Whether it’s changing file names of pictures from “IMG_XXXX.jpg” to organizing your MP3s, batch file renaming can both save you time and reduce frustration.  Here are two free and easy ways to rename large groups of files in OS X.

Automator

Batch renaming in Automator is quite simple, even if you’ve never used it before.

1. Open Automator, choose “Custom” when the screen prompts you to select a starting point.
2. Drag the Automator action “Get Specified Finder Items” to the right-hand window pane.
3. Drag the Automator action “Rename Finder Items” to the right-hand window pane.