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. 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: src/bin/date/date.1,v 1.72 2005/02/13 22:25:09 ru Exp $ 33.\" 34.Dd February 16, 2022 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 jRu 43.Op Fl r Ar seconds 44.Oo 45.Fl v/d 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 jnRu 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 jnu 65.Op Fl I Ns Op Ar FMT 66.Op Fl f Ar input_fmt 67.Op Fl r Ar ... 68.Op Fl v/d Ar ... 69.Op Ar new_date 70.Sh DESCRIPTION 71When invoked without arguments, the 72.Nm 73utility displays the current date and time. 74Otherwise, depending on the options specified, 75.Nm 76will set the date and time or print it in a user-defined way. 77.Pp 78The 79.Nm 80utility displays the date and time read from the kernel clock. 81When used to set the date and time, 82both the kernel clock and the hardware clock are updated. 83.Pp 84Only the superuser may set the date, 85and if the system securelevel (see 86.Xr securelevel 8 ) 87is greater than 1, 88the time may not be changed by more than 1 second. 89.Pp 90The options are as follows: 91.Bl -tag -width Ds 92.It Fl f 93Use 94.Ar input_fmt 95as the format string to parse the 96.Ar new_date 97provided rather than using the default 98.Sm off 99.Oo Oo Oo Oo Oo 100.Ar cc Oc 101.Ar yy Oc 102.Ar mm Oc 103.Ar dd Oc 104.Ar HH 105.Oc Ar MM Op Ar .ss 106.Sm on 107format. 108Parsing is done using 109.Xr strptime 3 . 110.It Fl I Ns Op Ar FMT 111Use 112.St -iso8601 113output format. 114.Ar FMT 115may be omitted, in which case the default is 116.Sq date . 117Valid 118.Ar FMT 119values are 120.Sq date , 121.Sq hours , 122.Sq minutes , 123and 124.Sq seconds . 125The date and time is formatted to the specified precision. 126The 127.St -iso8601 128format includes the timezone, except when 129.Ar FMT 130is 131.Sq date . 132.It Fl j 133Do not try to set the date. 134This allows you to use the 135.Fl f 136flag in addition to the 137.Cm + 138option to convert one date format to another. 139.It Fl n 140Obsolete flag, accepted and ignored for compatibility. 141.It Fl R 142Use RFC 2822 date and time output format. This is equivalent to use 143.Dq Li %a, %d %b %Y \&%T %z 144as 145.Ar output_fmt 146while 147.Ev LC_TIME 148is set to the 149.Dq C 150locale. 151.It Fl r Ar seconds 152Print the date and time represented by 153.Ar seconds , 154where 155.Ar seconds 156is the number of seconds since the Epoch 157(00:00:00 UTC, January 1, 1970; 158see 159.Xr time 3 ) , 160and can be specified in decimal, octal, or hex. 161.It Fl u 162Display or set the date in 163.Tn UTC 164(Coordinated Universal) time. 165.It Fl d 166For some compatibility with gnu date, the 167.Fl d 168option is an alias for the 169.Fl v 170option. 171In addition to the formats already supported, we now support 172.Ar +/-Ndays 173(seconds, minutes, hours, months, years, and abbreviations of same), 174.Ar next ... , 175.Ar last ... 176several month, day, and year arrangements, h:m[:s], and a few other 177things. 178Not all of these can be combined with prefixes and there is still a lot 179of missing support for gnu date compatibility. 180In particular the handling of TZ= timezone specifications is mis-applied 181and support for the "Z" suffix is missing. 182.It Fl v 183Adjust (i.e., take the current date and display the result of the 184adjustment; not actually set the date) the second, minute, hour, month 185day, week day, month or year according to 186.Ar val . 187If 188.Ar val 189is preceded with a plus or minus sign, 190the date is adjusted forwards or backwards according to the remaining string, 191otherwise the relevant part of the date is set. 192The date can be adjusted as many times as required using these flags. 193Flags are processed in the order given. 194.Pp 195When setting values 196(rather than adjusting them), 197seconds are in the range 0-59, minutes are in the range 0-59, hours are 198in the range 0-23, month days are in the range 1-31, week days are in the 199range 0-6 (Sun-Sat), 200months are in the range 1-12 (Jan-Dec) 201and years are in the range 80-38 or 1980-2038. 202.Pp 203If 204.Ar val 205is numeric, one of either 206.Ar y , 207.Ar m , 208.Ar w , 209.Ar d , 210.Ar H , 211.Ar M 212or 213.Ar S 214must be used to specify which part of the date is to be adjusted. 215.Pp 216The week day or month may be specified using a name rather than a 217number. 218If a name is used with the plus 219(or minus) 220sign, the date will be put forwards 221(or backwards) 222to the next 223(previous) 224date that matches the given week day or month. 225This will not adjust the date, 226if the given week day or month is the same as the current one. 227.Pp 228When a date is adjusted to a specific value or in units greater than hours, 229daylight savings time considerations are ignored. 230Adjustments in units of hours or less honor daylight saving time. 231So, assuming the current date is March 26, 0:30 and that the DST adjustment 232means that the clock goes forward at 01:00 to 02:00, using 233.Fl v No +1H 234will adjust the date to March 26, 2:30. 235Likewise, if the date is October 29, 0:30 and the DST adjustment means that 236the clock goes back at 02:00 to 01:00, using 237.Fl v No +3H 238will be necessary to reach October 29, 2:30. 239.Pp 240When the date is adjusted to a specific value that does not actually exist 241(for example March 26, 1:30 BST 2000 in the Europe/London timezone), 242the date will be silently adjusted forwards in units of one hour until it 243reaches a valid time. 244When the date is adjusted to a specific value that occurs twice 245(for example October 29, 1:30 2000), 246the resulting timezone will be set so that the date matches the earlier of 247the two times. 248.Pp 249Adjusting the date by months is inherently ambiguous because 250a month is a unit of variable length depending on the current date. 251This kind of date adjustment is applied in the most intuitive way. 252First of all, 253.Nm 254tries to preserve the day of the month. 255If it is impossible because the target month is shorter than the present one, 256the last day of the target month will be the result. 257For example, using 258.Fl v No +1m 259on May 31 will adjust the date to June 30, while using the same option 260on January 30 will result in the date adjusted to the last day of February. 261This approach is also believed to make the most sense for shell scripting. 262Nevertheless, be aware that going forth and back by the same number of 263months may take you to a different date. 264.Pp 265Refer to the examples below for further details. 266.El 267.Pp 268An operand with a leading plus 269.Pq Sq + 270sign signals a user-defined format string 271which specifies the format in which to display the date and time. 272The format string may contain any of the conversion specifications 273described in the 274.Xr strftime 3 275manual page, as well as any arbitrary text. 276A newline 277.Pq Ql \en 278character is always output after the characters specified by 279the format string. 280The format string for the default display is 281.Dq +%+ . 282.Pp 283If an operand does not have a leading plus sign, it is interpreted as 284a value for setting the system's notion of the current date and time. 285The canonical representation for setting the date and time is: 286.Pp 287.Bl -tag -width Ds -compact -offset indent 288.It Ar cc 289Century 290(either 19 or 20) 291prepended to the abbreviated year. 292.It Ar yy 293Year in abbreviated form 294(e.g., 89 for 1989, 06 for 2006). 295.It Ar mm 296Numeric month, a number from 1 to 12. 297.It Ar dd 298Day, a number from 1 to 31. 299.It Ar HH 300Hour, a number from 0 to 23. 301.It Ar MM 302Minutes, a number from 0 to 59. 303.It Ar ss 304Seconds, a number from 0 to 61 305(59 plus a maximum of two leap seconds). 306.El 307.Pp 308Everything but the minutes is optional. 309.Pp 310Time changes for Daylight Saving Time, standard time, leap seconds, 311and leap years are handled automatically. 312.Sh ENVIRONMENT 313The following environment variables affect the execution of 314.Nm : 315.Bl -tag -width Ds 316.It Ev TZ 317The timezone to use when displaying dates. 318The normal format is a pathname relative to 319.Pa /usr/share/zoneinfo . 320For example, the command 321.Dq TZ=America/Los_Angeles date 322displays the current time in California. 323See 324.Xr environ 7 325for more information. 326.El 327.Sh FILES 328.Bl -tag -width /var/log/messages -compact 329.It Pa /var/log/wtmpx 330record of date resets and time changes 331.It Pa /var/log/messages 332record of the user setting the time 333.El 334.Sh EXIT STATUS 335The 336.Nm 337utility exits 0 on success, 1 if unable to set the date, and 2 338if able to set the local date, but unable to set it globally. 339.Sh EXAMPLES 340The command: 341.Pp 342.Dl "date ""+DATE: %Y-%m-%d%nTIME: %H:%M:%S""" 343.Pp 344will display: 345.Bd -literal -offset indent 346DATE: 1987-11-21 347TIME: 13:36:16 348.Ed 349.Pp 350In the Europe/London timezone, the command: 351.Pp 352.Dl "date -v1m -v+1y" 353.Pp 354will display: 355.Pp 356.Dl "Sun Jan 4 04:15:24 GMT 1998" 357.Pp 358where it is currently 359.Li "Mon Aug 4 04:15:24 BST 1997" . 360.Pp 361The command: 362.Pp 363.Dl "date -v1d -v3m -v0y -v-1d" 364.Pp 365will display the last day of February in the year 2000: 366.Pp 367.Dl "Tue Feb 29 03:18:00 GMT 2000" 368.Pp 369So will do the command: 370.Pp 371.Dl "date -v30d -v3m -v0y -v-1m" 372.Pp 373because there is no such date as the 30th of February. 374.Pp 375The command: 376.Pp 377.Dl "date -v1d -v+1m -v-1d -v-fri" 378.Pp 379will display the last Friday of the month: 380.Pp 381.Dl "Fri Aug 29 04:31:11 BST 1997" 382.Pp 383where it is currently 384.Li "Mon Aug 4 04:31:11 BST 1997" . 385.Pp 386The command: 387.Pp 388.Dl "date 8506131627" 389.Pp 390sets the date to 391.Dq Li "June 13, 1985, 4:27 PM" . 392.Pp 393.Dl "date ""+%Y%m%d%H%M.%S""" 394.Pp 395may be used on one machine to print out the date 396suitable for setting on another. 397.Qq ( Li "+%m%d%H%M%Y.%S" 398for use on 399.Tn Linux . ) 400.Pp 401The command: 402.Pp 403.Dl "date 1432" 404.Pp 405sets the time to 406.Li "2:32 PM" , 407without modifying the date. 408.Pp 409The command: 410.Pp 411.Dl "TZ=America/Los_Angeles date -Iseconds -r 1533415339" 412.Pp 413will display 414.Pp 415.Dl "2018-08-04T13:42:19-07:00" 416.Pp 417Finally the command: 418.Pp 419.Dl "date -j -f ""%a %b %d %T %Z %Y"" ""`date`"" ""+%s""" 420.Pp 421can be used to parse the output from 422.Nm 423and express it in Epoch time. 424.Sh SEE ALSO 425.Xr gettimeofday 2 , 426.Xr strftime 3 , 427.Xr strptime 3 , 428.Xr utmpx 5 429.Sh STANDARDS 430The 431.Nm 432utility is expected to be compatible with 433.St -p1003.2 . 434.Pp 435The format selected by the 436.Fl I 437flag is compatible with 438.St -iso8601 . 439.Sh HISTORY 440A 441.Nm 442command appeared in 443.At v1 . 444.Pp 445The 446.Fl I 447flag was added in 448.Fx 12.0 449and 450.Dx 6.3 . 451