sub get_unique_filename {
    my ( $name, $max_tries ) = @_;
  return if not -e $name;
    $name =~ s/(\.[^\.]+)$//;
    my $ext = $1 ? $1 : '';
    my $tries = 1;
    my $max_tries ||= 100;
    while (  -e $name.$tries.$ext ) {
        $tries++;
        die "Could not make a unique filename for $name$ext\n" if $tries > $max_tries;
    }
  return $name.$tries.$ext;
}