The only thing I would add is to find yourself a copy of Lion's book: https://en.wikipedia.org/wiki/Lions%27_Commentary_on_UNIX_6th_Edition,_with… You can get a nicely bound version inexpensively from Amazon, although there are PDFs in the wild too. Like, others I would suggest starting with Sixth Edition if you want to follow John. The biggest advantage of Seventh besides having more complete toolchains is that the compiler matches K&R Version 1, so you are likely to have fewer issues, you will already be giving up ANSI (as described in K&R2). I started with Fifth years ago in the early/mid-1970s but quickly got Sixth's so I have little memory of it. I have played with it on simh since frankly, the differences between 5 and 6 are not going to be huge from a learning standpoint. ᐧ On Wed, May 5, 2021 at 2:09 PM Noel Chiappa <jnc(a)mercury.lcs.mit.edu> wrote: