DATE(1) — UNIX Programmer’s Manual
NAME
date − print and set the date
SYNOPSIS
date [ -n ] [ -u ] [ yymmddhhmm [ .ss ] ]
DESCRIPTION
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 -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:
date 8506131627
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.
FILES
/var/adm/wtmp to record time-setting. In /var/adm/messages, date records the name of the user setting the time.
SEE ALSO
gettimeofday(2), utmp(5), timed(8),
TSP: The Time Synchronization Protocol for UNIX 4.3BSD, R. Gusella and S. Zatti
DIAGNOSTICS
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.
‘You are not superuser: date not set’ if you try to change the date but are not the super-user. 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.
BUGS
The system attempts to keep the date in a format closely compatible with VMS. VMS, however, 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 — Revision 1.4 of 30/10/90