I feel that this needs posting again: http://www.debuggex.com/ http://www.debuggex.com/ Basically a great online tool for testing your regular expressions and

I feel that this needs posting again: http://www.debuggex.com/ http://www.debuggex.com/ Basically a great online tool for testing your regular expressions and stepping through what is actually happening. As soon as you get non-trivial, it's a Godsend.