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date

summary

    This subchapter looks at date, a UNIX (and Linux) command.

    date is used to set or view the system date and time.

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date

    This subchapter looks at date, a UNIX (and Linux) command.

    date is used to set or view the system date and time.

    $ date
    Mon Sep  3 00:56:17 PDT 2012
    $

    The format for the output is: day of the week, month, day of the month, 24 hour time, time zone, year.

formatted output

    Display the time and/or date with formatting by including formatting options (which can be used to set variables to a specific format).

    $ date '+DATE: %m/%d/%y%nTIME: %H:%M:%S'
    DATE: 11/23/13
    TIME: 22:12:19
    $

    Setting a variable with the current date:

    $ NOW=$(date +"%m/%d/%Y")
    $ echo $NOW
    11/23/2013
    $

Format specifiers (format string starts with +)

Specifier	Description	Values or example
Day
%a	weekday, abbreviated	Sun
%A	weekday, full	Sunday
%d	day of the month, two digits, zero filled	08
%e	day of the month	8
%j	day of year, zero filled	001Ð366
%u	day of week from Monday to Sunday	1Ð7
%w	day of week from Sunday to Saturday	0Ð6
Week
%U	week number, Sunday as first day of week	00Ð53
%W	week number, Monday as first day of week	00Ð53
%V	ISO standard week of the year	01Ð53
Month
%m	two-digit month number	01Ð12
%h	month name, abbreviated	Nov
%b	month name, localised abbreviation	Nov
%B	locale's full month, variable length	November
Year
%y	two-digit year	00Ð99
%Y	four-digit year	2013
%g	two-digit year corresponding to the %V week number
%G	four-digit year corresponding to the %V week number
Century
%C	two century digits from year	00Ð99
Date
%D	mm/dd/yy	11/24/13
%x	locale's date representation	11/24/2013
%F	%Y-%m-%d	2013-11-24
Hours
%l	hour (12 hour)	4
%I	hour (12 hour), zero-filled	04
%k	hour (24 hour)	4
%H	hour (24 hour), zero-padded	04
%p	locale's upper case AM or PM (blank in many locales)	AM
%P	locale's lower case am or pm	am
Minutes
%M	two-digit minute number	05
Seconds
%s	seconds since 00:00:00 1970-01-01 UTC (Unix epoch)	1385265929
%S	two-digit second number	00Ð60 (Includes 60 to accommodate a leap second)
%N	nanoseconds	000000000Ð999999999
Time
%r	hours, minutes, seconds (12-hour clock)	04:05:29 AM
%R	hours, minutes (24 hour clock)	04:05
%T	hours, minutes, seconds (24-hour clock)	04:05:29
%X	locale's time representation	11:07:26 AM
Date and time
%c	locale's date and time	Sat Nov 04 12:02:33 EST 1989
Time zone
%z	RFC-822 style numeric time zone	-0500
%Z	time zone name; nothing if no time zone is determinable	EST, EDT

literals:      %n newline      %% percent      %t horizontal tab

    By default, date normally fills numeric fields with zeroes. GNU date, but not BSD date, recognizes a modifier between the per cent sign (%) and the format specifier:

• hyphen (-): do not fill the field
• underscore (_): pad the field with spaces

    TZ Specifies the time zone, unless overridden by command line parameters. If neither is specified, the setting from /etc/localtime is used.

setting time and date

    Only the root or superuser an set the system date and time. In Mac OS X, you can use the clock system preferences t set the time and date. In Ubuntu-based Linux, you can click on the clock and select Time and Date settings from the menu or click on the System menu, select Adminsitration, select Time and Date.

    Set the time to noon:

    $ date 1200
    $

    Set the time to 3:30:30 a.m.:

    $ date 0330.30
    $

    Set the date to October 31st (Halloween) at 3:30 a.m.:

    $ date 10310330
    $

other

    On November 8, 2010, Ramesh Natarajan named this the number 49 most frequently used UNIX/Linux command at this web page 50 Most Frequently Used UNIX / Linux Commands (With Examples).

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