getopt。

g.py

import getopt
import sys

def usage(filename):
  print('usage: python {} [-h | --help]'.format(filename))

def main(filename, *argv):
  opts, args = getopt.getopt(argv, 'h', 'help')

  for opt, arg in opts:
    if opt in ('-h', '--help'):
      usage(filename)
      return 0

  return 0

if __name__ == '__main__':
  sys.exit(main(*sys.argv))