2 Ways to Batch Rename Files in OS X

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.


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.

Note: You will be prompted to add a “Copy Finder Items” action. If you want to be safe you could add this as well, but I usually don’t.

One potential workflow in Automator to batch rename files.

With Automator you can change the file name in the following ways:

  • Date/Time
  • Text
  • Change Case
  • Make Sequential
  • Replace Text
  • Name Single Item

The options are fairly self-explanatory, but there are some limitations.

Date/Time– you can only add a date or a time stamp, but not both. The stamp can only be added at the beginning or end of the file name.

Text– You can only add text at the beginning or end of the file name.

Change Case– You can only change the entire file name or extension at once. You can’t, for example, change moscow.jpg to Moscow.jpg.

Make Sequential– You can only add a sequence at the beginning or end of a file name.

Replace Text– This is where I think Automator really falls short. You can only replace a specific string, meaning the file name has to contain what you want to replace in order for Automator to do anything. What if I wanted to remove the last 3 characters from a file name and replace it with “xyz”? Not in Automator.

Name Single Item– I don’t know why you wouldn’t just change the name of the file in Finder without launching Automator, but for completeness the feature is included. You can change the base name (file name without extension), full name (file name with extension), or extension only.

– Choose which action you want and adjust the parameters of the action to suit your needs.

– Drag the Finder items to be renamed into the proper Window.
(Note: with “Get Specified Finder Items“, Automator will not distinguish between directories and files when running. If you want to drag a folder into Automator and have it work on the folder’s contents, use “Get Folder Contents.”)

– Press “Run.”

Automator is included with OS X and is located in the Applications directory by default.

Name Mangler

Name Mangler picks up where Automator falls short. While Automator has a wealth of other actions that you might find useful, Name Mangler does one thing and does it well.

To rename files, drag them into the left-hand window pane. The list of files pops up, and you can select filters (Folders, Folder Contents, Files) to dictate what gets renamed. This also means you can just drag a Folder into NM to rename the contents.

Name Mangler's main window shows a list of files as well as a preview of what the file name will be changed to.

NM offers the following default options:

  • Find and Replace– includes regular expression matching and an option to preserve extensions and ignore case.
  • Number Sequentially– Allows you to number in steps other than one, set a prefix and suffix, keep or remove the original name and extension. Unlike Automator, NM allows you to define a prefix or suffix to the sequence.
  • Change Case– Allows Capitalization, all capitals, or all lowercase. Allows similar preservation or changing of extensions.
  • Set Extension– fairly self-explanatory.
  • Add Prefix/Suffix– again, self-explanatory.
  • Remove/Insert Characters– this is where NM really has an advantage over Automator. You can remove any number of characters from a file name and specify an index to start with. So for example if you had a series of files named

    You could remove the “ACTXX” characters very easily by defining the number of characters to be removed (5) and the index to start removing at (8- the 8th character from the beginning, starting at 1). Furthermore, you can replace those same characters by inserting text at a specified index. Instead of “ACTXX” I might want “WestSideStory.” To make things even more customizable, you can specify whether the index should count from the beginning or the end of the file name.

But perhaps the most powerful feature included with Name Mangler is the ability to thread together multiple functions in the “Advanced” window. It’s name conversion description language allows you to write pseudo-scripts to tailor your file names to what you want. It might seem a little daunting, but it’s actually very easy for even a beginner with no programming knowledge to pick up the basics after reading the documentation.

Finally, Name Mangler allows you to save your settings as droplets so you can just drag and drop a collection of files to be renamed without actually launching the program.

I use Name Mangler almost exclusively at this point and haven’t found anything that even begins to compare. Do you know of other free batch renaming utilities?


Miles was a former author at MakeTechEasier.

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