As a professional programmer, I think that prof offers excellent advice. There's a difference between programming-in-the-abstract, and the mis-evolved "ls -l ls tar -zxvf rm rm rm ssh mv". Written by people in real-world dysfunctional settings.

There's alternatives to bash commandlines, to interactively explore/navigate running systems. Take REPLs, SQL prompts, etc.

Profs don't do their students any favors if they let poor design pass without comment. Unix has a history, which you can get if you read early papers from those involved, and users can critique it like they critique whatever website they use nowadays.