PDU-1 Glossary Astronomical terminology AU Astronomical Unit. A unit of length equal to the mean radius of the Earth's orbit. Unix copy command.
Output written to it is discarded.
The method the operating system uses to identify groups. What one is in when hacking, of course. Ability to enter such concentration at will correlates strongly with wizardliness. Being yanked out of hack mode may be experienced as a physical shock, and the sensation of being in hack mode is more than a little habituating. The intensity of this experience is probably by itself sufficient explanation for the existence of hackers, and explains why many resist being promoted out of positions where they can code.