One, you could be more clear that you're talking about non-ASCII filenames and not the contents. Someone above already seems confused on that point.

Two, the "backticks rename" method relies on your operating system shell. On DOS/Windows, the rename command allows wildcards in source and target, and the shell has weak support for non-ASCII filenames. The graphical shell probably has a completely different set of bugs when dealing with non-ASCII filenames.

Three, the internal rename() function relies on your operating system routines.

Four, whenever you say "non-ASCII" you should indicate what encoding you are using. ISO-2022-JP? Codepage 328? What types of characters are you trying to put into filenames?

Five, once you know the encoding you think you're using, look up the Encode modules and google around to see if anyone else has any similar problems or solutions.

The quality of the help is always proportional to the quality of the question. Said another way, if we can't understand you, we can't offer the advice you seek.