NAME

date − print and set the date

SYNOPSIS

date [ −nu ] [ −d dst ] [ −t timezone ] [ 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 -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 provides the number of minutes returned by future calls to gettimeofday(2) in tz_minuteswest.  date does not use this value to determine timezone.  See ctime(1) and zic(8) for information on changing the timezone date uses.  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

/usr/adm/wtmpfile to record time-setting
/usr/adm/messagesfile in which date records the name of the user setting the time

SEE ALSO

gettimeofday(2), ctime(3), utmp(5), timed(8), zic(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. 

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  —  November 23, 1987