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@(#)date.1 8.3 (Berkeley) 4/28/95
$Id: date.1,v 1.13 1997/08/04 03:37:05 brian Exp $
.Dd November 17, 1993 .Dt DATE 1 .Os .Sh NAME .Nm date .Nd display or set date and time .Sh SYNOPSIS .Nm date .Op Fl d Ar dst .Op Fl r Ar seconds .Op Fl t Ar minutes_west .Op Fl nu .Op Cm + Ns Ar format .Op Fl v Ar [+|-]val[ymwdHM] .Ar ... .Op [[[[yy]mm]dd]HH]MM[.ss] .Sh DESCRIPTION .Nm displays the current date and time when invoked without arguments. Providing arguments will format the date and time in a user-defined way or set the date. Only the superuser may set the date.
p The options are as follows: l -tag -width Ds t Fl d Set the kernel's value for daylight savings time. If .Ar dst is non-zero, future calls to .Xr gettimeofday 2 will return a non-zero .Ql tz_dsttime . t Fl n The utility .Xr timed 8 is used to synchronize the clocks on groups of machines. By default, if .Xr timed is running, .Nm date will set the time on all of the machines in the local group. The .Fl n option stops .Nm date from setting the time for other than the current machine. t Fl r Print out the date and time in .Ar seconds from the Epoch. t Fl t Set the kernel's value for minutes west of .Tn GMT . .Ar Minutes_west specifies the number of minutes returned in .Ql tz_minuteswest by future calls to .Xr gettimeofday 2 . t Fl u Display or set the date in .Tn UCT (universal) time. t Fl v Adjust the minute, hour, month day, week day, month or year according to .Ar val . If .Ar val is preceeded with a plus or minus sign, the date is adjusted forwards or backwards according to the remaining string, otherwise the relevent part of the date is set. The date can be adjusted as many times as required using these flags. Flags are processed in the order given.
p Minutes are in the range 0-59, hours are in the range 1-12, month days are in the range 1-31, week days are in the range 0-6 (sun-sat), months are in the range 1-12 (jan-dec) and years are in the range 80-38 or 1980-2038.
p If .Ar val is numeric, one of either .Ar y , .Ar m , .Ar w , .Ar d , .Ar H or .Ar M must be used to specify which part of the date is to be adjusted.
p The week day or month may be specified using a name rather than a number. If a name is used with the plus (or minus) sign, the date will be put forwards (or backwards) to the next (previous) date that matches the given week day or month. This will not adjust the date if the given week day or month is the same as the current one.
p Refer to the examples below for further details. .El
p An operand with a leading plus (``+'') sign signals a user-defined format string which specifies the format in which to display the date and time. The format string may contain any of the conversion specifications described in the .Xr strftime 3 manual page, as well as any arbitrary text. A <newline> character is always output after the characters specified by the format string. The format string for the default display is: d -literal -offset indent ``+%+'' .Ed
p If an operand does not have a leading plus sign, it is interpreted as a value for setting the system's notion of the current date and time. The canonical representation for setting the date and time is:
p l -tag -width Ds -compact -offset indent t Ar yy Year in abbreviated form (e.g. 89 for 1989, 06 for 2006). t Ar mm Numeric month. A number from 1 to 12. t Ar dd Day, a number from 1 to 31. t Ar hh Hour, a number from 0 to 23. t Ar mm Minutes, a number from 0 to 59. t Ar .ss Seconds, a number from 0 to 61 (59 plus a maximum of two leap seconds). .El
p Everything but the minutes is optional.
p Time changes for Daylight Saving and Standard time and leap seconds and years are handled automatically. .Sh EXAMPLES The command: d -literal -offset indent date ``+DATE: %m/%d/%y%nTIME: %H:%M:%S'' .Ed
p will display: d -literal -offset indent DATE: 11/21/87 TIME: 13:36:16 .Ed
p The command: d -literal -offset indent date -v1m -v+1y .Ed
p will display: d -literal -offset indent Sun Jan 4 03:15:24 GMT 1998 .Ed
p (where it is currently Mon Aug 4 04:15:24 BST 1997).
p The command: d -literal -offset indent date -v1d -v3m -v0y -v-1d .Ed
p will display the last day of February in the year 2000: d -literal -offset indent Tue Feb 29 03:18:00 GMT 2000 .Ed
p The command: d -literal -offset indent date -v1d -v+1m -v-1d -v-fri .Ed
p will display the last friday of the month: d -literal -offset indent Fri Aug 29 04:31:11 BST 1997 .Ed
p (where it is currently Mon Aug 4 04:31:11 BST 1997).
p The command: d -literal -offset indent date 8506131627 .Ed
p sets the date to .Dq Li "June 13, 1985, 4:27 PM" .
p The command: d -literal -offset indent date 1432 .Ed
p sets the time to .Li "2:32 PM" , without modifying the date. .Sh ENVIRONMENT VARIABLES The execution of .Nm is affected by the following evironment variables: l -tag -width Ds t Ev TZ The timezone to use when displaying dates. See .Xr environ 7 for more information. .El .Sh FILES l -tag -width /var/log/messages -compact t Pa /var/log/wtmp A record of date resets and time changes. t Pa /var/log/messages A record of the user setting the time. .El .Sh SEE ALSO .Xr gettimeofday 2 , .Xr strftime 3 , .Xr utmp 5 , .Xr timed 8 .Rs .%T "TSP: The Time Synchronization Protocol for UNIX 4.3BSD" .%A R. Gusella .%A S. Zatti .Re .Sh DIAGNOSTICS Exit status is 0 on success, 1 if unable to set the date, and 2 if able to set the local date, but unable to set it globally.
p Occasionally, when .Xr timed synchronizes the time on many hosts, the setting of a new time value may require more than a few seconds. On these occasions, .Nm date prints: .Ql Network time being set . The message .Ql Communication error with timed occurs when the communication between .Nm date and .Xr timed fails. .Sh BUGS The system attempts to keep the date in a format closely compatible with .Tn VMS . .Tn VMS , however, uses local time (rather than .Tn GMT ) and does not understand daylight-savings time. Thus, if you use both .Tn UNIX and .Tn VMS , .Tn VMS will be running on .Tn GMT . .Sh STANDARDS The .Nm date command is expected to be compatible with .St -p1003.2 . .Sh HISTORY A .Nm command appeared in .At v1 .