I think you may have focused in on the tangential sentence rather than the point about it being a conceptual overview with Unix commands being used as a metapho

I think you may have focused in on the tangential sentence rather than the point about it being a conceptual overview with Unix commands being used as a metaphor, i.e., not a literal example. E.g., they’re not typing `echo` commands in the same way that they’re not typing `gpg "make-key"` (which is not a real command).