21.1.5 Setting the time

If given an argument that does not start with ‘+’, date sets the system clock to the date and time specified by that argument (as described below). You must have appropriate privileges to set the system clock. The --date and --set options may not be used with such an argument. The --universal option may be used with such an argument to indicate that the specified date and time are relative to Coordinated Universal Time rather than to the local time zone.

The argument must consist entirely of digits, which have the following meaning:

‘MM’

month

‘DD’

day within month

‘hh’

hour

‘mm’

minute

‘CC’

first two digits of year (optional)

‘YY’

last two digits of year (optional)

‘ss’

second (optional)

The --set option also sets the system clock; see the next section.