Today’s useless linux command is ddate. The manpage reads thusly:

ddate prints the date in Discordian date format.

If called with no arguments, ddate will get the current system date, convert this to the Discordian date format and print this on the stan- dard output. Alternatively, a Gregorian date may be specified on the command line, in the form of a numerical day, month and year.

If a format string is specified, the Discordian date will be printed in a format specified by the string. This mechanism works similarly to the format string mechanism of date(1), only almost completely differently.