Indeed -- such a beautiful and concise book. After the first one or two chapters you know all of the AWK language, and then the rest of the book is making the knowledge practical with interesting examples (that's my memory of the book, anyway).

I was on a Go spree when I read this book, and after the first few chapters, I thought, "it'd be fun to write a version of AWK in Go". I ended up with https://github.com/benhoyt/goawk

And OP, thanks for posting. I'm the author of the LWN article. Nice to see it re-posted here some six months later. :-)