Did you check your home or in the folder that contains the script? Some programs print output there unless you give a full output path

This looks like where you choose output folder location:

### Create results directory, where output files are written to
my $out_dir = './results/';
if (-e $out_dir) {
    print "\n\n###Directory \'$out_dir\' already exists! Replace the directory and all its contents? [y|n] ";
    my $user_ask = <STDIN>;
    if ($user_ask =~ /y/i) {
    unlink glob $out_dir."*"; # remove all files in results directory
    rmdir $out_dir; # remove the empty directory
    } else {
    die "Script abborted!\n";
    }
}
mkdir $out_dir or die "Can't create directory \"$out_dir\": $!\n";

Are you getting any of the messages here printed to your terminal?

Try:

    my $out_dir = 'full/path/to/results/';