I'm not sure how I feel about the sort question being a super simple "fizzbuzz" type command line question in an interview. The problem with some of the CLI stuff is that its really a simple yes/no "do you remember that command name" type thing. For something like grep that makes sense. But as somebody who also lives in the terminal, I have mixed feelings about expecting things like wc, sort, xargs, etc out of a potential candidate.

Although, I do actually totally agree that the more a person knows about the CLI in general, the better they sometimes appear to be. I feel like learning to use command line tools also sort of inspires that general DRY attitude about software in general. Don't reinvent the wheel!