1.\" $OpenBSD: date.1,v 1.72 2021/04/29 00:47:53 deraadt Exp $ 2.\" $NetBSD: date.1,v 1.12 1996/03/12 04:32:37 phil Exp $ 3.\" 4.\" Copyright (c) 1980, 1990, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" This code is derived from software contributed to Berkeley by 8.\" the Institute of Electrical and Electronics Engineers, Inc. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 3. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)date.1 8.3 (Berkeley) 4/28/95 35.\" 36.Dd $Mdocdate: April 29 2021 $ 37.Dt DATE 1 38.Os 39.Sh NAME 40.Nm date 41.Nd display or set date and time 42.Sh SYNOPSIS 43.Nm date 44.Op Fl aju 45.Op Fl f Ar pformat 46.Op Fl r Ar seconds 47.Op Fl z Ar output_zone 48.Op Cm + Ns Ar format 49.Sm off 50.Oo Oo Oo Oo Oo Oo 51.Ar cc Oc 52.Ar yy Oc 53.Ar mm Oc 54.Ar dd Oc 55.Ar HH Oc 56.Ar MM 57.Op . Ar SS 58.Oc 59.Sm on 60.Sh DESCRIPTION 61When invoked without arguments, the 62.Nm 63utility displays the current date and time. 64Otherwise, depending on the options specified, 65.Nm 66will set the date and time or print it in a user-defined way. 67.Pp 68Changing the system date has some risks, as described in 69.Xr settimeofday 2 . 70Only the superuser may change the date. 71.Pp 72The options are as follows: 73.Bl -tag -width Ds 74.It Fl a 75Use the 76.Xr adjtime 2 77call to gradually skew the local time to the 78desired time rather than just hopping. 79.It Fl f Ar pformat 80Parse the specified time using 81.Xr strptime 3 82with a format string of 83.Ar pformat . 84.It Fl j 85Parse the provided date and time and display the result without changing 86the clock. 87.It Fl r Ar seconds 88Print out (in specified format) the date and time represented by 89.Ar seconds 90from the Epoch. 91.It Fl u 92Display or set the date in UTC (Coordinated Universal) time. 93.It Fl z Ar output_zone 94Just before printing the time, change to the specified timezone; 95see the description of 96.Ev TZ 97below. 98This can be used with 99.Fl j 100to easily convert time specifications from one zone to another. 101.El 102.Pp 103An operand with a leading plus sign 104.Pq Sq + 105signals a user-defined format 106string which specifies the format in which to display the date and time. 107The format string may contain any of the conversion specifications described 108in the 109.Xr strftime 3 110manual page, as well as any arbitrary text. 111A newline 112.Pq Ql \en 113character is always output after the characters specified by 114the format string. 115The format string for the default display is: 116.Bd -literal -offset indent 117%a %b %e %H:%M:%S %Z %Y 118.Ed 119.Pp 120If an operand does not have a leading plus sign, it is interpreted as 121a value for setting the system's notion of the current date and time. 122The canonical representation for setting the date and time is: 123.Pp 124.Bl -tag -width Ds -compact -offset indent 125.It Ar ccyy 126Year. 127If yy is specified, but cc is not, 128a value for yy between 69 and 99 results in a cc value of 19. 129Otherwise, a cc value of 20 is used. 130.It Ar mm 131Month: 132a number from 1 to 12. 133.It Ar dd 134Day: 135a number from 1 to 31. 136.It Ar HH 137Hour: 138a number from 0 to 23. 139.It Ar MM 140Minute: 141a number from 0 to 59. 142.It Ar SS 143Second: 144a number from 0 to 60 145(permitting a leap second), 146preceded by a period. 147.El 148.Pp 149Everything but the minute is optional. 150.Pp 151Time changes for Daylight Saving Time, standard time, leap seconds, 152and leap years are handled automatically. 153.Sh ENVIRONMENT 154.Bl -tag -width Ds 155.It Ev TZ 156The time zone to use when parsing or displaying dates. 157It is normally specified as a pathname relative to 158.Pa /usr/share/zoneinfo , 159though see 160.Xr tzset 3 161for more information. 162If this variable is not set, the time zone is determined based on 163.Pa /etc/localtime , 164which the administrator adjusts using 165the 166.Fl l 167option of 168.Xr zic 8 . 169.El 170.Sh FILES 171.Bl -tag -width /var/log/messages -compact 172.It Pa /var/log/wtmp 173record of date resets and time changes 174.It Pa /var/log/messages 175record of the user setting the time 176.El 177.Sh EXIT STATUS 178.Ex -std 179.Sh EXAMPLES 180Display the date using the specified format string: 181.Bd -literal -offset indent 182$ date "+DATE: %Y-%m-%d%nTIME: %H:%M:%S" 183DATE: 1987-11-21 184TIME: 13:36:16 185.Ed 186.Pp 187Set the date to 188June 13, 1985, 4:27 PM: 189.Pp 190.Dl # date 198506131627 191.Pp 192Set the time to 1932:32 PM, 194without modifying the date: 195.Pp 196.Dl # date 1432 197.Pp 198If the mailing list server located in California 199is being taken offline at 5:45 AM, 200work out what time it will be locally, here in Tokyo: 201.Pp 202.Dl $ TZ=America/Los_Angeles date -j -z Asia/Tokyo 0545 203.Sh SEE ALSO 204.Xr adjtime 2 , 205.Xr gettimeofday 2 , 206.Xr strftime 3 , 207.Xr utmp 5 , 208.Xr ntpd 8 , 209.Xr rdate 8 210.Sh STANDARDS 211The 212.Nm 213utility is compliant with the 214.St -p1003.1-2008 215specification. 216.Pp 217The flags 218.Op Fl afjrz , 219as well as the conversion specifiers 220.Ql \&%F , 221.Ql \&%G , 222.Ql \&%g , 223.Ql \&%k , 224.Ql \&%l , 225.Ql \&%R , 226.Ql \&%s , 227.Ql \&%v , 228and 229.Ql \&%+ , 230are extensions to that specification. 231.Pp 232This implementation requires the traditional 233.Bx 234date format, 235[[[[[cc]yy]mm]dd]HH]MM[.SS], 236which differs from the 237X/Open System Interfaces option of the 238.St -p1003.1-2008 239specification. 240.Sh HISTORY 241A 242.Nm 243command appeared in 244.At v1 . 245