Bulk File Extension Manipulation on macOS: A Step-by-Step Guide

Learn how to efficiently remove, add, and correct file extensions in bulk using Terminal commands on macOS.

File management tasks on macOS can sometimes involve the need to rename or alter file extensions in bulk. Whether you’re cleaning up mistakenly added extensions, standardizing file types, or fixing issues with double extensions, macOS’s Terminal offers powerful command-line tools to get the job done quickly and efficiently.

In this article, we’ll explore several practical examples of bulk file extension manipulation using the Terminal. These examples will help you understand how to handle common scenarios, such as removing unwanted extensions, standardizing file extensions, and more.

1. Removing Unwanted Extensions: .md.m Fix

Imagine you have a directory full of files that were mistakenly renamed with an extra .m extension, resulting in filenames like _index.md.m. To correct this, you can use a simple for loop to strip off the unnecessary .m extension.

Command:

for file in *.md.m; do mv "$file" "${file%.m}"; done

Explanation:

• for file in *.md.m; do ... done: This loop iterates over all files in the directory that end with .md.m.
• mv "$file" "${file%.m}": The mv command renames each file by removing…