1.\"- 2.\" Copyright (c) 1980, 1990, 1993 3.\" The Regents of the University of California. All rights reserved. 4.\" 5.\" This code is derived from software contributed to Berkeley by 6.\" the Institute of Electrical and Electronics Engineers, Inc. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)date.1 8.3 (Berkeley) 4/28/95 33.\" $FreeBSD$ 34.\" 35.Dd March 12, 2019 36.Dt DATE 1 37.Os 38.Sh NAME 39.Nm date 40.Nd display or set date and time 41.Sh SYNOPSIS 42.Nm 43.Op Fl jRu 44.Op Fl r Ar seconds | Ar filename 45.Oo 46.Fl v 47.Sm off 48.Op Cm + | - 49.Ar val Op Ar ymwdHMS 50.Sm on 51.Oc 52.Ar ... 53.Op Cm + Ns Ar output_fmt 54.Nm 55.Op Fl jnu 56.Sm off 57.Op Oo Oo Oo Oo Ar cc Oc Ar yy Oc Ar mm Oc Ar dd Oc Ar HH 58.Ar MM Op Ar .ss 59.Sm on 60.Nm 61.Op Fl jnRu 62.Fl f Ar input_fmt new_date 63.Op Cm + Ns Ar output_fmt 64.Nm 65.Op Fl jnu 66.Op Fl I Ns Op Ar FMT 67.Op Fl f Ar input_fmt 68.Op Fl r Ar ... 69.Op Fl v Ar ... 70.Op Ar new_date 71.Sh DESCRIPTION 72When invoked without arguments, the 73.Nm 74utility displays the current date and time. 75Otherwise, depending on the options specified, 76.Nm 77will set the date and time or print it in a user-defined way. 78.Pp 79The 80.Nm 81utility displays the date and time read from the kernel clock. 82When used to set the date and time, 83both the kernel clock and the hardware clock are updated. 84.Pp 85Only the superuser may set the date, 86and if the system securelevel (see 87.Xr securelevel 7 ) 88is greater than 1, 89the time may not be changed by more than 1 second. 90.Pp 91The options are as follows: 92.Bl -tag -width Ds 93.It Fl f 94Use 95.Ar input_fmt 96as the format string to parse the 97.Ar new_date 98provided rather than using the default 99.Sm off 100.Oo Oo Oo Oo Oo 101.Ar cc Oc 102.Ar yy Oc 103.Ar mm Oc 104.Ar dd Oc 105.Ar HH 106.Oc Ar MM Op Ar .ss 107.Sm on 108format. 109Parsing is done using 110.Xr strptime 3 . 111.It Fl I Ns Op Ar FMT 112Use 113.St -iso8601 114output format. 115.Ar FMT 116may be omitted, in which case the default is 117.Sq date . 118Valid 119.Ar FMT 120values are 121.Sq date , 122.Sq hours , 123.Sq minutes , 124and 125.Sq seconds . 126The date and time is formatted to the specified precision. 127When 128.Ar FMT 129is 130.Sq hours 131(or the more precise 132.Sq minutes 133or 134.Sq seconds ) , 135the 136.St -iso8601 137format includes the timezone. 138.It Fl j 139Do not try to set the date. 140This allows you to use the 141.Fl f 142flag in addition to the 143.Cm + 144option to convert one date format to another. 145.It Fl n 146By default, if the 147.Xr timed 8 148daemon is running, 149.Nm 150sets the time on all of the machines in the local group. 151The 152.Fl n 153option suppresses this behavior and causes the time to be set only on the 154current machine. 155.It Fl R 156Use RFC 2822 date and time output format. 157This is equivalent to using 158.Dq Li %a, %d %b %Y \&%T %z 159as 160.Ar output_fmt 161while 162.Ev LC_TIME 163is set to the 164.Dq C 165locale . 166.It Fl r Ar seconds 167Print the date and time represented by 168.Ar seconds , 169where 170.Ar seconds 171is the number of seconds since the Epoch 172(00:00:00 UTC, January 1, 1970; 173see 174.Xr time 3 ) , 175and can be specified in decimal, octal, or hex. 176.It Fl r Ar filename 177Print the date and time of the last modification of 178.Ar filename . 179.It Fl u 180Display or set the date in 181.Tn UTC 182(Coordinated Universal) time. 183.It Fl v 184Adjust (i.e., take the current date and display the result of the 185adjustment; not actually set the date) the second, minute, hour, month 186day, week day, month or year according to 187.Ar val . 188If 189.Ar val 190is preceded with a plus or minus sign, 191the date is adjusted forwards or backwards according to the remaining string, 192otherwise the relevant part of the date is set. 193The date can be adjusted as many times as required using these flags. 194Flags are processed in the order given. 195.Pp 196When setting values 197(rather than adjusting them), 198seconds are in the range 0-59, minutes are in the range 0-59, hours are 199in the range 0-23, month days are in the range 1-31, week days are in the 200range 0-6 (Sun-Sat), 201months are in the range 1-12 (Jan-Dec) 202and years are in the range 80-38 or 1980-2038. 203.Pp 204If 205.Ar val 206is numeric, one of either 207.Ar y , 208.Ar m , 209.Ar w , 210.Ar d , 211.Ar H , 212.Ar M 213or 214.Ar S 215must be used to specify which part of the date is to be adjusted. 216.Pp 217The week day or month may be specified using a name rather than a 218number. 219If a name is used with the plus 220(or minus) 221sign, the date will be put forwards 222(or backwards) 223to the next 224(previous) 225date that matches the given week day or month. 226This will not adjust the date, 227if the given week day or month is the same as the current one. 228.Pp 229When a date is adjusted to a specific value or in units greater than hours, 230daylight savings time considerations are ignored. 231Adjustments in units of hours or less honor daylight saving time. 232So, assuming the current date is March 26, 0:30 and that the DST adjustment 233means that the clock goes forward at 01:00 to 02:00, using 234.Fl v No +1H 235will adjust the date to March 26, 2:30. 236Likewise, if the date is October 29, 0:30 and the DST adjustment means that 237the clock goes back at 02:00 to 01:00, using 238.Fl v No +3H 239will be necessary to reach October 29, 2:30. 240.Pp 241When the date is adjusted to a specific value that does not actually exist 242(for example March 26, 1:30 BST 2000 in the Europe/London timezone), 243the date will be silently adjusted forwards in units of one hour until it 244reaches a valid time. 245When the date is adjusted to a specific value that occurs twice 246(for example October 29, 1:30 2000), 247the resulting timezone will be set so that the date matches the earlier of 248the two times. 249.Pp 250It is not possible to adjust a date to an invalid absolute day, so using 251the switches 252.Fl v No 31d Fl v No 12m 253will simply fail five months of the year. 254It is therefore usual to set the month before setting the day; using 255.Fl v No 12m Fl v No 31d 256always works. 257.Pp 258Adjusting the date by months is inherently ambiguous because 259a month is a unit of variable length depending on the current date. 260This kind of date adjustment is applied in the most intuitive way. 261First of all, 262.Nm 263tries to preserve the day of the month. 264If it is impossible because the target month is shorter than the present one, 265the last day of the target month will be the result. 266For example, using 267.Fl v No +1m 268on May 31 will adjust the date to June 30, while using the same option 269on January 30 will result in the date adjusted to the last day of February. 270This approach is also believed to make the most sense for shell scripting. 271Nevertheless, be aware that going forth and back by the same number of 272months may take you to a different date. 273.Pp 274Refer to the examples below for further details. 275.El 276.Pp 277An operand with a leading plus 278.Pq Sq + 279sign signals a user-defined format string 280which specifies the format in which to display the date and time. 281The format string may contain any of the conversion specifications 282described in the 283.Xr strftime 3 284manual page, as well as any arbitrary text. 285A newline 286.Pq Ql \en 287character is always output after the characters specified by 288the format string. 289The format string for the default display is 290.Dq +%+ . 291.Pp 292If an operand does not have a leading plus sign, it is interpreted as 293a value for setting the system's notion of the current date and time. 294The canonical representation for setting the date and time is: 295.Pp 296.Bl -tag -width Ds -compact -offset indent 297.It Ar cc 298Century 299(either 19 or 20) 300prepended to the abbreviated year. 301.It Ar yy 302Year in abbreviated form 303(e.g., 89 for 1989, 06 for 2006). 304.It Ar mm 305Numeric month, a number from 1 to 12. 306.It Ar dd 307Day, a number from 1 to 31. 308.It Ar HH 309Hour, a number from 0 to 23. 310.It Ar MM 311Minutes, a number from 0 to 59. 312.It Ar ss 313Seconds, a number from 0 to 60 314(59 plus a potential leap second). 315.El 316.Pp 317Everything but the minutes is optional. 318.Pp 319Time changes for Daylight Saving Time, standard time, leap seconds, 320and leap years are handled automatically. 321.Sh ENVIRONMENT 322The following environment variables affect the execution of 323.Nm : 324.Bl -tag -width Ds 325.It Ev TZ 326The timezone to use when displaying dates. 327The normal format is a pathname relative to 328.Pa /usr/share/zoneinfo . 329For example, the command 330.Dq TZ=America/Los_Angeles date 331displays the current time in California. 332See 333.Xr environ 7 334for more information. 335.El 336.Sh FILES 337.Bl -tag -width /var/log/messages -compact 338.It Pa /var/log/utx.log 339record of date resets and time changes 340.It Pa /var/log/messages 341record of the user setting the time 342.El 343.Sh EXIT STATUS 344The 345.Nm 346utility exits 0 on success, 1 if unable to set the date, and 2 347if able to set the local date, but unable to set it globally. 348.Sh EXAMPLES 349The command: 350.Pp 351.Dl "date ""+DATE: %Y-%m-%d%nTIME: %H:%M:%S""" 352.Pp 353will display: 354.Bd -literal -offset indent 355DATE: 1987-11-21 356TIME: 13:36:16 357.Ed 358.Pp 359In the Europe/London timezone, the command: 360.Pp 361.Dl "date -v1m -v+1y" 362.Pp 363will display: 364.Pp 365.Dl "Sun Jan 4 04:15:24 GMT 1998" 366.Pp 367where it is currently 368.Li "Mon Aug 4 04:15:24 BST 1997" . 369.Pp 370The command: 371.Pp 372.Dl "date -v1d -v3m -v0y -v-1d" 373.Pp 374will display the last day of February in the year 2000: 375.Pp 376.Dl "Tue Feb 29 03:18:00 GMT 2000" 377.Pp 378So will the command: 379.Pp 380.Dl "date -v3m -v30d -v0y -v-1m" 381.Pp 382because there is no such date as the 30th of February. 383.Pp 384The command: 385.Pp 386.Dl "date -v1d -v+1m -v-1d -v-fri" 387.Pp 388will display the last Friday of the month: 389.Pp 390.Dl "Fri Aug 29 04:31:11 BST 1997" 391.Pp 392where it is currently 393.Li "Mon Aug 4 04:31:11 BST 1997" . 394.Pp 395The command: 396.Pp 397.Dl "date 8506131627" 398.Pp 399sets the date to 400.Dq Li "June 13, 1985, 4:27 PM" . 401.Pp 402.Dl "date ""+%Y%m%d%H%M.%S""" 403.Pp 404may be used on one machine to print out the date 405suitable for setting on another. 406.Qq ( Li "+%m%d%H%M%Y.%S" 407for use on 408.Tn Linux . ) 409.Pp 410The command: 411.Pp 412.Dl "date 1432" 413.Pp 414sets the time to 415.Li "2:32 PM" , 416without modifying the date. 417.Pp 418The command 419.Pp 420.Dl "TZ=America/Los_Angeles date -Iseconds -r 1533415339" 421.Pp 422will display 423.Pp 424.Dl "2018-08-04T13:42:19-07:00" 425.Pp 426Finally the command: 427.Pp 428.Dl "date -j -f ""%a %b %d %T %Z %Y"" ""`date`"" ""+%s""" 429.Pp 430can be used to parse the output from 431.Nm 432and express it in Epoch time. 433.Sh DIAGNOSTICS 434Occasionally, when 435.Xr timed 8 436synchronizes the time on many hosts, the setting of a new time value may 437require more than a few seconds. 438On these occasions, 439.Nm 440prints: 441.Ql Network time being set . 442The message 443.Ql Communication error with timed 444occurs when the communication 445between 446.Nm 447and 448.Xr timed 8 449fails. 450.Pp 451It is invalid to combine the 452.Fl I 453flag with either 454.Fl R 455or an output format 456.Dq ( + Ns ... ) 457operand. 458If this occurs, 459.Nm 460prints: 461.Ql multiple output formats specified 462and exits with an error status. 463.Sh SEE ALSO 464.Xr locale 1 , 465.Xr gettimeofday 2 , 466.Xr getutxent 3 , 467.Xr strftime 3 , 468.Xr strptime 3 , 469.Xr timed 8 470.Rs 471.%T "TSP: The Time Synchronization Protocol for UNIX 4.3BSD" 472.%A R. Gusella 473.%A S. Zatti 474.Re 475.Sh STANDARDS 476The 477.Nm 478utility is expected to be compatible with 479.St -p1003.2 . 480The 481.Fl d , f , I , j , n , r , t , 482and 483.Fl v 484options are all extensions to the standard. 485.Pp 486The format selected by the 487.Fl I 488flag is compatible with 489.St -iso8601 . 490.Sh HISTORY 491A 492.Nm 493command appeared in 494.At v1 . 495.Pp 496The 497.Fl I 498flag was added in 499.Fx 12.0 . 500