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.\" %sccs.include.redist.roff% 8.\" 9.\" @(#)date.1 8.3 (Berkeley) 04/28/95 10.\" 11.Dd 12.Dt DATE 1 13.Os 14.Sh NAME 15.Nm date 16.Nd display or set date and time 17.Sh SYNOPSIS 18.Nm date 19.Op Fl d Ar dst 20.Op Fl r Ar seconds 21.Op Fl t Ar minutes_west 22.Op Fl nu 23.Op Cm + Ns Ar format 24.Op [yy[mm[dd[hh]]]]mm[\&.ss] 25.Sh DESCRIPTION 26.Nm Date 27displays the current date and time when invoked without arguments. 28Providing arguments will format the date and time in a user-defined 29way or set the date. 30Only the superuser may set the date. 31.Pp 32The options are as follows: 33.Bl -tag -width Ds 34.It Fl d 35Set the kernel's value for daylight savings time. 36If 37.Ar dst 38is non-zero, future calls 39to 40.Xr gettimeofday 2 41will return a non-zero 42.Ql tz_dsttime . 43.It Fl n 44The utility 45.Xr timed 8 46is used to synchronize the clocks on groups of machines. 47By default, if 48.Xr timed 49is running, 50.Nm date 51will set the time on all of the machines in the local group. 52The 53.Fl n 54option stops 55.Nm date 56from setting the time for other than the current machine. 57.It Fl r 58Print out the date and time in 59.Ar seconds 60from the Epoch. 61.It Fl t 62Set the kernel's value for minutes west of 63.Tn GMT . 64.Ar Minutes_west 65specifies the number of minutes returned in 66.Ql tz_minuteswest 67by future calls to 68.Xr gettimeofday 2 . 69.It Fl u 70Display or set the date in 71.Tn UCT 72(universal) time. 73.El 74.Pp 75An operand with a leading plus (``+'') sign signals a user-defined format 76string which specifies the format in which to display the date and time. 77The format string may contain any of the conversion specifications described 78in the 79.Xr strftime 3 80manual page, as well as any arbitrary text. 81A <newline> character is always output after the characters specified by 82the format string. 83The format string for the default display is: 84.Bd -literal -offset indent 85``%a %b %e %H:%M:%S %Z %Y''. 86.Ed 87.Pp 88If an operand does not have a leading plus sign, it is interpreted as 89a value for setting the system's notion of the current date and time. 90The canonical representation for setting the date and time is: 91.Pp 92.Bl -tag -width Ds -compact -offset indent 93.It Ar yy 94Year in abbreviated form (.e.g 89 for 1989). 95.It Ar mm 96Numeric month. 97A number from 1 to 12. 98.It Ar dd 99Day, a number from 1 to 31. 100.It Ar hh 101Hour, a number from 0 to 23. 102.It Ar mm 103Minutes, a number from 0 to 59. 104.It Ar .ss 105Seconds, a number from 0 to 61 (59 plus a a maximum of two leap seconds). 106.El 107.Pp 108Everything but the minutes is optional. 109.Pp 110Time changes for Daylight Saving and Standard time and leap seconds 111and years are handled automatically. 112.Sh EXAMPLES 113The command: 114.Bd -literal -offset indent 115date ``+DATE: %m/%d/%y%nTIME: %H:%M:%S'' 116.Ed 117.Pp 118will display: 119.Bd -literal -offset indent 120DATE: 11/21/87 121TIME: 13:36:16 122.Ed 123.Pp 124The command: 125.Bd -literal -offset indent 126date 8506131627 127.Ed 128.Pp 129sets the date to 130.Dq Li "June 13, 1985, 4:27 PM" . 131.Pp 132The command: 133.Bd -literal -offset indent 134date 1432 135.Ed 136.Pp 137sets the time to 138.Li "2:32 PM" , 139without modifying the date. 140.Sh ENVIRONMENTAL VARIABLES 141The following environment variables affect the execution of 142.Nm date : 143.Bl -tag -width TZ 144.It Ev TZ 145The timezone to use when displaying dates. 146See 147.Xr environ 7 148for more information. 149.El 150.Sh FILES 151.Bl -tag -width /var/log/messages -compact 152.It Pa /var/log/wtmp 153A record of date resets and time changes. 154.It Pa /var/log/messages 155A record of the user setting the time. 156.El 157.Sh SEE ALSO 158.Xr gettimeofday 2 , 159.Xr strftime 3 , 160.Xr utmp 5 , 161.Xr timed 8 162.Rs 163.%T "TSP: The Time Synchronization Protocol for UNIX 4.3BSD" 164.%A R. Gusella 165.%A S. Zatti 166.Re 167.Sh DIAGNOSTICS 168Exit status is 0 on success, 1 if unable to set the date, and 2 169if able to set the local date, but unable to set it globally. 170.Pp 171Occasionally, when 172.Xr timed 173synchronizes the time on many hosts, the setting of a new time value may 174require more than a few seconds. 175On these occasions, 176.Nm date 177prints: 178.Ql Network time being set . 179The message 180.Ql Communication error with timed 181occurs when the communication 182between 183.Nm date 184and 185.Xr timed 186fails. 187.Sh BUGS 188The system attempts to keep the date in a format closely compatible 189with 190.Tn VMS . 191.Tn VMS , 192however, uses local time (rather than 193.Tn GMT ) 194and does not understand daylight-savings time. 195Thus, if you use both 196.Tn UNIX 197and 198.Tn VMS , 199.Tn VMS 200will be running on 201.Tn GMT . 202.Sh STANDARDS 203The 204.Nm date 205command is expected to be compatible with 206.St -p1003.2 . 207