Regular expressions are one of those things that are incredibly powerful… if you know how to use them. It has taken quite a bit of time for me to learn the ins and outs of how they work, but once you get the hang of them there is almost always some variation that can be used in the different programming languages.
There have been some programs that try to lend a hand at building the regular expressions, but more often than not you’ll have to fork out some money for them. RegExr is looking to solve this problem. It is a free online regular expression builder that will show you the results of your regular expression in real-time.
I’ll be using this all of the time now, and it would have definitely been a great tool to have when I was trying to learn the ropes. Along the right side it includes a small “library” of the syntax available for building your regular expressions. That is a huge time saver so that you don’t have to keep referencing a cheat sheet.
If you don’t find the online version appealing they have also taken the liberty of converting it into a desktop application using Adobe’s AIR technology. That means it will run on Mac OS X, Windows, or Linux assuming that you have Adobe Air installed.