1.\" Copyright (c) 1980, 1990, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the Institute of Electrical and Electronics Engineers, Inc. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgement: 17.\" This product includes software developed by the University of 18.\" California, Berkeley and its contributors. 19.\" 4. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.\" @(#)date.1 8.3 (Berkeley) 4/28/95 36.\" $Id$ 37.\" 38.Dd November 17, 1993 39.Dt DATE 1 40.Os 41.Sh NAME 42.Nm date 43.Nd display or set date and time 44.Sh SYNOPSIS 45.Nm date 46.Op Fl d Ar dst 47.Op Fl r Ar seconds 48.Op Fl t Ar minutes_west 49.Op Fl nu 50.Op Cm + Ns Ar format 51.Op [yy[mm[dd[hh]]]]mm[\&.ss] 52.Sh DESCRIPTION 53.Nm 54displays the current date and time when invoked without arguments. 55Providing arguments will format the date and time in a user-defined 56way or set the date. 57Only the superuser may set the date. 58.Pp 59The options are as follows: 60.Bl -tag -width Ds 61.It Fl d 62Set the kernel's value for daylight savings time. 63If 64.Ar dst 65is non-zero, future calls 66to 67.Xr gettimeofday 2 68will return a non-zero 69.Ql tz_dsttime . 70.It Fl n 71The utility 72.Xr timed 8 73is used to synchronize the clocks on groups of machines. 74By default, if 75.Xr timed 76is running, 77.Nm date 78will set the time on all of the machines in the local group. 79The 80.Fl n 81option stops 82.Nm date 83from setting the time for other than the current machine. 84.It Fl r 85Print out the date and time in 86.Ar seconds 87from the Epoch. 88.It Fl t 89Set the kernel's value for minutes west of 90.Tn GMT . 91.Ar Minutes_west 92specifies the number of minutes returned in 93.Ql tz_minuteswest 94by future calls to 95.Xr gettimeofday 2 . 96.It Fl u 97Display or set the date in 98.Tn UCT 99(universal) time. 100.El 101.Pp 102An operand with a leading plus (``+'') sign signals a user-defined format 103string which specifies the format in which to display the date and time. 104The format string may contain any of the conversion specifications described 105in the 106.Xr strftime 3 107manual page, as well as any arbitrary text. 108A <newline> character is always output after the characters specified by 109the format string. 110The format string for the default display is: 111.Bd -literal -offset indent 112``+%+'' 113.Ed 114.Pp 115If an operand does not have a leading plus sign, it is interpreted as 116a value for setting the system's notion of the current date and time. 117The canonical representation for setting the date and time is: 118.Pp 119.Bl -tag -width Ds -compact -offset indent 120.It Ar yy 121Year in abbreviated form (.e.g 89 for 1989). 122.It Ar mm 123Numeric month. 124A number from 1 to 12. 125.It Ar dd 126Day, a number from 1 to 31. 127.It Ar hh 128Hour, a number from 0 to 23. 129.It Ar mm 130Minutes, a number from 0 to 59. 131.It Ar .ss 132Seconds, a number from 0 to 61 (59 plus a maximum of two leap seconds). 133.El 134.Pp 135Everything but the minutes is optional. 136.Pp 137Time changes for Daylight Saving and Standard time and leap seconds 138and years are handled automatically. 139.Sh EXAMPLES 140The command: 141.Bd -literal -offset indent 142date ``+DATE: %m/%d/%y%nTIME: %H:%M:%S'' 143.Ed 144.Pp 145will display: 146.Bd -literal -offset indent 147DATE: 11/21/87 148TIME: 13:36:16 149.Ed 150.Pp 151The command: 152.Bd -literal -offset indent 153date 8506131627 154.Ed 155.Pp 156sets the date to 157.Dq Li "June 13, 1985, 4:27 PM" . 158.Pp 159The command: 160.Bd -literal -offset indent 161date 1432 162.Ed 163.Pp 164sets the time to 165.Li "2:32 PM" , 166without modifying the date. 167.Sh ENVIRONMENT VARIABLES 168The execution of 169.Nm 170is affected by the following evironment variables: 171.Bl -tag -width Ds 172.It Ev TZ 173The timezone to use when displaying dates. 174See 175.Xr environ 7 176for more information. 177.El 178.Sh FILES 179.Bl -tag -width /var/log/messages -compact 180.It Pa /var/log/wtmp 181A record of date resets and time changes. 182.It Pa /var/log/messages 183A record of the user setting the time. 184.El 185.Sh SEE ALSO 186.Xr gettimeofday 2 , 187.Xr strftime 3 , 188.Xr utmp 5 , 189.Xr timed 8 190.Rs 191.%T "TSP: The Time Synchronization Protocol for UNIX 4.3BSD" 192.%A R. Gusella 193.%A S. Zatti 194.Re 195.Sh DIAGNOSTICS 196Exit status is 0 on success, 1 if unable to set the date, and 2 197if able to set the local date, but unable to set it globally. 198.Pp 199Occasionally, when 200.Xr timed 201synchronizes the time on many hosts, the setting of a new time value may 202require more than a few seconds. 203On these occasions, 204.Nm date 205prints: 206.Ql Network time being set . 207The message 208.Ql Communication error with timed 209occurs when the communication 210between 211.Nm date 212and 213.Xr timed 214fails. 215.Sh BUGS 216The system attempts to keep the date in a format closely compatible 217with 218.Tn VMS . 219.Tn VMS , 220however, uses local time (rather than 221.Tn GMT ) 222and does not understand daylight-savings time. 223Thus, if you use both 224.Tn UNIX 225and 226.Tn VMS , 227.Tn VMS 228will be running on 229.Tn GMT . 230.Sh STANDARDS 231The 232.Nm date 233command is expected to be compatible with 234.St -p1003.2 . 235.Sh HISTORY 236A 237.Nm 238command appeared in 239.At v1 . 240