Windows only: Ken Rename is a portable file renaming utility. The interface is straight forward with support for simple and complex renaming tasks. Ken Rename supports wildcards, macros, numbered file lists, string replacement and removal, and has an undo function to save you from a renaming mishap. Weighing in at under half a MB, Ken Rename is a handy addition to your flash drive toolkit. For a similar program with the welcome addition of a preview function, try WildRename. For a Mac friendly, but non-portable, alternative check out File List. Ken Rename is freeware, Windows only.