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 8.2 (Berkeley) 11/17/93 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. 81The format string for the default display is: 82.Bd -literal -offset indent 83``%a %b %e %H:%M:%S %Z n''. 84.Ed 85.Pp 86If an operand does not have a leading plus sign, it is interpreted as 87a value for setting the system's notion of the current date and time. 88The canonical representation for setting the date and time is: 89.Pp 90.Bl -tag -width Ds -compact -offset indent 91.It Ar yy 92Year in abbreviated form (.e.g 89 for 1989). 93.It Ar mm 94Numeric month. 95A number from 1 to 12. 96.It Ar dd 97Day, a number from 1 to 31. 98.It Ar hh 99Hour, a number from 0 to 23. 100.It Ar mm 101Minutes, a number from 0 to 59. 102.It Ar .ss 103Seconds, a number from 0 to 61 (59 plus a a maximum of two leap seconds). 104.El 105.Pp 106Everything but the minutes is optional. 107.Pp 108Time changes for Daylight Saving and Standard time and leap seconds 109and years are handled automatically. 110.Sh EXAMPLES 111The command: 112.Bd -literal -offset indent 113date ``+DATE: %m/%d/%y%nTIME: %H:%M:0n'' 114.Ed 115.Pp 116will display: 117.Bd -literal -offset indent 118DATE: 11/21/87 119TIME: 13:36:16 120.Ed 121.Pp 122The command: 123.Bd -literal -offset indent 124date 8506131627 125.Ed 126.Pp 127sets the date to 128.Dq Li "June 13, 1985, 4:27 PM" . 129.Pp 130The command: 131.Bd -literal -offset indent 132date 1432 133.Ed 134.Pp 135sets the time to 136.Li "2:32 PM" , 137without modifying the date. 138.Sh ENVIRONMENTAL VARIABLES 139The following environment variables affect the execution of 140.Nm date : 141.Bl -tag -width TZ 142.It Ev TZ 143The timezone to use when displaying dates. 144See 145.Xr environ 7 146for more information. 147.El 148.Sh FILES 149.Bl -tag -width /var/log/messages -compact 150.It Pa /var/log/wtmp 151A record of date resets and time changes. 152.It Pa /var/log/messages 153A record of the user setting the time. 154.El 155.Sh SEE ALSO 156.Xr gettimeofday 2 , 157.Xr strftime 3 , 158.Xr utmp 5 , 159.Xr timed 8 160.Rs 161.%T "TSP: The Time Synchronization Protocol for UNIX 4.3BSD" 162.%A R. Gusella 163.%A S. Zatti 164.Re 165.Sh DIAGNOSTICS 166Exit status is 0 on success, 1 if unable to set the date, and 2 167if able to set the local date, but unable to set it globally. 168.Pp 169Occasionally, when 170.Xr timed 171synchronizes the time on many hosts, the setting of a new time value may 172require more than a few seconds. 173On these occasions, 174.Nm date 175prints: 176.Ql Network time being set . 177The message 178.Ql Communication error with timed 179occurs when the communication 180between 181.Nm date 182and 183.Xr timed 184fails. 185.Sh BUGS 186The system attempts to keep the date in a format closely compatible 187with 188.Tn VMS . 189.Tn VMS , 190however, uses local time (rather than 191.Tn GMT ) 192and does not understand daylight-savings time. 193Thus, if you use both 194.Tn UNIX 195and 196.Tn VMS , 197.Tn VMS 198will be running on 199.Tn GMT . 200.Sh STANDARDS 201The 202.Nm date 203command is expected to be compatible with 204.St -p1003.2 . 205