History of apropos command I am writing a paper on my project, the goal of which is to write a new implementation of the `apropos(1)` command. While I realize that `apropos` was written in the early days of Unix when computing resources were scarce and hence its designers kept it simple. I am looking for a concrete source of information on this to back my point. Is there any historical document or artifact that describes when and why these commands were introduced into Unix? My Google searches have not returned anything useful so I was wondering whether perhaps those of you who have been involved with Unix since the early days might have some knowledge about it.

According to research by an OpenBSD committer, the `apropos` command appeared in 2BSD and was written by Bill Joy, like the rest of the `man` implementation. There's a theory floating around that `apropos` started out as an alias to `man -k`, but `man` in 2BSD didn't have a `-k` option, so it was presumably the other way round (ATT Research Unix had no `apropos` and a different meaning for `man -k`). So 2BSD `apropos.c` would be the earliest implementation of `apropos`.