# assumes that duplicates in first file should be ignored.
my %wanted;
open my $in, '<', '$file1' or die "$!\n";
while (my $line = <$in>) {
  chomp $line);
  $wanted{$line}++;
}

##</code><code>##

my $foo = (split /|/, $line)[1];

##</code><code>##

print OUT $line if $wanted{$foo};