New to Yosemite is the ability to batch rename files/folders. Quite handy for a folder full of pictures, audio files, documents, etc. The process is fairly simple, just select the group of files that you want to rename, [Control] + [Click] on the group of selected files, then in the contextual menu choose “Rename XX Items…”. You’ll then be prompted by a small drop-down selector that will allow you to do any of the following:

_Completely rename a group of files, and add a sequential number
_Add text to the beginning of all selected file names
_Add text to the end of all selected file names
_Perform text “find and replace"

This can be a very useful tool in your daily file organization and maintenance.