You can use argparse.
For example, with test.py:
import argparse
parser=argparse.ArgumentParser(
description='''My Description. And what a lovely description it is. ''',
epilog="""All's well that ends well.""")
parser.add_argument('--foo', type=int, default=42, help='FOO!')
parser.add_argument('bar', nargs='*', default=[1, 2, 3], help='BAR!')
args=parser.parse_args()
Running
% test.py -h
yields
usage: test.py [-h] [--foo FOO] [bar [bar ...]]
My Description. And what a lovely description it is.
positional arguments:
bar BAR!
optional arguments:
-h, --help show this help message and exit
--foo FOO FOO!