# 3.19 Standard Module `site`

This module is automatically imported during initialization.

In earlier versions of Python (up to and including 1.5a3), scripts or modules that needed to use site-specific modules would place `import site` somewhere near the top of their code. This is no longer necessary.

This will append site-specific paths to 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 (on Mac or Windows) or it uses first ``lib/pythonversion/site-packages`' and then ``lib/site-python`' (on Unix). For each of the distinct head-tail combinations, it sees if it refers to an existing directory, and if so, adds to `sys.path`, and also inspected for path configuration files.

A path configuration file is a file whose name has the form ``package.pth`'; 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.

For example, suppose `sys.prefix` and `sys.exec_prefix` are set to ``/usr/local`'. The Python 1.5 library is then installed in ``/usr/local/lib/python1.5`'. Suppose this has a subdirectory ``/usr/local/python1.5/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 directories are added to sys.path, in this order:

    /usr/local/python1.5/site-packages/bar
    /usr/local/python1.5/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. ,sitecustomize

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.