It's nice if you don't remember which os you are using

Because DOS and Unix are otherwise so alike? Hard to fathom, but be it as it may, a `dir` command not interpreting command line options like DOS's (or CP/M's -- which makes me think that even older OS might have had the directory listing command called `dir`) `dir` won't be of any help.

I think `dir` rather should flash the screen and screech out of the speaker to wake you up!