Function get_exec_path

Lib/os.py:649–690

Returns the sequence of directories that will be searched for the named executable (similar to a shell) when launching a process. *env* must be an environment variable dict or None. If *env* is None, os.environ will be used.

(env=None)

def get_exec_path(env=None):
    """Returns the sequence of directories that will be searched for the
    named executable (similar to a shell) when launching a process.

    *env* must be an environment variable dict or None.  If *env* is None,
    os.environ will be used.
    """
    # Use a local import instead of a global import to limit the number of
    # modules loaded at startup: the os module is always loaded at startup by
    # Python. It may also avoid a bootstrap issue.
    import warnings

    if env is None:
        env = environ

    # {b'PATH': ...}.get('PATH') and {'PATH': ...}.get(b'PATH') emit a
    # BytesWarning when using python -b or python -bb: ignore the warning
    with warnings.catch_warnings():
        warnings.simplefilter("ignore", BytesWarning)

        try:
            path_list = env.get('PATH')
        except TypeError:
            path_list = None

        if supports_bytes_environ:
            try:
                path_listb = env[b'PATH']
            except (KeyError, TypeError):
                pass
            else:
                if path_list is not None:
                    raise ValueError(
                        "env cannot contain 'PATH' and b'PATH' keys")
                path_list = path_listb

            if path_list is not None and isinstance(path_list, bytes):
                path_list = fsdecode(path_list)

    if path_list is None:
        path_list = defpath
    return path_list.split(pathsep)


# Change environ to automatically call putenv() and unsetenv()