OS X Yosemite includes a file batch rename tool
To batch rename files in OS X Yosemite, do this:
- Open a Finder window and select the documents you want to rename as a group.
- Control-click or right-click one of the selected files, then choose Rename from the contextual menu.
- Enter the common text you want to replace from each file name in the Find field.
- Enter the text you want to use instead for each file name in the Replace with field.
- Click Rename.
Enter the file name text you want to change, and the text you want instead
This is a handy way to quickly rename several files, but it is limited compared to some third-party utilities. Yosemite's rename tool doesn't, for example, let you enter variables so it can dynamically create file names for you. Still, it's a nice feature to have and it's one I've been using more than I expected.