Everywhere I work, whenever we interview new people, I end up telling this story. So I might as well write it down.

About fifteen years ago, I was being interviewed for some sys-admin job or other. There were two people, my prospective manager, and a techie. I remember nothing of the manager’s questions, so they must have been pretty standard. Then over to the techie, who asked me, with some gravitas, the single most stupid question I’ve ever been asked at interview.

Three letters of the alphabet are not valid options in GNU ls. What are they?

The story breaks down a little here, because it’s so long ago, I can’t remember the details. But I’m pretty sure “man ls will tell you” was not the answer he was looking for.

I don’t remember if I was offered the job or not.

ruby -e "p ('a'..'z').to_a - (%x(ls --help).downcase.scan(/^ +-(\w)/).flatten)