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<H1><A NAME="SECTION0052800000000000000000">
3.28 <tt class="module">site</tt> --
Site-specific configuration hook</A>
</H1>
<P>
<A NAME="module-site"><!--z--></A>
<P>
<b>This module is automatically imported during initialization.</b>
<P>
In earlier versions of Python (up to and including 1.5a3), scripts or
modules that needed to use site-specific modules would place
"<tt class="samp">import site</tt>" somewhere near the top of their code. This is no
longer necessary.
<P>
This will append site-specific paths to the module search path.
<a id='l2h-768'><!--x--></a>
<P>
It starts by constructing up to four directories from a head and a
tail part. For the head part, it uses <code>sys.prefix</code> and
<code>sys.exec_prefix</code>; empty heads are skipped. For
the tail part, it uses the empty string (on Macintosh or Windows) or
it uses first <span class="file">lib/python2.3/site-packages</span> and then
<span class="file">lib/site-python</span> (on <font style="font-variant: small-caps;">Unix</font>). For each of the distinct
head-tail combinations, it sees if it refers to an existing directory,
and if so, adds it to <code>sys.path</code> and also inspects the newly added
path for configuration files.
<a id='l2h-769'><!--x--></a><a id='l2h-770'><!--x--></a>
<P>
A path configuration file is a file whose name has the form
<span class="file"><var>package</var>.pth</span>; its contents are additional items (one
per line) to be added to <code>sys.path</code>. Non-existing items are
never added to <code>sys.path</code>, but no check is made that the item
refers to a directory (rather than a file). No item is added to
<code>sys.path</code> more than once. Blank lines and lines beginning with
<code>#</code> are skipped. Lines starting with <code>import</code> are executed.
<a id='l2h-772'><!--x--></a>
<a id='l2h-771'><!--x--></a>
<P>
For example, suppose <code>sys.prefix</code> and <code>sys.exec_prefix</code> are
set to <span class="file">/usr/local</span>. The Python 2.3.4 library is then
installed in <span class="file">/usr/local/lib/python2.3</span> (where only the
first three characters of <code>sys.version</code> are used to form the
installation path name). Suppose this has a subdirectory
<span class="file">/usr/local/lib/python2.3/site-packages</span> with three
subsubdirectories, <span class="file">foo</span>, <span class="file">bar</span> and <span class="file">spam</span>, and two
path configuration files, <span class="file">foo.pth</span> and <span class="file">bar.pth</span>. Assume
<span class="file">foo.pth</span> contains the following:
<P>
<div class="verbatim"><pre>
# foo package configuration
foo
bar
bletch
</pre></div>
<P>
and <span class="file">bar.pth</span> contains:
<P>
<div class="verbatim"><pre>
# bar package configuration
bar
</pre></div>
<P>
Then the following directories are added to <code>sys.path</code>, in this
order:
<P>
<div class="verbatim"><pre>
/usr/local/lib/python2.3/site-packages/bar
/usr/local/lib/python2.3/site-packages/foo
</pre></div>
<P>
Note that <span class="file">bletch</span> is omitted because it doesn't exist; the
<span class="file">bar</span> directory precedes the <span class="file">foo</span> directory because
<span class="file">bar.pth</span> comes alphabetically before <span class="file">foo.pth</span>; and
<span class="file">spam</span> is omitted because it is not mentioned in either path
configuration file.
<P>
After these path manipulations, an attempt is made to import a module
named <tt class="module">sitecustomize</tt><a id='l2h-773'><!--x--></a>, which can
perform arbitrary site-specific customizations. If this import fails
with an <tt class="exception">ImportError</tt> exception, it is silently ignored.
<P>
Note that for some non-<font style="font-variant: small-caps;">Unix</font> systems, <code>sys.prefix</code> and
<code>sys.exec_prefix</code> are empty, and the path manipulations are
skipped; however the import of
<tt class="module">sitecustomize</tt><a id='l2h-774'><!--x--></a> is still attempted.
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<span class="release-info">Release 2.3.4, documentation updated on May 20, 2004.</span>
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