Regular expression is really wonderful to parsing HTML or matching pattern. I use this a lot when i code. Actually when I learn any new langauge, first of all I first try whether it supports regex or not. I feel ezee when I found that.

http://icfun.blogspot.com/2008/04/ruby-regular-expression-handling.html

Here is about ruby regex. This was posted by me when I first learn ruby regex. So it will be helpfull for New coders.