Any time renaming gets more complicated than (a) bash curly braces or (b) rename command (Perl script that applies sed expression to each file name), I break out Emacs wdired.
Then you can use all the Emacs tools to perform a mass edit across multiple file names, and get them right before committing to the rename. Multiple cursors makes a great addition, as does iedit-mode.
This. When I figured out you could edit the directory listing like a file and then have Emacs apply those edits I felt like I had acquired superpowers.
Actually I generally feel like I have superpowers when I use Emacs. The feeling was stronger than usual that day.
Multiple cursors plus C-x C-q on a dired buffer is amazingly powerful: you literally just make changes to the lines in the buffer and run C-c C-c to commit them, or C-c C-k to cancel. I've used this for very powerful mass-renames before. (I imagine it also works for deleting files by removing that line but never needed to try it before.)
I use Emacs inside iTerm2. (i.e. `emacs -nw`) Do you know if the multiple cursors package (which I just found today thanks to your comment) works with that? Or is it only in the native windowed version?
Then you can use all the Emacs tools to perform a mass edit across multiple file names, and get them right before committing to the rename. Multiple cursors makes a great addition, as does iedit-mode.