If you aren't extremely proficient
with regular expressions right now,
then you should drop everything
and go become proficient with them.
I bet I use regular expressions
on 350 days out of every year:
in my editor,
on the command-line,
in my code...

Steve Yegge

All of us working with code and text from time to time run into a problem for which regular expressions would be the right solution. But too many people are not comfortable with regex and resort to much more labor-consuming approaches, such as manual editing or generic programming languages.

There are some very good books on regular expressions, as well as some handy tools. However if you would like to get some hands on experience with regex, there are not many places to go on the internet. This site aims to fix this problem. Once you complete all the interactive excercises here, you should become comfortable enough with regex, so that next time you are confronted with that kind of problem, you'll solve it gracefully.

Javascript dialect of regex is used here. Perhaps that's not exactly the same as used in your IDE or editor of choice. The good news is that most dialects are 95% similar, just check your reference.

If you are completely new to regular expressions, start with the short crash course. Otherwise proceed directly to the excercises, you can always refer to the cheatsheet at the bottom of the page. When really stuck (some excercises are tricky), it's ok to take a hint.

May the power of regex be with you.