c27272249b
- fix capitalization; - add reference to environ(7) in `SEE ALSO' section, as it is mentioned in the text. From patch by Bug Hunting.
247 lines
6.3 KiB
Groff
247 lines
6.3 KiB
Groff
.\" $NetBSD: date.1,v 1.42 2012/04/06 11:36:56 wiz Exp $
|
|
.\"
|
|
.\" Copyright (c) 1980, 1990, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" This code is derived from software contributed to Berkeley by
|
|
.\" the Institute of Electrical and Electronics Engineers, Inc.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)date.1 8.3 (Berkeley) 4/28/95
|
|
.\"
|
|
.Dd November 15, 2006
|
|
.Dt DATE 1
|
|
.Os
|
|
.Sh NAME
|
|
.Nm date
|
|
.Nd display or set date and time
|
|
.Sh SYNOPSIS
|
|
.Nm
|
|
.Op Fl ajnu
|
|
.Op Fl d Ar date
|
|
.Op Fl r Ar seconds
|
|
.Op Cm + Ns Ar format
|
|
.Sm off
|
|
.Oo Oo Oo Oo Oo Oo
|
|
.Ar CC Oc
|
|
.Ar yy Oc
|
|
.Ar mm Oc
|
|
.Ar dd Oc
|
|
.Ar HH Oc Ar MM Oo
|
|
.Li \&. Ar SS Oc Oc
|
|
.Sm on
|
|
.Sh DESCRIPTION
|
|
.Nm
|
|
displays the current date and time when invoked without arguments.
|
|
Providing arguments will format the date and time in a user-defined
|
|
way or set the date.
|
|
Only the superuser may set the date.
|
|
.Pp
|
|
The options are as follows:
|
|
.Bl -tag -width Ds
|
|
.It Fl a
|
|
Use
|
|
.Xr adjtime 2
|
|
to change the local system time slowly,
|
|
maintaining it as a monotonically increasing function.
|
|
.Fl a
|
|
implies
|
|
.Fl n .
|
|
.It Fl d Ar date
|
|
Parse the provided human-described date and time and display the result without
|
|
actually changing the system clock.
|
|
(See
|
|
.Xr parsedate 3
|
|
for examples.)
|
|
.It Fl j
|
|
Parse the provided canonical representation of date and time (described below)
|
|
and display the result without actually changing the system clock.
|
|
.It Fl n
|
|
The utility
|
|
.Xr timed 8
|
|
is used to synchronize the clocks on groups of machines.
|
|
By default, if
|
|
.Xr timed 8
|
|
is running,
|
|
.Nm
|
|
will set the time on all of the machines in the local group.
|
|
The
|
|
.Fl n
|
|
option stops
|
|
.Nm
|
|
from setting the time for other than the current machine.
|
|
.It Fl r Ar seconds
|
|
Print out the date and time that is
|
|
.Ar seconds
|
|
from the Epoch.
|
|
.It Fl u
|
|
Display or set the date in
|
|
.Tn UTC
|
|
(universal) time.
|
|
.El
|
|
.Pp
|
|
An operand with a leading plus
|
|
.Pq Cm +
|
|
sign signals a user-defined format
|
|
string which specifies the format in which to display the date and time.
|
|
The format string may contain any of the conversion specifications described
|
|
in the
|
|
.Xr strftime 3
|
|
manual page, as well as any arbitrary text.
|
|
A \*[Lt]newline\*[Gt] character is always output after the characters
|
|
specified by the format string.
|
|
The format string for the default display is:
|
|
.Bd -literal -offset indent
|
|
%a %b %e %H:%M:%S %Z %Y
|
|
.Ed
|
|
.Pp
|
|
If an operand does not have a leading plus sign, it is interpreted as
|
|
a value for setting the system's notion of the current date and time.
|
|
The canonical representation for setting the date and time is:
|
|
.Pp
|
|
.Bl -tag -width Ds -compact -offset indent
|
|
.It Ar CC
|
|
The first two digits of the year (the century).
|
|
.It Ar yy
|
|
The second two digits of the year.
|
|
If
|
|
.Ar yy
|
|
is specified, but
|
|
.Ar CC
|
|
is not, a value for
|
|
.Ar yy
|
|
between 69 and 99 results in a
|
|
.Ar CC
|
|
value of 19.
|
|
Otherwise, a
|
|
.Ar CC
|
|
value of 20 is used.
|
|
.It Ar mm
|
|
The month of the year, from 01 to 12.
|
|
.It Ar dd
|
|
The day of the month, from 01 to 31.
|
|
.It Ar HH
|
|
The hour of the day, from 00 to 23.
|
|
.It Ar MM
|
|
The minute of the hour, from 00 to 59.
|
|
.It Ar SS
|
|
The second of the minute, from 00 to 61.
|
|
.El
|
|
.Pp
|
|
Everything but the minutes is optional.
|
|
.Pp
|
|
Time changes for Daylight Saving and Standard Time and leap seconds
|
|
and years are handled automatically.
|
|
.Sh ENVIRONMENT
|
|
The following environment variables affect the execution of
|
|
.Nm :
|
|
.Bl -tag -width iTZ
|
|
.It Ev TZ
|
|
The timezone to use when displaying dates.
|
|
See
|
|
.Xr environ 7
|
|
for more information.
|
|
.El
|
|
.Sh FILES
|
|
.Bl -tag -width /var/log/messages -compact
|
|
.It Pa /etc/localtime
|
|
Symlink pointing to system's default timezone information file in
|
|
.Pa /usr/share/zoneinfo
|
|
directory.
|
|
.It Pa /var/log/wtmp
|
|
A record of date resets and time changes.
|
|
.It Pa /var/log/messages
|
|
A record of the user setting the time.
|
|
.El
|
|
.Sh EXAMPLES
|
|
The command:
|
|
.Bd -literal -offset indent
|
|
date '+DATE: %m/%d/%y%nTIME: %H:%M:%S'
|
|
.Ed
|
|
.Pp
|
|
will display:
|
|
.Bd -literal -offset indent
|
|
DATE: 11/21/87
|
|
TIME: 13:36:16
|
|
.Ed
|
|
.Pp
|
|
The command:
|
|
.Bd -literal -offset indent
|
|
date 8506131627
|
|
.Ed
|
|
.Pp
|
|
sets the date to
|
|
.Dq Li "June 13, 1985, 4:27 PM" .
|
|
.Pp
|
|
The command:
|
|
.Bd -literal -offset indent
|
|
date 1432
|
|
.Ed
|
|
.Pp
|
|
sets the time to
|
|
.Li "2:32 PM" ,
|
|
without modifying the date.
|
|
.Sh DIAGNOSTICS
|
|
Exit status is 0 on success, 1 if unable to set the date, and 2
|
|
if able to set the local date, but unable to set it globally.
|
|
.Pp
|
|
Occasionally, when
|
|
.Xr timed 8
|
|
synchronizes the time on many hosts, the setting of a new time value may
|
|
require more than a few seconds.
|
|
On these occasions,
|
|
.Nm
|
|
prints:
|
|
.Ql Network time being set .
|
|
The message
|
|
.Ql Communication error with
|
|
.Xr timed 8
|
|
occurs when the communication
|
|
between
|
|
.Nm
|
|
and
|
|
.Xr timed 8
|
|
fails.
|
|
.Sh SEE ALSO
|
|
.Xr adjtime 2 ,
|
|
.Xr gettimeofday 2 ,
|
|
.Xr settimeofday 2 ,
|
|
.Xr parsedate 3 ,
|
|
.Xr strftime 3 ,
|
|
.Xr utmp 5 ,
|
|
.Xr environ 7 ,
|
|
.Xr timed 8
|
|
.Rs
|
|
.%T "TSP: The Time Synchronization Protocol for UNIX 4.3BSD"
|
|
.%A R. Gusella
|
|
.%A S. Zatti
|
|
.Re
|
|
.Sh STANDARDS
|
|
The
|
|
.Nm
|
|
utility is expected to be compatible with
|
|
.St -p1003.2 .
|