For programming, they taught us enough to use the XEDIT line editor, the Fortran compiler, CATLIST for the directory.
You'd apply these in rote fashion, the goal was to get through your programming class. It wasn't an a OS design or computer architecture class. It was "calculate Easter Sunday in Fortan" class.
Our Fortran (F77) used channels 4 and 5 for console in and out (which could probably be redirected using some command, no doubt. I don't know if it was. NOS thing or some Fortran thing that we used 4 and 5.
But it had these other things that you'd touch on, if you were geeking a bit in the community. Things like Direct Storage using the ATTACH command (whatever that did), PROC files (scripts), PROC file libraries, DAYFILE (basically your job/command history).
I would like to have a deeper understanding about some of those concepts of how that OS worked, design choices they needed to make, etc.
Today, "everything" is UNIX. Or certainly viewed through UNIX glasses. Even Windows is UNIX today.