def _help(command):

    if command is not None:
        _help_command(command)
    else:
        logger.debug("DCOS bin path: {!r}".format(util.dcos_bin_path()))

        results = [(c, default_command_info(c))
                   for c in subcommand.default_subcommands()]
        paths = subcommand.list_paths()
        with ThreadPoolExecutor(max_workers=len(paths)) as executor:
            results += list(executor.map(subcommand.documentation, paths))
            commands_message = options\
                .make_command_summary_string(sorted(results))

        emitter.publish(
            "Command line utility for the Mesosphere Datacenter Operating\n"
            "System (DCOS). The Mesosphere DCOS is a distributed operating\n"
            "system built around Apache Mesos. This utility provides tools\n"
            "for easy management of a DCOS installation.\n")
        emitter.publish("Available DCOS commands:")
        emitter.publish(commands_message)
        emitter.publish(
            "\nGet detailed command description with 'dcos <command> --help'.")

        return 0
:param command: the command name for which you want to see a help
dataset/ETHPy150Open dcos/dcos-cli/cli/dcoscli/help/main.py/_help