Harry Fuecks have two new and great articles on regular expressions, and if you are like me a fan of regular expression you'll certainly enjoy it !! The articles are very well detailed from the very basic and concept of Regular expression to some real applications examples like validating a username, Hunting images, search and replace ... The application of regular expression are very large and you can really use it everywhere. Some great patterns that you should know, because you could need it anytime.

So going to take a crack at Yet Another Regular Expressions tutorial, with a focus on doing (in PHP) while slowly introducing you to regexp (shorthand for regular expression) syntax. This is going to span a few blog posts (will keep the contents below updated) and get progressively “more interesting”—not all for beginners but if you keep up, hopefully you’ll be able to grasp it. And although it’s “Regexes and PHP”, the regex syntax I’ll be using is largely portable to other programming languages.

The Joy of Regular Expressions [1] [2]