Generate Matches for Regular Expressions Using Rex

Regular expressions are one of the more cryptic tools developers utilize in every day work. Sure, just about anyone understands that ^\d\d$ matches a line containing exactly two digits, but you may need a cheat sheet to figure out a regex like \b(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b.