I learned enough vi to get by the few times I actually had to use it for that reason (nothing else installed). Which comes down to cursor movement, changing the

I learned enough vi to get by the few times I actually had to use it for that reason (nothing else installed). Which comes down to cursor movement, changing the mode, deleting lines and chars, and :wq! But in all these years I hardly ever encountered a situation where I had to edit some files on a machine that only had vi installed. Perhaps I would have learned it by now if that had been the case more often.