Today we explore a "gotcha" interview question from my past:

You accidentally run `chmod -x $(which chmod)`. How do you fix it?

You& #39;ll thrash around trying different things, all of which have some arbitrary reason they won& #39;t work.

"I& #39;ll copy it from another machine." "There are no other machines."

"I& #39;ll set the execute bit from python or perl." "There are no interpreters on your machine."

The "correct" answer is to cat the contents of $(which chmod) to another binary you& #39;re not using, then execute that.

`cat /bin/chmod > /bin/ping6; mv /bin/ping6 /bin chmod` will sort you out.

The problem is it& #39;s trivia, and not really discoverable in an interview scenario.

I do love puzzles like this—on Twitter, when no one’s career is hanging in the balance.

Other “wrong” answers include busybox, rescue partitions, stealing the binary from within a Docker container, and apparently telling the interviewer that it’s a terrible question.