my %already_seen;
while (<>) {
     my @temp = split /\s\, $_;
     my $key = $temp[1,2];
     if defined ($already_seen{$key} {
          # it is a duplicate 
          print $output2 $_;
     } else {
          $already_seen{$key} = 1;
          print $output2 $_;
     }
}