I've used x2x[0] (released 1996) in the past. One neat thing about x2x was that it only needed to be installed on of the machines and controlled the pointer an

I've used x2x[0] (released 1996) in the past. One neat thing about x2x was that it only needed to be installed on of the machines and controlled the pointer and keyboard through the X11 XTEST protocol. It was magical how well it worked. [0]: https://en.wikipedia.org/wiki/X2x https://en.wikipedia.org/wiki/X2x