If you aren't averse to using a third party package, on my personal projects I always found https://github.com/docopt/docopt https://github.com/docopt/docopt to

If you aren't averse to using a third party package, on my personal projects I always found https://github.com/docopt/docopt https://github.com/docopt/docopt to be nice. You can kill 2 birds with one stone by documenting your scripts while also providing the argument structure / parsing.