page does not mention it. As of January 2013, it was in heavy
  development, and (according to comments on its developer's list)
  growing steadily as the developers implemented useful features
  adapted from xterm.</p>

  <p>For instance, in 2013, the size counting libraries for st 0.3
  on my Debian testing machine was on a par with rxvt (and half
  that of xterm, which uses the <a href="xtoolkit/">X Toolkit
  library</a>). Revisiting it late in 2015, it had left rxvt behind
  and was nearly as large as xterm. Here are the sizes which I
  found in Fedora 22:</p>

  <table summary="ldd-size-fedora22" border="1">
    <tr>
      <th>LDD-Size</th>
      <th>Program</th>
    </tr>

    <tr>
      <td align="right" style="font-family: monospace;">
      3452986</td>
      <td>rxvt</td>
    </tr>

    <tr>
      <td align="right" style="font-family: monospace;">
      <em>6060960</em>
      </td>
      <td>st</td>
    </tr>

    <tr>
      <td align="right" style="font-family: monospace;">
      6771039</td>
      <td>mrxvt</td>
    </tr>

    <tr>
      <td align="right" style="font-family: monospace;">
      <em>7785780</em>
      </td>
      <td>xterm</td>
    </tr>

    <tr>
      <td align="right" style="font-family: monospace;">
      15060195</td>
      <td>urxvt</td>
    </tr>

    <tr>
      <td align="right" style="font-family: monospace;">
      20934874</td>
      <td>lxterminal</td>
    </tr>

    <tr>
      <td align="right" style="font-family: monospace;">
      21089908</td>
      <td>lilyterm</td>
    </tr>

    <tr>
      <td align="right" style="font-family: monospace;">
      21358156</td>
      <td>xfce4-terminal</td>
    </tr>

    <tr>
      <td align="right" style="font-family: monospace;">
      25738679</td>
      <td>roxterm</td>
    </tr>

    <tr>
      <td align="right" style="font-family: monospace;">
      31195794</td>
      <td>gnome-terminal</td>
    </tr>

    <tr>
      <td align="right" style="font-family: monospace;">
      32780414</td>
      <td>terminology</td>
    </tr>

    <tr>
      <td align="right" style="font-family: monospace;">
      87813125</td>
      <td>konsole</td>
    </tr>
  </table>

  <p>By the way, the project page quotes the <a href=
  "https://github.com/ThomasDickey/xterm-snapshots/blob/master/README">
  README</a> file from xterm's sources, omitting my editorial
  comment at the top noting that the <a href=
  "https://www.phrases.org.uk/meanings/abandon-hope-all-ye-who-enter-here.html">
  paraphrase</a> of the opening from Dante's <em>Inferno</em> dated
  from 1991, and pointing to this FAQ to provide better
  context.</p>

  <h3 id="bug_xgterm-id"><a name="bug_xgterm" id=
  "bug_xgterm">XGTERM</a> <a href=
  "ftp://iraf.noao.edu/iraf/x11iraf/">link</a></h3>

  <p>It has some features which are also in color_xterm:(non-bce
  ANSI color, colorBD and colorUL resources, cursor warping, etc.
  The main feature is its Tektronix graphics emulation, which is
  the main reason for this particular program. Neither program has
  a change-log, so it is not easy to say which influenced the
  other.</p>

  <p>That is from reading the source code. However testing under
  Debian, something is wrong with the resource processing (neither
  popup menus nor colors work).</p>

  <p>As of March 2022, Debian's <a href=
  "https://packages.debian.org/search?keywords=xgterm">xgterm</a>
  package does not install the terminal description which the IRAF
  developer provided. That was just an alias for xterm-r5, which
  still needs some work. If the &ldquo;xgterm&rdquo; terminal
  description is missing, xgterm falls back to &ldquo;xterm&rdquo;
  which is not a close match. To address this problem, ncurses
  provides a workable <a href=
  "/ncurses/terminfo.src.html#tic-xgterm">xgterm</a> terminal
  description.</p>

  <h3 id="bug_xiterm-id"><a name="bug_xiterm" id=
  "bug_xiterm">XITERM</a> <a href=
  "ftp://metalab.unc.edu/pub/Linux/X11/terms/">link</a></h3>

  <p>This appears to be rxvt 2.20, lightly reformatted, with a few
  ifdef's changed.</p>

  <p>That is, it was. The name was later appropriated by a
  different <a href=
  "http://web.archive.org/web/*/http://oss.software.ibm.com/linux/projects/iterm/">
  program</a>, which also uses the name <code>iterm</code>. Like
  gnome-terminal, iterm aims to be an xterm-emulator rather than a
  VT102- or VT220-emulator.</p>

  <p>An earlier <a href=
  "http://web.archive.org/web/*/http://www.openi18n.org">attempt</a>
  by the same author (the "CSI-xterm") incorporated in 2002 some of
  the changes I made for XFree86 xterm via cut and paste (but does
  not mention this in its README). The &ldquo;borrowed&rdquo;
  changes comprised about 10% of the patch provided for X11R6.5.1,
  summarized here:</p>

  <blockquote>
    <pre class="code-block">
xterm-6.5.1-i18n-0.7.patch.gz
 Imakefile     |   25 +
 RELNOTES-I18N |  104 ++++++
 XTerm.ad      |    1
 button.c      |  155 ++++++++-
 charproc.c    |  979 ++++++++++++++++++++++++++++++++++++++++++++++++++++------
 data.c        |    6
 data.h        |    4
 error.h       |    8
 fontutils.c   |   78 ++++
 fontutils.h   |    8
 input.c       |   11
 main.c        |   40 +-
 main.h        |    1
 misc.c        |   46 ++
 ptyx.h        |  156 ++++++++-
 screen.c      |  513 +++++++++++++++++++++++++++---
 scrollbar.c   |   36 +-
 util.c        |  218 +++++++++++-
 18 files changed, 2183 insertions(+), 206 deletions(-)
</pre>
  </blockquote>

  <p>This patch was said to be the basis for Solaris 10 xterm, and
  was briefly referred to as the Solaris "color xterm". It did not
  use the <code>bce</code> color model however, and Sun provided no
  terminal description for it.</p>

  <p>Back to <em>iterm</em>: the author's README in the patch used
  the same terminology as in the later work, demonstrating their
  relationship:</p>

  <blockquote>
    <pre class="code-block">
 This is a patch for the xterm of X11 release 6.5.1 to fix its
internationalization defects. This patch enables xterm to handle
whatever the character set encodings and scripts support underlining
operating system supports via the technology called CSI(Code Set
Independence) and XOM(X Output Method). Traditionally, several
X terminal emulators which are hard-wired to specific languages and
encodings were introduced to support local language requirements, such
as kterm, hanterm, cxterm, UTF-8 xterm and so on. This  truly
internationalized terminal emulator supersedes the needs of those
multiple locale specific terminalemulators.
</pre>
  </blockquote>

  <p>The key to understanding the "code set independence" is that
  the author intended to treat existing character encodings on an
  equal basis with Unicode and UTF-8. Some of that is reflected in
  the Solaris <em><a href=
  "http://docs.oracle.com/cd/E19253-01/817-2521/os-1208/index.html">
  International Language Environments Guide</a></em>, but in
  explaining <em>how</em> this is done, the documentation is weak,
  lacking detail.</p>

  <p>Either version of <em>iterm</em> has similar problems running
  <a href="/vttest/vttest.html">vttest</a>.</p>

  <h2 id="building_it-id"><a name="building_it" id=
  "building_it">How do I build <strong>XTerm</strong>?</a></h2>

  <p>Building a copy of xterm is simple, provided that you have a
  development configuration for X11:</p>

  <ul>
    <li>
      <p>Header files and libraries. If you do not have the header
      files (usually under /usr/include/X11) for your system, you
      are better off building the libraries yourself. Xterm can be
      built with either X11R5 or X11R6 libraries; however X11R6
      requires much more data to be installed before xterm will
      run. Xterm uses the <code>Xaw</code> library for popup
      menus.</p>
    </li>

    <li>
      <p>imake and <code>xmkmf</code>. These utilities produce a
      Makefile from the Imakefile. They are not essential, but
      useful, particularly on systems with unusual
      configurations.</p>
    </li>
  </ul>

  <p>If you have a working <code>xmkmf</code> script (or correctly
  configured imake utility), all you need to do is type</p>

  <blockquote>
    <pre class="code-block">
xmkmf
make
</pre>
  </blockquote>

  <p>I have written a <em>configure</em> script for xterm which can
  use <code>imake</code> (or <code>xmkmf</code>) to generate a
  Makefile from the Makefile.in. Or it can do without
  <code>imake</code> entirely. I have restructured xterm to
  eliminate most hardcoded <code>#ifdef</code>'s, replacing them
  with definitions that can be derived with the configuration
  script. The <em>configure</em> script is more flexible than
  <em>xmkmf</em>, since it allows you to enable or disable a
  variety of features. Type</p>

  <blockquote>
    <pre class="code-block">
configure --help
</pre>
  </blockquote>

  <p>to get a list of options.</p>

  <p>Though I have replaced most hardcoded ifdef's with
  autoconfigured values, it will still continue to build properly
  with the imake environment.</p>

  <p>However, I usually build xterm using the configure script. By
  default, it looks for imake and will use it to help with a few
  places where a reliable configure check cannot be created. One of
  these (see <a href="#narrowproto">Why doesn't the scrollbar
  work?</a>) can be a problem.</p>

  <p>As with all of my projects, I routinely check for strict
  compiler warnings. For gcc, that is done with the "gcc-stricter"
  script which you can find <a href=
  "/scripts/readme.html">here</a>. The X libraries have a
  longstanding issue had been ignored (as of mid-2012). To work
  around this (and get useful warnings), I applied this patch:</p>

  <blockquote>
    <pre class="code-block">
--- Intrinsic.h.orig    2009-08-25 13:22:15.000000000 -0400
+++ Intrinsic.h 2009-12-06 09:48:39.000000000 -0500
@@ -66,7 +66,11 @@

 #define XtSpecificationRelease 6

+#ifdef _CONST_X_STRING
+typedef const char *String;
+#else
 typedef char *String;
+#endif

 /* We do this in order to get "const" declarations to work right.  We
  * use _XtString instead of String so that C++ applications can
--- Xresource.h.orig    2009-07-19 14:43:21.000000000 -0400
+++ Xresource.h 2009-12-06 10:11:19.000000000 -0500
@@ -338,8 +338,8 @@
 } XrmOptionKind;

 typedef struct {
-    char           *option;        /* Option abbreviation in argv          */
-    char           *specifier;     /* Resource specifier                   */
+    _Xconst char    *option;       /* Option abbreviation in argv          */
+    _Xconst char    *specifier;            /* Resource specifier                   */
     XrmOptionKind   argKind;       /* Which style of option it is          */
     XPointer       value;          /* Value to provide if XrmoptionNoArg   */
 } XrmOptionDescRec, *XrmOptionDescList;
</pre>
  </blockquote>

  <p>I made note of it on the Xorg <a href=
  "http://lists.x.org/archives/xorg-devel/2010-May/009052.html">mailing
  list</a>, but as you can see, there was no response.</p>

  <p>Finally, I spent the requisitve time to integrate the
  change&mdash;and complete the process of transforming the
  <a href="xtoolkit/"><em>X Toolkit</em></a> documentation from
  nroff to docbook/xml.</p>

  <h2 id="report_bugs-id"><a name="report_bugs" id=
  "report_bugs">How do I report bugs?</a></h2>

  <p>You should report bugs to <a href=
  "mailto:dickey@invisible-island.net">me</a>. I also respond to
  bug reports in a number of bug-tracking systems, though some are
  less open to searches than others. See also:</p>

  <ul>
    <li>
      <p><a href=
      "/personal/bug-reports.html">reporting/patching</a>
      procedures.</p>
    </li>

    <li>
      <p><a href="/scripts/readme.html">analyzing problems with
      configure scripts</a></p>
    </li>
  </ul>

  <h2 id="more_info-id"><a name="more_info" id=
  "more_info">Additional Information</a></h2>

  <p>There appears to be no comprehensive source of information on
  xterm better than the documentation which comes with the source
  code</p>

  <ul>
    <li>
      <a href="/xterm/xterm.log.html">XTerm change log</a>
      <ul>
        <li>
          <p><a href="#xterm_man">The XTerm Manual</a></p>
        </li>

        <li>
          <p><a href="#ctlseqs_ms">XTerm Control Sequences</a></p>
        </li>

        <li>
          <p><a href="#resize_man">resize</a> &ndash; set TERMCAP
          and terminal settings to current xterm window size</p>
        </li>

        <li>
          <p><a href="#uxterm_man">uxterm</a> &ndash; a UTF-8
          wrapper for XTerm</p>
        </li>

        <li>
          <p><a href="#koi8rxterm_man">koi8rxterm</a> &ndash; a
          KOI8-R wrapper for XTerm</p>
        </li>

        <li>
          <p><a href="#luit_prog">luit</a> &ndash; Locale and ISO
          2022 support for Unicode terminals</p>
        </li>
      </ul>
    </li>

    <li>
      <p><a href="#other_sites">Other Sites</a></p>
    </li>

    <li>
      <p><a href="#ref_misleading">Interesting but misleading</a></p>
    </li>
  </ul>

  <h4 id="xterm_man-id"><a name="xterm_man" id="xterm_man">The
  XTerm Manual</a></h4>

  <p>The command-line options, X resources and similar configurable
  options of xterm are documented in the manual page.</p>

  <p>Here are copies of the file in various forms: <a href=
  "/xterm/manpage/xterm.html">html</a>, <a href=
  "/xterm/manpage/xterm.pdf">pdf</a>, <a href=
  "/xterm/manpage/xterm.ps">ps</a> and <a href=
  "/xterm/manpage/xterm.txt">text</a>.</p>

  <h4 id="ctlseqs_ms-id"><a name="ctlseqs_ms" id="ctlseqs_ms">Xterm
  Control Sequences</a></h4>

  <p>Control sequences, i.e., programming information are in the
  <code>ctlseqs.ms</code> file which I bundle with the <a href=
  "xterm.faq.html#latest_version">program source</a>. (It used to
  be in the same directory in the X distribution, but was moved to
  a different part of the tree long ago). Note that you must format
  this file with different options than a manpage, e.g.,</p>

  <blockquote>
    <pre class="code-block">
tbl ctlseqs.ms | nroff -ms &gt;ctlseqs.txt
tbl ctlseqs.ms | groff -ms &gt;ctlseqs.ps
</pre>
  </blockquote>

  <p>As a PostScript or PDF file, the individual letters of the
  control sequences are all boxed, for emphasis, but I find the
  text file equally readable.</p>

  <p>Here are copies of the file in various forms: <a href=
  "ctlseqs/ctlseqs.html">html</a>, <a href=
  "ctlseqs/ctlseqs.pdf">pdf</a>, <a href=
  "ctlseqs/ctlseqs.ps">ps</a> and <a href=
  "ctlseqs/ctlseqs.txt">text</a>.</p>

  <h4 id="resize_man-id"><a name="resize_man" id=
  "resize_man">resize &ndash; set TERMCAP and terminal settings to
  current xterm window size</a></h4>

  <p><em>resize</em> is useful by itself, but is maintained for
  historical reasons as part of xterm. <a href=
  "/xterm/manpage/resize.html">html</a>, <a href=
  "/xterm/manpage/resize.pdf">pdf</a>, <a href=
  "/xterm/manpage/resize.ps">ps</a> and <a href=
  "/xterm/manpage/resize.txt">text</a>.</p>

  <h4 id="uxterm_man-id"><a name="uxterm_man" id=
  "uxterm_man">uxterm &ndash; a UTF-8 wrapper for xterm</a></h4>

  <p>XTerm does not automatically <em>set</em> your locale. It can
  be told to <em>use</em> your locale settings. This is a shell
  script which sets xterm's resources to use UTF-8 encoding, and
  use UTF-8 fonts. There is a similar <em>lxterm</em> script, but
  it relies upon non-portable applications, unlike uxterm.</p>

  <p>Here are copies of uxterm's documentation: <a href=
  "/xterm/manpage/uxterm.html">html</a>, <a href=
  "/xterm/manpage/uxterm.pdf">pdf</a>, <a href=
  "/xterm/manpage/uxterm.ps">ps</a> and <a href=
  "/xterm/manpage/uxterm.txt">text</a>.</p>

  <p>Incidentally, there was a different program named
  &ldquo;uxterm&rdquo; before the shell script was added to xterm
  in <a href="xterm.log.html#xterm_137">mid-2000</a>. <a href=
  "https://web.archive.org/web/20130328091052/http://czyborra.com/unicode/terminals.html">
  Roman Czyborra commented</a> in 1998 that it was based on the
  original X11 xterm source (very likely, since
  &ldquo;strings&rdquo; run on the executable shows the xterm
  actions, resources and even the Tek4014 support). There are few
  references to it to provide details: the first appearance was in
  <a href=
  "http://www.unicode.org/mail-arch/unicode-ml/Archives-Old/UML001/0042.html">
  1994</a>, and the last was Czyborra's page in 1998. For the
  curious, there is a copy on <a href=
  "http://www.ibiblio.org/pub/packages/ccic/software/x-win/uxterm/uxterm.README">
  ibiblio.org</a> (no Linux executables, no source, however).</p>

  <h4 id="koi8rxterm_man-id"><a name="koi8rxterm_man" id=
  "koi8rxterm_man">koi8rxterm &ndash; a KOI8-R wrapper for
  xterm</a></h4>

  <p>As a special case, this wrapper is packaged with xterm to
  provide KOI8-R encoding.</p>

  <p>Here are copies of koi8rxterm's documentation: <a href=
  "/xterm/manpage/koi8rxterm.html">html</a>, <a href=
  "/xterm/manpage/koi8rxterm.pdf">pdf</a>, <a href=
  "/xterm/manpage/koi8rxterm.ps">ps</a> and <a href=
  "/xterm/manpage/koi8rxterm.txt">text</a>.</p>

  <h4 id="luit_prog-id"><a name="luit_prog" id="luit_prog">luit
  &ndash; Locale and ISO 2022 support for Unicode terminals</a></h4>

  <p><a href="/luit/luit.html">luit</a> also is maintained as part
  of xterm, since its upstream maintainer is inactive, and the
  ostensible maintainers have more than once delivered unusable
  versions, causing many bug reports to be issued against
  xterm.</p>

  <h3 id="other_sites-id"><a name="other_sites" id=
  "other_sites">Other Sites</a></h3>

  <ul>
    <li>
      <p>I have found Richard Shuford's archive to be invaluable
      for notes on the DEC VT220 and related terminals. This was a
      <a href=
      "http://web.eecs.utk.edu/~shuford/terminal_index.html">webpage</a>
      but was last seen via <a href=
      "ftp://cs.utk.edu/pub/shuford/">ftp</a>. I have a snapshot of
      the ftp site, here:</p>

      <ul>
        <li>
          <p><a href=
          "/archives/shuford/">ftp://invisible-island.net/shuford/</a></p>
        </li>

        <li>
          <p><a href=
          "https://invisible-mirror.net/archives/shuford/">http://invisible-mirror.net/archives/shuford/</a></p>
        </li>
      </ul>
    </li>

    <li>
      <p>Though not available at the time that I was collecting
      most of my notes, <a href="http://vt100.net">VT100.net</a> is
      also a good source of primary information.</p>
    </li>

    <li>
      <p>As part of my <a href="/personal/git-exports.html"><em>Git
      exports</em></a> work in 2016, I made a repository of the
      major X release copies of <a href=
      "https://github.com/ThomasDickey/old-xterm">xterm source</a>.
      Alan Coopersmith has a more extensive repository of the
      <a href=
      "https://cgit.freedesktop.org/~alanc/xc-historical/log/">X
      source</a>, which is also useful although it does not cover
      the full timespan. In my repository, I combined the
      controls-sequences document which was in <em>specs</em> with
      the program:</p>

      <ul>
        <li>
          <p>xterm was first released in X10R3, with a manual page
          in the <code>man</code> directory, and program in the
          <code>xterm</code> directory.</p>
        </li>

        <li>
          <p>The developers (re)organized the directory tree in
          X11, moving some manual pages under the <code>doc</code>
          tree, others went along with the source-code, and moving
          the programs such as xterm under a <code>clients</code>
          directory.</p>
        </li>

        <li>
          <p>The control-sequences document was first released in
          X11R4.</p>
        </li>

        <li>
          <p>When making the repository, I overlooked the X10
          manual page. Git isn't flexible enough to add that later,
          without re-creating the repository.</p>
        </li>
      </ul>

      <p>I use RCS as a starting point for creating Git
      repositories because it is the simplest way to capture each
      file's timestamp. Since the X developers switched source
      repositories between X10 and X11, and the RCS identifiers
      were no longer in sequence, I used a script to change those
      identifiers to a form that would not interfere with checking
      the sources into RCS.</p>

      <p>The dates shown are, of course, for the xterm
      source-code:</p>

      <table summary="historical xterm source code">
        <tr>
          <th rowspan="2">Date</th>
          <th rowspan="2">Release</th>
          <th>Mine</th>
          <th>Alan's</th>
        </tr>

        <tr>
          <th><a href=
          "https://github.com/ThomasDickey/old-xterm/commits/8c1136d1b2593d44ef5e0c31f9917a8fb336443a/main.c">
          old-xterm</a>
          </th>
          <th><a href=
          "https://cgit.freedesktop.org/~alanc/xc-historical/log/xc/programs/xterm">
          Program</a>
          </th>
          <th><a href=
          "https://cgit.freedesktop.org/~alanc/xc-historical/log/xc/doc/specs/xterm">
          Specs</a>
          </th>
        </tr>

        <tr>
          <td>2005-12-14</td>
          <td><em>X11R6.9.0</em>
          </td>
          <td><a href=
          "https://github.com/ThomasDickey/old-xterm/tree/8c1136d1b2593d44ef5e0c31f9917a8fb336443a">
          link</a>
          </td>
          <td><em>n/a</em>
          </td>
          <td><em>n/a</em>
          </td>
        </tr>

        <tr>
          <td>2005-01-12</td>
          <td><em>X11R6.8.2</em>
          </td>
          <td><a href=
          "https://github.com/ThomasDickey/old-xterm/tree/8f53683fb3286c4b9f7e56b035657c019a8b510c">
          link</a>
          </td>
          <td><em>n/a</em>
          </td>
          <td><em>n/a</em>
          </td>
        </tr>

        <tr>
          <td>2004-08-20</td>
          <td><em>X11R6.8.0</em>
          </td>
          <td><a href=
          "https://github.com/ThomasDickey/old-xterm/tree/244c3c87895b75f50d994c8ed0b0b0b570acb02b">
          link</a>
          </td>
          <td><em>n/a</em>
          </td>
          <td><em>n/a</em>
          </td>
        </tr>

        <tr>
          <td>2004-04-02</td>
          <td><em>X11R6.7</em>
          </td>
          <td><a href=
          "https://github.com/ThomasDickey/old-xterm/tree/72f78591baaef305e639393c8570f33154801342">
          link</a>
          </td>
          <td><em>n/a</em>
          </td>
          <td><em>n/a</em>
          </td>
        </tr>

        <tr>
          <td>2001-02-09</td>
          <td><em>X11R6.6</em>
          </td>
          <td><a href=
          "https://github.com/ThomasDickey/old-xterm/tree/588551b210f997e94d7062068e473b03dd7f7adc">
          link</a>
          </td>
          <td><em>n/a</em>
          </td>
          <td><em>n/a</em>
          </td>
        </tr>

        <tr>
          <td>2000-08-21</td>
          <td><em>X11R6.5.1</em>
          </td>
          <td><a href=
          "https://github.com/ThomasDickey/old-xterm/tree/6171bddbd473ca531a927f98253b617200a2f7de">
          link</a>
          </td>
          <td><em>n/a</em>
          </td>
          <td><em>n/a</em>
          </td>
        </tr>

        <tr>
          <td>1998-02-09</td>
          <td><em>X11R6.4</em>
          </td>
          <td><a href=
          "https://github.com/ThomasDickey/old-xterm/tree/09772a9703eeaf63ab990189453f64ea718c7005">
          link</a>
          </td>
          <td><em>n/a</em>
          </td>
          <td><em>n/a</em>
          </td>
        </tr>

        <tr>
          <td>1996-12-09</td>
          <td><em>X11R6.3</em>
          </td>
          <td><a href=
          "https://github.com/ThomasDickey/old-xterm/tree/593e9a29ebed6609b07f4133e034b43400e8cc51">
          link</a>
          </td>
          <td><em>n/a</em>
          </td>
          <td><em>n/a</em>
          </td>
        </tr>

        <tr>
          <td>1996-02-02</td>
          <td><em>X11R6.1</em>
          </td>
          <td><a href=
          "https://github.com/ThomasDickey/old-xterm/tree/1f18f60614c20fce722891b772017b5647eb9259">
          link</a>
          </td>
          <td><em>n/a</em>
          </td>
          <td><em>n/a</em>
          </td>
        </tr>

        <tr>
          <td>1995-01-30</td>
          <td><em>X11R6</em>
          </td>
          <td><a href=
          "https://github.com/ThomasDickey/old-xterm/tree/279c9960fc4d19e249ec7af2fb7c7d9c2987d369">
          link</a>
          </td>
          <td><a href=
          "https://cgit.freedesktop.org/~alanc/xc-historical/tree/xc/programs/xterm?id=9d5f53a3923a1a4bd6fa8afb3d7afdd448767187">
          link</a>
          </td>
          <td><a href=
          "https://cgit.freedesktop.org/~alanc/xc-historical/tree/xc/doc/specs/xterm/ctlseqs.ms?id=68409e15e071bae349d54111b27d9b78c1dd6c5a">
          link</a>
          </td>
        </tr>

        <tr>
          <td>1993-11-11</td>
          <td><em>X11R5</em>
          </td>
          <td><a href=
          "https://github.com/ThomasDickey/old-xterm/tree/5534cf360d381e75057bef3eaf401acad5a6360e">
          link</a>
          </td>
          <td><a href=
          "https://cgit.freedesktop.org/~alanc/xc-historical/tree/xc/programs/xterm?id=8dd835dffa5a2928cec818fb0148c9c2838caa4b">
          link</a>
          </td>
          <td><a href=
          "https://cgit.freedesktop.org/~alanc/xc-historical/tree/xc/doc/specs/xterm/ctlseqs.ms?id=f9475442485638537e74bd44ea38d792eecdbecc">
          link</a>
          </td>
        </tr>

        <tr>
          <td>1989-12-23</td>
          <td><em>X11R4</em>
          </td>
          <td><a href=
          "https://github.com/ThomasDickey/old-xterm/tree/aff055339109b8fe7bf146aecc340a622bae235e">
          link</a>
          </td>
          <td><a href=
          "https://cgit.freedesktop.org/~alanc/xc-historical/tree/xc/programs/xterm?id=ad6566ec83c49abca29536932627a41c9a1004da">
          link</a>
          </td>
          <td><a href=
          "https://cgit.freedesktop.org/~alanc/xc-historical/commit/xc/doc/specs/xterm?id=9b99668bad70ce523d88920d98ae7b686d9c3289">
          link</a>
          </td>
        </tr>

        <tr>
          <td>1988-10-27</td>
          <td><em>X11R3</em>
          </td>
          <td><a href=
          "https://github.com/ThomasDickey/old-xterm/tree/1c2422714c26256ff4c3717d1529cec141f22b49">
          link</a>
          </td>
          <td><a href=
          "https://cgit.freedesktop.org/~alanc/xc-historical/tree/xc/programs/xterm?id=009e20249100057a1ae15f0c1c04f6d964c0dd81">
          link</a>
          </td>
          <td><em>n/a</em>
          </td>
        </tr>

        <tr>
          <td>1988-03-01</td>
          <td><em>X11R2</em>
          </td>
          <td><a href=
          "https://github.com/ThomasDickey/old-xterm/tree/aaf6f073d6039955fa7fa56675a5ea10dc9e21b6">
          link</a>
          </td>
          <td><a href=
          "https://cgit.freedesktop.org/~alanc/xc-historical/tree/xc/programs/xterm?id=243d9b2d557b95812e51097e98d8f4be79df78d5">
          link</a>
          </td>
          <td><em>n/a</em>
          </td>
        </tr>

        <tr>
          <td>1987-09-15</td>
          <td><em>X11R1</em>
          </td>
          <td><a href=
          "https://github.com/ThomasDickey/old-xterm/tree/6bf1714f13b7811c3e28d186bfc9942d971edd9b">
          link</a>
          </td>
          <td><em>n/a</em>
          </td>
          <td><em>n/a</em>
          </td>
        </tr>

        <tr>
          <td>1986-12-25</td>
          <td><em>X10R4</em>
          </td>
          <td><a href=
          "https://github.com/ThomasDickey/old-xterm/tree/d448c6d7373c3bc3df4c75e815baa1e645462893">
          link</a>
          </td>
          <td><em>n/a</em>
          </td>
          <td><em>n/a</em>
          </td>
        </tr>

        <tr>
          <td>1986-05-17</td>
          <td><em>X10R3</em>
          </td>
          <td><a href=
          "https://github.com/ThomasDickey/old-xterm/tree/28267a54e0b2f5daf75846ba8ee5030a1d177a52">
          link</a>
          </td>
          <td><em>n/a</em>
          </td>
          <td><em>n/a</em>
          </td>
        </tr>
      </table>
    </li>
  </ul>

  <h3 id="ref_misleading-id"><a name="ref_misleading" id=
  "ref_misleading">Interesting but misleading:</a></h3>

  <ul>
    <li id="mis:vt100-color">
      <p>The ncurses FAQ <em><a href=
      "/ncurses/ncurses.faq.html#vt100_color" id="vt100_color"
      name="vt100_color">How do I get color with VT100?</a></em>
      discusses a widely cited bit of misinformation.<br>
      For instance, this <a href=
      "https://www.google.com/search?q=%22http%3A%2F%2Fwww.termsys.demon.co.uk%2Fvtansi.htm%22">
      web search</a> gives 3,000 hits in March 2015.</p>
    </li>

    <li id="mis:backspace-delete">
      <p>Also widely cited, <a href=
      "http://www.ibb.net/~anne/keyboard/keyboard.html">Consistent
      BackSpace and Delete Configuration</a> gives advice regarding
      <a href="#xterm_erase">backspace and delete</a> keys which is
      heavily biased toward Linux. For instance:</p>

      <ul>
        <li>
          <p>the <em>console</em> referred to is the Linux console,
          which initially had as a goal <em>VT220</em> emulation.
          Linux never came close to meeting that goal, which was
          abandoned in the late 1990s when UTF-8 became more
          important.</p>

          <p>As part of that, Linux's keyboard was (actually
          modelled on xterm) said to be <em>VT220</em>, and its
          coding for the backspace key sent <code>DEL</code>. In
          contrast, ncurses' terminal database says
          <code>kbs</code> for the <a href=
          "/ncurses/terminfo.src.html#tic-vt220">vt220</a> sends
          <code>^H</code> (<code>BS</code>).</p>
        </li>

        <li>
          <p>the guideline uses &ldquo;newer&rdquo;,
          &ldquo;right&rdquo; and &ldquo;correct&rdquo; in the part
          which describes <code>DEL</code>, versus
          &ldquo;dirty&rdquo; and &ldquo;break&rdquo;,
          &ldquo;broken&rdquo; in that addressing
          <code>BS</code>.</p>
        </li>
      </ul>

      <p>In addition to bias, the technical remedies are unsuitable
      for generic advice. In particular, the comments about
      terminfo, <code>xmodmap</code> and xterm's translations
      resource are suitable only for special cases because the
      proposed solutions create problems of their own.</p>

      <p>The page itself was written in 1997, with only minor fixes
      since then. Thus, it does not reflect any of the improvements
      made to xterm. Its lack of relevance does not prevent people
      from citing it. For instance, <a href=
      "http://unix.stackexchange.com/questions/180087/why-pressing-ctrl-h-in-xterm-tmux-sends/180106#180106">
      this page</a>'s <em>accepted answer</em> recommends that
      (although neither gives a useful answer to the question).
      Here are a few clues:</p>

      <ul>
        <li>
          <p>Debian's current package for ncurses uses the
          <code>--with-xterm-kbs</code> configure option which I
          added in <a href="/ncurses/NEWS.html#t20120211">2012</a>.
          Debian also applies patches to many of the terminal
          descriptions, including adding a patched copy of xterm's
          terminfo file to ncurses's terminfo file.</p>

          <p>The patched copy is redundant and a source of problems
          (since the two overlap, with slightly different goals
          regarding PC- and VT220-style keyboards). My intent in
          adding the configure option to ncurses was to wean them
          away from the patch. That has not happened yet.</p>
        </li>

        <li>
          <a href="http://tmux.sourceforge.net/">tmux</a> is
          (mostly) a terminfo application. However, it does not use
          the terminal database's <code>kbs</code> value. Rather
          (referring to the source for 1.9a), it uses the termios
          setting:
          <blockquote>
            <!--{{atr2html-->

            <p style="font-family: monospace; font-size: 10pt;"
            class="code-block">
            &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="comment">/*<br>
            </span>
            &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="comment">*&nbsp;Check&nbsp;for&nbsp;backspace&nbsp;key&nbsp;using&nbsp;termios&nbsp;VERASE&nbsp;-&nbsp;the&nbsp;terminfo<br>
            </span>
            &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="comment">*&nbsp;kbs&nbsp;entry&nbsp;is&nbsp;extremely&nbsp;unreliable,&nbsp;so&nbsp;cannot&nbsp;be&nbsp;safely<br>
            </span>
            &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="comment">*&nbsp;used.&nbsp;termios&nbsp;should&nbsp;have&nbsp;a&nbsp;better&nbsp;idea.<br>
            </span>
            &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="comment">*/</span><br>

            &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;bspace&nbsp;=&nbsp;tty-&gt;tio.c_cc[VERASE];<br>

            &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">if</span>&nbsp;(bspace&nbsp;!=&nbsp;_POSIX_VDISABLE&nbsp;&amp;&amp;&nbsp;key&nbsp;==&nbsp;bspace)<br>

            &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;key&nbsp;=&nbsp;KEYC_BSPACE;<br>

            <!--atr2html}}--></p>
          </blockquote>

          <p>At the same time, <code>tmux</code> sets
          <code>$TERM</code> to &ldquo;screen&rdquo;, by default.
          Debian patches that terminal description, too.
          Applications running inside <code>tmux</code> use that
          terminal description. If instead <code>tmux</code>
          translated the backspace key to match the value from
          <a href=
          "/ncurses/man/curs_termattrs.3x.html">erasechar</a> (for
          the given <code>$TERM</code>), its clients would receive
          consistent information.</p>

          <p>Thus, rather than blaming the user (for a "badly
          configured" xterm), the actual problem is a design flaw
          in <code>tmux</code> which should have been sent to its
          developers in a bug report.</p>
        </li>
      </ul>
    </li>

    <li id="mis:all-escapes">
      <p>One of the PuTTY developers has a list named
      &ldquo;all-escapes&rdquo; which begins</p>

      <blockquote>
        <pre class="code-block">
# This file is hoped to document all the escape sequences supported by
# terminals that are vaguely compliant with ECMA-48 and friends.
</pre>
      </blockquote>

      <p>It has been an occasional topic for comment:</p>

      <ul>
        <li>
          <a href=
          "https://comp.os.vms.narkive.com/xY2s5Mns/decterm-special-escape-sequences">
          DECterm special escape sequences ?</a> (Fri Dec 29
          08:28:11 2006 on <em>comp.os.vms</em>):
          <blockquote>
            <pre class="code-block">
Michael Unger &lt;spam.to.unger@spamgourmet.com&gt; wrote:
&gt; On 2006-12-28 06:20, "JF Mezei" wrote:
&gt;&gt; [...]
&gt;&gt;
&gt;&gt; I tried google, and there are so many sites that list one or two espape
&gt;&gt; sequence that it is nearly impossible to find out whether what I am looking
&gt;&gt; for exists or not.

&gt; There are quite a lot of escape sequences documented in
&gt; &lt;<a rel="nofollow" href=
"http://bjh21.me.uk/all-escapes/all-escapes.txt">http://bjh21.me.uk/all-escapes/all-escapes.txt</a>&gt; ...

...unfortunately, they're just heaped together in one place, without
a cross-reference (which would show that they're from several types
of terminals).

For a clue regarding the depth of this file, note the first line

        # $Id: all-escapes.txt,v 1.32 2005/09/14 12:00:06 ben Exp @

and the 1999's pervading the text. It's basically a cut/paste job
from 1999 with a handful of changes past that point. Compare with

        <a href=
"/archives/ncurses/terminfo.src.gz">ftp://invisible-island.net/ncurses/terminfo.src.gz</a>

or any of the references cited.
</pre>
          </blockquote>
        </li>

        <li>
          <a href=
          "https://unix.stackexchange.com/questions/295871/why-does-cating-an-executable-keep-changing-the-title-of-putty?rq=1">
          Why does cating an executable keep changing the title of
          PuTTY?</a> (July 14, 2016 on StackOverflow)
          <blockquote>
            <pre class="code-block">
PuTTY recognizes many (by no means all) of the escape sequences used for xterm,
Linux console and some less familiar terminals.  One of PuTTY's developers
compiled a list of all of the ones that might be of interest, about 650 items.
...
For whatever reason, they disliked the notion of referring directly to the
documentation for Linux and xterm, but used secondary sources.
</pre>
          </blockquote>

          <p>The comment about secondary sources was prompted by
          noticing that although xterm and vttest are mentioned
          more than a hundred times within the document, neither is
          listed in the header. Also, the references within the
          document are all from September 1999 (<a href=
          "xterm.log.html#xterm_116">xterm #116</a>). For DEC
          terminals as well, this uses secondary sources (perhaps
          just as well, since including all of the sequences listed
          in DEC's manuals would make the file much larger). Most
          of the links listed in the header are dead anyway.</p>

          <p>The file changes infrequently, but has changed within
          the past year (in 2020). There is an <a rel="nofollow"
          href=
          "https://bjh21.me.uk/all-escapes/all-escapes.xhtml">xhtml
          version</a>, perhaps inspired by <a rel="nofollow" href=
          "http://rtfm.etla.org/xterm/ctlseq.html">this old
          page</a> (also from 1999).</p>
        </li>
      </ul>
    </li>

    <li id="mis:ncdware">
      <p>Noted <a href=
      "http://stackoverflow.com/questions/24833129/how-to-change-the-window-title-of-te-based-on-vt320">
      here</a>, someone pointed out an <a href=
      "http://bio.gsi.de/DOCS/NCDWARE/V5.0.000/HTML/term_em8.htm">NCDware
      document</a> describing its terminal control sequences.</p>

      <p>Disregarding the title <em>Using VT320 Terminal Emulator
      Escape Sequences</em>, it described some variant of xterm
      rather than a DEC VT320. VT320s for example had no "alternate
      screen". Nor did it have a feature for the "curses (1)
      fix".</p>

      <p>The NCD documentation (dated December 12, 1997) does not
      mention xterm. A <a href=
      "http://www.textfiles.com/bitsavers/pdf/ncd/9300584A_NCDware_Reference_Manual_Oct1997.pdf">
      related manual</a> does mention xterm, but only in other
      sections. There are other issues with the manual. For
      example, aixterm (<a href=
      "/xterm/xterm.log.html#xterm_39">16-color</a>) control
      sequences are documented as "NCD-specific values". NCD did
      add escape sequences for status line (<a href=
      "#bug_kterm">kterm</a> did this as well, according to the
      6.2.0 sources dated July 1996), as well as VT220 national
      replacement characters (which I added early in <a href=
      "/xterm/xterm.log.html#xterm_70">1998</a>).</p>
    </li>

    <li id="mis:geekery">
      <p><em><a href=
      "http://aperiodic.net/phil/archives/Geekery/term-function-keys.html">
      Terminal Function Key Escape Codes</a></em> has good
      intentions, but falls astray in several respects.<br>
      For a different treatment of the same material, see my
      notes:</p>

      <blockquote>
        <p><em><a href="/xterm/xterm-function-keys.html">Table of
        function-keys for XTerm and other Terminal
        Emulators</a></em>
        </p>
      </blockquote>

      <p>First off, it (like the the <a href=
      "#vte:xconsortium">documentation</a> for GNOME Terminal)
      misattributes work which I did, crediting the X
      Consortium:</p>

      <blockquote class="code-block">
        <p>This brings me to xterm. xterm has a long history, and
        the function key definitions have changed over time. The
        <strong>original</strong> xterm from the X Consortium (even
        before they were absorbed by The Open Group) used escape
        codes based on the VT220, but extended to cover the range
        from F1 to <strong>F48</strong>. F1 through F12 generated,
        respectively, codes <code>^[[11~</code> to
        <code>^[[15~</code>, <code>^[[17~</code> to
        <code>^[[21~</code>, <code>^[[23~</code>, and
        <code>^[[24~</code>. <em><code>Shift-F1</code></em> through
        <em><code>Shift-F12</code></em> were used for F13 through
        F24, and generated codes from <code>^[[11;2~</code> to
        <code>^[[24;2~</code>. Similarly
        <em><code>Ctrl-F1</code></em> through
        <em><code>Ctrl-F12</code></em> were used for F25 through
        F36 and generated codes <code>^[[11;5~</code> to
        <code>^[[24;5~</code>, and
        <em><code>Ctrl-Shift-F1</code></em> through
        <em><code>Ctrl-Shift-F12</code></em> were used for F37
        through F48 and generated codes <code>^[[11;6~</code> to
        <code>^[[24;6~</code>. None of the base xterm
        <code>$TERM</code> types on my system correspond to this
        series of escape codes, though you can still get xterm to
        exhibit the old behavior by setting the
        <code>OldXtermFKeys</code> resource to 'true'.</p>
      </blockquote>

      <p>Not only that, but the comment (and much of the page) is
      inaccurate. For instance:</p>

      <ul>
        <li>
          <p>The X Consortium went out of business late in 1996
          (see <a href=
          "http://www.opengroup.org/tech/desktop/Press_Releases/xccloses.htm">
          press release</a> from July 1996).</p>

          <ul>
            <li>
              <p>The first release of X11R6 was done <a href=
              "https://www.x.org/releases/X11R6.1/RELNOTES.TXT">early
              in 1996</a> by X Consortium.</p>
            </li>

            <li>
              <p>I've been working on xterm since before that (see
              <a href="#my_history">history</a>).</p>
            </li>
          </ul>
        </li>

        <li>
          <p>The X Consortium xterm only knew about function keys
          up to <strong>F20</strong>.</p>

          <ul>
            <li>
              <p>X11R5 defined only 20 function keys, and xterm
              used only those since May 1991.<br>
              X11R6 changes to xterm did not take advantage of
              additional keys aside from the
              <em><code>Insert</code></em> and
              <em><code>Delete</code></em> on the keypad.</p>
            </li>

            <li>
              <p>Further changes by The Open Group through X11R6.6
              made no changes to xterm's handling of special
              keys.</p>
            </li>

            <li>
              <p>That came in xterm <a href=
              "/xterm/xterm.log.html#xterm_130">patch #130</a>
              (2000/3/1), starting with the SCO function-keys
              feature.</p>
            </li>
          </ul>
        </li>

        <li>
          <p>The X Consortium xterm didn't know about using
          <em><code>Shift</code></em> to get F13 through F24.</p>

          <ul>
            <li>
              <p>I introduced a similar feature (using
              <em><code>Control</code></em>) in <a href=
              "/xterm/xterm.log.html#xterm_51">patch #51</a>
              (1997/9/15) as the <a href=
              "#how2_fkeys"><code>sunKeyboard</code></a>
              resource.<br>
              I did this to leave <em><code>Shift</code></em> for
              the VT220 UDK (user-defined keys).</p>
            </li>

            <li>
              <p><strong>rxvt</strong> used
              <em><code>Shift</code></em>; the key combination was
              popular.</p>
            </li>

            <li>
              <p>Alexander V Lukyanov's changes in <a href=
              "/xterm/xterm.log.html#xterm_121">patch #121</a> to
              update the terminal descriptions for these keys took
              that into account.</p>
            </li>
          </ul>
        </li>

        <li>
          <p>The X Consortium xterm didn't know about using
          <em><code>Control</code></em> to get F25 through F36.</p>

          <ul>
            <li>
              <p>Even with X11R6, the last function key was
              <em><code>XK_F35</code></em>.</p>
            </li>

            <li>
              <p>However, since xterm <a href=
              "/xterm/xterm.log.html#xterm_94">patch #94</a>
              (1999/3/27), it accepts modifiers (shift, control,
              alt) to extend the actual set of keys to generate
              different escape sequences.</p>
            </li>
          </ul>
        </li>

        <li>
          <p>The escape sequences described all date from 2002
          (xterm <a href="/xterm/xterm.log.html#xterm_167">patch
          #167</a>).</p>

          <ul>
            <li>
              <p>Besides function-keys, there are two other groups
              of special keys on the keyboard: cursor and
              editing-keypad.</p>
            </li>

            <li>
              <p>Before then, the &ldquo;2&rdquo; and
              &ldquo;5&rdquo; in cursor- and home/end sequences
              would be first (before the semicolon).</p>
            </li>

            <li>
              <p>By that point, GNOME Terminal and KDE Konsole had
              copied the earlier behavior, and failed to follow
              this change.</p>
            </li>

            <li>
              <p>At the time, I preferred the VT220 keyboard (that
              does not support modified special keys).</p>
            </li>

            <li>
              <p>However, the <em>app-defaults</em> file which I
              provided with xterm did not set the
              <code>sunKeyboard</code> resource to do this.<br>
              Packagers routinely altered the recommended
              configuration, so this difference was not noticed for
              a while.</p>
            </li>

            <li>
              <p>In response to a <a href=
              "https://bugzilla.redhat.com/show_bug.cgi?id=122815">bug
              report</a>, I switched to the Sun/PC keyboard, using
              the <a href=
              "/ncurses/NEWS.html#t20040717">xterm-pc-fkeys</a>
              building blocks in ncurses' terminfo description for
              xterm.</p>
            </li>
          </ul>
        </li>

        <li>
          <p>The X Consortium xterm had incomplete support for
          VT100 keypad.</p>

          <ul>
            <li>
              <p>I added a resource <code>sunKeyboard</code> to
              tell xterm to look at other keyboards to simulate the
              keypad.</p>
            </li>

            <li>
              <p>To do this, I made F1 through F4 act like the
              VT100 PF1 through PF4.</p>
            </li>

            <li>
              <p>That came in xterm <a href=
              "/xterm/xterm.log.html#xterm_79">patch #79</a>
              (1998/6/28).</p>
            </li>

            <li>
              <p>Not everyone liked that, so I added another
              resource to allow turning off the change to F1
              through F4.</p>
            </li>

            <li>
              <p>Actually <code>OldXtermFKeys</code> is the
              resource <em>class</em>; the actual resource is
              <code>oldXtermFKeys</code>.</p>
            </li>
          </ul>
        </li>
      </ul>

      <p>By the way, although The Open Group made changes, none of
      those have been incorporated in this version of xterm. That
      was intentional (see <a href=
      "https://invisible-island.net/personal/copyrights.html">discussion</a>).
      Consequently, the xterm copyright makes no mention of The
      Open Group.</p>
    </li>
  </ul>

  <h2 id="future_work-id"><a name="future_work" id=
  "future_work">Ongoing/future work</a></h2>

  <ul>
    <li>
      <p>soft (downloadable) fonts</p>
    </li>

    <li>
      <p>printer interface</p>

      <p>Done, except for the corresponding support in the VT52
      emulation. It would be nice to have a dialog to control
      this.</p>
    </li>

    <li>
      <p>allow alternate libraries for popup-menus and dialogs</p>

      <p>My configure script currently provides tests for the
      variations of Athena widgets (Xaw3D, neXtaw). I intend to
      make additional changes to support <a href=
      "xterm.faq.html#bug_mxterm">Motif scrollbars and menus</a>.
      Motif requires a different style of interface for the menus:
      binding a popup menu to control right mouse may cause the
      server to hang. As an intermediate step, I implemented a
      toolbar for the Athena widgets. In turn, that works well
      enough except with XFree86 4.x: the Xaw library geometry
      management is broken. (Other implementations of the Athena
      widgets work well enough).</p>
    </li>

    <li>
      <p>popup window that shows hex code for content of a
      character cell and hexadecimal keyboard entry for all Unicode
      characters (ISO 14755)</p>
    </li>

    <li>
      <p>correct cut&amp;paste of TAB character</p>
    </li>
  </ul>
</body>
</html>