[t-3]

Yes, it works on most printers. My Brother laser printer has a menu option to print out it's network settings, which gives ~20 different protocols with ports which can be used. I don't think you can control the print settings with netcat, but I'm probably wrong. Mostly I use lpr, but the netcat trick is very useful sometimes.

[EnigmaCurry]

Fascinating, I printed a network report from an HP printer and it listed several services, one of which was:

    9100 Printing = Enabled

So I guessed that I could netcat to port 9100

    cat something.pdf | nc 192.168.1.2 9100

It worked! The printer sat waiting for more content, so I had to press Ctrl-C to kill netcat, but then it immediately printed what it had sent. The margins were off (not like if I had printed through a print driver).