I just noticed that netpipes doesn't support bidirectional pipes.
So I made my own version.
Now I can say in computer A that "plis 12345 -io ohjelma" and in computer B
that "pcon A 12345 -io ohjelma2", and they communicate together then.
My example utilization was that I can send the picture of SNES-emulator to
another computer via network, and grab the keyboard input there, so get two
consoles to the same game.
My friend wanted to watch when I play FF6, but didn't want to sit next to my
monitor, and asked if he could get the picture to his monitor.
And he got it.
Then he asked if he could play it from his computer at the same time as me...
And now it works too.
Other ways of use can everybody invent theirselves.
It's really easy to make simple server software with this.
For example, do "plis 79 -io finger" and then you have a finger-service.
Or "plis 5555 -o 'cat signature'" and then port 5555 gives your signature.