Knowing your regular expressions is the secret elixir of development. In the Bugslayer column, I’ve already mentioned Jeffrey E. F. Friedl’s phenomenal Mastering Regular Expressions, but found some great resources on the web I had never seen. The first is Steve Smith’s excellent repository of regular expression examples at www.regexlib.com. It’s a great place to see real world examples (and to borrow a few you needed!). Numerous folks have written tools that help you develop regular expressions. They all have their advantages and I am using all three of these right now as I type this: Roy Osherove’s Regulator, Chris Sells’ RegexDesigner, and Eric Gunnerson’s Regular Expression Workbench.