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 May 7, 2015 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 d Ar dst 66.Op Fl t Ar minutes_west 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 7 ) 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 input_fmt 101as the format string to parse the 102.Ar new_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 134Use RFC 2822 date and time output format. This is equivalent to use 135.Dq Li %a, %d %b %Y \&%T %z 136as 137.Ar output_fmt 138while 139.Ev LC_TIME 140is set to the 141.Dq C 142locale . 143.It Fl r Ar seconds 144Print the date and time represented by 145.Ar seconds , 146where 147.Ar seconds 148is the number of seconds since the Epoch 149(00:00:00 UTC, January 1, 1970; 150see 151.Xr time 3 ) , 152and can be specified in decimal, octal, or hex. 153.It Fl r Ar filename 154Print the date and time of the last modification of 155.Ar filename . 156.It Fl t Ar minutes_west 157Set the system's value for minutes west of 158.Tn GMT . 159.Ar minutes_west 160specifies the number of minutes returned in 161.Fa tz_minuteswest 162by future calls to 163.Xr gettimeofday 2 . 164.It Fl u 165Display or set the date in 166.Tn UTC 167(Coordinated Universal) time. 168.It Fl v 169Adjust (i.e., take the current date and display the result of the 170adjustment; not actually set the date) the second, minute, hour, month 171day, week day, month or year according to 172.Ar val . 173If 174.Ar val 175is preceded with a plus or minus sign, 176the date is adjusted forwards or backwards according to the remaining string, 177otherwise the relevant part of the date is set. 178The date can be adjusted as many times as required using these flags. 179Flags are processed in the order given. 180.Pp 181When setting values 182(rather than adjusting them), 183seconds are in the range 0-59, minutes are in the range 0-59, hours are 184in the range 0-23, month days are in the range 1-31, week days are in the 185range 0-6 (Sun-Sat), 186months are in the range 1-12 (Jan-Dec) 187and years are in the range 80-38 or 1980-2038. 188.Pp 189If 190.Ar val 191is numeric, one of either 192.Ar y , 193.Ar m , 194.Ar w , 195.Ar d , 196.Ar H , 197.Ar M 198or 199.Ar S 200must be used to specify which part of the date is to be adjusted. 201.Pp 202The week day or month may be specified using a name rather than a 203number. 204If a name is used with the plus 205(or minus) 206sign, the date will be put forwards 207(or backwards) 208to the next 209(previous) 210date that matches the given week day or month. 211This will not adjust the date, 212if the given week day or month is the same as the current one. 213.Pp 214When a date is adjusted to a specific value or in units greater than hours, 215daylight savings time considerations are ignored. 216Adjustments in units of hours or less honor daylight saving time. 217So, assuming the current date is March 26, 0:30 and that the DST adjustment 218means that the clock goes forward at 01:00 to 02:00, using 219.Fl v No +1H 220will adjust the date to March 26, 2:30. 221Likewise, if the date is October 29, 0:30 and the DST adjustment means that 222the clock goes back at 02:00 to 01:00, using 223.Fl v No +3H 224will be necessary to reach October 29, 2:30. 225.Pp 226When the date is adjusted to a specific value that does not actually exist 227(for example March 26, 1:30 BST 2000 in the Europe/London timezone), 228the date will be silently adjusted forwards in units of one hour until it 229reaches a valid time. 230When the date is adjusted to a specific value that occurs twice 231(for example October 29, 1:30 2000), 232the resulting timezone will be set so that the date matches the earlier of 233the two times. 234.Pp 235It is not possible to adjust a date to an invalid absolute day, so using 236the switches 237.Fl v No 31d Fl v No 12m 238will simply fail five months of the year. 239It is therefore usual to set the month before setting the day; using 240.Fl v No 12m Fl v No 31d 241always works. 242.Pp 243Adjusting the date by months is inherently ambiguous because 244a month is a unit of variable length depending on the current date. 245This kind of date adjustment is applied in the most intuitive way. 246First of all, 247.Nm 248tries to preserve the day of the month. 249If it is impossible because the target month is shorter than the present one, 250the last day of the target month will be the result. 251For example, using 252.Fl v No +1m 253on May 31 will adjust the date to June 30, while using the same option 254on January 30 will result in the date adjusted to the last day of February. 255This approach is also believed to make the most sense for shell scripting. 256Nevertheless, be aware that going forth and back by the same number of 257months may take you to a different date. 258.Pp 259Refer to the examples below for further details. 260.El 261.Pp 262An operand with a leading plus 263.Pq Sq + 264sign signals a user-defined format string 265which specifies the format in which to display the date and time. 266The format string may contain any of the conversion specifications 267described in the 268.Xr strftime 3 269manual page, as well as any arbitrary text. 270A newline 271.Pq Ql \en 272character is always output after the characters specified by 273the format string. 274The format string for the default display is 275.Dq +%+ . 276.Pp 277If an operand does not have a leading plus sign, it is interpreted as 278a value for setting the system's notion of the current date and time. 279The canonical representation for setting the date and time is: 280.Pp 281.Bl -tag -width Ds -compact -offset indent 282.It Ar cc 283Century 284(either 19 or 20) 285prepended to the abbreviated year. 286.It Ar yy 287Year in abbreviated form 288(e.g., 89 for 1989, 06 for 2006). 289.It Ar mm 290Numeric month, a number from 1 to 12. 291.It Ar dd 292Day, a number from 1 to 31. 293.It Ar HH 294Hour, a number from 0 to 23. 295.It Ar MM 296Minutes, a number from 0 to 59. 297.It Ar ss 298Seconds, a number from 0 to 61 299(59 plus a maximum of two leap seconds). 300.El 301.Pp 302Everything but the minutes is optional. 303.Pp 304Time changes for Daylight Saving Time, standard time, leap seconds, 305and leap years are handled automatically. 306.Sh ENVIRONMENT 307The following environment variables affect the execution of 308.Nm : 309.Bl -tag -width Ds 310.It Ev TZ 311The timezone to use when displaying dates. 312The normal format is a pathname relative to 313.Pa /usr/share/zoneinfo . 314For example, the command 315.Dq TZ=America/Los_Angeles date 316displays the current time in California. 317See 318.Xr environ 7 319for more information. 320.El 321.Sh FILES 322.Bl -tag -width /var/log/messages -compact 323.It Pa /var/log/utx.log 324record of date resets and time changes 325.It Pa /var/log/messages 326record of the user setting the time 327.El 328.Sh EXIT STATUS 329The 330.Nm 331utility exits 0 on success, 1 if unable to set the date, and 2 332if able to set the local date, but unable to set it globally. 333.Sh EXAMPLES 334The command: 335.Pp 336.Dl "date ""+DATE: %Y-%m-%d%nTIME: %H:%M:%S""" 337.Pp 338will display: 339.Bd -literal -offset indent 340DATE: 1987-11-21 341TIME: 13:36:16 342.Ed 343.Pp 344In the Europe/London timezone, the command: 345.Pp 346.Dl "date -v1m -v+1y" 347.Pp 348will display: 349.Pp 350.Dl "Sun Jan 4 04:15:24 GMT 1998" 351.Pp 352where it is currently 353.Li "Mon Aug 4 04:15:24 BST 1997" . 354.Pp 355The command: 356.Pp 357.Dl "date -v1d -v3m -v0y -v-1d" 358.Pp 359will display the last day of February in the year 2000: 360.Pp 361.Dl "Tue Feb 29 03:18:00 GMT 2000" 362.Pp 363So will the command: 364.Pp 365.Dl "date -v3m -v30d -v0y -v-1m" 366.Pp 367because there is no such date as the 30th of February. 368.Pp 369The command: 370.Pp 371.Dl "date -v1d -v+1m -v-1d -v-fri" 372.Pp 373will display the last Friday of the month: 374.Pp 375.Dl "Fri Aug 29 04:31:11 BST 1997" 376.Pp 377where it is currently 378.Li "Mon Aug 4 04:31:11 BST 1997" . 379.Pp 380The command: 381.Pp 382.Dl "date 8506131627" 383.Pp 384sets the date to 385.Dq Li "June 13, 1985, 4:27 PM" . 386.Pp 387.Dl "date ""+%Y%m%d%H%M.%S""" 388.Pp 389may be used on one machine to print out the date 390suitable for setting on another. 391.Qq ( Li "+%m%d%H%M%Y.%S" 392for use on 393.Tn Linux . ) 394.Pp 395The command: 396.Pp 397.Dl "date 1432" 398.Pp 399sets the time to 400.Li "2:32 PM" , 401without modifying the date. 402.Pp 403Finally the command: 404.Pp 405.Dl "date -j -f ""%a %b %d %T %Z %Y"" ""`date`"" ""+%s""" 406.Pp 407can be used to parse the output from 408.Nm 409and express it in Epoch time. 410.Sh DIAGNOSTICS 411Occasionally, when 412.Xr timed 8 413synchronizes the time on many hosts, the setting of a new time value may 414require more than a few seconds. 415On these occasions, 416.Nm 417prints: 418.Ql Network time being set . 419The message 420.Ql Communication error with timed 421occurs when the communication 422between 423.Nm 424and 425.Xr timed 8 426fails. 427.Sh SEE ALSO 428.Xr locale 1 , 429.Xr gettimeofday 2 , 430.Xr getutxent 3 , 431.Xr strftime 3 , 432.Xr strptime 3 , 433.Xr timed 8 434.Rs 435.%T "TSP: The Time Synchronization Protocol for UNIX 4.3BSD" 436.%A R. Gusella 437.%A S. Zatti 438.Re 439.Sh STANDARDS 440The 441.Nm 442utility is expected to be compatible with 443.St -p1003.2 . 444The 445.Fl d , f , j , n , r , t , 446and 447.Fl v 448options are all extensions to the standard. 449.Sh HISTORY 450A 451.Nm 452command appeared in 453.At v1 . 454