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DATE(1)                 NetBSD General Commands Manual                 DATE(1)


NAME

     date -- display or set date and time


SYNOPSIS

     date [-ajnRu] [-d date] [-r seconds] [+format]
          [[[[[[CC]yy]mm]dd]HH]MM[.SS]]
     date [-ajnRu] -f input_format new_date [+format]


DESCRIPTION

     date 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.

     The options are as follows:

     -a          Use adjtime(2) to change the local system time slowly, main-
                 taining it as a monotonically increasing function.  -a
                 implies -n.

     -d date     Parse the provided human-described date and time and display
                 the result without actually changing the system clock.  (See
                 parsedate(3) for examples.)

     -f input_fmt
                 Use input_fmt as the format string to parse the new_date pro-
                 vided rather than using the default
                 [[[[[CC]yy]mm]dd]HH]MM[.SS] format.  Parsing is done using
                 strptime(3).

     -j          Parse the provided canonical representation of date and time
                 (described below) and display the result without actually
                 changing the system clock.

     -n          The utility timed(8) is used to synchronize the clocks on
                 groups of machines.  By default, if timed(8) is running, date
                 will set the time on all of the machines in the local group.
                 The -n option stops date from setting the time for other than
                 the current machine.

     -R          Use a default display format that conforms to the date and
                 time specification in RFC 5322 (Internet Message Format).

     -r seconds  Print out the date and time that is seconds from the Epoch.

     -u          Display or set the date in UTC (universal) time.

     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 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:

           %a %b %e %H:%M:%S %Z %Y

     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:

           CC      The first two digits of the year (the century).
           yy      The second two digits of the year.  If yy is specified, but
                   CC is not, a value for yy between 69 and 99 results in a CC
                   value of 19.  Otherwise, a CC value of 20 is used.
           mm      The month of the year, from 01 to 12.
           dd      The day of the month, from 01 to 31.
           HH      The hour of the day, from 00 to 23.
           MM      The minute of the hour, from 00 to 59.
           SS      The second of the minute, from 00 to 60.

     Everything but the minutes is optional.

     Time changes for Daylight Saving and Standard Time and leap seconds and
     years are handled automatically.


ENVIRONMENT

     The following environment variables affect the execution of date:

     TZ               The timezone to use when displaying dates.  See
                      environ(7) for more information.


FILES

     /etc/localtime                    Symlink pointing to system's default
                                       timezone information file in
                                       /usr/share/zoneinfo directory.
     /usr/lib/locale/<L>/LC_TIME       Description of time locale <L>.
     /usr/share/zoneinfo               Time zone information directory.
     /usr/share/zoneinfo/posixrules    Used with POSIX-style TZ's.
     /usr/share/zoneinfo/GMT           For UTC leap seconds.
     /var/log/wtmp                     A record of date resets and time
                                       changes.
     /var/log/messages                 A record of the user setting the time.

     If /usr/share/zoneinfo/GMT is absent, UTC leap seconds are loaded from
     /usr/share/zoneinfo/posixrules.


EXAMPLES

     The command:

           date '+DATE: %m/%d/%y%nTIME: %H:%M:%S'

     will display:

           DATE: 11/21/87
           TIME: 13:36:16

     The command:

           date 8506131627

     sets the date to ``June 13, 1985, 4:27 PM''.

     The command:

           date 1432

     sets the time to 2:32 PM, without modifying the date.

     The command:

           date +%s

     prints the current time as seconds since the Epoch.


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.

     Occasionally, when timed(8) synchronizes the time on many hosts, the set-
     ting of a new time value may require more than a few seconds.  On these
     occasions, date prints: `Network time being set'.  The message
     `Communication error with' timed(8) occurs when the communication between
     date and timed(8) fails.


SEE ALSO

     adjtime(2), gettimeofday(2), settimeofday(2), parsedate(3), strftime(3),
     utmp(5), environ(7), timed(8)

     R. Gusella and S. Zatti, TSP: The Time Synchronization Protocol for UNIX
     4.3BSD.


STANDARDS

     The date utility is expected to be compatible with IEEE Std 1003.2
     (``POSIX.2'').


HISTORY

     A date utility appeared in Version 1 AT&T UNIX.

NetBSD 9.4                       May 31, 2023                       NetBSD 9.4