This is the best command line utility library for ruby that i've used: <a href="http://visionmedia.github.com/commander/" rel="nofollow">http://visionmedia.github.com/commander/</a>
Oh, this is nice. I've felt that other "command line utility" libraries for Ruby have been way more complicated than they needed to be. I'm converting some of my simple Ruby scripts and utilities to this to give it a try.