timezone(4)                    DG/UX R4.11MU05                   timezone(4)


NAME
       timezone - set default system time zone and locale

SYNOPSIS
       /etc/TIMEZONE, /etc/TIMEZONE.csh

DESCRIPTION
       The files /etc/TIMEZONE and /etc/TIMEZONE.csh set and export the
       following environment variables:

       TZ                  time zone

       NLSPATH             search path for message catalogs

       LANG                local language

       These files are included into other shell scripts (for example,
       /etc/profile and /etc/cshrc) to establish this localization
       information.  /etc/TIMEZONE is also read by /etc/init to initialize
       the timezone and locale information for the system startup
       procedures.

       To change the values of these environment variables, you may edit
       these files directly, or use admdate(1M) and admnls(1M), which can be
       invoked from sysadm(1M).

       If /etc/TIMEZONE is missing, it is created at system startup by
       copying the file /etc/TIMEZONE.proto.  If /etc/TIMEZONE.csh is
       missing, it is created at system startup by copying the file
       /etc/TIMEZONE.csh.proto.

       NLSPATH and LANG are described in environ(5) and setlocale(3C).  The
       default value of NLSPATH (in the proto files) is
       "/usr/lib/nls/msg/%L/%N".  The default value of LANG is "C".

       TZ can be either the name of a timezone database file found under the
       directory /usr/lib/locale/TZ, preceded by a colon (e.g.
       ":US/Eastern"), or else a string that describes the timezone rules.
       The syntax of such a rule string can be described as follows:

       TZ             ->         zone
                           | zone signed_time
                           | zone signed_time zone
                           | zone signed_time zone dst
       zone           ->         letter letter letter
       signed_time         ->         sign time
                           | time
       time           ->         hour
                           | hour : minute
                           | hour : minute : second
       dst            ->         signed_time
                           | signed_time , dst_date , dst_date
                           | , dst_date , dst_date
       dst_date            ->         julian
                           | julian / time
       letter              ->          a | A | b | B | ... | z | Z
       hour                ->          00 | 01 | ... | 23
       minute              ->          00 | 01 | ... | 59
       second              ->          00 | 01 | ... | 59
       julian              ->          001 | 002 | ...| 366
       sign           ->          - | +


EXAMPLES
       The contents of the file /etc/TIMEZONE could be

            # Time Zone
            TZ=:US/Eastern
            export TZ
            # Message catalog search path
            NLSPATH=/usr/lib/nls/msg/%L/%N
            export NLSPATH
            # Language
            LANG=C
            export C

       A simple setting for TZ for New Jersey could be

            TZ=EST5EDT

       where EST is the abbreviation for the main time zone, 5 is the
       difference, in hours, between GMT (Greenwich Mean Time) and the main
       time zone, and EDT is the abbreviation for the alternate time zone.

       The most complex representation of the same setting, for the year
       1986, is

            TZ="EST5:00:00EDT4:00:00,117/2:00:00,299/2:00:00"

       where EST is the abbreviation for the main time zone, 5:00:00 is the
       difference, in hours, minutes, and seconds between GMT and the main
       time zone, EDT is the abbreviation for the alternate time zone,
       4:00:00 is the difference, in hours, minutes, and seconds between GMT
       and the alternate time zone, 117 is the number of the day of the year
       (Julian day) when the alternate time zone will take effect, 2:00:00
       is the number of hours, minutes, and seconds past midnight when the
       alternate time zone will take effect, 299 is the number of the day of
       the year when the alternate time zone will end, and 2:00:00 is the
       number of hours, minutes, and seconds past midnight when the
       alternate time zone will end.

       A southern hemisphere setting such as the Cook Islands could be

            TZ="KDT9:30KST10:00,64/5:00,303/20:00"

       This setting means that KDT is the abbreviation for the main time
       zone, KST is the abbreviation for the alternate time zone, KST is 9
       hours and 30 minutes later than GMT, KDT is 10 hours later than GMT,
       the starting date of KDT is the 64th day at 5 AM, and the ending date
       of KDT is the 303rd day at 8 PM.

       Starting and ending times are relative to the alternate time zone.
       If the alternate time zone start and end dates and the time are not
       provided, the days for the United States that year will be used and
       the time will be 2 AM.  If the start and end dates are provided but
       the time is not provided, the time will be midnight.

       Note that in most installations, TZ is set to the correct value by
       default when the user logs on, via the local /etc/profile file (see
       profile(4)).

NOTES
       When the longer format is used, the TZ variable must be surrounded by
       double quotes as shown.

       The system administrator must change the Julian start and end days
       annually if the longer form of the TZ variable is used.

       Setting the time during the interval of change from the main time
       zone to the alternate time zone or vice versa can produce
       unpredictable results.

SEE ALSO
       zic(1M), ctime(3C), setlocale(3C), profile(4), environ(5).


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