If you ask a question about parsing HTML with regex, you will certainly be referenced to this famous rant. Though there is not a canonical rant for it, I've also been told that regex aren't powerful enough to parse SQL.
I'm a self-taught programmer, so I don't know much about languages from a theoretical perspective. Practically speaking, what are examples of languages or grammars that regex can always parse successfully?
Edit: To clarify, I'd really like a few examples of languages that are used in the real world that fit in the category of regular languages, rather than some axioms or equivalent conditions, etc.