Is it magic or is it tmux?

There’s a particular kind of epiphany available to the person who watches the full power of tmux being used for the first time. It’s the kind that sneaks up on you not because the underlying technology is exotic (it isn’t; tmux is just a program that multiplexes pseudo-terminals, a thing Unix has been doing since approximately forever) but because the gap between the banaltiy of simply using a terminal and the power of layering tmux on top of it is wide enough that your brain does a silent double take.

Imagine you and your friend, possibly on opposite coasts, possibly with an ocean between you, ssh’d into the same modest little linux box somewhere, both attached to the same tmux session, which is itself just a running process holding some terminal state in memory. And when your friend types, you see her type. Not a recording of it, not a compressed video feed over Zoom, just the actual characters being typed in real time, arriving to you in the same instant they arrive to your friend, because there is no “her terminal” and “your terminal,” there is only The Terminal, and you are both looking at it, sharing the same cursor and editing the same text.

And the magic isn’t that it does something new. The magic is that sharing the same text with your friend was enough the whole time.