Here's what I've tried:
1. gem install awesome_print
2. echo "require 'ap'" >> ~/.irbrc
3. chmod u+x ~/.irbrc
4. script/console
5. ap { :test => 'value' }
Result:
NameError: undefined local variable or method `ap' for #
Adding "require 'rubygems'" to my ~/.irbrc file seemed to do the trick.