Me neither. I just asked two colleagues (one on MacOS, one on Ubuntu) and got the same “huh, I never knew?” response I had. Sure there are tons of unknown comm

Me neither. I just asked two colleagues (one on MacOS, one on Ubuntu) and got the same “huh, I never knew?” response I had. Sure there are tons of unknown commands on any OS, but a one-letter command you've never heard of somehow amplifies the amazement.