Folder Utility can be used to maintain backup copies of folders on a second drive or a network drive. You can maintain matching copies or copies that append from the source to the backup (target) directory. The append copy only deletes files in the backup directory that are replaced by newer files from the source directory. Folder Utility can be used to rename all the files in a folder. Add a number to mp3 files so they play in ripped order instead of normal alphabetical order. Add the picture taken date to jpg (picture) files so they can be sorted easily by day. Convert all files in a folder to upper or lower case. Modify file names using search and replace, adding to the beginning or end, or removing a fixed number of characters from the beginning or end. Folder Utility includes all the folder size features as the Folder Size program and displays a folder tree with the following information: total size of files, size of files not in sub-folders, total size on disk or number of files. Show sorted filenames in a folder and copy all or selected names to clipboard.