#$1 is the matched regex, including duplicated elements.

my $match = $1."\n";

my @match_to_array = split("(\n)",$match);

my %seen = ();
my @r = ();

foreach my $a (@match_to_array) {
    unless ($seen{$a}) {
        push @r, $a;
        $seen{$a}++;
    }
}
print @r;