Every once in a while I see people using what looks like terminal in their mac, except that in what seems to be 1 window they have a vertical 'split.' On one side of the split, they have emacs or something, and in the other they have something else.
How is this possible, to How can I have two independent things happening at once in the same terminal window, divided by a vertical split? It looks a lot like split pane, but split pane is a horizontal split and the actions are mirrored in the panes.


