@b0rk@social.jvns.ca in a community college class years ago I had one instructor lay out explicitly how command line options are usually arranged and I've been furious ever since that all *nix/shell instructors don't do that. it's so ubiquitous that we forget really fast how obvious it's not!
relatedly, usage conventions like [optional] and , also not universal but common enough that folks don't bother explaining them.