sub untaint {
    my $val = shift;
    $val =~ s/[^\w.-]/_/g;   # tr/A-Za-z0-9.-/_/c is faster but less easy to read for some
    $val =~ m/([^\w.-])/;
    my $clean_taint_free_val = $1;
  return $clean_taint_free_val;
}