http://www.perlmonks.org?node_id=137809


in reply to Re: Re: Time Zones and Users
in thread Time Zones and Users

From Time::Zone (which is the same as Time::Timezone iirc):
$TZ = defined($ENV{'TZ'}) ? ( $ENV{'TZ'} ? $ENV{'TZ'} : 'GMT' ) : '' unless $TZ;
Where $TZ is taken as the first argument (to the functions needing a base timezone). =)

So, in other words, you can pass it a value and it does not rely on there being a TZ environment variable.