%a = map {($_=>1)} @a;
@duplicates = grep { exists $a{$_} } @b;

my %hash = ();
my @elemente_beider_arrays = ();
foreach(@A){
  $hash{$_}++;
}
foreach(@B){
  push(@elemente_beider_arrays,$_) if($hash{$_});
}

print "Diese Elemente sind in beiden Arrays:\n";
print $_,"\n" for(@elemente_beider_arrays);

foreach $zeile (@A) {
   foreach $zeile2 (@B) {
     if($zeile2 eq $zeile) {
      push (@ergebnis, $zeile2);
     }
    }
  }