def list_backups(path, limit=None):
    '''
    .. versionadded:: 0.17.0

    Lists the previous versions of a file backed up using Salt's :doc:`file
    state backup </ref/states/backup_mode>` system.

    path
        The path on the minion to check for backups
    limit
        Limit the number of results to the most recent N backups

    CLI Example:

    .. code-block:: bash

        salt '*' file.list_backups /foo/bar/baz.txt
    '''
    path = os.path.expanduser(path)

    try:
        limit = int(limit)
    except TypeError:
        pass
    except __HOLE__:
        log.error('file.list_backups: \'limit\' value must be numeric')
        limit = None

    bkroot = _get_bkroot()
    parent_dir, basename = os.path.split(path)
    if salt.utils.is_windows():
        # ':' is an illegal filesystem path character on Windows
        src_dir = parent_dir.replace(':', '_')
    else:
        src_dir = parent_dir[1:]
    # Figure out full path of location of backup file in minion cache
    bkdir = os.path.join(bkroot, src_dir)

    if not os.path.isdir(bkdir):
        return {}

    files = {}
    for fname in [x for x in os.listdir(bkdir)
                  if os.path.isfile(os.path.join(bkdir, x))]:
        if salt.utils.is_windows():
            # ':' is an illegal filesystem path character on Windows
            strpfmt = '{0}_%a_%b_%d_%H-%M-%S_%f_%Y'.format(basename)
        else:
            strpfmt = '{0}_%a_%b_%d_%H:%M:%S_%f_%Y'.format(basename)
        try:
            timestamp = datetime.datetime.strptime(fname, strpfmt)
        except ValueError:
            # File didn't match the strp format string, so it's not a backup
            # for this file. Move on to the next one.
            continue
        if salt.utils.is_windows():
            str_format = '%a %b %d %Y %H-%M-%S.%f'
        else:
            str_format = '%a %b %d %Y %H:%M:%S.%f'
        files.setdefault(timestamp, {})['Backup Time'] = \
            timestamp.strftime(str_format)
        location = os.path.join(bkdir, fname)
        files[timestamp]['Size'] = os.stat(location).st_size
        files[timestamp]['Location'] = location

    return dict(list(zip(
        list(range(len(files))),
        [files[x] for x in sorted(files, reverse=True)[:limit]]
    )))
dataset/ETHPy150Open saltstack/salt/salt/modules/file.py/list_backups