Edit: Found it - its /usr/share/units/definitions.units (on Pop!_OS, so probably same on Ubuntu/Debian). The FAQ[0] mentions: > units on SunOS doesn't know a

Edit: Found it - its /usr/share/units/definitions.units (on Pop!_OS, so probably same on Ubuntu/Debian). The FAQ[0] mentions: > units on SunOS doesn't know about "millilightseconds." > Yes. So? I used to populate my units.dat file with tons of extra prefixes and units. And actually, I think I was using AIX to run units; I don't know if it knew about millilightseconds. Take a look at the units.dat shipped with Linux these days. It definitely knows about millilightseconds. I tried locate for units.dat but couldn't find it. Anyone knows where is it? Not keen on running a system-wide find. [0]: https://www.ibiblio.org/harris/500milemail-faq.html https://www.ibiblio.org/harris/500milemail-faq.html