Just what it says on the tin.
Enter a regular expression and some test data, and you can interactively debug and develop regular expressions in realtime for just about any programming language.
A website into which you paste some text and then interactively click the parts you want to filter for. It builds you regular expressions in several programming languages that you can use as-is and They Just Work(tm).
A silly page that has lots of useful stuff about unix, infosec, hacking, it, scripts, permissions, regexp, CLI tools, and other geek stuff.
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