Rubular: a Ruby regular expression editor and tester

This tool is indispensable when dealing with regex. Plug in a sample search string, and then start banging on the regex to match it. There are some differences I’ve found between regex in Ruby vs. Javascript, but even then it helps to get you most of the way there.

Rubular: a Ruby regular expression editor and tester.

H/T to Justin for pointing me in this direction some time ago.