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date(1)								      date(1)



NAME

  date - Displays or sets the date

SYNOPSIS

  Without Superuser Authority -	Displays the Date


  date [-u] [+field_descriptor ...]

  With Superuser Authority - Sets the Date


  date [-nu] [MMddhhmm.ssyy | alternate_date_format] [+field_descriptor	...]

  Using	XCU5.0 - Sets or Displays the Date


  date [-u] mmddHHMM[yy]

  date [-u] [+field_descriptor ...]

  Using	the Century Field Provided by Compaq - Sets the	Date


  date mmddHHMM[[cc]yy]	[.ss]

  date [[cc]yy]mmddHHMM[.ss]

  date mmddHHMM[.ss[[cc]yy]]

STANDARDS

  Interfaces documented	on this	reference page conform to industry standards
  as follows:

  date:	 XCU5.0

  Refer	to the standards(5) reference page for more information	about indus-
  try standards	and associated tags.

OPTIONS

  -n  [Tru64 UNIX]  Does not set the time globally on all machines in a	local
      area network that	have their clocks synchronized (superuser only).

  -u  Performs operations as if	the TZ environment variable was	set to the
      string GMT0.  Otherwise, date uses the time zone indicated by the	TZ
      environment variable or the system default if that variable is not set.




DESCRIPTION

  The date command displays the	date and, with superuser authority, sets the
  system date. The date	command	has been enhanced to support setting the sys-
  tem date past	the year 1999, thus providing customers	with the ability to
  begin	testing	their software for potential century rollover problems.

  Displaying the Date


  The date command writes the current date and time to standard	output if
  called with no options or with a option list that begins with	a + (plus
  sign).

  If you follow	date with a + (plus sign) and a	field descriptor, you can
  control the output of	the command.  You must precede each field descriptor
  with a % (percent sign).  The	system replaces	the field descriptor with the
  specified value.  Enter a literal % as %%.  The date command copies any
  other	characters to standard output without change. The date command always
  ends the string with a newline character.  Output fields are fixed size
  (zero	padded if necessary).

  [Tru64 UNIX]	The date command prints	out a usage message on any unrecog-
  nized	options	or input.

  Field	Descriptors


  a   Displays the locale's abbreviated	weekday	name (Sun to Sat or the	non-
      English equivalent).

  A   Displays the locale's full weekday name.

  b   Displays the locale's abbreviated	month name.

  B   Displays the locale's full month name.

  c   Displays the locale's appropriate	time and date representation.

  C   Displays the locale's century (the year divided by 100 and truncated to
      an integer) as a decimal number (00 to 99).

  d   Displays the day of month	as a decimal number (01	to 31).

  D   Displays the date	in the format mm/dd/yy independent of the value
      specified	by the LC_TIME environment variable, if	defined.

  e   Displays the day of the month as a decimal number	(1 to 31 in a 2-digit
      field with leading space fill).

  Ec  Specifies	the locale's alternative date and time representation.

  EC  Specifies	the name of the	base year (period) in the locale's alterna-
      tive representation.

  Ex  Specifies	the locale's alternative date representation.

  EX  Specifies	the locale's alternative time representation.

  Ey  Specifies	the offset from	%EC (year only)	in the locale's	alternative
      representation.

  EY  Specifies	the full alternative year representation.

  h   A	synonym	for %b.

  H   Displays the hour	as a decimal number (00	to 23).

  I   Displays the hour	as a decimal number (01	to 12).

  j   Displays the day of year as a decimal number (001	to 366).

  m   Displays the month of year as a decimal number (01 to 12).

  M   Displays the minute as a decimal number (00 to 59).

  n   Inserts a	newline	character.

  N   [Tru64 UNIX]  Represents the alternative era name.

  o   [Tru64 UNIX]  Represents the alternative era year.

  Od  Specifies	the day	of the month using the locale's	alternative numeric
      symbols.

  Oe  Specifies	the day	of the month using the locale's	alternative numeric
      symbols.

  OH  Specifies	the hour (24-hour clock) using the locale's alternative
      numeric symbols.

  OI  Specifies	the hour (12-hour clock) using the locale's alternative
      numeric symbols.

  Om  Specifies	the month using	the locale's alternative numeric symbols.

  OM  Specifies	the minutes using the locale's alternative numeric symbols.

  OS  Specifies	the seconds using the locale's alternative numeric symbols.

  Ou  Specifies	the weekday as a number	in the locale's	alternative represen-
      tation (Monday=1).

  OU  Specifies	the week number	of the year (Sunday as the first day of	the
      week) using the locale's alternative numeric symbols.

  Ow  Specifies	the weekday as a number	in the locale's	alternative represen-
      tation (Sunday = 0).

  OW  Specifies	the week number	of the year (Monday as the first day of	the
      week) using the locale's alternative numeric symbols.

  Oy  Specifies	the year (offset from %C) in alternative representation.

  p   Displays the locale's equivalent of either AM or PM.

  r   Displays the time	(12-hour clock)	using AM/PM notation (or the non-
      English equivalent) in the format	hh:mm:ss AM or hh:mm:ss	PM.

  S   Displays the second as a decimal number (00 to 61).

  t   Inserts a	tab character.

  T   Displays the time	in 24-hour clock format	as hh:mm:ss (the default), or
      as specified by the LC_TIME environment variable,	if defined.

  u   Displays the weekday as a	decimal	number [1,7], with 1 representing
      Monday.

  U   Displays the week	number of the year (Sunday is the first	day of the
      week) as a decimal number	(00 to 53).  All days in a new year preceding
      the first	Sunday are considered to be in week 0.

  V   Displays the week	number of the year (Monday as the first	day of the
      week) as a decimal number	(01 to 53).  If	the week containing January 1
      has four or more days in the new year, then it is	considered week	1;
      otherwise, it is week 53 of the previous year, and the next week is
      week 1.

  w   Displays the day of the week as a	decimal	number (Sunday = 0).

  W   Displays the week	number of the year (Monday is the first	day of the
      week) as a decimal number	(00 to 53).  All days in a new year preceding
      the first	Monday are considered to be in week 0.

  x   Displays the locale's appropriate	date representation.

  X   Displays the locale's appropriate	time representation.

  y   Displays the last	two numbers of the year	as a decimal number (00	to
      99).

  Y   Displays the full	year as	a decimal number.

  Z   Displays the time	zone name, or no characters if the time	zone cannot
      be determined.

  %%  Inserts a	% character.

  Setting the Date


  Only a user operating	with superuser authority can change the	date and
  time.

  The default input format for setting the date	is mmddHHMM[[cc]yy][.ss]
  where:

    +  mm is the month number (01=January).

    +  dd is the number	of the day in the month.

    +  HH is the hour in the day (using	a 24-hour clock).

    +  MM is the number	of minutes.

    +  cc is the first two digits of the year.

    +  yy is the last two digits of the	year.  If this field is	omitted, the
       current year is used.

    +  ss is the number	of seconds.

  The LC_TIME variable,	if defined, controls the ordering of the day (dd) and
  month	(mm) numbers in	these formats.	The default order is the month (mm)
  followed by the day (dd).

  Each of the Compaq formats allows you	to specify the century (first two
  digits of the	year).	This century field (cc)	is optional to ensure that
  input	formats	previously accepted by the date	command	are still supported.

  Currently, theXCU5.0 format does not have a century field.  This is con-
  sistent with current X/Open specifications regarding the date	command.  The
  century field	will be	added to this format in	a future release of the
  operating system once	this new field is officially supported in future
  revisions of X/Open's	UNIX specification.

  [Tru64 UNIX]	Reset the date in single-user mode only. Changing the date in
  multiuser mode could cause the creation and modifications dates for user
  files	to be inconsistent.

  [Tru64 UNIX]	To change the year, the	system disk must be updated with the
  new year information.	To change the year, in single-user mode	enter the
  following command after you enter a date containing a	new year:

       mount -u	/

  The mount -u / command writes	the new	year into the superblock on the	sys-
  tem disk. The	root file system is now	mounted	read/write.

  Handling of Two-Digit	Year Input


  When the year	is specified using two digits (as in the XCU5.0	format or
  when the [cc]	field is omitted from the Compaq formats), the century is
  determined in	the following manner: if the specified two-digit year is
  between 69 and 99 inclusive, the 20th	century	is assumed (that is, 19yy);
  otherwise, the 21st century is assumed (that is, 20yy).

  This algorithm for determining the century is	consistent with	current
  drafts of forthcoming	X/Open UNIX specifications regarding two-digit year
  handling in various system interfaces	and commands, including	the date com-
  mand.	 This algorithm	is based on the	standard UNIX epoch (12:00:00 AM Jan
  1, 1970 UTC),	minus one year to account for different	time zones.  Internal
  UNIX time handling is	based on the number of seconds in this epoch.

  Handling of Ambiguous	Input


  If the input string is ambiguous, that is, if	the format cannot be con-
  clusively determined from the	data, the date command will issue a warning
  to stderr and	assume the mmddHHMM[[cc]yy][.ss] format.  To avoid ambiguous
  input, use one of the	three Compaq formats and specify the [cc] field.

EXAMPLES

   1.  To display current date and time, enter:
	    date

       Depending on your current locale, the output might look like one	of
       the following:
	    Thu	Apr 16	13:21:30 EDT  1998

	    jeu	16 avr	17:21:30 CUT  1998

	    tor	16 apr	17:21:30 CUT  1998

       The first output	line is	for an American	English	locale,	the second is
       for a French locale, and	the third is for a Danish locale.

   2.  To set the date and time, enter:
	    date  02171425.45

       This sets the date and time to 14:25:45 (45 seconds after 2:25 p.m.)
       February	17 of the current year.

   3.  To display the date and time in a specified format, enter:
	    date  +"%r	%d  %h	%y  (%a)"

       This displays the date (assume current year is 1993) shown in Example
       2 as:
	    02:25:45  PM  17  Feb  99  (Fri)



  Do not set the date in multi-user mode.




  Year 2000 Examples


  To set the date to 09:34:00 AM Jan 7,	2000:

   1.  Using the mmddHHMM[[cc]yy][.ss] Compaq format:
	    date 010709342000
	    date 0107093400.00
	    date 010709342000.00

   2.  Using the [[cc]yy]mmddHHMM[.ss] Compaq format:
	    date 0001070934
	    date 200001070934
	    date 200001070934.00

   3.  Using the mmddHHMM[.ss[[cc]yy]] Compaq format:
	    date 01070934.0000
	    date 01070934.002000

   4.  Using the mmddHHMM[yy]  format:
	    date 0107093400

   5.  An example of ambiguous input:  XCU5.0
	    date 0101010000

       This input could	be recognized as one of	the following formats:

       mmddHHMM[[cc]yy][.ss] meaning 01:00:00 AM Jan 1,	2000

       [[cc]yy]mmddHHMM[.ss] meaning 12:00:00 AM Jan 1,	2001

       In this case, the date command will display a warning and assume	the
       mmddHHMM[[cc]yy][.ss] format, setting the date to 01:00:00 AM Jan 1,
       2000.

ENVIRONMENT VARIABLES

  The following	environment variables affect the execution of date:

  LANG
      Provides a default value for the internationalization variables that
      are unset	or null. If LANG is unset or null, the corresponding value
      from the default locale is used. If any of the internationalization
      variables	contain	an invalid setting, the	utility	behaves	as if none of
      the variables had	been defined.

  LC_ALL
      If set to	a non-empty string value, overrides the	values of all the
      other internationalization variables.

  LC_CTYPE
      Determines the locale for	the interpretation of sequences	of bytes of
      text data	as characters (for example, single-byte	as opposed to multi-
      byte characters in arguments).

  LC_MESSAGES
      Determines the locale for	the format and contents	of diagnostic mes-
      sages written to standard	error.

  LC_TIME
      Determines the format of the date	and time strings written by date.

  NLSPATH
      Determines the location of message catalogues for	the processing of
      LC_MESSAGES.

  TZ  Determines the time zone in which	the time and date are written, unless
      the -u option is specified.  If the TZ variable is not set and the -u
      option is	not specified, a system	default	time zone is used.

SEE ALSO

  Functions:  gettimeofday(2)

  Routines:  ctime(3), getclock(3), setclock(3)

  Standards:  standards(5)

  Command and Shell User's Guide