Renaming multiple files can be a tedious process when doing so manually, but the Finder in OS X can make it easier to rename a batch of files at once on your Mac. Instead of relying on a third party app, use this handy tip to quickly rename a batch of files without breaking a sweat.
Step 1: Select the files that you wish to rename.
Step 2: Right click, and select Rename Files. This will open the Rename Finder Items box.
Step 3: You can use any of the dropdown boxes to establish renaming rules however you would like, but I personally like using Format instead of Add Text or Replace Text for the renaming style. This allows you to give the batch of files an entire new base name. Use the Custom Format box to insert the base name of the files.
The Name and Format dropdown box lets you choose how you wish to differentiate the files. You can do so by adding an index number, counter or date.
The Where dropdown box lets you choose where to add the differentiator. You can choose to do so after the name, or before the name. If you choose one of the numerical values, you can also apply a starting number. I recommend starting with 10 since the rename utility doesn’t let you pad a leading zero for single digit numbers.
Step 4: Once you are satisfied with your naming decision, click the Rename button to enact the changes. If you don’t like how it turns out, you can always use Command+Z and try it again.
Yes, it’s possible to use third-party apps like Name Mangler 3 or Better Rename 9 to do the same thing, but unless you need advanced renaming capabilities, Finder’s built in renaming utility can usually get the job done well.