why the lucky stiff wrote:
> Yes, I've been taking forever.  Well, what can I say?  Answering threats 
> is quite consuming.  (But apologies to those of you whose threats have 
> been too jarring for me to reply or breathe.)
> 
> Today I'm passing on to you the first fruits of a big batch of material 
> forthcoming.  The Tiger's Vest (with a Basic Introduction to Irb.)
> 
>  http://poignantguide.net/ruby/expansion-pak-1.html
> 
> Stick around.  Picture a man with a balloon, pinching the air out 
> slowly, cats tied to his leg.  If you can do that, then you're all 
> prepped for chapter 5.
> 
> Thank you, -talkers.
> 
> _why
> 
> 

Using Debian unstable, irb1.8, I had to issue 

require 'irb/completion'
conf.use_readline = true

to get completion. 

I have added this in my ~/.irbrc to get it automatically loaded:

require 'irb/completion'
IRB.conf[:use_readline] = true


Raph