Yeah, this is a pretty cool post I never considered doing something like this in the shell. It seems silly to me that I forget how powerful basic tooling in the native shell can be.. sometimes I have a jackhammer and I forget that a sledgehammer will do the job just fine.
Just for anyone else, you could probably end up in a similar corner with perl - but in both cases it's likely a case of "holding it wrong" - ruby borrows heavily from perl which borrowed heavily from shell with sed, awk, grep, cut and friends.
So this kind of thing should be quite doable in a short ruby script - or a few short scripts - albeit written in "shell" style, with eg '-n or -p (wrap code in "while gets...end",-p with "puts _"), probably along with -a (automatically split lines).
Its in some senses an entirely different dialect of ruby, though.
