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.\" $FreeBSD: src/bin/date/date.1,v 1.34.2.15 2003/02/24 03:01:00 trhodes Exp $ 37.\" $DragonFly: src/bin/date/date.1,v 1.2 2003/06/17 04:22:49 dillon Exp $ 38.\" 39.Dd November 17, 1993 40.Dt DATE 1 41.Os 42.Sh NAME 43.Nm date 44.Nd display or set date and time 45.Sh SYNOPSIS 46.Nm 47.Op Fl jnu 48.Op Fl d Ar dst 49.Op Fl r Ar seconds 50.Op Fl t Ar minutes_west 51.Oo 52.Fl v 53.Sm off 54.Op Cm + | - 55.Ar val Op Ar ymwdHMS 56.Sm on 57.Oc 58.Ar ... 59.Oo 60.Fl f 61.Ar fmt date | 62.Sm off 63.Op Oo Oo Oo Oo Ar cc Oc Ar yy Oc Ar mm Oc Ar dd Oc Ar HH 64.Ar MM Op Ar .ss 65.Sm on 66.Oc 67.Op Cm + Ns Ar format 68.Sh DESCRIPTION 69When invoked without arguments, the 70.Nm 71utility displays the current date and time. 72Otherwise, depending on the options specified, 73.Nm 74will set the date and time or print it in a user-defined way. 75.Pp 76The 77.Nm 78utility displays the date and time read from the kernel clock. 79When used to set the date and time, 80both the kernel clock and the hardware clock are updated. 81.Pp 82Only the superuser may set the date, 83and if the system securelevel (see 84.Xr securelevel 8 ) 85is greater than 1, 86the time may not be changed by more than 1 second. 87.Pp 88The options are as follows: 89.Bl -tag -width Ds 90.It Fl d Ar dst 91Set the kernel's value for daylight saving time. 92If 93.Ar dst 94is non-zero, future calls 95to 96.Xr gettimeofday 2 97will return a non-zero for 98.Fa tz_dsttime . 99.It Fl f 100Use 101.Ar fmt 102as the format string to parse the 103.Ar date 104provided rather than using the default 105.Sm off 106.Oo Oo Oo Oo Oo 107.Ar cc Oc 108.Ar yy Oc 109.Ar mm Oc 110.Ar dd Oc 111.Ar HH 112.Oc Ar MM Op Ar .ss 113.Sm on 114format. 115Parsing is done using 116.Xr strptime 3 . 117.It Fl j 118Do not try to set the date. 119This allows you to use the 120.Fl f 121flag in addition to the 122.Cm + 123option to convert one date format to another. 124.It Fl n 125By default, if the 126.Xr timed 8 127daemon is running, 128.Nm 129sets the time on all of the machines in the local group. 130The 131.Fl n 132option suppresses this behavior and causes the time to be set only on the 133current machine. 134.It Fl r Ar seconds 135Print the date and time represented by 136.Ar seconds , 137where 138.Ar seconds 139is the number of seconds since the Epoch 140(00:00:00 UTC, January 1, 1970; 141see 142.Xr time 3 ) , 143and can be specified in decimal, octal, or hex. 144.It Fl t Ar minutes_west 145Set the system's value for minutes west of 146.Tn GMT . 147.Ar minutes_west 148specifies the number of minutes returned in 149.Fa tz_minuteswest 150by future calls to 151.Xr gettimeofday 2 . 152.It Fl u 153Display or set the date in 154.Tn UTC 155(Coordinated Universal) time. 156.It Fl v 157Adjust (i.e., take the current date and display the result of the 158adjustment; not actually set the date) the second, minute, hour, month 159day, week day, month or year according to 160.Ar val . 161If 162.Ar val 163is preceded with a plus or minus sign, 164the date is adjusted forwards or backwards according to the remaining string, 165otherwise the relevant part of the date is set. 166The date can be adjusted as many times as required using these flags. 167Flags are processed in the order given. 168.Pp 169When setting values 170(rather than adjusting them), 171seconds are in the range 0-59, minutes are in the range 0-59, hours are 172in the range 0-23, month days are in the range 1-31, week days are in the 173range 0-6 (Sun-Sat), 174months are in the range 1-12 (Jan-Dec) 175and years are in the range 80-38 or 1980-2038. 176.Pp 177If 178.Ar val 179is numeric, one of either 180.Ar y , 181.Ar m , 182.Ar w , 183.Ar d , 184.Ar H , 185.Ar M 186or 187.Ar S 188must be used to specify which part of the date is to be adjusted. 189.Pp 190The week day or month may be specified using a name rather than a 191number. 192If a name is used with the plus 193(or minus) 194sign, the date will be put forwards 195(or backwards) 196to the next 197(previous) 198date that matches the given week day or month. 199This will not adjust the date, 200if the given week day or month is the same as the current one. 201.Pp 202When a date is adjusted to a specific value or in units greater than hours, 203daylight savings time considerations are ignored. 204Adjustments in units of hours or less honor daylight saving time. 205So, assuming the current date is March 26, 0:30 and that the DST adjustment 206means that the clock goes forward at 01:00 to 02:00, using 207.Fl v No +1H 208will adjust the date to March 26, 2:30. 209Likewise, if the date is October 29, 0:30 and the DST adjustment means that 210the clock goes back at 02:00 to 01:00, using 211.Fl v No +3H 212will be necessary to reach October 29, 2:30. 213.Pp 214When the date is adjusted to a specific value that doesn't actually exist 215(for example March 26, 1:30 BST 2000 in the Europe/London timezone), 216the date will be silently adjusted forwards in units of one hour until it 217reaches a valid time. 218When the date is adjusted to a specific value that occurs twice 219(for example October 29, 1:30 2000), 220the resulting timezone will be set so that the date matches the earlier of 221the two times. 222.Pp 223Refer to the examples below for further details. 224.El 225.Pp 226An operand with a leading plus 227.Pq Sq + 228sign signals a user-defined format string 229which specifies the format in which to display the date and time. 230The format string may contain any of the conversion specifications 231described in the 232.Xr strftime 3 233manual page, as well as any arbitrary text. 234A newline 235.Pq Ql \en 236character is always output after the characters specified by 237the format string. 238The format string for the default display is 239.Dq +%+ . 240.Pp 241If an operand does not have a leading plus sign, it is interpreted as 242a value for setting the system's notion of the current date and time. 243The canonical representation for setting the date and time is: 244.Pp 245.Bl -tag -width Ds -compact -offset indent 246.It Ar cc 247Century 248(either 19 or 20) 249prepended to the abbreviated year. 250.It Ar yy 251Year in abbreviated form 252(e.g. 89 for 1989, 06 for 2006). 253.It Ar mm 254Numeric month, a number from 1 to 12. 255.It Ar dd 256Day, a number from 1 to 31. 257.It Ar HH 258Hour, a number from 0 to 23. 259.It Ar MM 260Minutes, a number from 0 to 59. 261.It Ar ss 262Seconds, a number from 0 to 61 263(59 plus a maximum of two leap seconds). 264.El 265.Pp 266Everything but the minutes is optional. 267.Pp 268Time changes for Daylight Saving Time, standard time, leap seconds, 269and leap years are handled automatically. 270.Sh EXAMPLES 271The command: 272.Pp 273.Dl "date ""+DATE: %Y-%m-%d%nTIME: %H:%M:%S""" 274.Pp 275will display: 276.Bd -literal -offset indent 277DATE: 1987-11-21 278TIME: 13:36:16 279.Ed 280.Pp 281In the Europe/London timezone, the command: 282.Pp 283.Dl "date -v1m -v+1y" 284.Pp 285will display: 286.Pp 287.Dl "Sun Jan 4 04:15:24 GMT 1998" 288.Pp 289where it is currently Mon Aug 4 04:15:24 BST 1997. 290.Pp 291The command: 292.Pp 293.Dl "date -v1d -v3m -v0y -v-1d" 294.Pp 295will display the last day of February in the year 2000: 296.Pp 297.Dl "Tue Feb 29 03:18:00 GMT 2000" 298.Pp 299The command: 300.Pp 301.Dl "date -v1d -v+1m -v-1d -v-fri" 302.Pp 303will display the last Friday of the month: 304.Pp 305.Dl "Fri Aug 29 04:31:11 BST 1997" 306.Pp 307where it is currently Mon Aug 4 04:31:11 BST 1997. 308.Pp 309The command: 310.Pp 311.Dl "date 8506131627" 312.Pp 313sets the date to 314.Dq Li "June 13, 1985, 4:27 PM" . 315.Pp 316.Dl "date ""+%Y%m%d%H%M.%S""" 317.Pp 318may be used on one machine to print out the date 319suitable for setting on another. 320.Pp 321The command: 322.Pp 323.Dl "date 1432" 324.Pp 325sets the time to 326.Li "2:32 PM" , 327without modifying the date. 328.Sh ENVIRONMENT 329The following environment variables affect the execution of 330.Nm : 331.Bl -tag -width Ds 332.It Ev TZ 333The timezone to use when displaying dates. 334The normal format is a pathname relative to 335.Pa /usr/share/zoneinfo . 336For example, the command 337.Dq TZ=America/Los_Angeles date 338displays the current time in California. 339See 340.Xr environ 7 341for more information. 342.El 343.Sh FILES 344.Bl -tag -width /var/log/messages -compact 345.It Pa /var/log/wtmp 346record of date resets and time changes 347.It Pa /var/log/messages 348record of the user setting the time 349.El 350.Sh SEE ALSO 351.Xr gettimeofday 2 , 352.Xr strftime 3 , 353.Xr strptime 3 , 354.Xr utmp 5 , 355.Xr timed 8 356.Rs 357.%T "TSP: The Time Synchronization Protocol for UNIX 4.3BSD" 358.%A R. Gusella 359.%A S. Zatti 360.Re 361.Sh DIAGNOSTICS 362The 363.Nm 364utility exits 0 on success, 1 if unable to set the date, and 2 365if able to set the local date, but unable to set it globally. 366.Pp 367Occasionally, when 368.Xr timed 8 369synchronizes the time on many hosts, the setting of a new time value may 370require more than a few seconds. 371On these occasions, 372.Nm 373prints: 374.Ql Network time being set . 375The message 376.Ql Communication error with timed 377occurs when the communication 378between 379.Nm 380and 381.Xr timed 8 382fails. 383.Sh STANDARDS 384The 385.Nm 386utility is expected to be compatible with 387.St -p1003.2 . 388.Sh HISTORY 389A 390.Nm 391command appeared in 392.At v1 . 393