Docopt looks like a useful library, but I'd be interested to see how intelligent the "help" parsing is when faced with slight variations in the format.

Using Commons-CLI in Java actually goes the opposite direction and if can be reasonably terse (one line per parameter or option) but it's also got to be wrapped in a class and have the rest of the Java boilerplate (a main method to execute, etc).

Perhaps I'll try it on my next NodeJS project.