[ghaff]

I'm sure it varies. There are certainly "Intro to..." MOOCs out there that mirror in-person courses that basically jump right into theory and just reference some Python (or whatever) textbook. And the discussion boards are filled with people obviously completely out of their depth with even getting started.

There are, of course, other courses more pitched to people with no experience at all. And presumably in person there are TAs and fellow students who can help someone who really doesn't have any background in programming, setting up programming environments, basic OS functions, etc.