Please forgive me if I state the obvious, but I just found out about this great gem called Wirble. Wirble adds tab-completion and syntax-highlighting to irb.
Installation is really simple, just install the gem (gem install wirble) and add this to your .irbrc:
require 'rubygems'
require 'wirble'
Wirble.init
Wirble.colorize
For a console with a dark background everything looks pretty good but I prefer a light background where yellow is not easy to read. Thanks to the really helpful README the solution was easy to find. I had to add a few more lines to my .irbrc to change some settings from yellow and white to something readable in my console.
require 'rubygems'
require 'wirble'
Wirble.init
Wirble.colorize
colors = Wirble::Colorize.colors.merge({
:object_class => :purple,
:symbol => :purple,
:symbol_prefix => :purple
})
Wirble::Colorize.colors = colors