
``site`` --- Site-specific configuration hook
*********************************************

**This module is automatically imported during initialization.** The
automatic import can be suppressed using the interpreter's *-S*
option.

Importing this module will append site-specific paths to the module
search path.

It starts by constructing up to four directories from a head and a
tail part. For the head part, it uses ``sys.prefix`` and
``sys.exec_prefix``; empty heads are skipped.  For the tail part, it
uses the empty string and then ``lib/site-packages`` (on Windows) or
``lib/python|version|/site-packages`` and then ``lib/site-python`` (on
Unix and Macintosh).  For each of the distinct head-tail combinations,
it sees if it refers to an existing directory, and if so, adds it to
``sys.path`` and also inspects the newly added path for configuration
files.

A path configuration file is a file whose name has the form
``package.pth`` and exists in one of the four directories mentioned
above; its contents are additional items (one per line) to be added to
``sys.path``.  Non-existing items are never added to ``sys.path``, but
no check is made that the item refers to a directory (rather than a
file).  No item is added to ``sys.path`` more than once.  Blank lines
and lines beginning with ``#`` are skipped.  Lines starting with
``import`` (followed by space or tab) are executed.

For example, suppose ``sys.prefix`` and ``sys.exec_prefix`` are set to
``/usr/local``.  The Python X.Y library is then installed in
``/usr/local/lib/python*X.Y*`` (where only the first three characters
of ``sys.version`` are used to form the installation path name).
Suppose this has a subdirectory
``/usr/local/lib/python*X.Y*/site-packages`` with three
subsubdirectories, ``foo``, ``bar`` and ``spam``, and two path
configuration files, ``foo.pth`` and ``bar.pth``.  Assume ``foo.pth``
contains the following:

   # foo package configuration

   foo
   bar
   bletch

and ``bar.pth`` contains:

   # bar package configuration

   bar

Then the following version-specific directories are added to
``sys.path``, in this order:

   /usr/local/lib/pythonX.Y/site-packages/bar
   /usr/local/lib/pythonX.Y/site-packages/foo

Note that ``bletch`` is omitted because it doesn't exist; the ``bar``
directory precedes the ``foo`` directory because ``bar.pth`` comes
alphabetically before ``foo.pth``; and ``spam`` is omitted because it
is not mentioned in either path configuration file.

After these path manipulations, an attempt is made to import a module
named ``sitecustomize``, which can perform arbitrary site-specific
customizations. If this import fails with an ``ImportError``
exception, it is silently ignored.

Note that for some non-Unix systems, ``sys.prefix`` and
``sys.exec_prefix`` are empty, and the path manipulations are skipped;
however the import of ``sitecustomize`` is still attempted.

site.PREFIXES

   A list of prefixes for site package directories

site.ENABLE_USER_SITE

   Flag showing the status of the user site directory. True means the
   user site directory is enabled and added to sys.path. When the flag
   is None the user site directory is disabled for security reasons.

site.USER_SITE

   Path to the user site directory for the current Python version or
   None

site.USER_BASE

   Path to the base directory for user site directories

PYTHONNOUSERSITE

PYTHONUSERBASE

site.addsitedir(sitedir, known_paths=None)

   Adds a directory to sys.path and processes its pth files.
