date - print and set the date
date [-nu] [-d dst] [-t timezone] [yymmddhhmm [.ss] ]
If no arguments are given, the current date and time are printed. Providing an argument
will set the desired date; only the superuser can set the date. The -d and -t flags set
the kernel's values for daylight savings time and minutes west of GMT. If dst is non-
zero, future calls to gettimeofday(2) will return a non-zero tz_dsttime. Timezone pro-
vides the number of minutes returned by future calls to gettimeofday(2) in tz_minuteswest.
The -u flag is used to display or set the date in GMT (universal) time. yy represents the
last two digits of the year; the first mm is the month number; dd is the day number; hh is
the hour number (24 hour system); the second mm is the minute number; .ss is optional and
represents the seconds. For example:
sets the date to June 13 1985, 4:27 PM. The year, month and day may be omitted; the
default values will be the current ones. The system operates in GMT. Date takes care of
the conversion to and from local standard and daylight-saving time.
If timed(8) is running to synchronize the clocks of machines in a local area network, date
sets the time globally on all those machines unless the -n option is given.
/usr/adm/wtmp to record time-setting. In /usr/adm/messages, date records the name of the
user setting the time.
gettimeofday(2), utmp(5), timed(8),
TSP: The Time Synchronization Protocol for UNIX 4.3BSD, R. Gusella and S. Zatti
Exit status is 0 on success, 1 on complete failure to set the date, and 2 on successfully
setting the local date but failing globally.
Occasionally, when timed synchronizes the time on many hosts, the setting of a new time
value may require more than a few seconds. On these occasions, date prints: `Network time
being set'. The message `Communication error with timed' occurs when the communication
between date and timed fails.
The system attempts to keep the date in a format closely compatible with VMS. VMS, how-
ever, uses local time (rather than GMT) and does not understand daylight-saving time.
Thus, if you use both UNIX and VMS, VMS will be running on GMT.
4th Berkeley Distribution March 24, 1987 DATE(1)