Chris Marsh wrote: > Regex Coach (http://www.weitz.de/regex-coach/) is a great tool for > checking regex patterns, as is Expresso > (http://www.ultrapico.com/Expresso.htm). Both are free. Since these exclude Mac OS X users (one includes an outdated, unmaintained version): http://homepage.mac.com/roger_jolly/software/index.html#regexhibit ... and a simpler, pared down utility: http://gavmacprogramming.wordpress.com/2007/04/21/a-rubycocoa-regular-expression-checker/