I have old samba server files that does not show special characters like ä,ö,ü,õ in file names. They are showed as ? mark. Because of that my clients cannot open those files or folders. They see the files and folders, but their names are blank. In server they are showed like this: T??tunnid.doc for example.

Once I rename them with `mv` command, then my clients can open the folders and files with no problems. 

Does anyone know any script that I can use to rename all the files that have ? mark in them. So they show - instead. I would like to rename the files in specific folder for example /samba/documents/...