This is far more interesting than I thought.
It is 50 years ago that Unix as we know it came out (i.e. not the very first one).
So the Freedos channel tried to work as one would have worked 50 years ago.
After showing the man pages and commands from the various versions of unix, the vid get interesting.
Using a vt100 or 200 emulator, he uses the ed line editor to write a fortran60 program and documentation in nroff, a mark up language.
I like using ed because it keeps you quite focussed - as you'll see you're usually only working within the scope of a paragraph, but you can still make global changes - it is really as easy as he shows.
Ed is the predecessor of vi, vim etc.
On my system I have only the problem of using the left arrow key and rolling back and forwards with the up and down arrow keys. This is fixed by calling ed with rlwrap thus:
rlwrap ed filename
What interested me was nroff - it's the markup with which man pages are written, and as you can see in the video, is used for any documentation/publishing.
This old paper is easy to read, it explains nroff (also vi etc.):
Word Processing Made Easy Using UNIX [PDF}(https://archive.org/download/395768306-word-processing-using-unix/395768306-Word-Processing-Using-UNIX.pdf)
A reference book:
Unix Text Processing PDF
