usr/src/bin/date/date.1

.\" Copyright (c) 1980 Regents of the University of California.
.\" All rights reserved.  The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\"
.\"     @(#)date.1      6.2 (Berkeley) %G%
.\"
.TH DATE 1 ""
.UC 4
.SH NAME
date \- print and set the date
.SH SYNOPSIS
.B date
.RB "[ -u ] [ yymmddhhmm [ " . "ss ] ]"
.SH 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
.I -u
flag is used to display or set the date in GMT (universal) time.
.I yy
represents the last two digits of the year;
the first
.I mm
is the month number;
.I dd
is the day number;
.I hh
is the hour number (24 hour system);
the second
.I mm
is the minute number;
.BI . ss
is optional and represents the seconds.
For example:
.IP
date 8506131627
.PP
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.
.I Date
takes care of the conversion to and from
local standard and daylight-saving time.
.PP
If
.I timed(8)
is running to synchronize the clocks of machines in a local
area network, \fIdate\fP sets the time globally on all those
machines.
.SH FILES
/usr/adm/wtmp to record time-setting.
In /usr/adm/messages, \fIdate\fP records the name of the user
setting the time.
.SH SEE ALSO
gettimeofday(2), utmp(5), timed(8),
.br
\fITSP: The Time Synchronization Protocol for UNIX 4.3BSD\fP,
R. Gusella and S. Zatti
.SH DIAGNOSTICS
`You are not superuser: date not set' if you try to change the date
but are not the super-user.
Occasionally, when \fItimed\fP synchronizes the time on many hosts,
the setting of a new time value may require more than a few seconds.
On these occasions, \fIdate\fP prints: `Network time being set'.
The message `Communication error with timed' occurs when the communication
between \fIdate\fP and \fItimed\fP fails.
.SH 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.