Thanks a lot for the recommendation, I did enjoy the read!

I was wondering about encryption (is this what you’re talking about?) because these algorithms change so frequently I’d be surprised if they had anything back then considered ‘secure’ by now.

You can use backreferences \1 \2 etc. but you can also give them names explicitly.
it looks like this: (?<name>inner-regex)
Some flavors support it, kotlins doesn’t apparently.

I don’t actually know whether POSIX grep would support named groups :o