Greetings fellow rubyists! 
I am looking for a way of checking which location a library I use is
at. Let me demonstrate with an example:

Let's assume that I have a hypotetical programa program, foo.rb . That
program requires a library, as in
   require 'bar'

The problem is, I have 4 different versions of bar.rb and one bar.so,
and would like to know which one I am using. How would I go around
figuring this out?

Cheers!

  -C.W.S.