#!/usr/bin/perl 

@wanted = qw(BAD OSTYPE TZ TERM);
foreach $val (@wanted) {
   if ($ENV{$val}) {
      print "$val \t is \t $ENV{$val}\n";
   } else {
      print "$val \t is \t undefined\n";
   }
}

##</code><code>##

BAD      is      undefined
OSTYPE   is      OpenBSD
TZ       is      undefined
TERM     is      xterm