I don't actually remember much about config.sys, despite spending much of my formative years editing it in the attempt to claw back as much of that 640k as possible.
But I do remember "copy con filename.txt", which I'm hoping is the answer to the second part of your question.
I actually had to walk a coworker through some Windows and Linux and it was a bit stunning to realize that there are now highly technical people who didn't know how to do things like switch directories, print a list of files in the current directory, etc. My parents never knew they were doing me a favor by buying a computer that ran Windows 3.1 so poorly that I needed to do everything in DOS.
That was exactly what I was thinking of, though the rest of what I remember about config.sys revolves around battles with emm386. Ah, for the simplicity of the 286.
It's weird hos DOS perversity made it super-easy to pick up unix when Linux became available, but I've retained a loathing of unnecessarily short commands like 'cp' 'mv' and especially 'man', probably in proportion to the difficulty of guessing them.