Perl do not process unicode filenames from command line, but this is rather OS's fault, not Perl one.

BTW, what operating Windows you have..?
Err, what system operates your windows?
what is your $^O? :)

All in all, you'll better off overriding 'open' for such purposes, the danger do not worth the risk!

If your $^O is MSWin32, then following my advice could help: Re: enumerate windows unicode filenames

HTH