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<H2><A NAME="SECTION00132100000000000000000">
11.2.10 Common problems and solutions</A>
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<UL>
<LI>Most HTTP servers buffer the output from CGI scripts until the
script is completed.  This means that it is not possible to display a
progress report on the client's display while the script is running.

<P>
</LI>
<LI>Check the installation instructions above.

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</LI>
<LI>Check the HTTP server's log files.  ("<tt class="samp">tail -f logfile</tt>" in a
separate window may be useful!)

<P>
</LI>
<LI>Always check a script for syntax errors first, by doing something
like "<tt class="samp">python script.py</tt>".

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</LI>
<LI>If your script does not have any syntax errors, try adding
"<tt class="samp">import cgitb; cgitb.enable()</tt>" to the top of the script.

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</LI>
<LI>When invoking external programs, make sure they can be found.
Usually, this means using absolute path names -- <a class="envvar" id='l2h-3176' xml:id='l2h-3176'>PATH</a> is
usually not set to a very useful value in a CGI script.

<P>
</LI>
<LI>When reading or writing external files, make sure they can be read
or written by the userid under which your CGI script will be running:
this is typically the userid under which the web server is running, or some
explicitly specified userid for a web server's "<tt class="samp">suexec</tt>" feature.

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<LI>Don't try to give a CGI script a set-uid mode.  This doesn't work on
most systems, and is a security liability as well.
</LI>
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<span class="release-info">Release 2.4.2, documentation updated on 28 September 2005.</span>
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