$ click_

  Click is a Python package for creating beautiful command line interfaces
  in a composable way with as little code as necessary.  It's the "Command
  Line Interface Creation Kit".  It's highly configurable but comes with
  sensible defaults out of the box.

  It aims to make the process of writing command line tools quick and fun
  while also preventing any frustration caused by the inability to implement
  an intended CLI API.

  Click in three points:

  -   arbitrary nesting of commands
  -   automatic help page generation
  -   supports lazy loading of subcommands at runtime

  Read the docs at http://click.pocoo.org/

  This library is a work in progress.  Please give feedback!