(coreutils.info.gz) Examples of date

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(coreutils.info.gz) Options for date

(coreutils.info.gz) date invocation

 
 21.1.7 Examples of 'date'
 -------------------------
 
 Here are a few examples.  Also see the documentation for the '-d' option
 in the previous section.
 
    * To print the date of the day before yesterday:
 
           date --date='2 days ago'
 
    * To print the date of the day three months and one day hence:
 
           date --date='3 months 1 day'
 
    * To print the day of year of Christmas in the current year:
 
           date --date='25 Dec' +%j
 
    * To print the current full month name and the day of the month:
 
           date '+%B %d'
 
      But this may not be what you want because for the first nine days
      of the month, the '%d' expands to a zero-padded two-digit field,
      for example 'date -d 1may '+%B %d'' will print 'May 01'.
 
    * To print a date without the leading zero for one-digit days of the
      month, you can use the (GNU extension) '-' flag to suppress the
      padding altogether:
 
           date -d 1may '+%B %-d'
 
    * To print the current date and time in the format required by many
      non-GNU versions of 'date' when setting the system clock:
 
           date +%m%d%H%M%Y.%S
 
    * To set the system clock forward by two minutes:
 
           date --set='+2 minutes'
 
    * To print the date in RFC 2822 format, use 'date --rfc-2822'.  Here
      is some example output:
 
           Fri, 09 Sep 2005 13:51:39 -0700
 
    * To convert a date string to the number of seconds since the epoch
      (which is 1970-01-01 00:00:00 UTC), use the '--date' option with
      the '%s' format.  That can be useful in sorting and/or graphing
      and/or comparing data by date.  The following command outputs the
      number of the seconds since the epoch for the time two minutes
      after the epoch:
 
           date --date='1970-01-01 00:02:00 +0000' +%s
           120
 
      If you do not specify time zone information in the date string,
      'date' uses your computer's idea of the time zone when interpreting
      the string.  For example, if your computer's time zone is that of
      Cambridge, Massachusetts, which was then 5 hours (i.e., 18,000
      seconds) behind UTC:
 
           # local time zone used
           date --date='1970-01-01 00:02:00' +%s
           18120
 
    * If you're sorting or graphing dated data, your raw date values may
      be represented as seconds since the epoch.  But few people can look
      at the date '946684800' and casually note "Oh, that's the first
      second of the year 2000 in Greenwich, England."
 
           date --date='2000-01-01 UTC' +%s
           946684800
 
      An alternative is to use the '--utc' ('-u') option.  Then you may
      omit 'UTC' from the date string.  Although this produces the same
      result for '%s' and many other format sequences, with a time zone
      offset different from zero, it would give a different result for
      zone-dependent formats like '%z'.
 
           date -u --date=2000-01-01 +%s
           946684800
 
      To convert such an unwieldy number of seconds back to a more
      readable form, use a command like this:
 
           # local time zone used
           date -d '1970-01-01 UTC 946684800 seconds' +"%Y-%m-%d %T %z"
           1999-12-31 19:00:00 -0500
 
      Or if you do not mind depending on the '@' feature present since
      coreutils 5.3.0, you could shorten this to:
 
           date -d @946684800 +"%F %T %z"
           1999-12-31 19:00:00 -0500
 
      Often it is better to output UTC-relative date and time:
 
           date -u -d '1970-01-01 946684800 seconds' +"%Y-%m-%d %T %z"
           2000-01-01 00:00:00 +0000
 
    * Typically the seconds count omits leap seconds, but some systems
      are exceptions.  Because leap seconds are not predictable, the
      mapping between the seconds count and a future timestamp is not
      reliable on the atypical systems that include leap seconds in their
      counts.
 
      Here is how the two kinds of systems handle the leap second at
      2012-06-30 23:59:60 UTC:
 
           # Typical systems ignore leap seconds:
           date --date='2012-06-30 23:59:59 +0000' +%s
           1341100799
           date --date='2012-06-30 23:59:60 +0000' +%s
           date: invalid date '2012-06-30 23:59:60 +0000'
           date --date='2012-07-01 00:00:00 +0000' +%s
           1341100800
 
           # Atypical systems count leap seconds:
           date --date='2012-06-30 23:59:59 +0000' +%s
           1341100823
           date --date='2012-06-30 23:59:60 +0000' +%s
           1341100824
           date --date='2012-07-01 00:00:00 +0000' +%s
           1341100825
 

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(coreutils.info.gz) Options for date

(coreutils.info.gz) date invocation