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.\" 4. 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 April 26, 2014 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 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 t Ar minutes_west 154Set the system's value for minutes west of 155.Tn GMT . 156.Ar minutes_west 157specifies the number of minutes returned in 158.Fa tz_minuteswest 159by future calls to 160.Xr gettimeofday 2 . 161.It Fl u 162Display or set the date in 163.Tn UTC 164(Coordinated Universal) time. 165.It Fl v 166Adjust (i.e., take the current date and display the result of the 167adjustment; not actually set the date) the second, minute, hour, month 168day, week day, month or year according to 169.Ar val . 170If 171.Ar val 172is preceded with a plus or minus sign, 173the date is adjusted forwards or backwards according to the remaining string, 174otherwise the relevant part of the date is set. 175The date can be adjusted as many times as required using these flags. 176Flags are processed in the order given. 177.Pp 178When setting values 179(rather than adjusting them), 180seconds are in the range 0-59, minutes are in the range 0-59, hours are 181in the range 0-23, month days are in the range 1-31, week days are in the 182range 0-6 (Sun-Sat), 183months are in the range 1-12 (Jan-Dec) 184and years are in the range 80-38 or 1980-2038. 185.Pp 186If 187.Ar val 188is numeric, one of either 189.Ar y , 190.Ar m , 191.Ar w , 192.Ar d , 193.Ar H , 194.Ar M 195or 196.Ar S 197must be used to specify which part of the date is to be adjusted. 198.Pp 199The week day or month may be specified using a name rather than a 200number. 201If a name is used with the plus 202(or minus) 203sign, the date will be put forwards 204(or backwards) 205to the next 206(previous) 207date that matches the given week day or month. 208This will not adjust the date, 209if the given week day or month is the same as the current one. 210.Pp 211When a date is adjusted to a specific value or in units greater than hours, 212daylight savings time considerations are ignored. 213Adjustments in units of hours or less honor daylight saving time. 214So, assuming the current date is March 26, 0:30 and that the DST adjustment 215means that the clock goes forward at 01:00 to 02:00, using 216.Fl v No +1H 217will adjust the date to March 26, 2:30. 218Likewise, if the date is October 29, 0:30 and the DST adjustment means that 219the clock goes back at 02:00 to 01:00, using 220.Fl v No +3H 221will be necessary to reach October 29, 2:30. 222.Pp 223When the date is adjusted to a specific value that does not actually exist 224(for example March 26, 1:30 BST 2000 in the Europe/London timezone), 225the date will be silently adjusted forwards in units of one hour until it 226reaches a valid time. 227When the date is adjusted to a specific value that occurs twice 228(for example October 29, 1:30 2000), 229the resulting timezone will be set so that the date matches the earlier of 230the two times. 231.Pp 232It is not possible to adjust a date to an invalid absolute day, so using 233the switches 234.Fl v No 31d Fl v No 12m 235will simply fail five months of the year. 236It is therefore usual to set the month before setting the day; using 237.Fl v No 12m Fl v No 31d 238always works. 239.Pp 240Adjusting the date by months is inherently ambiguous because 241a month is a unit of variable length depending on the current date. 242This kind of date adjustment is applied in the most intuitive way. 243First of all, 244.Nm 245tries to preserve the day of the month. 246If it is impossible because the target month is shorter than the present one, 247the last day of the target month will be the result. 248For example, using 249.Fl v No +1m 250on May 31 will adjust the date to June 30, while using the same option 251on January 30 will result in the date adjusted to the last day of February. 252This approach is also believed to make the most sense for shell scripting. 253Nevertheless, be aware that going forth and back by the same number of 254months may take you to a different date. 255.Pp 256Refer to the examples below for further details. 257.El 258.Pp 259An operand with a leading plus 260.Pq Sq + 261sign signals a user-defined format string 262which specifies the format in which to display the date and time. 263The format string may contain any of the conversion specifications 264described in the 265.Xr strftime 3 266manual page, as well as any arbitrary text. 267A newline 268.Pq Ql \en 269character is always output after the characters specified by 270the format string. 271The format string for the default display is 272.Dq +%+ . 273.Pp 274If an operand does not have a leading plus sign, it is interpreted as 275a value for setting the system's notion of the current date and time. 276The canonical representation for setting the date and time is: 277.Pp 278.Bl -tag -width Ds -compact -offset indent 279.It Ar cc 280Century 281(either 19 or 20) 282prepended to the abbreviated year. 283.It Ar yy 284Year in abbreviated form 285(e.g., 89 for 1989, 06 for 2006). 286.It Ar mm 287Numeric month, a number from 1 to 12. 288.It Ar dd 289Day, a number from 1 to 31. 290.It Ar HH 291Hour, a number from 0 to 23. 292.It Ar MM 293Minutes, a number from 0 to 59. 294.It Ar ss 295Seconds, a number from 0 to 61 296(59 plus a maximum of two leap seconds). 297.El 298.Pp 299Everything but the minutes is optional. 300.Pp 301Time changes for Daylight Saving Time, standard time, leap seconds, 302and leap years are handled automatically. 303.Sh ENVIRONMENT 304The following environment variables affect the execution of 305.Nm : 306.Bl -tag -width Ds 307.It Ev TZ 308The timezone to use when displaying dates. 309The normal format is a pathname relative to 310.Pa /usr/share/zoneinfo . 311For example, the command 312.Dq TZ=America/Los_Angeles date 313displays the current time in California. 314See 315.Xr environ 7 316for more information. 317.El 318.Sh FILES 319.Bl -tag -width /var/log/messages -compact 320.It Pa /var/log/utx.log 321record of date resets and time changes 322.It Pa /var/log/messages 323record of the user setting the time 324.El 325.Sh EXIT STATUS 326The 327.Nm 328utility exits 0 on success, 1 if unable to set the date, and 2 329if able to set the local date, but unable to set it globally. 330.Sh EXAMPLES 331The command: 332.Pp 333.Dl "date ""+DATE: %Y-%m-%d%nTIME: %H:%M:%S""" 334.Pp 335will display: 336.Bd -literal -offset indent 337DATE: 1987-11-21 338TIME: 13:36:16 339.Ed 340.Pp 341In the Europe/London timezone, the command: 342.Pp 343.Dl "date -v1m -v+1y" 344.Pp 345will display: 346.Pp 347.Dl "Sun Jan 4 04:15:24 GMT 1998" 348.Pp 349where it is currently 350.Li "Mon Aug 4 04:15:24 BST 1997" . 351.Pp 352The command: 353.Pp 354.Dl "date -v1d -v3m -v0y -v-1d" 355.Pp 356will display the last day of February in the year 2000: 357.Pp 358.Dl "Tue Feb 29 03:18:00 GMT 2000" 359.Pp 360So will the command: 361.Pp 362.Dl "date -v3m -v30d -v0y -v-1m" 363.Pp 364because there is no such date as the 30th of February. 365.Pp 366The command: 367.Pp 368.Dl "date -v1d -v+1m -v-1d -v-fri" 369.Pp 370will display the last Friday of the month: 371.Pp 372.Dl "Fri Aug 29 04:31:11 BST 1997" 373.Pp 374where it is currently 375.Li "Mon Aug 4 04:31:11 BST 1997" . 376.Pp 377The command: 378.Pp 379.Dl "date 8506131627" 380.Pp 381sets the date to 382.Dq Li "June 13, 1985, 4:27 PM" . 383.Pp 384.Dl "date ""+%Y%m%d%H%M.%S""" 385.Pp 386may be used on one machine to print out the date 387suitable for setting on another. 388.Qq ( Li "+%m%d%H%M%Y.%S" 389for use on 390.Tn Linux . ) 391.Pp 392The command: 393.Pp 394.Dl "date 1432" 395.Pp 396sets the time to 397.Li "2:32 PM" , 398without modifying the date. 399.Pp 400Finally the command: 401.Pp 402.Dl "date -j -f ""%a %b %d %T %Z %Y"" ""`date`"" ""+%s""" 403.Pp 404can be used to parse the output from 405.Nm 406and express it in Epoch time. 407.Sh DIAGNOSTICS 408Occasionally, when 409.Xr timed 8 410synchronizes the time on many hosts, the setting of a new time value may 411require more than a few seconds. 412On these occasions, 413.Nm 414prints: 415.Ql Network time being set . 416The message 417.Ql Communication error with timed 418occurs when the communication 419between 420.Nm 421and 422.Xr timed 8 423fails. 424.Sh SEE ALSO 425.Xr locale 1 , 426.Xr gettimeofday 2 , 427.Xr getutxent 3 , 428.Xr strftime 3 , 429.Xr strptime 3 , 430.Xr timed 8 431.Rs 432.%T "TSP: The Time Synchronization Protocol for UNIX 4.3BSD" 433.%A R. Gusella 434.%A S. Zatti 435.Re 436.Sh STANDARDS 437The 438.Nm 439utility is expected to be compatible with 440.St -p1003.2 . 441The 442.Fl d , f , j , n , r , t , 443and 444.Fl v 445options are all extensions to the standard. 446.Sh HISTORY 447A 448.Nm 449command appeared in 450.At v1 . 451