in reply to Removing unwanted chars from filename.

I would strongly recommend Corion's Text::CleanFragment.

As for your regex, note that [:ascii:] is defined as "Any character in the ASCII character set", and the string you've shown here is entirely ASCII, so your code is "working". Perhaps you meant s/[^[:alnum:]]//g or e.g. s/[^[:alnum:]._-]//g instead? (Update: and though tr/A-Za-z0-9._-//cd should be faster, the above module handles Unicode well, so that's why I'd still recommend that)