def get_help(command_name, configuration_file):
    """
        Returns the cli help string.

        :param command_name: Name of the cli call (usually sys.argv[0]).
        :type command_name: str
        :param configuration_file: Name of the default configuration file.
        :type configuration_file: str
        :return: The formatted help string ready to be displayed.
        :rtype: str

        .. seealso:: backupper.cli.main
    """
    help_string = (
        """Usage: {} [OPTIONS...]

  -h, --help			Displays the current help and exits.
  -f, --config-file		Specifies an alternative YAML config file (default: {}).
  -b, --backup-dir		Specifies an alternative backup directory (overrides the one set in the YAML config file).
  -d, --delete_old_backups	If true, will delete old backups (overrides the one set in the YAML config file).
"""
        .format(command_name, configuration_file))
    return help_string
