units is a Unix computer program for conversion of units of weights and measures. It has a huge database of units, including esoteric and historical units. This for instance allows you to convert velocities specified in furlongs per fortnight, if you really wish.

The database units.dat, in plain text format, is in fact a good source of information in itself.

units has been a standard part of Unix since the early Bell Laboratories versions.

The GNU free software version is written by Adrian Mariano.