coreutils: Options for date

1 
1 21.1.6 Options for ‘date’
1 -------------------------
1 
11 The program accepts the following options.  Also see ⇒Common
 options.
1 
1 ‘-d DATESTR’
1 ‘--date=DATESTR’
1      Display the date and time specified in DATESTR instead of the
1      current date and time.  DATESTR can be in almost any common format.
1      It can contain month names, time zones, ‘am’ and ‘pm’, ‘yesterday’,
1      etc.  For example, ‘--date="2004-02-27 14:19:13.489392193 +0530"’
1      specifies the instant of time that is 489,392,193 nanoseconds after
1      February 27, 2004 at 2:19:13 PM in a time zone that is 5 hours and
1      30 minutes east of UTC.
1      Note: input currently must be in locale independent format.  E.g.,
1      the LC_TIME=C below is needed to print back the correct date in
1      many locales:
1           date -d "$(LC_TIME=C date)"
1      ⇒Date input formats.
1 
1 ‘--debug’
1      Annotate the parsed date, display the effective time zone, and warn
1      about potential misuse.
1 
1 ‘-f DATEFILE’
1 ‘--file=DATEFILE’
1      Parse each line in DATEFILE as with ‘-d’ and display the resulting
1      date and time.  If DATEFILE is ‘-’, use standard input.  This is
1      useful when you have many dates to process, because the system
1      overhead of starting up the ‘date’ executable many times can be
1      considerable.
1 
1 ‘-I[TIMESPEC]’
1 ‘--iso-8601[=TIMESPEC]’
1      Display the date using an ISO 8601 format, ‘%Y-%m-%d’.
1 
1      The argument TIMESPEC specifies the number of additional terms of
1      the time to include.  It can be one of the following:
1      ‘auto’
1           Print just the date.  This is the default if TIMESPEC is
1           omitted.
1 
1      ‘hours’
1           Append the hour of the day to the date.
1 
1      ‘minutes’
1           Append the hours and minutes.
1 
1      ‘seconds’
1           Append the hours, minutes and seconds.
1 
1      ‘ns’
1           Append the hours, minutes, seconds and nanoseconds.
1 
1      If showing any time terms, then include the time zone using the
1      format ‘%:z’.  This format is always suitable as input for the
1      ‘--date’ (‘-d’) and ‘--file’ (‘-f’) options, regardless of the
1      current locale.
1 
1 ‘-r FILE’
1 ‘--reference=FILE’
1      Display the date and time of the last modification of FILE, instead
1      of the current date and time.
1 
1 ‘-R’
1 ‘--rfc-email’
1      Display the date and time using the format ‘%a, %d %b %Y %H:%M:%S
1      %z’, evaluated in the C locale so abbreviations are always in
1      English.  For example:
1 
1           Fri, 09 Sep 2005 13:51:39 -0700
1 
1      This format conforms to Internet RFCs 5322
1      (https://tools.ietf.org/search/rfc5322), 822
1      (https://tools.ietf.org/search/rfc2822) and 822
1      (https://tools.ietf.org/search/rfc822), the current and previous
1      standards for Internet email.  For compatibility with older
1      versions of ‘date’, ‘--rfc-2822’ and ‘--rfc-822’ are aliases for
1      ‘--rfc-email’.
1 
1 ‘--rfc-3339=TIMESPEC’
1      Display the date using a format specified by Internet RFC 3339
1      (https://tools.ietf.org/search/rfc3339).  This is like
1      ‘--iso-8601’, except that a space rather than a ‘T’ separates dates
1      from times.  This format is always suitable as input for the
1      ‘--date’ (‘-d’) and ‘--file’ (‘-f’) options, regardless of the
1      current locale.
1 
1      The argument TIMESPEC specifies how much of the time to include.
1      It can be one of the following:
1 
1      ‘date’
1           Print just the full-date, e.g., ‘2005-09-14’.  This is
1           equivalent to the format ‘%Y-%m-%d’.
1 
1      ‘seconds’
1           Print the full-date and full-time separated by a space, e.g.,
1           ‘2005-09-14 00:56:06+05:30’.  The output ends with a numeric
1           time-offset; here the ‘+05:30’ means that local time is five
1           hours and thirty minutes east of UTC.  This is equivalent to
1           the format ‘%Y-%m-%d %H:%M:%S%:z’.
1 
1      ‘ns’
1           Like ‘seconds’, but also print nanoseconds, e.g., ‘2005-09-14
1           00:56:06.998458565+05:30’.  This is equivalent to the format
1           ‘%Y-%m-%d %H:%M:%S.%N%:z’.
1 
1 ‘-s DATESTR’
1 ‘--set=DATESTR’
11      Set the date and time to DATESTR.  See ‘-d’ above.  See also ⇒
      Setting the time.
1 
1 ‘-u’
1 ‘--utc’
1 ‘--universal’
1      Use Universal Time by operating as if the ‘TZ’ environment variable
1      were set to the string ‘UTC0’.  UTC stands for Coordinated
1      Universal Time, established in 1960.  Universal Time is often
1      called “Greenwich Mean Time” (GMT) for historical reasons.
1      Typically, systems ignore leap seconds and thus implement an
1      approximation to UTC rather than true UTC.
1