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 November 15, 2014 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 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 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 133Use RFC 2822 date and time output format. This is equivalent to use 134.Dq Li %a, %d %b %Y \&%T %z 135as 136.Ar output_fmt 137while 138.Ev LC_TIME 139is set to the 140.Dq C 141locale. 142.It Fl r Ar seconds 143Print the date and time represented by 144.Ar seconds , 145where 146.Ar seconds 147is the number of seconds since the Epoch 148(00:00:00 UTC, January 1, 1970; 149see 150.Xr time 3 ) , 151and can be specified in decimal, octal, or hex. 152.It Fl t Ar minutes_west 153Set the system's value for minutes west of 154.Tn GMT . 155.Ar minutes_west 156specifies the number of minutes returned in 157.Fa tz_minuteswest 158by future calls to 159.Xr gettimeofday 2 . 160.It Fl u 161Display or set the date in 162.Tn UTC 163(Coordinated Universal) time. 164.It Fl v 165Adjust (i.e., take the current date and display the result of the 166adjustment; not actually set the date) the second, minute, hour, month 167day, week day, month or year according to 168.Ar val . 169If 170.Ar val 171is preceded with a plus or minus sign, 172the date is adjusted forwards or backwards according to the remaining string, 173otherwise the relevant part of the date is set. 174The date can be adjusted as many times as required using these flags. 175Flags are processed in the order given. 176.Pp 177When setting values 178(rather than adjusting them), 179seconds are in the range 0-59, minutes are in the range 0-59, hours are 180in the range 0-23, month days are in the range 1-31, week days are in the 181range 0-6 (Sun-Sat), 182months are in the range 1-12 (Jan-Dec) 183and years are in the range 80-38 or 1980-2038. 184.Pp 185If 186.Ar val 187is numeric, one of either 188.Ar y , 189.Ar m , 190.Ar w , 191.Ar d , 192.Ar H , 193.Ar M 194or 195.Ar S 196must be used to specify which part of the date is to be adjusted. 197.Pp 198The week day or month may be specified using a name rather than a 199number. 200If a name is used with the plus 201(or minus) 202sign, the date will be put forwards 203(or backwards) 204to the next 205(previous) 206date that matches the given week day or month. 207This will not adjust the date, 208if the given week day or month is the same as the current one. 209.Pp 210When a date is adjusted to a specific value or in units greater than hours, 211daylight savings time considerations are ignored. 212Adjustments in units of hours or less honor daylight saving time. 213So, assuming the current date is March 26, 0:30 and that the DST adjustment 214means that the clock goes forward at 01:00 to 02:00, using 215.Fl v No +1H 216will adjust the date to March 26, 2:30. 217Likewise, if the date is October 29, 0:30 and the DST adjustment means that 218the clock goes back at 02:00 to 01:00, using 219.Fl v No +3H 220will be necessary to reach October 29, 2:30. 221.Pp 222When the date is adjusted to a specific value that does not actually exist 223(for example March 26, 1:30 BST 2000 in the Europe/London timezone), 224the date will be silently adjusted forwards in units of one hour until it 225reaches a valid time. 226When the date is adjusted to a specific value that occurs twice 227(for example October 29, 1:30 2000), 228the resulting timezone will be set so that the date matches the earlier of 229the two times. 230.Pp 231Adjusting the date by months is inherently ambiguous because 232a month is a unit of variable length depending on the current date. 233This kind of date adjustment is applied in the most intuitive way. 234First of all, 235.Nm 236tries to preserve the day of the month. 237If it is impossible because the target month is shorter than the present one, 238the last day of the target month will be the result. 239For example, using 240.Fl v No +1m 241on May 31 will adjust the date to June 30, while using the same option 242on January 30 will result in the date adjusted to the last day of February. 243This approach is also believed to make the most sense for shell scripting. 244Nevertheless, be aware that going forth and back by the same number of 245months may take you to a different date. 246.Pp 247Refer to the examples below for further details. 248.El 249.Pp 250An operand with a leading plus 251.Pq Sq + 252sign signals a user-defined format string 253which specifies the format in which to display the date and time. 254The format string may contain any of the conversion specifications 255described in the 256.Xr strftime 3 257manual page, as well as any arbitrary text. 258A newline 259.Pq Ql \en 260character is always output after the characters specified by 261the format string. 262The format string for the default display is 263.Dq +%+ . 264.Pp 265If an operand does not have a leading plus sign, it is interpreted as 266a value for setting the system's notion of the current date and time. 267The canonical representation for setting the date and time is: 268.Pp 269.Bl -tag -width Ds -compact -offset indent 270.It Ar cc 271Century 272(either 19 or 20) 273prepended to the abbreviated year. 274.It Ar yy 275Year in abbreviated form 276(e.g., 89 for 1989, 06 for 2006). 277.It Ar mm 278Numeric month, a number from 1 to 12. 279.It Ar dd 280Day, a number from 1 to 31. 281.It Ar HH 282Hour, a number from 0 to 23. 283.It Ar MM 284Minutes, a number from 0 to 59. 285.It Ar ss 286Seconds, a number from 0 to 61 287(59 plus a maximum of two leap seconds). 288.El 289.Pp 290Everything but the minutes is optional. 291.Pp 292Time changes for Daylight Saving Time, standard time, leap seconds, 293and leap years are handled automatically. 294.Sh ENVIRONMENT 295The following environment variables affect the execution of 296.Nm : 297.Bl -tag -width Ds 298.It Ev TZ 299The timezone to use when displaying dates. 300The normal format is a pathname relative to 301.Pa /usr/share/zoneinfo . 302For example, the command 303.Dq TZ=America/Los_Angeles date 304displays the current time in California. 305See 306.Xr environ 7 307for more information. 308.El 309.Sh FILES 310.Bl -tag -width /var/log/messages -compact 311.It Pa /var/log/wtmp 312record of date resets and time changes 313.It Pa /var/log/messages 314record of the user setting the time 315.El 316.Sh EXIT STATUS 317The 318.Nm 319utility exits 0 on success, 1 if unable to set the date, and 2 320if able to set the local date, but unable to set it globally. 321.Sh EXAMPLES 322The command: 323.Pp 324.Dl "date ""+DATE: %Y-%m-%d%nTIME: %H:%M:%S""" 325.Pp 326will display: 327.Bd -literal -offset indent 328DATE: 1987-11-21 329TIME: 13:36:16 330.Ed 331.Pp 332In the Europe/London timezone, the command: 333.Pp 334.Dl "date -v1m -v+1y" 335.Pp 336will display: 337.Pp 338.Dl "Sun Jan 4 04:15:24 GMT 1998" 339.Pp 340where it is currently 341.Li "Mon Aug 4 04:15:24 BST 1997" . 342.Pp 343The command: 344.Pp 345.Dl "date -v1d -v3m -v0y -v-1d" 346.Pp 347will display the last day of February in the year 2000: 348.Pp 349.Dl "Tue Feb 29 03:18:00 GMT 2000" 350.Pp 351So will do the command: 352.Pp 353.Dl "date -v30d -v3m -v0y -v-1m" 354.Pp 355because there is no such date as the 30th of February. 356.Pp 357The command: 358.Pp 359.Dl "date -v1d -v+1m -v-1d -v-fri" 360.Pp 361will display the last Friday of the month: 362.Pp 363.Dl "Fri Aug 29 04:31:11 BST 1997" 364.Pp 365where it is currently 366.Li "Mon Aug 4 04:31:11 BST 1997" . 367.Pp 368The command: 369.Pp 370.Dl "date 8506131627" 371.Pp 372sets the date to 373.Dq Li "June 13, 1985, 4:27 PM" . 374.Pp 375.Dl "date ""+%Y%m%d%H%M.%S""" 376.Pp 377may be used on one machine to print out the date 378suitable for setting on another. 379.Qq ( Li "+%m%d%H%M%Y.%S" 380for use on 381.Tn Linux . ) 382.Pp 383The command: 384.Pp 385.Dl "date 1432" 386.Pp 387sets the time to 388.Li "2:32 PM" , 389without modifying the date. 390.Pp 391Finally the command: 392.Pp 393.Dl "date -j -f ""%a %b %d %T %Z %Y"" ""`date`"" ""+%s""" 394.Pp 395can be used to parse the output from 396.Nm 397and express it in Epoch time. 398.Sh DIAGNOSTICS 399Occasionally, when 400.Xr timed 8 401synchronizes the time on many hosts, the setting of a new time value may 402require more than a few seconds. 403On these occasions, 404.Nm 405prints: 406.Ql Network time being set . 407The message 408.Ql Communication error with timed 409occurs when the communication 410between 411.Nm 412and 413.Xr timed 8 414fails. 415.Sh SEE ALSO 416.Xr gettimeofday 2 , 417.Xr strftime 3 , 418.Xr strptime 3 , 419.Xr utmp 5 , 420.Xr timed 8 421.Rs 422.%T "TSP: The Time Synchronization Protocol for UNIX 4.3BSD" 423.%A R. Gusella 424.%A S. Zatti 425.Re 426.Sh STANDARDS 427The 428.Nm 429utility is expected to be compatible with 430.St -p1003.2 . 431.Sh HISTORY 432A 433.Nm 434command appeared in 435.At v1 . 436