> There are versions of ruby such as -
>
> Ruby 1.8.6-p398
> Ruby 1.8.7-p330
> Ruby 1.9.1-p430
> Ruby 1.8.7-p249
> Ruby 1.9.1-p378
> Ruby 1.9.2-p0
> Ruby 1.9.2-p136
>
> ...

p denotes the patch level. You can find out the patch level you are using with:

$ ruby -e 'puts RUBY_PATCHLEVEL'

-- 
Anurag Priyam
http://about.me/yeban/