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.\" $FreeBSD$ 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 46.Op Fl jnu 47.Op Fl d Ar dst 48.Op Fl r Ar seconds 49.Op Fl t Ar minutes_west 50.Oo 51.Fl v 52.Sm off 53.Op Cm + | - 54.Ar val Op Ar ymwdHMS 55.Sm on 56.Oc 57.Ar ... 58.Oo 59.Fl f 60.Ar fmt date | 61.Sm off 62.Op Oo Oo Oo Oo Ar cc Oc Ar yy Oc Ar mm Oc Ar dd Oc Ar HH 63.Ar MM Op Ar .ss 64.Sm on 65.Oc 66.Op Cm + Ns Ar format 67.Sh DESCRIPTION 68When invoked without arguments, the 69.Nm 70utility displays the current date and time. 71Otherwise, depending on the options specified, 72.Nm 73will set the date and time or print it in a user-defined way. 74.Pp 75The 76.Nm 77utility displays the date and time read from the kernel clock. 78When used to set the date and time, 79both the kernel clock and the hardware clock are updated. 80.Pp 81Only the superuser may set the date, 82and if the system securelevel (see 83.Xr securelevel 8 ) 84is greater than 1, 85the time may not be changed by more than 1 second. 86.Pp 87The options are as follows: 88.Bl -tag -width Ds 89.It Fl d Ar dst 90Set the kernel's value for daylight saving time. 91If 92.Ar dst 93is non-zero, future calls 94to 95.Xr gettimeofday 2 96will return a non-zero for 97.Fa tz_dsttime . 98.It Fl f 99Use 100.Ar fmt 101as the format string to parse the 102.Ar date 103provided rather than using the default 104.Sm off 105.Oo Oo Oo Oo Oo 106.Ar cc Oc 107.Ar yy Oc 108.Ar mm Oc 109.Ar dd Oc 110.Ar HH 111.Oc Ar MM Op Ar .ss 112.Sm on 113format. 114Parsing is done using 115.Xr strptime 3 . 116.It Fl j 117Do not try to set the date. 118This allows you to use the 119.Fl f 120flag in addition to the 121.Cm + 122option to convert one date format to another. 123.It Fl n 124By default, if the 125.Xr timed 8 126daemon is running, 127.Nm 128sets the time on all of the machines in the local group. 129The 130.Fl n 131option suppresses this behavior and causes the time to be set only on the 132current machine. 133.It Fl r Ar seconds 134Print the date and time represented by 135.Ar seconds , 136where 137.Ar seconds 138is the number of seconds since the Epoch 139(00:00:00 UTC, January 1, 1970; 140see 141.Xr time 3 ) , 142and can be specified in decimal, octal, or hex. 143.It Fl t Ar minutes_west 144Set the system's value for minutes west of 145.Tn GMT . 146.Ar minutes_west 147specifies the number of minutes returned in 148.Fa tz_minuteswest 149by future calls to 150.Xr gettimeofday 2 . 151.It Fl u 152Display or set the date in 153.Tn UTC 154(Coordinated Universal) time. 155.It Fl v 156Adjust (i.e., take the current date and display the result of the 157adjustment; not actually set the date) the second, minute, hour, month 158day, week day, month or year according to 159.Ar val . 160If 161.Ar val 162is preceded with a plus or minus sign, 163the date is adjusted forwards or backwards according to the remaining string, 164otherwise the relevant part of the date is set. 165The date can be adjusted as many times as required using these flags. 166Flags are processed in the order given. 167.Pp 168When setting values 169(rather than adjusting them), 170seconds are in the range 0-59, minutes are in the range 0-59, hours are 171in the range 1-12, month days are in the range 1-31, week days are in the 172range 0-6 (Sun-Sat), 173months are in the range 1-12 (Jan-Dec) 174and years are in the range 80-38 or 1980-2038. 175.Pp 176If 177.Ar val 178is numeric, one of either 179.Ar y , 180.Ar m , 181.Ar w , 182.Ar d , 183.Ar H , 184.Ar M 185or 186.Ar S 187must be used to specify which part of the date is to be adjusted. 188.Pp 189The week day or month may be specified using a name rather than a 190number. 191If a name is used with the plus 192(or minus) 193sign, the date will be put forwards 194(or backwards) 195to the next 196(previous) 197date that matches the given week day or month. 198This will not adjust the date, 199if the given week day or month is the same as the current one. 200.Pp 201When a date is adjusted to a specific value or in units greater than hours, 202daylight savings time considerations are ignored. 203Adjustments in units of hours or less honor daylight saving time. 204So, assuming the current date is March 26, 0:30 and that the DST adjustment 205means that the clock goes forward at 01:00 to 02:00, using 206.Fl v No +1H 207will adjust the date to March 26, 2:30. 208Likewise, if the date is October 29, 0:30 and the DST adjustment means that 209the clock goes back at 02:00 to 01:00, using 210.Fl v No +3H 211will be necessary to reach October 29, 2:30. 212.Pp 213When the date is adjusted to a specific value that doesn't actually exist 214(for example March 26, 1:30 BST 2000 in the Europe/London timezone), 215the date will be silently adjusted forwards in units of one hour until it 216reaches a valid time. 217When the date is adjusted to a specific value that occurs twice 218(for example October 29, 1:30 2000), 219the resulting timezone will be set so that the date matches the earlier of 220the two times. 221.Pp 222Refer to the examples below for further details. 223.El 224.Pp 225An operand with a leading plus 226.Pq Sq + 227sign signals a user-defined format string 228which specifies the format in which to display the date and time. 229The format string may contain any of the conversion specifications 230described in the 231.Xr strftime 3 232manual page, as well as any arbitrary text. 233A newline 234.Pq Ql \en 235character is always output after the characters specified by 236the format string. 237The format string for the default display is 238.Dq +%+ . 239.Pp 240If an operand does not have a leading plus sign, it is interpreted as 241a value for setting the system's notion of the current date and time. 242The canonical representation for setting the date and time is: 243.Pp 244.Bl -tag -width Ds -compact -offset indent 245.It Ar cc 246Century 247(either 19 or 20) 248prepended to the abbreviated year. 249.It Ar yy 250Year in abbreviated form 251(e.g. 89 for 1989, 06 for 2006). 252.It Ar mm 253Numeric month, a number from 1 to 12. 254.It Ar dd 255Day, a number from 1 to 31. 256.It Ar HH 257Hour, a number from 0 to 23. 258.It Ar MM 259Minutes, a number from 0 to 59. 260.It Ar ss 261Seconds, a number from 0 to 61 262(59 plus a maximum of two leap seconds). 263.El 264.Pp 265Everything but the minutes is optional. 266.Pp 267Time changes for Daylight Saving Time, standard time, leap seconds, 268and leap years are handled automatically. 269.Sh EXAMPLES 270The command: 271.Bd -literal -offset indent 272date "+DATE: %Y-%m-%d%nTIME: %H:%M:%S" 273.Ed 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.Bd -literal -offset indent 283date -v1m -v+1y 284.Ed 285.Pp 286will display: 287.Bd -literal -offset indent 288Sun Jan 4 04:15:24 GMT 1998 289.Ed 290.Pp 291where it is currently Mon Aug 4 04:15:24 BST 1997. 292.Pp 293The command: 294.Bd -literal -offset indent 295date -v1d -v3m -v0y -v-1d 296.Ed 297.Pp 298will display the last day of February in the year 2000: 299.Bd -literal -offset indent 300Tue Feb 29 03:18:00 GMT 2000 301.Ed 302.Pp 303The command: 304.Bd -literal -offset indent 305date -v1d -v+1m -v-1d -v-fri 306.Ed 307.Pp 308will display the last Friday of the month: 309.Bd -literal -offset indent 310Fri Aug 29 04:31:11 BST 1997 311.Ed 312.Pp 313where it is currently Mon Aug 4 04:31:11 BST 1997. 314.Pp 315The command: 316.Bd -literal -offset indent 317date 8506131627 318.Ed 319.Pp 320sets the date to 321.Dq Li "June 13, 1985, 4:27 PM" . 322.Pp 323The command: 324.Bd -literal -offset indent 325date 1432 326.Ed 327.Pp 328sets the time to 329.Li "2:32 PM" , 330without modifying the date. 331.Sh ENVIRONMENT 332The following environment variables affect the execution of 333.Nm : 334.Bl -tag -width Ds 335.It Ev TZ 336The timezone to use when displaying dates. 337The normal format is a pathname relative to 338.Pa /usr/share/zoneinfo . 339For example, the command 340.Dq TZ=America/Los_Angeles date 341displays the current time in California. 342See 343.Xr environ 7 344for more information. 345.El 346.Sh FILES 347.Bl -tag -width /var/log/messages -compact 348.It Pa /var/log/wtmp 349record of date resets and time changes 350.It Pa /var/log/messages 351record of the user setting the time 352.El 353.Sh SEE ALSO 354.Xr gettimeofday 2 , 355.Xr strftime 3 , 356.Xr strptime 3 , 357.Xr utmp 5 , 358.Xr timed 8 359.Rs 360.%T "TSP: The Time Synchronization Protocol for UNIX 4.3BSD" 361.%A R. Gusella 362.%A S. Zatti 363.Re 364.Sh DIAGNOSTICS 365The 366.Nm 367utility exits 0 on success, 1 if unable to set the date, and 2 368if able to set the local date, but unable to set it globally. 369.Pp 370Occasionally, when 371.Xr timed 8 372synchronizes the time on many hosts, the setting of a new time value may 373require more than a few seconds. 374On these occasions, 375.Nm 376prints: 377.Ql Network time being set . 378The message 379.Ql Communication error with timed 380occurs when the communication 381between 382.Nm 383and 384.Xr timed 8 385fails. 386.Sh STANDARDS 387The 388.Nm 389utility is expected to be compatible with 390.St -p1003.2 . 391.Sh HISTORY 392A 393.Nm 394command appeared in 395.At v1 . 396