def get_cmd_args(input):
    """Retuns cmd and its args from the input string.
    
    Args:
        input: the input string captured from the command line.

    Returns:
        (command, args[])
    """
    arr = input.split(' ', 1)
    if arr.__len__() == 1:
        cmd, args = arr[0], []
    elif arr.__len__() == 2:
        cmd, args = arr
        args = args.split(' ')
    else:
        cmd, args = None, []
    return cmd, args