date

Display or set date and time.
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 can set the date.

Syntax
      date [-jnRu] [-r seconds | filename] [-v [+|-]val[ymwdHMS]] ... [+output_fmt]
      date [-ju] [[[mm]dd]HH]MM[[cc]yy][.ss]
      date [-jRu] -f input_fmt new_date [+output_fmt]
      date [-jnu] [-I[FMT]] [-f input_fmt] [-r ...] [-v ...] [new_date]

Key
   -f      Use input_fmt as the format string to parse the new_date provided rather than using the
           default [[[mm]dd]HH]MM[[cc]yy][.ss] format.  Parsing is done using strptime(3).

   -I[FMT]
           Use ISO 8601 output format.  FMT may be omitted, in which case the default is 'date'.
           Valid FMT values are ‘date’, ‘hours’, ‘minutes’, and ‘seconds’.
           The date and time is formatted to the specified precision.  When FMT is ‘hours’ (or the more
           precise ‘minutes’ or ‘seconds’), the ISO 8601 format includes the timezone.

   -j      Do not try to set the date.  This allows you to use the -f flag in addition to the + option
           to convert one date format to another.  Note that any date or time components unspecified
           by the -f format string take their values from the current time.

   -n      Obsolete flag, accepted and ignored for compatibility.

   -R      Use RFC 2822 date and time output format.
           This is equivalent to using "%a, %d %b %Y %T %z" as output_fmt while LC_TIME is set to the "C" locale.

   -r seconds
           Print the date and time represented by seconds, where seconds is the number of seconds since
           the Epoch (00:00:00 UTC, January 1, 1970; see time(3)), and can be specified in decimal, octal, or hex.

   -r filename
           Print the date and time of the last modification of filename.

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

   -v      Adjust (i.e., take the current date and display the result of the adjustment; not actually set the date)
           the second, minute, hour, month day, week day, month or year according to val.
           If val is preceded with a plus or minus sign, the date is adjusted forwards or backwards according to the
           remaining string, otherwise the relevant 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.

           When setting values (rather than adjusting them), seconds are in the range 0-59, minutes are in the range 0-59,
           hours are in the range 0-23, 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.

           If val is numeric, one of either y, m, w, d, H, M or S must be used to specify which part of the date is to
           be adjusted.

           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.

           When a date is adjusted to a specific value or in units greater than hours, daylight savings time considerations
           are ignored.  Adjustments in units of hours or less honor daylight saving time.
           So, assuming the current date is March 26, 0:30 and that the DST adjustment means that the clock goes  forward
           at 01:00 to 02:00, using -v +1H will adjust the date to March 26, 2:30.
           Likewise, if the date is October 29, 0:30 and the DST adjustment means that the clock goes back at 02:00 to 01:00,
           using -v +3H will be necessary to reach October 29, 2:30.

           When the date is adjusted to a specific value that does not actually exist (for example March 26, 1:30 BST 2000
           in the Europe/London timezone), the date will be silently adjusted forwards in units of one hour until it reaches
           a valid time.  When the date is adjusted to a specific value that occurs twice (for example October 29, 1:30 2000),
           the resulting timezone will be set so that the date matches the earlier of the two times.

           It is not possible to adjust a date to an invalid absolute day, so using the switches -v 31d -v 12m will simply fail
           five months of the year.  It is therefore usual to set the month before setting the day; using -v 12m -v 31d always works.

           Adjusting the date by months is inherently ambiguous because a month is a unit of variable length depending
           on the current date.  This kind of date adjustment is applied in the most intuitive way.
           First of all, date tries to preserve the day of the month.  If it is impossible because the target month is shorter
           than the present one, the last day of the target month will be the result.
           For example, using -v +1m on May 31 will adjust the date to June 30, while using the same option on January 30 will
           result in the date adjusted to the last day of February.  This approach is also believed to make the most sense for
           shell scripting.  Nevertheless, be aware that going forth and back by the same number of months may take you to a
           different date.

           Refer to the examples below for further details.

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 can 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     Century (either 19 or 20) prepended to the abbreviated year.

     yy     Year in abbreviated form (e.g., 89 for 1989, 06 for 2006).
                   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     Numeric month, from 1 to 12.
     dd     The day of the month, from 1 to 31.
     hh     The hour of the day, from 0 to 23.
     mm     The minute of the hour, from 0 to 59.
     ss     Seconds, a number from 0 to 60 (59 plus a potential leap second).

     Everything but the minutes is optional.

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

Environment Variables

TZ The timezone to use when displaying dates. See environment variables for more.

Files

/var/log/messages A record of the user setting the time.

EXIT Status

The date utility exits 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.

On macOS, date is a BSD utility, not a bash feature. On machines with GNU coreutils see here for the date syntax.

Examples

Print the date as an ISO 8601 compliant date/time string:
$ date -u -I seconds

You can also get the same thing by manually selecting the 8601 elements manually:

$ date +"%Y-%m-%dT%H:%M:%S%Z"

Output the date and time on two lines (%n separates):
$ date "+DATE: %m/%d/%y%nTIME: %H:%M:%S"

DATE: 11/06/22
TIME: 19:28:54

Output the date:
$ date "+DATE: %Y-%m-%d%

DATE: 2022-11-06

Set the time to 2:32 PM, without modifying the date:

$ date 1432

Set the date to 'June 13, 1985, 4:27 PM':
$ date 0613162785

Set the time to 2:32 PM, without modifying the date:
$ date 1432

In the Europe/London timezone, the command:

$ date -v1m -v+1y

will display: Sun Jan 4 04:15:24 GMT 1998
where it is currently Mon Aug 4 04:15:24 BST 1997.

Print out the date suitable for setting on another machine:

$ date "+%m%d%H%M%Y.%S"

Store the current date in a variable (in year-month-day format)
$ mydate=`date "+%Y-%m-%d";`
$ echo The date is: ${mydate};

“Carpe Diem - Seize the day” - Horace

Related macOS commands

timed(8)
cal - Display a calendar.
crontab - Schedule a command to run at a later time.
time - Measure Program Resource Use.
touch - Change file timestamps.
TimeZones


 
Copyright © 1999-2024 SS64.com
Some rights reserved