Provided by: manpages-posix_2.16-1_all bug

NAME

       date - write the date and time

SYNOPSIS

       date [-u] [+format]

       date [-u] mmddhhmm[[cc]yy]

DESCRIPTION

       The  date  utility shall write the date and time to standard output  or
       attempt to set the system date and time.  By default, the current  date
       and  time  shall  be  written.  If  an  operand  beginning  with '+' is
       specified, the output  format  of  date  shall  be  controlled  by  the
       conversion specifications and other text in the operand.

OPTIONS

       The  date  utility  shall  conform  to  the  Base Definitions volume of
       IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.

       The following option shall be supported:

       -u     Perform operations as if the TZ environment variable was set  to
              the string "UTC0" , or its equivalent historical value of "GMT0"
              . Otherwise, date shall use the timezone  indicated  by  the  TZ
              environment  variable  or the system default if that variable is
              unset or null.

OPERANDS

       The following operands shall be supported:

       +format
              When the format is specified, each conversion specifier shall be
              replaced in the standard output by its corresponding value.  All
              other characters shall be copied to the output  without  change.
              The output shall always be terminated with a <newline>.

   Conversion Specifications
       %a     Locale's abbreviated weekday name.

       %A     Locale's full weekday name.

       %b     Locale's abbreviated month name.

       %B     Locale's full month name.

       %c     Locale's appropriate date and time representation.

       %C     Century (a year divided by 100 and truncated to an integer) as a
              decimal number [00,99].

       %d     Day of the month as a decimal number [01,31].

       %D     Date in the format mm/dd/yy.

       %e     Day of the month as a decimal number [1,31] in a two-digit field
              with leading space character fill.

       %h     A synonym for %b .

       %H     Hour (24-hour clock) as a decimal number [00,23].

       %I     Hour (12-hour clock) as a decimal number [01,12].

       %j     Day of the year as a decimal number [001,366].

       %m     Month as a decimal number [01,12].

       %M     Minute as a decimal number [00,59].

       %n     A <newline>.

       %p     Locale's equivalent of either AM or PM.

       %r     12-hour  clock  time  [01,12]  using  the AM/PM notation; in the
              POSIX locale, this shall be equivalent to %I : %M : %S %p .

       %S     Seconds as a decimal number [00,60].

       %t     A <tab>.

       %T     24-hour clock time [00,23] in the format HH:MM:SS.

       %u     Weekday as a decimal number [1,7] (1=Monday).

       %U     Week of the year (Sunday as the first day  of  the  week)  as  a
              decimal  number  [00,53].  All  days in a new year preceding the
              first Sunday shall be considered to be in week 0.

       %V     Week of the year (Monday as the first day  of  the  week)  as  a
              decimal  number  [01,53].  If  the week containing January 1 has
              four or more days in the new year, then it shall  be  considered
              week  1;  otherwise,  it  shall be the last week of the previous
              year, and the next week shall be week 1.

       %w     Weekday as a decimal number [0,6] (0=Sunday).

       %W     Week of the year (Monday as the first day  of  the  week)  as  a
              decimal  number  [00,53].  All  days in a new year preceding the
              first Monday shall be considered to be in week 0.

       %x     Locale's appropriate date representation.

       %X     Locale's appropriate time representation.

       %y     Year within century [00,99].

       %Y     Year with century as a decimal number.

       %Z     Timezone name, or no characters if no timezone is determinable.

       %%     A percent sign character.

       See the Base Definitions volume of IEEE Std 1003.1-2001, Section 7.3.5,
       LC_TIME for the conversion specifier values in the POSIX locale.

   Modified Conversion Specifications
       Some  conversion  specifiers  can  be  modified by the E and O modifier
       characters to indicate a different format or specification as specified
       in  the  LC_TIME locale description (see the Base Definitions volume of
       IEEE Std 1003.1-2001, Section 7.3.5,  LC_TIME).  If  the  corresponding
       keyword  (see  era,  era_year,  era_d_fmt,  and  alt_digits in the Base
       Definitions volume of IEEE Std 1003.1-2001, Section 7.3.5, LC_TIME)  is
       not  specified  or not supported for the current locale, the unmodified
       conversion specifier value shall be used.

       %Ec    Locale's alternative appropriate date and time representation.

       %EC    The name of the base year (period) in the  locale's  alternative
              representation.

       %Ex    Locale's alternative date representation.

       %EX    Locale's alternative time representation.

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

       %EY    Full alternative year representation.

       %Od    Day of month using the locale's alternative numeric symbols.

       %Oe    Day of month using the locale's alternative numeric symbols.

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

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

       %Om    Month using the locale's alternative numeric symbols.

       %OM    Minutes using the locale's alternative numeric symbols.

       %OS    Seconds using the locale's alternative numeric symbols.

       %Ou    Weekday as a number in the locale's  alternative  representation
              (Monday = 1).

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

       %OV    Week number of the year (Monday as the first day  of  the  week,
              rules  corresponding  to  %V  ),  using the locale's alternative
              numeric symbols.

       %Ow    Weekday as a number in the locale's  alternative  representation
              (Sunday = 0).

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

       %Oy    Year (offset from %C ) in alternative representation.

       mmddhhmm[[cc]yy]

              Attempt to set the system date and time from the value given  in
              the  operand.  This is only possible if the user has appropriate
              privileges and the system permits the setting of the system date
              and  time.  The  first  mm  is the month (number); dd is the day
              (number); hh is the hour (number, 24-hour system); the second mm
              is  the  minute (number); cc is the century and is the first two
              digits of the year (this is optional); yy is the last two digits
              of  the year and is optional.  If century is not specified, then
              values in the range [69,99] shall refer to years  1969  to  1999
              inclusive,  and values in the range [00,68] shall refer to years
              2000 to 2068 inclusive. The current year is the default if yy is
              omitted.

       Note:
              It  is expected that in a future version of IEEE Std 1003.1-2001
              the default century inferred from a 2-digit  year  will  change.
              (This  would  apply  to all commands accepting a 2-digit year as
              input.)

STDIN

       Not used.

INPUT FILES

       None.

ENVIRONMENT VARIABLES

       The following environment variables shall affect the execution of date:

       LANG   Provide a default value for the  internationalization  variables
              that  are  unset  or  null.  (See the Base Definitions volume of
              IEEE Std 1003.1-2001,    Section    8.2,    Internationalization
              Variables  for  the precedence of internationalization variables
              used to determine the values of locale categories.)

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

       LC_CTYPE
              Determine  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
              Determine  the  locale  that should be used to affect the format
              and contents of diagnostic messages written to standard error.

       LC_TIME
              Determine the format and  contents  of  date  and  time  strings
              written by date.

       NLSPATH
              Determine the location of message catalogs for the processing of
              LC_MESSAGES .

       TZ     Determine the timezone in which the time and date  are  written,
              unless  the  -u option is specified. If the TZ variable is unset
              or null and -u is not specified, an unspecified  system  default
              timezone is used.

ASYNCHRONOUS EVENTS

       Default.

STDOUT

       When no formatting operand is specified, the output in the POSIX locale
       shall be equivalent to specifying:

              date "+%a %b %e %H:%M:%S %Z %Y"

STDERR

       The standard error shall be used only for diagnostic messages.

OUTPUT FILES

       None.

EXTENDED DESCRIPTION

       None.

EXIT STATUS

       The following exit values shall be returned:

        0     The date was written successfully.

       >0     An error occurred.

CONSEQUENCES OF ERRORS

       Default.

       The following sections are informative.

APPLICATION USAGE

       Conversion specifiers are of unspecified format when not in  the  POSIX
       locale.  Some of them can contain <newline>s in some locales, so it may
       be difficult to use the format shown in standard output for parsing the
       output of date in those locales.

       The  range of values for %S extends from 0 to 60 seconds to accommodate
       the occasional leap second.

       Although certain of the conversion specifiers in the POSIX locale (such
       as  the name of the month) are shown with initial capital letters, this
       need not be the case in other locales. Programs using these fields  may
       need  to adjust the capitalization if the output is going to be used at
       the beginning of a sentence.

       The date  string  formatting  capabilities  are  intended  for  use  in
       Gregorian-style  calendars, possibly with a different starting year (or
       years). The %x and %c conversion specifications, however, are  intended
       for  local  representation;  these  may  be  based on a different, non-
       Gregorian calendar.

       The %C conversion specification was introduced to allow a fallback  for
       the  %EC  (alternative  year format base year); it can be viewed as the
       base of the current subdivision in the Gregorian calendar. The  century
       number  is  calculated  as  the year divided by 100 and truncated to an
       integer; it should not be confused with the use of ordinal numbers  for
       centuries  (for  example,  "twenty-first century".) Both the %Ey and %y
       can then be viewed as the offset from %EC and %C , respectively.

       The E and O modifiers modify the traditional conversion specifiers,  so
       that  they  can  always  be  used,  even  if the implementation (or the
       current locale) does not support the modifier.

       The E modifier supports alternative date formats, such as the  Japanese
       Emperor's  Era,  as  long  as these are based on the Gregorian calendar
       system. Extending the E modifiers to other date elements may provide an
       implementation-defined  extension  capable of supporting other calendar
       systems, especially in combination with the O modifier.

       The O modifier supports  time  and  date  formats  using  the  locale's
       alternative numerical symbols, such as Kanji or Hindi digits or ordinal
       number representation.

       Non-European locales, whether they use Latin  digits  in  computational
       items  or  not,  often  have  local forms of the digits for use in date
       formats. This is not totally unknown even in Europe; a variant of dates
       uses  Roman  numerals  for  the months: the third day of September 1991
       would be written as 3.IX.1991. In Japan,  Kanji  digits  are  regularly
       used  for  dates;  in Arabic-speaking countries, Hindi digits are used.
       The %d , %e , %H , %I , %m , %S , %U , %w ,  %W  ,  and  %y  conversion
       specifications  always  return  the date and time field in Latin digits
       (that is, 0 to 9). The %O modifier was introduced to  support  the  use
       for  display  purposes  of non-Latin digits. In the LC_TIME category in
       localedef,  the  optional  alt_digits  keyword  is  intended  for  this
       purpose.  As  an  example,  assume  the  following  (partial) localedef
       source:

              alt_digits  "";"I";"II";"III";"IV";"V";"VI";"VII";"VIII" \
                          "IX";"X";"XI";"XII"
              d_fmt       "%e.%Om.%Y"

       With the above date, the command:

              date "+%x"

       would yield 3.IX.1991. With the same d_fmt, but without the alt_digits,
       the command would yield 3.9.1991.

EXAMPLES

        1. The  following  are input/output examples of date used at arbitrary
           times in the POSIX locale:

           $ date
           Tue Jun 26 09:58:10 PDT 1990

           $ date "+DATE: %m/%d/%y%nTIME: %H:%M:%S"
           DATE: 11/02/91
           TIME: 13:36:16

           $ date "+TIME: %r"
           TIME: 01:36:32 PM

        2. Examples for Denmark, where the default date and time format is  %a
           %d %b %Y %T %Z :

           $ LANG=da_DK.iso_8859-1 date
           ons 02 okt 1991 15:03:32 CET

           $ LANG=da_DK.iso_8859-1 \
               date "+DATO: %A den %e. %B %Y%nKLOKKEN: %H:%M:%S"
           DATO: onsdag den 2. oktober 1991
           KLOKKEN: 15:03:56

        3. Examples  for Germany, where the default date and time format is %a
           %d . %h . %Y , %T %Z :

           $ LANG=De_DE.88591 date
           Mi 02.Okt.1991, 15:01:21 MEZ

           $ LANG=De_DE.88591 date "+DATUM: %A, %d. %B %Y%nZEIT: %H:%M:%S"
           DATUM: Mittwoch, 02. Oktober 1991
           ZEIT: 15:02:02

        4. Examples for France, where the default date and time format  is  %a
           %d %h %Y %Z %T :

           $ LANG=Fr_FR.88591 date
           Mer 02 oct 1991 MET 15:03:32

           $ LANG=Fr_FR.88591 date "+JOUR: %A %d %B %Y%nHEURE: %H:%M:%S"
           JOUR: Mercredi 02 octobre 1991
           HEURE: 15:03:56

RATIONALE

       Some  of  the  new  options for formatting are from the ISO C standard.
       The -u option was introduced to allow portable  access  to  Coordinated
       Universal  Time (UTC). The string "GMT0" is allowed as an equivalent TZ
       value  to  be  compatible  with  all  of  the  systems  using  the  BSD
       implementation, where this option originated.

       The  %e  format  conversion  specification  (adopted from System V) was
       added because the ISO C  standard  conversion  specifications  did  not
       provide  any  way  to produce the historical default date output during
       the first nine days of any month.

       There are two  varieties  of  day  and  week  numbering  supported  (in
       addition  to  any  others  created  with the locale-dependent %E and %O
       modifier characters):

        * The historical variety in which Sunday is the first day of the  week
          and  the  weekdays  preceding  the  first  Sunday  of  the  year are
          considered week 0. These are represented by %w and %U . A variant of
          this  is  %W  , using Monday as the first day of the week, but still
          referring to week 0. This view of the calendar was retained  because
          so  many historical applications depend on it and the ISO C standard
          strftime() function, on which many date implementations  are  based,
          was defined in this way.

        * The  international  standard,  based  on  the ISO 8601:2000 standard
          where Monday is the first weekday and the algorithm  for  the  first
          week  number  is  more  complex:  If  the  week  (Monday  to Sunday)
          containing January 1 has four or more days in the new year, then  it
          is  week  1;  otherwise, it is week 53 of the previous year, and the
          next week is week 1. These are represented  by  the  new  conversion
          specifications  %u  and  %V  ,  added  as  a result of international
          comments.

FUTURE DIRECTIONS

       None.

SEE ALSO

       The  System  Interfaces  volume  of   IEEE Std 1003.1-2001,   printf(),
       strftime()

COPYRIGHT

       Portions  of  this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003  by  the  Institute  of
       Electrical  and  Electronics  Engineers, Inc and The Open Group. In the
       event of any discrepancy between this version and the original IEEE and
       The  Open Group Standard, the original IEEE and The Open Group Standard
       is the referee document. The original Standard can be  obtained  online
       at http://www.opengroup.org/unix/online.html .