There’s a lot of old tooling that still has its charm. Last week I was deeply impressed by Awk…
(which is not to say that awk is _better_ than TCL, they're different things. Only to say that for me TCL has been eclipsed by things like Python or Clojure, while awk still has a few places where it shines quite brightly indeed.)
I think jq brings a lot of that cool awk mentality forward. I'm consistently impressed by all of the neat things it can do.