Metamorphose 2 is an advanced batch file and folder renamer for Linux and Windows. The application features a wide range of renaming options, allows previewing changes before applying them, allows saving the renaming rules for future use, and much more.

Metamorphose is a free, open source program to mass rename files and folders for Windows, Linux and Mac OS X.

The application has many great features such as using photo EXIF data or mp3 ID3 tags for renaming, undo renaming operation in case of mistakes, preview every item to be renamed before applying changes and of course basic features like adding a prefix, suffix, etc to files, mass replace, insert or modify, length modification and so on. Basically most of the option can also be found in pyRename, but I find Metamorphose easier to use (and Metamorphose working on Windows and Mac OS X is another difference).