> Is this a Linux feature or FreeBSD magic, as like the article seems to credit it?
Being able to just send wave data to the audio device "file" is pretty common on most systems that smell like Unix.
The netcat trickery from the article works on any platforms where netcat is available, what file formats are specifically supported varies by printer. Most will take text and Postscript (though some famous printers like the LaserJet 4 still had PS as an optional addon), anything more complicated is implementation-specific.
