NAME

       DateTime::TimeZone::Local::Unix - Determine the local system's time zone on Unix

VERSION

       version 2.53

SYNOPSIS

         my $tz = DateTime::TimeZone->new( name => 'local' );

         my $tz = DateTime::TimeZone::Local->TimeZone();

DESCRIPTION

       This module provides methods for determining the local time zone on a Unix platform.

HOW THE TIME ZONE IS DETERMINED

       This class tries the following methods of determining the local time zone:

       •   $ENV{TZ}

           It checks $ENV{TZ} for a valid time zone name.

       •   /etc/localtime

           If this file is a symlink to an Olson database time zone file (usually in
           /usr/share/zoneinfo) then it uses the target file's path name to determine the time
           zone name. For example, if the path is /usr/share/zoneinfo/America/Chicago, the time
           zone is "America/Chicago".

           Some systems just copy the relevant file to /etc/localtime instead of making a
           symlink.  In this case, we look in /usr/share/zoneinfo for a file that has the same
           size and content as /etc/localtime to determine the local time zone.

       •   /etc/timezone

           If this file exists, it is read and its contents are used as a time zone name.

       •   /etc/TIMEZONE

           If this file exists, it is opened and we look for a line starting like "TZ = ...". If
           this is found, it should indicate a time zone name.

       •   /etc/sysconfig/clock

           If this file exists, it is opened and we look for a line starting like "TIMEZONE =
           ..." or "ZONE = ...". If this is found, it should indicate a time zone name.

       •   /etc/default/init

           If this file exists, it is opened and we look for a line starting like "TZ=...". If
           this is found, it should indicate a time zone name.

       Note: Some systems such as virtual machine boxes may lack any of these files. You can
       confirm that this is case by running:

           $ ls -l /etc/localtime /etc/timezone /etc/TIMEZONE \
               /etc/sysconfig/clock /etc/default/init

       If this is the case, then when checking for timezone handling you are likely to get an
       exception:

           $ perl -wle 'use DateTime; DateTime->now( time_zone => "local" )'
           Cannot determine local time zone

       In that case, you should consult your system man pages for details on how to address that
       problem. In one such case reported to us, a FreeBSD virtual machine had been built without
       any of these files. The user was able to run the FreeBSD tzsetup utility. That installed
       /etc/localtime, after which the above timezone diagnostic ran silently, i.e., without
       throwing an exception.

SUPPORT

       Bugs may be submitted at <https://github.com/houseabsolute/DateTime-TimeZone/issues>.

SOURCE

       The source code repository for DateTime-TimeZone can be found at
       <https://github.com/houseabsolute/DateTime-TimeZone>.

AUTHOR

       Dave Rolsky <autarch@urth.org>

COPYRIGHT AND LICENSE

       This software is copyright (c) 2022 by Dave Rolsky.

       This is free software; you can redistribute it and/or modify it under the same terms as
       the Perl 5 programming language system itself.

       The full text of the license can be found in the LICENSE file included with this
       distribution.