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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
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<TITLE>The Answer Guy 36: troubleshooting</TITLE>
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<H4>"The Linux Gazette...<I>making Linux just a little more fun!</I>"</H4>
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<H4>By James T. Dennis,
<a href="mailto:answerguy@ssc.com">answerguy@ssc.com</a><BR>
Starshine Technical Services,
<A HREF="http://www.starshine.org/">http://www.starshine.org/</A>
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<!-- begin 23 -->
<H3 align="left"><img src="../../gx/dennis/qbubble.gif" height="50" width="60"
alt="(?) " border="0">troubleshooting</H3>
<p><strong>From Matthew Easton on Wed, 06 May 1998
</strong></p>
<BLOCKQUOTE>
</BLOCKQUOTE>
<P><STRONG><IMG SRC="../../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
One thing I notice as I try to learn more about Linux, is that much of the
information I come across is very specific to a particular situation or a
particular piece of software. I'd like to get away from the 'step by step
instructions for software x' and construct a "bag of tricks" that will
allow me to solve problems myself.
</STRONG></P>
<P><STRONG>
To explain: In my job I troubleshoot Macintosh hardware and software. If
you had a problem with a Mac I could tell you some things to check and
several procedures to try-- and even if I was unfamiliar with the
particular application that was failing you, chances are pretty good that
things would be functioning in the end.
</STRONG></P>
<P><STRONG>
</STRONG></P>
<BLOCKQUOTE><IMG SRC="../../gx/dennis/bbub.gif" alt="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
That is why we have professional technical support, system
administration, help desk, repair technicians etc.
</BLOCKQUOTE>
<BLOCKQUOTE>
The issue is similar for a number of trades and professions.
</BLOCKQUOTE>
<BLOCKQUOTE>
Even the Mac for all its vaunted "easy of use" and consistency
really requires a significant acculturation to a large number
of assumptions. I know this from very recent first hand
experience since I gave my mother her very first computer
earlier this year --- it was a Mac Performa.
</BLOCKQUOTE>
<BLOCKQUOTE>
</BLOCKQUOTE>
<P><STRONG><IMG SRC="../../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Granted the user interface is greatly simplified under Macintosh compared
to Linux, but are there any general principles or things to look for, or
standard procedures for troubleshooting software under Linux, or tools?
</STRONG></P>
<BLOCKQUOTE><IMG SRC="../../gx/dennis/bbub.gif" alt="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
The simplicity of Macs and Windows can largely be summed up
as:
</BLOCKQUOTE>
<BLOCKQUOTE>
If you don't see a menu option, button or dialog for
it --- you probably can't do it.
</BLOCKQUOTE>
<BLOCKQUOTE>
</BLOCKQUOTE>
<BLOCKQUOTE>
(I realize this is a bit of an over simplication --- there are
whole books of Mac and Windows "tricks" that are slowly gleaned
over time).
</BLOCKQUOTE>
<BLOCKQUOTE>
These system make a reasonable subset of their functionality
available on their face (through full-screen menu driven user
interfaces). That whole issue of "icons" and "GUI's" is
completely a red herring since they really are just menus
under all the hype. I have a friend who said that the easiest
system she'd ever worked on was an AS/400 (running OS/400
naturally enough). She described (even showed me, once) the
interface and it did sound pretty handy.
</BLOCKQUOTE>
<BLOCKQUOTE>
Unix is usually described as a "toolbox." The analogy is
reasonable. If I handed you a real box full of hammers,
screwdrivers, nail guns, pliers, drills, saws, wrenches
sockets, and similar physical tools it wouldn't help you
build or rewire your house, fix your car or anything ---
until you learned the appropriate construction and mechanical
trades that use these tools.
</BLOCKQUOTE>
<BLOCKQUOTE>
Similarly we find that some programmers under Unix can
be just as confused and incapacitated when faced with
system or technical administrative issues as an auto mechanic
might be when faced with a plumbing problem. Naturally
a plumber or mechanic is more likely to successfully take
on other "handyperson" repairs than someone with <EM>no</EM> related
experience.
</BLOCKQUOTE>
<BLOCKQUOTE>
Another way of thinking about these OS' is in terms of
culture and language. Natural language (including idiom)
is entwined with many cultural assumptions. Unix/Linux
conventions can be seen as a "language" for expressing demands
of your computer (via the shell, through myriad configuration
files, even in the Motif, <A HREF="http://www.kde.org/">KDE</A>,
OpenLook and other GUI's that we encounter).
</BLOCKQUOTE>
<BLOCKQUOTE>
The advantage of this "linguistic" point of view is that
it approaches the level of complexity of a Unix system.
When I was an electrician I doubt I encountered more than
two hundred different tools, and probably less than two
thousand different components (connectors, fittings, brackets,
etc). (Thousands of sizes and minor differences --- but not
different in terms of usage semantics).
</BLOCKQUOTE>
<BLOCKQUOTE>
On this Linux box if I switch to a bash shell prompt and
double tap on the "Tab" key on a blank line (forcing it to
try command completion) it warns me that I have over
2300 commands available to me. Many of these are full
programming languages or environments like awk, perl, and
emacs (elisp). Similarly I once determined that my
copy of emacs (or was it xemacs) had about 1500 interactively
accessible functions built into it. (If I installed the
emacs '<tt>calc</tt>' (a large mathematics package) that
would probably double.
</BLOCKQUOTE>
<BLOCKQUOTE>
So there's quite a bit of depth and breadth available.
</BLOCKQUOTE>
<P><STRONG><IMG SRC="../../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
For example: How do I deal with a segmentation fault? Or, if an
application installs broken and reinstalling the RPM package still does not
work, is there a way to get Linux to tell me what is missing or corrupted?
And what can I do about a program that (under X windows) briefly appears
and then dies without error messages?
</STRONG></P>
<P><STRONG>
</STRONG></P>
<BLOCKQUOTE><IMG SRC="../../gx/dennis/bbub.gif" alt="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
In many cases these can be tracked down using '<tt>strace</tt>'
(the system call tracer).
</BLOCKQUOTE>
<BLOCKQUOTE>
Any segmentation fault is a bug in the program (or
corruption in its binaries or libraries). Robust programs
should handle bad data, corrupted configuration files, etc,
gracefully.
</BLOCKQUOTE>
<BLOCKQUOTE>
Packages that fail to operate as expected might be buggy,
or they migh have inadequate documentation. I personally
like to see programs that have some sort of "diagnostics"
or "check option" to help me track down problems with them.
</BLOCKQUOTE>
<BLOCKQUOTE>
('<tt>sendmail</tt>' and '<tt>named</tt>' are notable culprits
in this case).
</BLOCKQUOTE>
<P><STRONG><IMG SRC="../../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Thanks for any clarification on these or any other mysteries. . .
<br>Matt Easton
</STRONG></P>
<BLOCKQUOTE><IMG SRC="../../gx/dennis/bbub.gif" alt="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
That will take an entire book.
</BLOCKQUOTE>
<BLOCKQUOTE>
(Incidentally I found this message languishing in an
old drafts folder and decided to finish it up and
send it off. I really wanted to say much more on this
topic --- but I decided to write a book instead.
</BLOCKQUOTE>
<!-- sig -->
<!-- end 23 -->
<!--startcut ======================================================= -->
<P> <hr> <P>
<H5 align="center"><a href="http://www.linuxgazette.com/ssc.copying.html"
>Copyright ©</a> 1999, James T. Dennis
<BR>Published in <I>The Linux Gazette</I> Issue 36 January 1999</H5>
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