with one line of code.

here's what I have:

    if ($line =~ / /){
        $orig=$line;
        ($mod=$line) =~ s/ /_/g; #space to underscore
        $mod =~ s|[^_ -[:alnum:]]||g;
        $mod =~ s|_-_|-|g;

        print "$orig ==> $mod\n";
    }