Massren is a command line tool that can be used to rename multiple files using your own text editor. Multiple-rename tools are usually difficult to use from the command line since any regular expression needs to be escaped, and each tool uses its own syntax and flavor of regex. The advantage of massren is that you are using the text editor you use every day, and so can use all its features.
The tool works by creating a file that contains the filenames of the target directory, and opening this file in the text editor. You can then modify the filenames there directly. Once done, save the text file and the files will be renamed. Lines that are not changed will simply be ignored.
Rename multiple files using your own text editor. It should work with any text editor, including vim, emacs, Sublime Text or notepad.
Safety checks - since this is a multiple rename tool, various checks are in place to ensure that nothing gets accidentally renamed. For example, the program will check that the files are not being changed by something else while the list of filenames is being edited. If the number of files before and after saving the file is different, the operation will also be cancelled.