@c This is part of the Emacs manual.
@c Copyright (C) 1985--1987, 1993--1995, 1997, 2001--2020 Free Software
@c Foundation, Inc.
@c See file emacs.texi for copying conditions.
@node Rmail
@chapter Reading Mail with Rmail
@cindex Rmail
@cindex reading mail
@findex rmail
@findex rmail-mode
@vindex rmail-mode-hook

  Rmail is an Emacs subsystem for reading and disposing of mail that
you receive.  Rmail stores mail messages in files called Rmail files.
Reading the messages in an Rmail file is done in a special major mode,
Rmail mode, which redefines most letters to run commands for managing mail.

  Emacs also comes with a much more sophisticated and flexible
subsystem for reading mail, called Gnus.  Gnus is a very large
package, and is therefore described in its own manual, see @ref{Top,,,
gnus, The Gnus Newsreader}.

@menu
* Basic: Rmail Basics.       Basic concepts of Rmail, and simple use.
* Scroll: Rmail Scrolling.   Scrolling through a message.
* Motion: Rmail Motion.      Moving to another message.
* Deletion: Rmail Deletion.  Deleting and expunging messages.
* Inbox: Rmail Inbox.        How mail gets into the Rmail file.
* Files: Rmail Files.        Using multiple Rmail files.
* Output: Rmail Output.      Copying messages out to files.
* Labels: Rmail Labels.      Classifying messages by labeling them.
* Attrs: Rmail Attributes.   Certain standard labels, called attributes.
* Reply: Rmail Reply.        Sending replies to messages you are viewing.
* Summary: Rmail Summary.    Summaries show brief info on many messages.
* Sort: Rmail Sorting.       Sorting messages in Rmail.
* Display: Rmail Display.    How Rmail displays a message; customization.
* Coding: Rmail Coding.      How Rmail handles decoding character sets.
* Editing: Rmail Editing.    Editing message text and headers in Rmail.
* Digest: Rmail Digest.      Extracting the messages from a digest message.
* Rot13: Rmail Rot13.        Reading messages encoded in the rot13 code.
* Movemail::                 More details of fetching new mail.
* Remote Mailboxes::         Retrieving mail from remote mailboxes.
* Other Mailbox Formats::    Retrieving mail from local mailboxes in
                             various formats.
@end menu

@node Rmail Basics
@section Basic Concepts of Rmail

@cindex primary Rmail file
@vindex rmail-file-name
  Using Rmail in the simplest fashion, you have one Rmail file
@file{~/RMAIL} in which all of your mail is saved.  It is called your
@dfn{primary Rmail file}.  The command @kbd{M-x rmail} reads your primary
Rmail file, merges new mail in from your inboxes, displays the first
message you haven't read yet, and lets you begin reading.  The variable
@code{rmail-file-name} specifies the name of the primary Rmail file.

@cindex current message (Rmail)
  Rmail displays only one message in the Rmail file at a time.
The message that is shown is called the @dfn{current message}.  Rmail
mode's special commands can do such things as delete the current
message, copy it into another file, send a reply, or move to another
message.  You can also create multiple Rmail files (@pxref{Files}) and
use Rmail to move messages between them (@pxref{Rmail Output}).

@cindex message number (Rmail)
  Within the Rmail file, messages are normally arranged sequentially in
order of receipt; you can specify other ways to sort them (@pxref{Rmail
Sorting}).  Messages are identified by consecutive integers which are
their @dfn{message numbers}.  The number of the current message is
displayed in Rmail's mode line, followed by the total number of messages
in the file.  You can move to a message by specifying its message number
with the @kbd{j} key (@pxref{Rmail Motion}).

@kindex s @r{(Rmail)}
@findex rmail-expunge-and-save
  Following the usual conventions of Emacs, changes in an Rmail file
become permanent only when you save the file.  You can save it with
@kbd{s} (@code{rmail-expunge-and-save}), which also expunges deleted
messages from the file first (@pxref{Rmail Deletion}).  To save the
file without expunging, use @kbd{C-x C-s}.  Rmail automatically saves
the Rmail file after merging new mail from an inbox file (@pxref{Rmail
Inbox}).

@kindex q @r{(Rmail)}
@findex rmail-quit
@kindex b @r{(Rmail)}
@findex rmail-bury
  You can exit Rmail with @kbd{q} (@code{rmail-quit}); this expunges
and saves the Rmail file, then buries the Rmail buffer as well as its
summary buffer, if present (@pxref{Rmail Summary}).  But there is no
need to exit formally.  If you switch from Rmail to editing in
other buffers, and never switch back, you have exited.  Just make sure
to save the Rmail file eventually (like any other file you have
changed).  @kbd{C-x s} is a suitable way to do this (@pxref{Save
Commands}).  The Rmail command @kbd{b}, @code{rmail-bury}, buries the
Rmail buffer and its summary without expunging and saving the Rmail file.

@node Rmail Scrolling
@section Scrolling Within a Message

  When Rmail displays a message that does not fit on the screen, you
must scroll through it to read the rest.  You could do this with the
usual scrolling commands: @kbd{C-v}, @kbd{M-v} and @kbd{M-<}
(@pxref{Scrolling}), but in Rmail scrolling is so frequent that it
deserves to be easier.

@table @kbd
@item @key{SPC}
Scroll forward (@code{scroll-up-command}).
@item @key{DEL}
@itemx S-@key{SPC}
Scroll backward (@code{scroll-down-command}).
@item .
Scroll to start of message (@code{rmail-beginning-of-message}).
@item /
Scroll to end of message (@code{rmail-end-of-message}).
@end table

@kindex SPC @r{(Rmail)}
@kindex DEL @r{(Rmail)}
@kindex S-SPC @r{(Rmail)}
  Since the most common thing to do while reading a message is to
scroll through it by screenfuls, Rmail makes @key{SPC} and @key{DEL}
(or @kbd{S-@key{SPC}}) do the same as @kbd{C-v} (@code{scroll-up-command})
and @kbd{M-v} (@code{scroll-down-command}) respectively.

@kindex . @r{(Rmail)}
@kindex / @r{(Rmail)}
@findex rmail-beginning-of-message
@findex rmail-end-of-message
  The command @kbd{.} (@code{rmail-beginning-of-message}) scrolls back to the
beginning of the selected message.  This is not quite the same as @kbd{M-<}:
for one thing, it does not set the mark; for another, it resets the buffer
boundaries of the current message if you have changed them (e.g., by
editing, @pxref{Rmail Editing}).  Similarly, the command @kbd{/}
(@code{rmail-end-of-message}) scrolls forward to the end of the
selected message.
@c The comment about buffer boundaries is still true in mbox Rmail, if
@c less likely to be relevant.

@node Rmail Motion
@section Moving Among Messages

  The most basic thing to do with a message is to read it.  The way to
do this in Rmail is to make the message current.  The usual practice is
to move sequentially through the file, since this is the order of
receipt of messages.  When you enter Rmail, you are positioned at the
first message that you have not yet made current (that is, the first one
that has the @samp{unseen} attribute; @pxref{Rmail Attributes}).  Move
forward to see the other new messages; move backward to re-examine old
messages.

@table @kbd
@item n
Move to the next nondeleted message, skipping any intervening deleted
messages (@code{rmail-next-undeleted-message}).
@item p
Move to the previous nondeleted message
(@code{rmail-previous-undeleted-message}).
@item M-n
Move to the next message, including deleted messages
(@code{rmail-next-message}).
@item M-p
Move to the previous message, including deleted messages
(@code{rmail-previous-message}).
@item C-c C-n
Move to the next message with the same subject as the current one
(@code{rmail-next-same-subject}).
@item C-c C-p
Move to the previous message with the same subject as the current one
(@code{rmail-previous-same-subject}).
@item j
Move to the first message.  With argument @var{n}, move to
message number @var{n} (@code{rmail-show-message}).
@item >
Move to the last message (@code{rmail-last-message}).
@item <
Move to the first message (@code{rmail-first-message}).
@item M-s @var{regexp} @key{RET}
Move to the next message containing a match for @var{regexp}
(@code{rmail-search}).
@item - M-s @var{regexp} @key{RET}
Move to the previous message containing a match for @var{regexp}.
(This is @kbd{M-s} with a negative argument.)
@end table

@kindex n @r{(Rmail)}
@kindex p @r{(Rmail)}
@kindex M-n @r{(Rmail)}
@kindex M-p @r{(Rmail)}
@findex rmail-next-undeleted-message
@findex rmail-previous-undeleted-message
@findex rmail-next-message
@findex rmail-previous-message
  @kbd{n} and @kbd{p} are the usual way of moving among messages in
Rmail.  They move through the messages sequentially, but skip over
deleted messages, which is usually what you want to do.  Their command
definitions are named @code{rmail-next-undeleted-message} and
@code{rmail-previous-undeleted-message}.  If you do not want to skip
deleted messages---for example, if you want to move to a message to
undelete it---use the variants @kbd{M-n} and @kbd{M-p}
(@code{rmail-next-message} and @code{rmail-previous-message}).  A
numeric argument to any of these commands serves as a repeat
count.

  In Rmail, you can specify a numeric argument by typing just the
digits.  You don't need to type @kbd{C-u} first.  You can also specify
a negative argument by typing just @kbd{-}.

@kindex M-s @r{(Rmail)}
@findex rmail-search
@cindex searching in Rmail
  The @kbd{M-s} (@code{rmail-search}) command is Rmail's version of
search.  The usual incremental search command @kbd{C-s} works in Rmail,
but it searches only within the current message.  The purpose of
@kbd{M-s} is to search for another message.  It reads a regular
expression (@pxref{Regexps}) nonincrementally, then searches starting at
the beginning of the following message for a match.  It then selects
that message.  If @var{regexp} is empty, @kbd{M-s} reuses the regexp
used the previous time.

  To search backward in the file for another message, give @kbd{M-s} a
negative argument.  In Rmail you can do this with @kbd{- M-s}.  This
begins searching from the end of the previous message.

  It is also possible to search for a message based on labels.
@xref{Rmail Labels}.

@kindex C-c C-n @r{(Rmail)}
@kindex C-c C-p @r{(Rmail)}
@findex rmail-next-same-subject
@findex rmail-previous-same-subject
  The @kbd{C-c C-n} (@code{rmail-next-same-subject}) command moves to
the next message with the same subject as the current one.  A prefix
argument serves as a repeat count.  With a negative argument, this
command moves backward, acting like @kbd{C-c C-p}
(@code{rmail-previous-same-subject}).  When comparing subjects, these
commands ignore the prefixes typically added to the subjects of
replies.  These commands are useful for reading all of the messages
pertaining to the same subject, a.k.a.@: @dfn{thread}.

@kindex j @r{(Rmail)}
@kindex > @r{(Rmail)}
@kindex < @r{(Rmail)}
@findex rmail-show-message
@findex rmail-last-message
@findex rmail-first-message
  To move to a message specified by absolute message number, use @kbd{j}
(@code{rmail-show-message}) with the message number as argument.  With
no argument, @kbd{j} selects the first message.  @kbd{<}
(@code{rmail-first-message}) also selects the first message.  @kbd{>}
(@code{rmail-last-message}) selects the last message.

@node Rmail Deletion
@section Deleting Messages

@cindex deletion (Rmail)
  When you no longer need to keep a message, you can @dfn{delete} it.  This
flags it as ignorable, and some Rmail commands pretend it is no longer
present; but it still has its place in the Rmail file, and still has its
message number.

@cindex expunging (Rmail)
  @dfn{Expunging} the Rmail file actually removes the deleted messages.
The remaining messages are renumbered consecutively.
@c The following is neither true (there is also unforward, sorting,
@c etc), nor especially interesting.
@c Expunging is the only action that changes the message number of any
@c message, except for undigestifying (@pxref{Rmail Digest}).

@table @kbd
@item d
Delete the current message, and move to the next nondeleted message
(@code{rmail-delete-forward}).
@item C-d
Delete the current message, and move to the previous nondeleted
message (@code{rmail-delete-backward}).
@item u
Undelete the current message, or move back to the previous deleted
message and undelete it (@code{rmail-undelete-previous-message}).
@item x
Expunge the Rmail file (@code{rmail-expunge}).
@end table

@kindex d @r{(Rmail)}
@kindex C-d @r{(Rmail)}
@findex rmail-delete-forward
@findex rmail-delete-backward
  There are two Rmail commands for deleting messages.  Both delete the
current message and select another.  @kbd{d}
(@code{rmail-delete-forward}) moves to the following message, skipping
messages already deleted, while @kbd{C-d} (@code{rmail-delete-backward})
moves to the previous nondeleted message.  If there is no nondeleted
message to move to in the specified direction, the message that was just
deleted remains current.  A numeric prefix argument serves as a repeat
count, to allow deletion of several messages in a single command.  A
negative argument reverses the meaning of @kbd{d} and @kbd{C-d}.

@c mention other hooks, e.g., show message hook?
@vindex rmail-delete-message-hook
  Whenever Rmail deletes a message, it runs the hook
@code{rmail-delete-message-hook}.  When the hook functions are invoked,
the message has been marked deleted, but it is still the current message
in the Rmail buffer.

@cindex undeletion (Rmail)
@kindex x @r{(Rmail)}
@findex rmail-expunge
@kindex u @r{(Rmail)}
@findex rmail-undelete-previous-message
  To make all the deleted messages finally vanish from the Rmail file,
type @kbd{x} (@code{rmail-expunge}).  Until you do this, you can still
@dfn{undelete} the deleted messages.  The undeletion command, @kbd{u}
(@code{rmail-undelete-previous-message}), is designed to cancel the
effect of a @kbd{d} command in most cases.  It undeletes the current
message if the current message is deleted.  Otherwise it moves backward
to previous messages until a deleted message is found, and undeletes
that message.  A numeric prefix argument serves as a repeat count, to
allow undeletion of several messages in a single command.

  You can usually undo a @kbd{d} with a @kbd{u} because the @kbd{u}
moves back to and undeletes the message that the @kbd{d} deleted.  But
this does not work when the @kbd{d} skips a few already-deleted messages
that follow the message being deleted; then the @kbd{u} command
undeletes the last of the messages that were skipped.  There is no clean
way to avoid this problem.  However, by repeating the @kbd{u} command,
you can eventually get back to the message that you intend to
undelete.  You can also select a particular deleted message with
the @kbd{M-p} command, then type @kbd{u} to undelete it.

  A deleted message has the @samp{deleted} attribute, and as a result
@samp{deleted} appears in the mode line when the current message is
deleted.  In fact, deleting or undeleting a message is nothing more than
adding or removing this attribute.  @xref{Rmail Attributes}.

@node Rmail Inbox
@section Rmail Files and Inboxes
@cindex inbox file

  When you receive mail locally, the operating system places incoming
mail for you in a file that we call your @dfn{inbox}.  When you start
up Rmail, it runs a C program called @command{movemail} to copy the new
messages from your inbox into your primary Rmail file, which
also contains other messages saved from previous Rmail sessions.  It
is in this file that you actually read the mail with Rmail.  This
operation is called @dfn{getting new mail}.  You can get new mail at
any time in Rmail by typing @kbd{g}.

@vindex rmail-primary-inbox-list
@cindex @env{MAIL} environment variable
  The variable @code{rmail-primary-inbox-list} contains a list of the
files that are inboxes for your primary Rmail file.  If you don't set
this variable explicitly, Rmail uses the @env{MAIL} environment
variable, or, as a last resort, a default inbox based on
@code{rmail-spool-directory}.  The default inbox file depends on your
operating system; often it is @file{/var/mail/@var{username}},
@file{/var/spool/mail/@var{username}}, or
@file{/usr/spool/mail/@var{username}}.

  You can specify the inbox file(s) for any Rmail file for the current
session with the command @code{set-rmail-inbox-list}; see @ref{Rmail
Files}.

  There are two reasons for having separate Rmail files and inboxes.

@enumerate
@item
The inbox file format varies between operating systems and according to
the other mail software in use.  Only one part of Rmail needs to know
about the alternatives, and it need only understand how to convert all
of them to Rmail's own format.

@item
It is very cumbersome to access an inbox file without danger of losing
mail, because it is necessary to interlock with mail delivery.
Moreover, different operating systems use different interlocking
techniques.  The strategy of moving mail out of the inbox once and for
all into a separate Rmail file avoids the need for interlocking in all
the rest of Rmail, since only Rmail operates on the Rmail file.
@end enumerate

@cindex mbox files
@vindex rmail-mbox-format
  Rmail uses the standard @samp{mbox} format, introduced by Unix and
GNU systems for inbox files, as its internal format of Rmail files.
(In fact, there are a few slightly different mbox formats.  The
differences are not very important, but you can set the variable
@code{rmail-mbox-format} to tell Rmail which form your system uses.
See that variable's documentation for more details.)

@vindex rmail-preserve-inbox
  When getting new mail, Rmail first copies the new mail from the
inbox file to the Rmail file; then it saves the Rmail file; then it
clears out the inbox file.  This way, a system crash may cause
duplication of mail between the inbox and the Rmail file, but cannot
lose mail.  If @code{rmail-preserve-inbox} is non-@code{nil}, then
Rmail does not clear out the inbox file when it gets new mail.  You
may wish to set this, for example, on a portable computer you use to
check your mail via POP while traveling, so that your mail will remain
on the server and you can save it later on your main desktop
workstation.

  In some cases, Rmail copies the new mail from the inbox file
indirectly.  First it runs the @command{movemail} program to move the mail
from the inbox to an intermediate file called
@file{.newmail-@var{inboxname}}, in the same directory as the Rmail
file.  Then Rmail merges the new mail from that file, saves the Rmail
file, and only then deletes the intermediate file.  If there is a crash
at the wrong time, this file continues to exist, and Rmail will use it
again the next time it gets new mail from that inbox.

  If Rmail is unable to convert the data in
@file{.newmail-@var{inboxname}} into mbox format, it renames the file to
@file{RMAILOSE.@var{n}} (@var{n} is an integer chosen to make the name
unique) so that Rmail will not have trouble with the data again.  You
should look at the file, find whatever message confuses Rmail (probably
one that includes the control-underscore character, octal code 037), and
delete it.  Then you can use @kbd{1 g} to get new mail from the
corrected file.

@node Rmail Files
@section Multiple Rmail Files

  Rmail operates by default on your @dfn{primary Rmail file}, which is named
@file{~/RMAIL} and receives your incoming mail from your system inbox file.
But you can also have other Rmail files and edit them with Rmail.  These
files can receive mail through their own inboxes, or you can move messages
into them with explicit Rmail commands (@pxref{Rmail Output}).

@table @kbd
@item i @var{file} @key{RET}
Read @var{file} into Emacs and run Rmail on it (@code{rmail-input}).
@ignore
@item M-x set-rmail-inbox-list @key{RET} @var{files} @key{RET}
Specify inbox file names for current Rmail file to get mail from.
@end ignore
@item g
Merge new mail from current Rmail file's inboxes
(@code{rmail-get-new-mail}).
@item C-u g @var{file} @key{RET}
Merge new mail from inbox file @var{file}.
@end table

@kindex i @r{(Rmail)}
@findex rmail-input
  To run Rmail on a file other than your primary Rmail file, you can use
the @kbd{i} (@code{rmail-input}) command in Rmail.  This visits the file
in Rmail mode.  You can use @kbd{M-x rmail-input} even when not in
Rmail, but it is easier to type @kbd{C-u M-x rmail}, which does the
same thing.

  The file you read with @kbd{i} should normally be a valid mbox file.
If it is not, Rmail tries to convert its text to mbox format, and
visits the converted text in the buffer.  If you save the buffer, that
converts the file.

  If you specify a file name that doesn't exist, @kbd{i} initializes a
new buffer for creating a new Rmail file.

@vindex rmail-secondary-file-directory
@vindex rmail-secondary-file-regexp
  You can also select an Rmail file from a menu.  In the Classify menu,
choose the Input Rmail File item; then choose the Rmail file you want.
The variables @code{rmail-secondary-file-directory} and
@code{rmail-secondary-file-regexp} specify which files to offer in the
menu: the first variable says which directory to find them in; the
second says which files in that directory to offer (all those that match
the regular expression).  If no files match, you cannot select this menu
item.  These variables also apply to choosing a file for output
(@pxref{Rmail Output}).
@c FIXME matches only checked when Rmail file first visited?

@c This is commented out because we want to advertise rmail-inbox-list
@c instead.
@ignore
@findex set-rmail-inbox-list
  Each Rmail file can contain a list of inbox file names; you can specify
this list with @kbd{M-x set-rmail-inbox-list @key{RET} @var{files}
@key{RET}}.  The argument can contain any number of file names, separated
by commas.  It can also be empty, which specifies that this file should
have no inboxes.  Once you specify a list of inboxes in an Rmail file,
the  Rmail file remembers it permanently until you specify a different list.
@end ignore

@vindex rmail-inbox-list
  The inbox files to use are specified by the variable
@code{rmail-inbox-list}, which is buffer-local in Rmail mode.  As a
special exception, if you have specified no inbox files for your primary
Rmail file, it uses the @env{MAIL} environment variable, or your
standard system inbox.

@kindex g @r{(Rmail)}
@findex rmail-get-new-mail
  The @kbd{g} command (@code{rmail-get-new-mail}) merges mail into the
current Rmail file from its inboxes.  If the Rmail file has no
inboxes, @kbd{g} does nothing.  The command @kbd{M-x rmail} also
merges new mail into your primary Rmail file.

@cindex merge mail from file (Rmail)
  To merge mail from a file that is not the usual inbox, give the
@kbd{g} key a numeric argument, as in @kbd{C-u g}.  Then it reads a file
name and merges mail from that file.  The inbox file is not deleted or
changed in any way when @kbd{g} with an argument is used.  This is,
therefore, a general way of merging one file of messages into another.

@node Rmail Output
@section Copying Messages Out to Files

  These commands copy messages from an Rmail file into another file.

@table @kbd
@item o @var{file} @key{RET}
Append a full copy of the current message to the file @var{file}
(@code{rmail-output}).

@item C-o @var{file} @key{RET}
Append a copy of the current message, as displayed, to the file
@var{file} (@code{rmail-output-as-seen}).

@item w @var{file} @key{RET}
Output just the message body to the file @var{file}, taking the default
file name from the message @samp{Subject} header.
@end table

@kindex o @r{(Rmail)}
@findex rmail-output
@kindex C-o @r{(Rmail)}
@findex rmail-output-as-seen
  The commands @kbd{o} and @kbd{C-o} copy the current message into a
specified file, adding it at the end.  A positive prefix argument
serves as a repeat count: that many consecutive messages will be
copied to the specified file, starting with the current one and
ignoring deleted messages.

The two commands differ mainly in how much to copy: @kbd{o} copies the
full message headers, even if they are not all visible, while
@kbd{C-o} copies exactly the headers currently displayed and no more.
@xref{Rmail Display}.  In addition, @kbd{o} converts the message to
Babyl format (used by Rmail in Emacs version 22 and before) if the
file is in Babyl format; @kbd{C-o} cannot output to Babyl files at
all.
@c FIXME remove BABYL mention in some future version?

  If the output file is currently visited in an Emacs buffer, the
output commands append the message to that buffer.  It is up to you to
save the buffer eventually in its file.

@kindex w @r{(Rmail)}
@findex rmail-output-body-to-file
  Sometimes you may receive a message whose body holds the contents of a
file.  You can save the body to a file (excluding the message header)
with the @kbd{w} command (@code{rmail-output-body-to-file}).  Often
these messages contain the intended file name in the @samp{Subject}
field, so the @kbd{w} command uses the @samp{Subject} field as the
default for the output file name (after replacing some characters that
cannot be portably used in file names).  However, the file name is
read using the minibuffer, so you can specify a different name if you
wish.

  You can also output a message to an Rmail file chosen with a menu.
In the Classify menu, choose the Output Rmail File menu item; then
choose the Rmail file you want.  This outputs the current message to
that file, like the @kbd{o} command.  The variables
@code{rmail-secondary-file-directory} and
@code{rmail-secondary-file-regexp} specify which files to offer in the
menu: the first variable says which directory to find them in; the
second says which files in that directory to offer (all those that
match the regular expression).  If no files match, you cannot select
this menu item.

  Copying a message with @kbd{o} or @kbd{C-o} gives the original copy
of the message the @samp{filed} attribute, so that @samp{filed}
appears in the mode line when such a message is current.

@vindex rmail-delete-after-output
  If you like to keep just a single copy of every mail message, set
the variable @code{rmail-delete-after-output} to @code{t}; then the
@kbd{o}, @kbd{C-o} and @kbd{w} commands delete the original message
after copying it.  (You can undelete it afterward if you wish, see
@ref{Rmail Deletion}.)

@vindex rmail-output-reset-deleted-flag
  By default, @kbd{o} will leave the deleted status of a message it
outputs as it was on the original message; thus, a message deleted
before it was output will appear as deleted in the output file.
Setting the variable @code{rmail-output-reset-deleted-flag} to a
non-@code{nil} value countermands that: the copy of the message will
have its deleted status reset, so the message will appear as undeleted
in the output file.  In addition, when this variable is
non-@code{nil}, specifying a positive argument to @kbd{o} will not
ignore deleted messages when looking for consecutive messages to
output.

@vindex rmail-output-file-alist
  The variable @code{rmail-output-file-alist} lets you specify
intelligent defaults for the output file, based on the contents of the
current message.  The value should be a list whose elements have this
form:

@example
(@var{regexp} . @var{name-exp})
@end example

@noindent
If there's a match for @var{regexp} in the current message, then the
default file name for output is @var{name-exp}.  If multiple elements
match the message, the first matching element decides the default file
name.  The subexpression @var{name-exp} may be a string constant giving
the file name to use, or more generally it may be any Lisp expression
that yields a file name as a string.  @code{rmail-output-file-alist}
applies to both @kbd{o} and @kbd{C-o}.

@vindex rmail-automatic-folder-directives
Rmail can automatically save messages from your primary Rmail file
(the one that @code{rmail-file-name} specifies) to other files, based
on the value of the variable @code{rmail-automatic-folder-directives}.
This variable is a list of elements (@samp{directives}) that say which
messages to save where.  Each directive is a list consisting of an
output file, followed by one or more pairs of a header name and a regular
expression.  If a message has a header matching the specified regular
expression, that message is saved to the given file.  If the directive
has more than one header entry, all must match.  Rmail checks directives
when it shows a message from the file @code{rmail-file-name}, and
applies the first that matches (if any).  If the output file is
@code{nil}, the message is deleted, not saved.  For example, you can use
this feature to save messages from a particular address, or with a
particular subject, to a dedicated file.

@node Rmail Labels
@section Labels
@cindex label (Rmail)
@cindex attribute (Rmail)

  Each message can have various @dfn{labels} assigned to it as a means
of classification.  Each label has a name; different names are different
labels.  Any given label is either present or absent on a particular
message.  A few label names have standard meanings and are given to
messages automatically by Rmail when appropriate; these special labels
are called @dfn{attributes}.
@ifnottex
(@xref{Rmail Attributes}.)
@end ifnottex
All other labels are assigned only by users.

@table @kbd
@item a @var{label} @key{RET}
Assign the label @var{label} to the current message (@code{rmail-add-label}).
@item k @var{label} @key{RET}
Remove the label @var{label} from the current message (@code{rmail-kill-label}).
@item C-M-n @var{labels} @key{RET}
Move to the next message that has one of the labels @var{labels}
(@code{rmail-next-labeled-message}).
@item C-M-p @var{labels} @key{RET}
Move to the previous message that has one of the labels @var{labels}
(@code{rmail-previous-labeled-message}).
@item l @var{labels} @key{RET}
@itemx C-M-l @var{labels} @key{RET}
Make a summary of all messages containing any of the labels @var{labels}
(@code{rmail-summary-by-labels}).
@end table

@kindex a @r{(Rmail)}
@kindex k @r{(Rmail)}
@findex rmail-add-label
@findex rmail-kill-label
  The @kbd{a} (@code{rmail-add-label}) and @kbd{k}
(@code{rmail-kill-label}) commands allow you to assign or remove any
label on the current message.  If the @var{label} argument is empty, it
means to assign or remove the label most recently assigned or removed.

  Once you have given messages labels to classify them as you wish, there
are three ways to use the labels: in moving, in summaries, and in sorting.

@kindex C-M-n @r{(Rmail)}
@kindex C-M-p @r{(Rmail)}
@findex rmail-next-labeled-message
@findex rmail-previous-labeled-message
  @kbd{C-M-n @var{labels} @key{RET}}
(@code{rmail-next-labeled-message}) moves to the next message that has
one of the labels @var{labels}.  The argument @var{labels} specifies
one or more label names, separated by commas.  @kbd{C-M-p}
(@code{rmail-previous-labeled-message}) is similar, but moves
backwards to previous messages.  A numeric argument to either command
serves as a repeat count.

  The command @kbd{C-M-l @var{labels} @key{RET}}
(@code{rmail-summary-by-labels}) displays a summary containing only the
messages that have at least one of a specified set of labels.  The
argument @var{labels} is one or more label names, separated by commas.
@xref{Rmail Summary}, for information on summaries.

  If the @var{labels} argument to @kbd{C-M-n}, @kbd{C-M-p} or
@kbd{C-M-l} is empty, it means to use the last set of labels specified
for any of these commands.

  @xref{Rmail Sorting}, for information on sorting messages with labels.

@node Rmail Attributes
@section Rmail Attributes

  Some labels such as @samp{deleted} and @samp{filed} have built-in
meanings, and Rmail assigns them to messages automatically at
appropriate times; these labels are called @dfn{attributes}.  Here is
a list of Rmail attributes:

@table @samp
@item unseen
Means the message has never been current.  Assigned to messages when
they come from an inbox file, and removed when a message is made
current.  When you start Rmail, it initially shows the first message
that has this attribute.
@item deleted
Means the message is deleted.  Assigned by deletion commands and
removed by undeletion commands (@pxref{Rmail Deletion}).
@item filed
Means the message has been copied to some other file.  Assigned by the
@kbd{o} and @kbd{C-o} file output commands (@pxref{Rmail Output}).
@item answered
Means you have mailed an answer to the message.  Assigned by the @kbd{r}
command (@code{rmail-reply}).  @xref{Rmail Reply}.
@item forwarded
Means you have forwarded the message.  Assigned by the @kbd{f} command
(@code{rmail-forward}).  @xref{Rmail Reply}.
@item edited
Means you have edited the text of the message within Rmail.
@xref{Rmail Editing}.
@item resent
Means you have resent the message.  Assigned by the command @kbd{M-x
rmail-resend}.  @xref{Rmail Reply}.
@item retried
Means you have retried a failed outgoing message.  Assigned by the
command @kbd{M-x rmail-retry-failure}.  @xref{Rmail Reply}.
@end table

  All other labels are assigned or removed only by users, and have no
standard meaning.

@node Rmail Reply
@section Sending Replies

  Rmail has several commands to send outgoing mail.  @xref{Sending
Mail}, for information on using Message mode, including certain
features meant to work with Rmail.  What this section documents are
the special commands of Rmail for entering the mail buffer used to
compose the outgoing message.  Note that the usual keys for sending
mail---@kbd{C-x m}, @kbd{C-x 4 m}, and @kbd{C-x 5 m}---also work
normally in Rmail mode.

@table @kbd
@item m
Send a message (@code{rmail-mail}).
@item c
Continue editing the already started outgoing message (@code{rmail-continue}).
@item r
Send a reply to the current Rmail message (@code{rmail-reply}).
@item f
Forward the current message to other users (@code{rmail-forward}).
@item C-u f
Resend the current message to other users (@code{rmail-resend}).
@item M-m
Try sending a bounced message a second time (@code{rmail-retry-failure}).
@end table

@kindex r @r{(Rmail)}
@findex rmail-reply
@cindex reply to a message
  The most common reason to send a message while in Rmail is to reply
to the message you are reading.  To do this, type @kbd{r}
(@code{rmail-reply}).  This displays a mail composition buffer in
another window, much like @kbd{C-x 4 m}, but preinitializes the
@samp{Subject}, @samp{To}, @samp{CC}, @samp{In-Reply-To} and
@samp{References} header fields based on the message you are replying
to.  The @samp{To} field starts out as the address of the person who
sent the message you received, and the @samp{CC} field starts out with
all the other recipients of that message.

@vindex mail-dont-reply-to-names
  You can exclude certain recipients from being included automatically
in replies, using the variable @code{mail-dont-reply-to-names}.  Its
value should be a regular expression; any recipients that match are
excluded from the @samp{CC} field.  They are also excluded from the
@samp{To} field, unless this would leave the field empty.  If this
variable is @code{nil}, then the first time you compose a reply it is
initialized to a default value that matches your own address.

  To reply only to the sender of the original message, enter
the reply command with a numeric argument: @kbd{C-u r} or @kbd{1 r}.
This omits the @samp{CC} field completely for a particular reply.

  Once the mail composition buffer has been initialized, editing and
sending the mail goes as usual (@pxref{Sending Mail}).  You can edit
the presupplied header fields if they are not what you want.  You can
also use commands such as @kbd{C-c C-y}, which yanks in the message
that you are replying to (@pxref{Mail Commands}).  You can also switch
to the Rmail buffer, select a different message there, switch back,
and yank the new current message.

@kindex M-m @r{(Rmail)}
@findex rmail-retry-failure
@cindex retrying a failed message
@vindex rmail-retry-ignored-headers
  Sometimes a message does not reach its destination.  Mailers usually
send the failed message back to you, enclosed in a @dfn{failure
message}.  The Rmail command @kbd{M-m} (@code{rmail-retry-failure})
prepares to send the same message a second time: it sets up a
mail composition buffer with the same text and header fields as before.  If
you type @kbd{C-c C-c} right away, you send the message again exactly
the same as the first time.  Alternatively, you can edit the text or
headers and then send it.  The variable
@code{rmail-retry-ignored-headers}, in the same format as
@code{rmail-ignored-headers} (@pxref{Rmail Display}), controls which
headers are stripped from the failed message when retrying it.

@kindex f @r{(Rmail)}
@findex rmail-forward
@cindex forwarding a message
  Another frequent reason to send mail in Rmail is to @dfn{forward} the
current message to other users.  @kbd{f} (@code{rmail-forward}) makes
this easy by preinitializing the mail composition buffer with the current
message as the text, and a subject of the form @code{[@var{from}:
@var{subject}]}, where @var{from} and @var{subject} are the sender and
subject of the original message.  All you have to do is fill in the
recipients and send.  When you forward a message, recipients get a
message which is from you, and which has the original message in
its contents.

@vindex rmail-enable-mime-composing
@findex unforward-rmail-message
  Rmail offers two formats for forwarded messages.  The default is to
use the MIME format (@pxref{Rmail Display}).  This includes the original
message as a separate part.  You can use a simpler format if you
prefer, by setting the variable @code{rmail-enable-mime-composing} to
@code{nil}.  In this case, Rmail just includes the original message
enclosed between two delimiter lines.  It also modifies every line
that starts with a dash, by inserting @w{@samp{- }} at the start of
the line.  When you receive a forwarded message in this format, if it
contains something besides ordinary text---for example, program source
code---you might find it useful to undo that transformation.  You can
do this by selecting the forwarded message and typing @kbd{M-x
unforward-rmail-message}.  This command extracts the original
forwarded message, deleting the inserted @w{@samp{- }} strings, and
inserts it into the Rmail file as a separate message immediately
following the current one.

@findex rmail-resend
  @dfn{Resending} is an alternative similar to forwarding; the
difference is that resending sends a message that is from the
original sender, just as it reached you---with a few added header fields
(@samp{Resent-From} and @samp{Resent-To}) to indicate that it came via
you.  To resend a message in Rmail, use @kbd{C-u f}.  (@kbd{f} runs
@code{rmail-forward}, which invokes @code{rmail-resend} if you provide a
numeric argument.)

@kindex m @r{(Rmail)}
@findex rmail-mail
  Use the @kbd{m} (@code{rmail-mail}) command to start editing an
outgoing message that is not a reply.  It leaves the header fields empty.
Its only difference from @kbd{C-x 4 m} is that it makes the Rmail buffer
accessible for @kbd{C-c C-y}, just as @kbd{r} does.
@ignore
@c Not a good idea, because it does not include Reply-To etc.
Thus, @kbd{m} can be used to reply to or forward a message; it can do
anything @kbd{r} or @kbd{f} can do.
@end ignore

@kindex c @r{(Rmail)}
@findex rmail-continue
  The @kbd{c} (@code{rmail-continue}) command resumes editing the
mail composition buffer, to finish editing an outgoing message you were
already composing, or to alter a message you have sent.

@vindex rmail-mail-new-frame
  If you set the variable @code{rmail-mail-new-frame} to a
non-@code{nil} value, then all the Rmail commands to start sending a
message create a new frame to edit it in.  This frame is deleted when
you send the message.
@ignore
@c FIXME does not work with Message -> Kill Message
, or when you use the @samp{Cancel} item in the @samp{Mail} menu.
@end ignore

  All the Rmail commands to send a message use the mail-composition
method that you have chosen (@pxref{Mail Methods}).

@node Rmail Summary
@section Summaries
@cindex summary (Rmail)

  A @dfn{summary} is a buffer containing one line per message to give
you an overview of the mail in an Rmail file.  Each line shows the
message number and date, the sender, the line count, the labels, and
the subject.  Moving point in the summary buffer selects messages as
you move to their summary lines.  Almost all Rmail commands are valid
in the summary buffer also; when used there, they apply to the message
described by the current line of the summary.

  A summary buffer applies to a single Rmail file only; if you are
editing multiple Rmail files, each one can have its own summary buffer.
The summary buffer name is made by appending @samp{-summary} to the
Rmail buffer's name.  Normally only one summary buffer is displayed at a
time.

@menu
* Rmail Make Summary::       Making various sorts of summaries.
* Rmail Summary Edit::       Manipulating messages from the summary.
@end menu

@node Rmail Make Summary
@subsection Making Summaries

  Here are the commands to create a summary for the current Rmail
buffer.  Once the Rmail buffer has a summary, changes in the Rmail
buffer (such as deleting or expunging messages, and getting new mail)
automatically update the summary.

@table @kbd
@item h
@itemx C-M-h
Summarize all messages (@code{rmail-summary}).
@item l @var{labels} @key{RET}
@itemx C-M-l @var{labels} @key{RET}
Summarize messages that have one or more of the specified labels
(@code{rmail-summary-by-labels}).
@item C-M-r @var{rcpts} @key{RET}
Summarize messages that match the specified recipients
(@code{rmail-summary-by-recipients}).
@item C-M-t @var{topic} @key{RET}
Summarize messages that have a match for the specified regexp
@var{topic} in their subjects (@code{rmail-summary-by-topic}).
@item C-M-s @var{regexp} @key{RET}
Summarize messages whose headers match the specified regular expression
@var{regexp} (@code{rmail-summary-by-regexp}).
@item C-M-f @var{senders} @key{RET}
Summarize messages that match the specified senders.
(@code{rmail-summary-by-senders}).
@end table

@kindex h @r{(Rmail)}
@findex rmail-summary
  The @kbd{h} or @kbd{C-M-h} (@code{rmail-summary}) command fills the summary buffer
for the current Rmail buffer with a summary of all the messages in the buffer.
It then displays and selects the summary buffer in another window.

@kindex l @r{(Rmail)}
@kindex C-M-l @r{(Rmail)}
@findex rmail-summary-by-labels
  @kbd{C-M-l @var{labels} @key{RET}} (@code{rmail-summary-by-labels}) makes
a partial summary mentioning only the messages that have one or more of the
labels @var{labels}.  @var{labels} should contain label names separated by
commas.

@kindex C-M-r @r{(Rmail)}
@findex rmail-summary-by-recipients
  @kbd{C-M-r @var{rcpts} @key{RET}} (@code{rmail-summary-by-recipients})
makes a partial summary mentioning only the messages that have one or
more recipients matching the regular expression @var{rcpts}.  This is matched
against the @samp{To}, @samp{From}, and @samp{CC} headers (supply a prefix
argument to exclude the @samp{CC} header).

@kindex C-M-t @r{(Rmail)}
@findex rmail-summary-by-topic
  @kbd{C-M-t @var{topic} @key{RET}} (@code{rmail-summary-by-topic})
makes a partial summary mentioning only the messages whose subjects have
a match for the regular expression @var{topic}.  With a prefix argument,
the match is against the whole message, not just the subject.

@kindex C-M-s @r{(Rmail)}
@findex rmail-summary-by-regexp
  @kbd{C-M-s @var{regexp} @key{RET}} (@code{rmail-summary-by-regexp})
makes a partial summary that mentions only the messages whose headers
(including the date and the subject lines) match the regular
expression @var{regexp}.

@kindex C-M-f @r{(Rmail)}
@findex rmail-summary-by-senders
  @kbd{C-M-f @var{senders} @key{RET}} (@code{rmail-summary-by-senders})
makes a partial summary that mentions only the messages whose @samp{From}
fields match the regular expression @var{senders}.

  Note that there is only one summary buffer for any Rmail buffer;
making any kind of summary discards any previous summary.

@vindex rmail-summary-window-size
@vindex rmail-summary-line-count-flag
  The variable @code{rmail-summary-window-size} says how many lines to
use for the summary window.  The variable
@code{rmail-summary-line-count-flag} controls whether the summary line
for a message should include the line count of the message.  Setting
this option to @code{nil} might speed up the generation of summaries.

@node Rmail Summary Edit
@subsection Editing in Summaries

  You can use the Rmail summary buffer to do almost anything you can do
in the Rmail buffer itself.  In fact, once you have a summary buffer,
there's no need to switch back to the Rmail buffer.

  You can select and display various messages in the Rmail buffer, from
the summary buffer, just by moving point in the summary buffer to
different lines.  It doesn't matter what Emacs command you use to move
point; whichever line point is on at the end of the command, that
message is selected in the Rmail buffer.

@vindex rmail-summary-scroll-between-messages
  Almost all Rmail commands work in the summary buffer as well as in
the Rmail buffer.  Thus, @kbd{d} in the summary buffer deletes the
current message, @kbd{u} undeletes, and @kbd{x} expunges.  (However,
in the summary buffer, if there are no more undeleted messages in the
relevant direction, the delete commands go to the first or last
message, rather than staying on the current message.)  @kbd{o} and
@kbd{C-o} output the current message to a FILE; @kbd{r} starts a reply
to it; etc.  You can scroll the current message while remaining in the
summary buffer using @key{SPC} and @key{DEL}.  However, in the summary
buffer scrolling past the end or the beginning of a message with
@key{SPC} or @key{DEL} goes, respectively, to the next or previous
undeleted message.  Customize the
@code{rmail-summary-scroll-between-messages} option to @code{nil} to
disable scrolling to next/previous messages.

@findex rmail-summary-undelete-many
@kbd{M-u} (@code{rmail-summary-undelete-many}) undeletes all deleted
messages in the summary.  A prefix argument means to undelete that many
of the previous deleted messages.

  The Rmail commands to move between messages also work in the summary
buffer, but with a twist: they move through the set of messages included
in the summary.  They also ensure the Rmail buffer appears on the screen
(unlike cursor motion commands, which update the contents of the Rmail
buffer but don't display it in a window unless it already appears).
Here is a list of these commands:

@table @kbd
@item n
Move to next line, skipping lines saying ``deleted'', and select its
message (@code{rmail-summary-next-msg}).
@item p
Move to previous line, skipping lines saying ``deleted'', and select
its message (@code{rmail-summary-previous-msg}).
@item M-n
Move to next line and select its message (@code{rmail-summary-next-all}).
@item M-p
Move to previous line and select its message
(@code{rmail-summary-previous-all}).
@item >
Move to the last line, and select its message
(@code{rmail-summary-last-message}).
@item <
Move to the first line, and select its message
(@code{rmail-summary-first-message}).
@item j
@itemx @key{RET}
Select the message on the current line (ensuring that the Rmail buffer
appears on the screen; @code{rmail-summary-goto-msg}).  With argument
@var{n}, select message number @var{n} and move to its line in the
summary buffer; this signals an error if the message is not listed in
the summary buffer.
@item M-s @var{pattern} @key{RET}
Search through messages for @var{pattern} starting with the current
message; select the message found, and move point in the summary buffer
to that message's line (@code{rmail-summary-search}).  A prefix argument
acts as a repeat count; a negative argument means search backward
(equivalent to @code{rmail-summary-search-backward}.)
@item C-M-n @var{labels} @key{RET}
Move to the next message with at least one of the specified labels
(@code{rmail-summary-next-labeled-message}).  @var{labels} is a
comma-separated list of labels.  A prefix argument acts as a repeat
count.
@item C-M-p @var{labels} @key{RET}
Move to the previous message with at least one of the specified labels
(@code{rmail-summary-previous-labeled-message}).
@item C-c C-n @key{RET}
Move to the next message with the same subject as the current message
(@code{rmail-summary-next-same-subject}).  A prefix argument acts as a
repeat count.
@item C-c C-p @key{RET}
Move to the previous message with the same subject as the current message
(@code{rmail-summary-previous-same-subject}).
@end table

@vindex rmail-redisplay-summary
  Deletion, undeletion, and getting new mail, and even selection of a
different message all update the summary buffer when you do them in the
Rmail buffer.  If the variable @code{rmail-redisplay-summary} is
non-@code{nil}, these actions also bring the summary buffer back onto
the screen.

@kindex Q @r{(Rmail summary)}
@findex rmail-summary-wipe
@kindex q @r{(Rmail summary)}
@findex rmail-summary-quit
@kindex b @r{(Rmail summary)}
@findex rmail-summary-bury
  When you are finished using the summary, type @kbd{Q}
(@code{rmail-summary-wipe}) to delete the summary buffer's window.  You
can also exit Rmail while in the summary: @kbd{q}
(@code{rmail-summary-quit}) deletes the summary window, then exits from
Rmail by saving the Rmail file and switching to another buffer.
Alternatively, @kbd{b} (@code{rmail-summary-bury}) simply buries the
Rmail summary and buffer.

@node Rmail Sorting
@section Sorting the Rmail File
@cindex sorting Rmail file
@cindex Rmail file sorting

@table @kbd
@findex rmail-sort-by-date
@item C-c C-s C-d
@itemx M-x rmail-sort-by-date
Sort messages of current Rmail buffer by date.

@findex rmail-sort-by-subject
@item C-c C-s C-s
@itemx M-x rmail-sort-by-subject
Sort messages of current Rmail buffer by subject.

@findex rmail-sort-by-author
@item C-c C-s C-a
@itemx M-x rmail-sort-by-author
Sort messages of current Rmail buffer by author's name.

@findex rmail-sort-by-recipient
@item C-c C-s C-r
@itemx M-x rmail-sort-by-recipient
Sort messages of current Rmail buffer by recipient's name.

@findex rmail-sort-by-correspondent
@item C-c C-s C-c
@itemx M-x rmail-sort-by-correspondent
Sort messages of current Rmail buffer by the name of the other
correspondent.

@findex rmail-sort-by-lines
@item C-c C-s C-l
@itemx M-x rmail-sort-by-lines
Sort messages of current Rmail buffer by number of lines.

@findex rmail-sort-by-labels
@item C-c C-s C-k @key{RET} @var{labels} @key{RET}
@itemx M-x rmail-sort-by-labels @key{RET} @var{labels} @key{RET}
Sort messages of current Rmail buffer by labels.  The argument
@var{labels} should be a comma-separated list of labels.  The order of
these labels specifies the order of messages; messages with the first
label come first, messages with the second label come second, and so on.
Messages that have none of these labels come last.
@end table

  The Rmail sort commands perform a @emph{stable sort}: if there is no
reason to prefer either one of two messages, their order remains
unchanged.  You can use this to sort by more than one criterion.  For
example, if you use @code{rmail-sort-by-date} and then
@code{rmail-sort-by-author}, messages from the same author appear in
order by date.

  With a prefix argument, all these commands reverse the order of
comparison.  This means they sort messages from newest to oldest, from
biggest to smallest, or in reverse alphabetical order.

  The same keys in the summary buffer run similar functions; for
example, @kbd{C-c C-s C-l} runs @code{rmail-summary-sort-by-lines}.
These commands always sort the whole Rmail buffer, even if the summary
is only showing a subset of messages.

  Note that you cannot undo a sort, so you may wish to save the Rmail
buffer before sorting it.

@node Rmail Display
@section Display of Messages

  This section describes how Rmail displays mail headers,
@acronym{MIME} sections and attachments, URLs, and encrypted messages.

@table @kbd
@item t
Toggle display of complete header (@code{rmail-toggle-header}).
@end table

@kindex t @r{(Rmail)}
@findex rmail-toggle-header
  Before displaying each message for the first time, Rmail reformats
its header, hiding uninteresting header fields to reduce clutter.  The
@kbd{t} (@code{rmail-toggle-header}) command toggles this, switching
between showing the reformatted header fields and showing the
complete, original header.  With a positive prefix argument, the
command shows the reformatted header; with a zero or negative prefix
argument, it shows the full header.  Selecting the message again also
reformats it if necessary.

@vindex rmail-ignored-headers
@vindex rmail-displayed-headers
@vindex rmail-nonignored-headers
  The variable @code{rmail-ignored-headers} holds a regular expression
specifying the header fields to hide; any matching header line will be
hidden.  The variable @code{rmail-nonignored-headers} overrides this:
any header field matching that regular expression is shown even if it
matches @code{rmail-ignored-headers} too.  The variable
@code{rmail-displayed-headers} is an alternative to these two
variables; if non-@code{nil}, this should be a regular expression
specifying which headers to display (the default is @code{nil}).

@vindex rmail-highlighted-headers
  Rmail highlights certain header fields that are especially
interesting---by default, the @samp{From} and @samp{Subject} fields.
This highlighting uses the @code{rmail-highlight} face.  The variable
@code{rmail-highlighted-headers} holds a regular expression specifying
the header fields to highlight; if it matches the beginning of a
header field, that whole field is highlighted.  To disable this
feature, set @code{rmail-highlighted-headers} to @code{nil}.

@cindex MIME messages (Rmail)
@vindex rmail-enable-mime
  If a message is in @acronym{MIME} (Multipurpose Internet Mail
Extensions) format and contains multiple parts (@acronym{MIME}
entities), Rmail displays each part with a @dfn{tagline}.  The tagline
summarizes the part's index, size, and content type.  Depending on the
content type, it may also contain one or more buttons; these perform
actions such as saving the part into a file.

@table @kbd
@findex rmail-mime-toggle-hidden
@item @key{RET}
Hide or show the @acronym{MIME} part at point
(@code{rmail-mime-toggle-hidden}).

@findex rmail-mime-next-item
@item @key{TAB}
Move point to the next @acronym{MIME} tagline button.
(@code{rmail-mime-next-item}).

@findex rmail-mime-previous-item
@item S-@key{TAB}
Move point to the previous @acronym{MIME} part
(@code{rmail-mime-previous-item}).

@findex rmail-mime
@item v
@kindex v @r{(Rmail)}
Toggle between @acronym{MIME} display and raw message
(@code{rmail-mime}).
@end table

  Each plain-text @acronym{MIME} part is initially displayed
immediately after its tagline, as part of the Rmail buffer (unless the
message has an @acronym{HTML} part, see below), while @acronym{MIME}
parts of other types are represented only by their taglines, with
their actual contents hidden.  In either case, you can toggle a
@acronym{MIME} part between its displayed and hidden states by typing
@key{RET} anywhere in the part---or anywhere in its tagline (except
for buttons for other actions, if there are any).  Type @key{RET} (or
click with the mouse) to activate a tagline button, and @key{TAB} to
cycle point between tagline buttons.

  The @kbd{v} (@code{rmail-mime}) command toggles between the default
@acronym{MIME} display described above, and a raw display showing
the undecoded @acronym{MIME} data.  With a prefix argument, this
command toggles the display of only an entity at point.

@vindex rmail-mime-prefer-html
  If the message has an @acronym{HTML} @acronym{MIME} part, Rmail
displays it in preference to the plain-text part, if Emacs can render
@acronym{HTML}@footnote{
This capability requires that Emacs be built with @file{libxml2}
support or that you have the Lynx browser installed.}.  To prevent
that, and have the plain-text part displayed instead, customize the
variable @code{rmail-mime-prefer-html} to a @code{nil} value.

  To prevent Rmail from handling MIME decoded messages, change the
variable @code{rmail-enable-mime} to @code{nil}.  When this is the
case, the @kbd{v} (@code{rmail-mime}) command instead creates a
temporary buffer to display the current @acronym{MIME} message.

@findex rmail-epa-decrypt
@cindex encrypted mails (reading in Rmail)
  If the current message is an encrypted one, use the command @kbd{M-x
rmail-epa-decrypt} to decrypt it, using the EasyPG library
(@pxref{Top,, EasyPG, epa, EasyPG Assistant User's Manual}).

  You can highlight and activate URLs in the Rmail buffer using Goto
Address mode:

@c FIXME goto-addr.el commentary says to use goto-address instead.
@example
(add-hook 'rmail-show-message-hook 'goto-address-mode)
@end example

@noindent
Then you can browse these URLs by clicking on them with @kbd{mouse-2}
(or @kbd{mouse-1} quickly) or by moving to one and typing @kbd{C-c
@key{RET}}.  @xref{Goto Address mode, Activating URLs, Activating URLs}.

@node Rmail Coding
@section Rmail and Coding Systems

@cindex decoding mail messages (Rmail)
  Rmail automatically decodes messages which contain non-@acronym{ASCII}
characters, just as Emacs does with files you visit and with subprocess
output.  Rmail uses the standard @samp{charset=@var{charset}} header in
the message, if any, to determine how the message was encoded by the
sender.  It maps @var{charset} into the corresponding Emacs coding
system (@pxref{Coding Systems}), and uses that coding system to decode
message text.  If the message header doesn't have the @samp{charset}
specification, or if @var{charset} is not recognized,
Rmail chooses the coding system with the usual Emacs heuristics and
defaults (@pxref{Recognize Coding}).

@cindex fixing incorrectly decoded mail messages
  Occasionally, a message is decoded incorrectly, either because Emacs
guessed the wrong coding system in the absence of the @samp{charset}
specification, or because the specification was inaccurate.  For
example, a misconfigured mailer could send a message with a
@samp{charset=iso-8859-1} header when the message is actually encoded
in @code{koi8-r}.  When you see the message text garbled, or some of
its characters displayed as hex codes or empty boxes, this may have
happened.

@findex rmail-redecode-body
  You can correct the problem by decoding the message again using the
right coding system, if you can figure out or guess which one is
right.  To do this, invoke the @kbd{M-x rmail-redecode-body} command.
It reads the name of a coding system, and then redecodes the message
using the coding system you specified.  If you specified the right
coding system, the result should be readable.

@vindex rmail-file-coding-system
  When you get new mail in Rmail, each message is translated
automatically from the coding system it is written in, as if it were a
separate file.  This uses the priority list of coding systems that you
have specified.  If a MIME message specifies a character set, Rmail
obeys that specification.  For reading and saving Rmail files
themselves, Emacs uses the coding system specified by the variable
@code{rmail-file-coding-system}.  The default value is @code{nil},
which means that Rmail files are not translated (they are read and
written in the Emacs internal character code).

@node Rmail Editing
@section Editing Within a Message

  Most of the usual Emacs key bindings are available in Rmail mode,
though a few, such as @kbd{C-M-n} and @kbd{C-M-h}, are redefined by
Rmail for other purposes.  However, the Rmail buffer is normally read
only, and most of the letters are redefined as Rmail commands.  If you
want to edit the text of a message, you must use the Rmail command
@kbd{e}.

@table @kbd
@item e
Edit the current message as ordinary text.
@end table

@kindex e @r{(Rmail)}
@findex rmail-edit-current-message
  The @kbd{e} command (@code{rmail-edit-current-message}) switches from
Rmail mode into Rmail Edit mode, another major mode which is nearly the
same as Text mode.  The mode line indicates this change.

@findex rmail-cease-edit
@findex rmail-abort-edit
  In Rmail Edit mode, letters insert themselves as usual and the Rmail
commands are not available.  You can edit the message body and header
fields.  When you are finished editing the message, type @kbd{C-c C-c}
(@code{rmail-cease-edit}) to switch back to Rmail mode.
Alternatively, you can return to Rmail mode but cancel any editing
that you have done, by typing @kbd{C-c C-]} (@code{rmail-abort-edit}).

@vindex rmail-edit-mode-hook
  Entering Rmail Edit mode runs the hook @code{text-mode-hook}; then
it runs the hook @code{rmail-edit-mode-hook} (@pxref{Hooks}).
Returning to ordinary Rmail mode adds the attribute @samp{edited} to
the message, if you have made any changes in it (@pxref{Rmail Attributes}).

@node Rmail Digest
@section Digest Messages
@cindex digest message
@cindex undigestify

  A @dfn{digest message} is a message which exists to contain and carry
several other messages.  Digests are used on some mailing
lists; all the messages that arrive for the list during a period of time
such as one day are put inside a single digest which is then sent to the
subscribers.  Transmitting the single digest uses less computer
time than transmitting the individual messages even though the total
size is the same, because of the per-message overhead in network mail
transmission.

@findex undigestify-rmail-message
  When you receive a digest message, the most convenient way to read it is
to @dfn{undigestify} it: to turn it back into many individual messages.
Then you can read and delete the individual messages as it suits you.
To do this, select the digest message and type the command @kbd{M-x
undigestify-rmail-message}.  This extracts the submessages as separate
Rmail messages, and inserts them following the digest.  The digest
message itself is flagged as deleted.

@node Rmail Rot13
@section Reading Rot13 Messages
@cindex rot13 code

  Mailing list messages that might offend or annoy some readers are sometimes
encoded in a simple code called @dfn{rot13}---so named because it
rotates the alphabet by 13 letters.  This code is not for secrecy, as it
provides none; rather, it enables those who wish to avoid
seeing the real text of the message.  For example, a review of a film
might use rot13 to hide important plot points.

@findex rot13-other-window
  To view a buffer that uses the rot13 code, use the command @kbd{M-x
rot13-other-window}.  This displays the current buffer in another window
which applies the code when displaying the text.

@node Movemail
@section @command{movemail} program
@cindex @command{movemail} program

  Rmail uses the @command{movemail} program to move mail from your inbox to
your Rmail file (@pxref{Rmail Inbox}).  When loaded for the first time,
Rmail attempts to locate the @command{movemail} program and determine its
version.  There are two versions of the @command{movemail} program: the
GNU Mailutils version (@pxref{movemail,,,mailutils,GNU mailutils}),
and an Emacs-specific version that is built and installed unless Emacs
was configured @option{--with-mailutils} in effect.
The two @command{movemail} versions support the same
command line syntax and the same basic subset of options.  However, the
Mailutils version offers additional features and is more secure.

  The Emacs version of @command{movemail} can retrieve mail from the
usual Unix mailbox formats.  @strong{Warning}: Although it can also use the POP3
protocol, this is not recommended because it does not support POP3 via
encrypted TLS channels.

  The Mailutils version is able to handle a wide set of mailbox
formats, such as plain Unix mailboxes, @code{maildir} and @code{MH}
mailboxes, etc.  It is able to access remote mailboxes using the POP3
or IMAP4 protocol, and can retrieve mail from them using a TLS
encrypted channel.  It also accepts mailbox arguments in @acronym{URL}
form.  The detailed description of mailbox @acronym{URL}s can be found
@c Note this node seems to be missing in some versions of mailutils.info?
in @ref{URL,,,mailutils,Mailbox URL Formats}.  In short, a
@acronym{URL} is:

@smallexample
@var{proto}://[@var{user}[:@var{password}]@@]@var{host-or-file-name}[:@var{port}]
@end smallexample

@noindent
where square brackets denote optional elements.

@table @var
@item proto
Specifies the @dfn{mailbox protocol}, or @dfn{format} to
use.  The exact semantics of the rest of @acronym{URL} elements depends
on the actual value of @var{proto} (see below).

@item user
User name to access the remote mailbox.

@item password
User password to access the remote mailbox.

@item host-or-file-name
Hostname of the remote server for remote mailboxes or file name of a
local mailbox.

@item port
Optional port number, if not the default for that protocol.
@end table

@noindent
@var{proto} can be one of:

@table @code
@item mbox
Usual Unix mailbox format.  In this case, @var{user}, @var{pass} and
@var{port} are not used, and @var{host-or-file-name} denotes the file
name of the mailbox file, e.g., @code{mbox:///var/spool/mail/smith}.

@item mh
A local mailbox in the @acronym{MH} format.  @var{user}, @var{pass}
and @var{port} are not used.  @var{host-or-file-name} denotes the name
of @acronym{MH} folder, e.g., @code{mh:///Mail/inbox}.

@item maildir
A local mailbox in the @acronym{maildir} format.  @var{user},
@var{pass} and @var{port} are not used, and @var{host-or-file-name}
denotes the name of @code{maildir} mailbox, e.g.,
@code{maildir:///mail/inbox}.

@item file
Any local file in mailbox format.  Its actual format is detected
automatically by @command{movemail}.

@item pop
@itemx pops
A remote mailbox to be accessed via POP3 protocol.  @var{user}
specifies the remote user name to use, @var{pass} may be used to
specify the user password, @var{host-or-file-name} is the name or IP
address of the remote mail server to connect to, and @var{port} is the
port number; e.g., @code{pop://smith:guessme@@remote.server.net:995}.
If the server supports it, @command{movemail} tries to use an
encrypted connection---use the @samp{pops} form to require one.

@item imap
@itemx imaps
A remote mailbox to be accessed via IMAP4 protocol.  @var{user}
specifies the remote user name to use, @var{pass} may be used to
specify the user password, @var{host-or-file-name} is the name or IP
address of the remote mail server to connect to, and @var{port} is the
port number; e.g., @code{imap://smith:guessme@@remote.server.net:993}.
If the server supports it, @command{movemail} tries to use an
encrypted connection---use the @samp{imaps} form to require one.
@end table

  Alternatively, you can specify the file name of the mailbox to use.
This is equivalent to specifying the @samp{file} protocol:

@smallexample
/var/spool/mail/@var{user} @equiv{} file:///var/spool/mail/@var{user}
@end smallexample

@vindex rmail-movemail-program
@vindex rmail-movemail-search-path
  The variable @code{rmail-movemail-program} controls which version of
@command{movemail} to use.  If that is a string, it specifies the
absolute file name of the @command{movemail} executable.  If it is
@code{nil}, Rmail searches for @command{movemail} in the directories
listed in @code{rmail-movemail-search-path}, then in @code{exec-path}
(@pxref{Shell}), then in @code{exec-directory}.

@node Remote Mailboxes
@section Retrieving Mail from Remote Mailboxes
@pindex movemail

  Some sites use a method called POP3 for accessing users' inbox data
instead of storing the data in inbox files.  The Mailutils
@command{movemail} by default supports POP3 with TLS encryption.
@strong{Warning:} Although the @command{Emacs movemail} supports POP3,
its use for this is not recommended since it does not support encrypted
connections---the Mailutils version does.
Both versions of @command{movemail} work only with POP3, not with
older versions of POP.

@cindex @env{MAILHOST} environment variable
@cindex POP3 mailboxes
  You can specify
a POP3 inbox by using a POP3 @dfn{URL} (@pxref{Movemail}).  A POP3
@acronym{URL} is of the form
@samp{pop://@var{username}@@@var{hostname}:@var{port}}, where
@var{hostname} and @var{port} are the host name (or IP address)
and port number of the remote mail
server and @var{username} is the user name on that server.
Additionally, you may specify the password in the mailbox @acronym{URL}:
@samp{pop://@var{username}:@var{password}@@@var{hostname}:@var{port}}.  In this
case, @var{password} takes preference over the one set by
@code{rmail-remote-password} (see below).  This is especially useful
if you have several remote mailboxes with different passwords.
If using Mailutils @command{movemail}, you may wish to use
@samp{pops} in place of @samp{pop}.

  For backward compatibility, Rmail also supports an alternative way of
specifying remote POP3 mailboxes.  Specifying an inbox name in the form
@samp{po:@var{username}:@var{hostname}:@var{port}} is equivalent to
@samp{pop://@var{username}@@@var{hostname}:@var{port}}.  If you omit the
@var{:hostname} part, the @env{MAILHOST} environment variable specifies
the machine on which to look for the POP3 server.

@cindex IMAP mailboxes
  Another method for accessing remote mailboxes is IMAP@.  This method is
supported only by the Mailutils @command{movemail}.  To specify an IMAP
mailbox in the inbox list, use the following mailbox @acronym{URL}:
@samp{imap://@var{username}[:@var{password}]@@@var{hostname}:@var{port}}.  The
@var{password} part is optional, as described above.  You may wish to
use @samp{imaps} in place of @samp{imap}.

@vindex rmail-remote-password
@vindex rmail-remote-password-required
  Accessing a remote mailbox may require a password.  Rmail uses the
following algorithm to retrieve it:

@enumerate
@item
If a @var{password} is present in the mailbox URL (see above), it is
used.
@item
If the variable @code{rmail-remote-password-required} is @code{nil},
Rmail assumes no password is required.
@item
If the variable @code{rmail-remote-password} is non-@code{nil}, its
value is used.
@item
Otherwise, Rmail will ask you for the password to use.
@end enumerate

@vindex rmail-movemail-flags
  If you need to pass additional command-line flags to @command{movemail},
set the variable @code{rmail-movemail-flags} a list of the flags you
wish to use.  Do not use this variable to pass the @samp{-p} flag to
preserve your inbox contents; use @code{rmail-preserve-inbox} instead.

@cindex Kerberos POP3 authentication
  The @command{movemail} program installed at your site may support
Kerberos authentication.  If it is supported, it is used by default
whenever you attempt to retrieve POP3 mail when
@code{rmail-remote-password} and @code{rmail-remote-password-required}
are unset.

@cindex reverse order in POP3 inboxes
  Some POP3 servers store messages in reverse order.  If your server does
this, and you would rather read your mail in the order in which it was
received, you can tell @command{movemail} to reverse the order of
downloaded messages by adding the @samp{-r} flag to
@code{rmail-movemail-flags}.

@cindex TLS encryption (Rmail)
  Mailutils @command{movemail} supports TLS encryption.  If you wish to
use it, add the @samp{--tls} flag to @code{rmail-movemail-flags}.

@node Other Mailbox Formats
@section Retrieving Mail from Local Mailboxes in Various Formats

  If your incoming mail is stored on a local machine in a format other
than Unix mailbox, you will need the Mailutils @command{movemail} to
retrieve it.  @xref{Movemail}, for the detailed description of
@command{movemail} versions.  For example, to access mail from an inbox in
@code{maildir} format located in @file{/var/spool/mail/in}, you would
include the following in the Rmail inbox list:

@smallexample
maildir:///var/spool/mail/in
@end smallexample