My favorite library for this is docopt[0], which parses the docstring at the top of your script. It’s a lot easier for people reading your code to see the usage up front rather than scrolling to the bottom and finding your main() and reading the argparse calls:

  #!/usr/bin/env python3
  “””
  Usage: ./myscript.py <arg> [<optionalarg>]
  “””
  from docopt import docopt

  if __name__ == ‘__main__’:
      args = docopt(__doc__)
      print(args[‘<arg>’], args[‘<optionalarg>’] or ‘foo’)

[0]: https://github.com/docopt/docopt