Among the different tools available for better productivity while writing regular expressions, RegexBuddy (http://www.regexbuddy.com/) by Just Great Software Co. Ltd. is outstanding.

The mastermind behind Just Great Software is Jan Goyvaerts, the same person who is behind Regular-Expressions.info (http://www.regular-expressions.info/), one of the most well-known references on the Internet for regular expressions.

With RegexBuddy, we can use a visual interface for building, testing, and debugging regular expressions. The debug feature is almost unique, and provides a great mechanism to understand how the regular expression engine is working behind the scenes. In the following screenshot, we can see RegexBuddy debugging the execution of a regular expression:

RegexBuddy debugging a regular expression

It does have other features, such as a library of commonly used regular expressions and a code generator for different programming environments.

Although it has a couple of downsides, its license is proprietary and the only build available is for Windows. However, the execution on Linux using the wine emulator is supported.