MotionObj has released Regex (http://motionobj.com/regex/), a new app for testing regular expressions running on Mac OS X 10.6.6 or later. It’s available for US$4.99 at the Mac App Store in the Developer Tools category.
Regex features an interface for testing and constructing regular expressions. It offers dynamic highlighting of matches while the regular expression or sample text is being modified. It also supports capture groups and matching options such as case-insensitive matches.
With Regex, you can paste in a regular expression and a piece of sample text to work against and the tool allows you to tweak the regular expression, as well as the sample text and the matches will be highlighted dynamically. It supports capture groups and more.