Mass rename file extensions on Mac OS X
You want to change the file extension of a large number of files? With Renamer4Mac you can quickly and easily batch rename the file extensions of many files, for example from .htm to .html, or .jpeg to .jpg. This short tutorial will show you how.Step 1: Install Renamer4Mac
Download Renamer4Mac and then install it by dragging it into your Applications directory.Step 2: Drag in files
Drag the files whose extensions you wish to rename into Renamer4Mac.
Tip: You can also drag in entire directories. This way you can include entire folder hierarchies in one go.
Step 3: Switch to Search & Replace mode
Click on the Search & Replace tab:
Step 4: Apply renames to file extensions only
Select "Extension only" to restrict our renames to the file extensions. This avoids accidental renames of files that contain "htm" somewhere in their filename.
Step 5: Set the new file extension
Enter the current file extension htm in the Search field and new file extension html in the Replace filed
Step 6: Check with live preview
Before you commit the changes it's a good idea to check with Renamer4Mac's built-in live preview table that your files will be renamed correctly.