foreach my $intersect_file (@intersect_keys) {
    my $execs = $system_file_data{$intersect_file};  # Array ref
    foreach my $exec (@$exec) {
       print("$exec\n");
    }
}

##</code><code>##

foreach my $intersect_file (@intersect_keys) {
    foreach my $exec (@{ $system_file_data{$intersect_file} }) {
       print("$exec\n");
    }
}