Page 12 of the example pdf ends with "On Linux, the PATH looks something like this:", but then there's no PATH example shown.
Yes, the linked sample pages are just randomly taken pages from the book PDF, as I put it together quickly for the Show HN. Apologies. I will make a better example when I rework the landing page.
Page 13 isn't in the example pdf. It's a bunch of scattered pages to give you a feel for the whole thing.