[CarolineW]

OK, so as kazinator has pointed out, awk is now a mandatory part of Posix, and so is genuinely a part of "shell". My reply there says that I and my colleagues still think of awk as fundamentally different from other pipeline facilities such as tr, sed, sort, uniq, and so on, but I can see why it could, perhaps should, be though of as being "shell".

So it's shell. I might, however, given my background, and remembering as I do its first introduction, always have trouble thinking of it as such.