I've been crash-coursing Python the last couple weeks; I've played with it in the past, but it feels good to go back through and refresh on the fundamentals, and it's nice to feel like it's a usable tool in my belt for accomplishing...things. Like finding classes in a CSS file that aren't actually used in an HTML file.
RegEx, which is slowly becoming more-decipherable line-noise to me, is pretty critical for this sort of thing. Last night I found this Jake Albaugh blog post about using regex in Sublime Text, which I found pretty readable and useful. And that of course lead me back to sites like RegExr.com and RegEx101.com which are indespensibly useful when trying to build up a complex expression.