foreach my $folder (@folders) {
# for instance folder1

      next if ($folder eq ".");
      next if ($folder eq "..");
      my $fqname = catdir( $output, $folder );

#$fqname is /mnt/music/output/folder1

      if ( -d $fqname ) {

#passed the test       

          if (glob("$fqname/*.cue")) {

# yes there is /mnt/music/found/output/folder1/a.cue

             print "$fqname:   cue found\n";

#prints: /mnt/music/found/output/folder1/: cue found

              my ($cue) = <$fqname/*.cue>;
             

# my ($cue) grabs /mnt/music/output/folder1/a.cue
             
          }
          elsif(!glob(("fqname/*.cue"))) {
               print "$fqname: no  cue found\n";
               next;
          }
      }
  }