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