Surprisingly, this is fairly hard to do with regular expressions. You really want to outsource this to someone else's library. But, if you must, here's the reg

Surprisingly, this is fairly hard to do with regular expressions. You really want to outsource this to someone else's library. But, if you must, here's the regex from one library: http://ex-parrot.com/~pdw/Mail-RFC822-Address.html http://ex-parrot.com/~pdw/Mail-RFC822-Address.html Not exactly a one liner, though.