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.\" 4. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)date.1 8.3 (Berkeley) 4/28/95 32.\" $FreeBSD$ 33.\" 34.Dd November 17, 1993 35.Dt DATE 1 36.Os 37.Sh NAME 38.Nm date 39.Nd display or set date and time 40.Sh SYNOPSIS 41.Nm 42.Op Fl ju 43.Op Fl r Ar seconds 44.Oo 45.Fl v 46.Sm off 47.Op Cm + | - 48.Ar val Op Ar ymwdHMS 49.Sm on 50.Oc 51.Ar ... 52.Op Cm + Ns Ar output_fmt 53.Nm 54.Op Fl jnu 55.Sm off 56.Op Oo Oo Oo Oo Ar cc Oc Ar yy Oc Ar mm Oc Ar dd Oc Ar HH 57.Ar MM Op Ar .ss 58.Sm on 59.Nm 60.Op Fl jnu 61.Fl f Ar input_fmt new_date 62.Op Cm + Ns Ar output_fmt 63.Nm 64.Op Fl d Ar dst 65.Op Fl t Ar minutes_west 66.Sh DESCRIPTION 67When invoked without arguments, the 68.Nm 69utility displays the current date and time. 70Otherwise, depending on the options specified, 71.Nm 72will set the date and time or print it in a user-defined way. 73.Pp 74The 75.Nm 76utility displays the date and time read from the kernel clock. 77When used to set the date and time, 78both the kernel clock and the hardware clock are updated. 79.Pp 80Only the superuser may set the date, 81and if the system securelevel (see 82.Xr securelevel 8 ) 83is greater than 1, 84the time may not be changed by more than 1 second. 85.Pp 86The options are as follows: 87.Bl -tag -width Ds 88.It Fl d Ar dst 89Set the kernel's value for daylight saving time. 90If 91.Ar dst 92is non-zero, future calls 93to 94.Xr gettimeofday 2 95will return a non-zero for 96.Fa tz_dsttime . 97.It Fl f 98Use 99.Ar input_fmt 100as the format string to parse the 101.Ar new_date 102provided rather than using the default 103.Sm off 104.Oo Oo Oo Oo Oo 105.Ar cc Oc 106.Ar yy Oc 107.Ar mm Oc 108.Ar dd Oc 109.Ar HH 110.Oc Ar MM Op Ar .ss 111.Sm on 112format. 113Parsing is done using 114.Xr strptime 3 . 115.It Fl j 116Do not try to set the date. 117This allows you to use the 118.Fl f 119flag in addition to the 120.Cm + 121option to convert one date format to another. 122.It Fl n 123By default, if the 124.Xr timed 8 125daemon is running, 126.Nm 127sets the time on all of the machines in the local group. 128The 129.Fl n 130option suppresses this behavior and causes the time to be set only on the 131current machine. 132.It Fl r Ar seconds 133Print the date and time represented by 134.Ar seconds , 135where 136.Ar seconds 137is the number of seconds since the Epoch 138(00:00:00 UTC, January 1, 1970; 139see 140.Xr time 3 ) , 141and can be specified in decimal, octal, or hex. 142.It Fl t Ar minutes_west 143Set the system's value for minutes west of 144.Tn GMT . 145.Ar minutes_west 146specifies the number of minutes returned in 147.Fa tz_minuteswest 148by future calls to 149.Xr gettimeofday 2 . 150.It Fl u 151Display or set the date in 152.Tn UTC 153(Coordinated Universal) time. 154.It Fl v 155Adjust (i.e., take the current date and display the result of the 156adjustment; not actually set the date) the second, minute, hour, month 157day, week day, month or year according to 158.Ar val . 159If 160.Ar val 161is preceded with a plus or minus sign, 162the date is adjusted forwards or backwards according to the remaining string, 163otherwise the relevant part of the date is set. 164The date can be adjusted as many times as required using these flags. 165Flags are processed in the order given. 166.Pp 167When setting values 168(rather than adjusting them), 169seconds are in the range 0-59, minutes are in the range 0-59, hours are 170in the range 0-23, month days are in the range 1-31, week days are in the 171range 0-6 (Sun-Sat), 172months are in the range 1-12 (Jan-Dec) 173and years are in the range 80-38 or 1980-2038. 174.Pp 175If 176.Ar val 177is numeric, one of either 178.Ar y , 179.Ar m , 180.Ar w , 181.Ar d , 182.Ar H , 183.Ar M 184or 185.Ar S 186must be used to specify which part of the date is to be adjusted. 187.Pp 188The week day or month may be specified using a name rather than a 189number. 190If a name is used with the plus 191(or minus) 192sign, the date will be put forwards 193(or backwards) 194to the next 195(previous) 196date that matches the given week day or month. 197This will not adjust the date, 198if the given week day or month is the same as the current one. 199.Pp 200When a date is adjusted to a specific value or in units greater than hours, 201daylight savings time considerations are ignored. 202Adjustments in units of hours or less honor daylight saving time. 203So, assuming the current date is March 26, 0:30 and that the DST adjustment 204means that the clock goes forward at 01:00 to 02:00, using 205.Fl v No +1H 206will adjust the date to March 26, 2:30. 207Likewise, if the date is October 29, 0:30 and the DST adjustment means that 208the clock goes back at 02:00 to 01:00, using 209.Fl v No +3H 210will be necessary to reach October 29, 2:30. 211.Pp 212When the date is adjusted to a specific value that doesn't actually exist 213(for example March 26, 1:30 BST 2000 in the Europe/London timezone), 214the date will be silently adjusted forwards in units of one hour until it 215reaches a valid time. 216When the date is adjusted to a specific value that occurs twice 217(for example October 29, 1:30 2000), 218the resulting timezone will be set so that the date matches the earlier of 219the two times. 220.Pp 221Refer to the examples below for further details. 222.El 223.Pp 224An operand with a leading plus 225.Pq Sq + 226sign signals a user-defined format string 227which specifies the format in which to display the date and time. 228The format string may contain any of the conversion specifications 229described in the 230.Xr strftime 3 231manual page, as well as any arbitrary text. 232A newline 233.Pq Ql \en 234character is always output after the characters specified by 235the format string. 236The format string for the default display is 237.Dq +%+ . 238.Pp 239If an operand does not have a leading plus sign, it is interpreted as 240a value for setting the system's notion of the current date and time. 241The canonical representation for setting the date and time is: 242.Pp 243.Bl -tag -width Ds -compact -offset indent 244.It Ar cc 245Century 246(either 19 or 20) 247prepended to the abbreviated year. 248.It Ar yy 249Year in abbreviated form 250(e.g., 89 for 1989, 06 for 2006). 251.It Ar mm 252Numeric month, a number from 1 to 12. 253.It Ar dd 254Day, a number from 1 to 31. 255.It Ar HH 256Hour, a number from 0 to 23. 257.It Ar MM 258Minutes, a number from 0 to 59. 259.It Ar ss 260Seconds, a number from 0 to 61 261(59 plus a maximum of two leap seconds). 262.El 263.Pp 264Everything but the minutes is optional. 265.Pp 266Time changes for Daylight Saving Time, standard time, leap seconds, 267and leap years are handled automatically. 268.Sh EXAMPLES 269The command: 270.Pp 271.Dl "date ""+DATE: %Y-%m-%d%nTIME: %H:%M:%S""" 272.Pp 273will display: 274.Bd -literal -offset indent 275DATE: 1987-11-21 276TIME: 13:36:16 277.Ed 278.Pp 279In the Europe/London timezone, the command: 280.Pp 281.Dl "date -v1m -v+1y" 282.Pp 283will display: 284.Pp 285.Dl "Sun Jan 4 04:15:24 GMT 1998" 286.Pp 287where it is currently 288.Li "Mon Aug 4 04:15:24 BST 1997" . 289.Pp 290The command: 291.Pp 292.Dl "date -v1d -v3m -v0y -v-1d" 293.Pp 294will display the last day of February in the year 2000: 295.Pp 296.Dl "Tue Feb 29 03:18:00 GMT 2000" 297.Pp 298The command: 299.Pp 300.Dl "date -v1d -v+1m -v-1d -v-fri" 301.Pp 302will display the last Friday of the month: 303.Pp 304.Dl "Fri Aug 29 04:31:11 BST 1997" 305.Pp 306where it is currently 307.Li "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.Qq ( Li "+%m%d%H%M%Y.%S" 321for use on 322.Tn Linux . ) 323.Pp 324The command: 325.Pp 326.Dl "date 1432" 327.Pp 328sets the time to 329.Li "2:32 PM" , 330without modifying the date. 331.Pp 332Finally the command: 333.Pp 334.Dl "date -j -f ""%a %b %d %T %Z %Y"" ""`date`"" ""+%s""" 335.Pp 336can be used to parse the ouput from 337.Nm 338and express it in epoch time. 339.Sh ENVIRONMENT 340The following environment variables affect the execution of 341.Nm : 342.Bl -tag -width Ds 343.It Ev TZ 344The timezone to use when displaying dates. 345The normal format is a pathname relative to 346.Pa /usr/share/zoneinfo . 347For example, the command 348.Dq TZ=America/Los_Angeles date 349displays the current time in California. 350See 351.Xr environ 7 352for more information. 353.El 354.Sh FILES 355.Bl -tag -width /var/log/messages -compact 356.It Pa /var/log/wtmp 357record of date resets and time changes 358.It Pa /var/log/messages 359record of the user setting the time 360.El 361.Sh SEE ALSO 362.Xr gettimeofday 2 , 363.Xr strftime 3 , 364.Xr strptime 3 , 365.Xr utmp 5 , 366.Xr timed 8 367.Rs 368.%T "TSP: The Time Synchronization Protocol for UNIX 4.3BSD" 369.%A R. Gusella 370.%A S. Zatti 371.Re 372.Sh DIAGNOSTICS 373The 374.Nm 375utility exits 0 on success, 1 if unable to set the date, and 2 376if able to set the local date, but unable to set it globally. 377.Pp 378Occasionally, when 379.Xr timed 8 380synchronizes the time on many hosts, the setting of a new time value may 381require more than a few seconds. 382On these occasions, 383.Nm 384prints: 385.Ql Network time being set . 386The message 387.Ql Communication error with timed 388occurs when the communication 389between 390.Nm 391and 392.Xr timed 8 393fails. 394.Sh STANDARDS 395The 396.Nm 397utility is expected to be compatible with 398.St -p1003.2 . 399.Sh HISTORY 400A 401.Nm 402command appeared in 403.At v1 . 404