Edit File: site.txt
:mod:`site` --- Site-specific configuration hook ================================================ .. module:: site :synopsis: Module responsible for site-specific configuration. **Source code:** :source:`Lib/site.py` -------------- .. highlightlang:: none **This module is automatically imported during initialization.** The automatic import can be suppressed using the interpreter's :option:`-S` option. .. index:: triple: module; search; path Importing this module will append site-specific paths to the module search path and add a few builtins. .. index:: pair: site-python; directory pair: site-packages; directory 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 :file:`lib/site-packages` (on Windows) or :file:`lib/python{X.Y}/site-packages` and then :file:`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 :file:`{name}.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``, and 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. .. versionchanged:: 2.6 A space or tab is now required after the import keyword. .. index:: single: package triple: path; configuration; file For example, suppose ``sys.prefix`` and ``sys.exec_prefix`` are set to :file:`/usr/local`. The Python X.Y library is then installed in :file:`/usr/local/lib/python{X.Y}`. Suppose this has a subdirectory :file:`/usr/local/lib/python{X.Y}/site-packages` with three subsubdirectories, :file:`foo`, :file:`bar` and :file:`spam`, and two path configuration files, :file:`foo.pth` and :file:`bar.pth`. Assume :file:`foo.pth` contains the following:: # foo package configuration foo bar bletch and :file:`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 :file:`bletch` is omitted because it doesn't exist; the :file:`bar` directory precedes the :file:`foo` directory because :file:`bar.pth` comes alphabetically before :file:`foo.pth`; and :file:`spam` is omitted because it is not mentioned in either path configuration file. .. index:: module: sitecustomize After these path manipulations, an attempt is made to import a module named :mod:`sitecustomize`, which can perform arbitrary site-specific customizations. It is typically created by a system administrator in the site-packages directory. If this import fails with an :exc:`ImportError` exception, it is silently ignored. .. index:: module: usercustomize After this, an attempt is made to import a module named :mod:`usercustomize`, which can perform arbitrary user-specific customizations, if :data:`ENABLE_USER_SITE` is true. This file is intended to be created in the user site-packages directory (see below), which is part of ``sys.path`` unless disabled by :option:`-s`. An :exc:`ImportError` will be 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 :mod:`sitecustomize` and :mod:`usercustomize` is still attempted. .. data:: PREFIXES A list of prefixes for site-packages directories. .. versionadded:: 2.6 .. data:: ENABLE_USER_SITE Flag showing the status of the user site-packages directory. ``True`` means that it is enabled and was added to ``sys.path``. ``False`` means that it was disabled by user request (with :option:`-s` or :envvar:`PYTHONNOUSERSITE`). ``None`` means it was disabled for security reasons (mismatch between user or group id and effective id) or by an administrator. .. versionadded:: 2.6 .. data:: USER_SITE Path to the user site-packages for the running Python. Can be ``None`` if :func:`getusersitepackages` hasn't been called yet. Default value is :file:`~/.local/lib/python{X.Y}/site-packages` for UNIX and non-framework Mac OS X builds, :file:`~/Library/Python/{X.Y}/lib/python/site-packages` for Mac framework builds, and :file:`{%APPDATA%}\\Python\\Python{XY}\\site-packages` on Windows. This directory is a site directory, which means that :file:`.pth` files in it will be processed. .. versionadded:: 2.6 .. data:: USER_BASE Path to the base directory for the user site-packages. Can be ``None`` if :func:`getuserbase` hasn't been called yet. Default value is :file:`~/.local` for UNIX and Mac OS X non-framework builds, :file:`~/Library/Python/{X.Y}` for Mac framework builds, and :file:`{%APPDATA%}\\Python` for Windows. This value is used by Distutils to compute the installation directories for scripts, data files, Python modules, etc. for the :ref:`user installation scheme <inst-alt-install-user>`. See also :envvar:`PYTHONUSERBASE`. .. versionadded:: 2.6 .. function:: addsitedir(sitedir, known_paths=None) Add a directory to sys.path and process its :file:`.pth` files. Typically used in :mod:`sitecustomize` or :mod:`usercustomize` (see above). .. function:: getsitepackages() Return a list containing all global site-packages directories (and possibly site-python). .. versionadded:: 2.7 .. function:: getuserbase() Return the path of the user base directory, :data:`USER_BASE`. If it is not initialized yet, this function will also set it, respecting :envvar:`PYTHONUSERBASE`. .. versionadded:: 2.7 .. function:: getusersitepackages() Return the path of the user-specific site-packages directory, :data:`USER_SITE`. If it is not initialized yet, this function will also set it, respecting :envvar:`PYTHONNOUSERSITE` and :data:`USER_BASE`. .. versionadded:: 2.7 The :mod:`site` module also provides a way to get the user directories from the command line: .. code-block:: sh $ python3 -m site --user-site /home/user/.local/lib/python3.3/site-packages .. program:: site If it is called without arguments, it will print the contents of :data:`sys.path` on the standard output, followed by the value of :data:`USER_BASE` and whether the directory exists, then the same thing for :data:`USER_SITE`, and finally the value of :data:`ENABLE_USER_SITE`. .. cmdoption:: --user-base Print the path to the user base directory. .. cmdoption:: --user-site Print the path to the user site-packages directory. If both options are given, user base and user site will be printed (always in this order), separated by :data:`os.pathsep`. If any option is given, the script will exit with one of these values: ``O`` if the user site-packages directory is enabled, ``1`` if it was disabled by the user, ``2`` if it is disabled for security reasons or by an administrator, and a value greater than 2 if there is an error. .. seealso:: :pep:`370` -- Per user site-packages directory