When I use Merb's built in console, I get tab auto-completion similar to a standard bash prompt. I find this useful and would like to enable it in non-merb IRB sessions. How do I get auto-completion in IRB?
require 'irb/completion' in your irbrc.
If that doesn't work try bond, http://tagaholic.me/bond/:
require 'bond'; require 'bond/completion'
Bond not only improves irb's completion, http://tagaholic.me/2009/07/22/better-irb-completion-with-bond.html, but also offers an easy dsl for making custom autocompletions.