Shell command to bulk change file extensions in a directory (Linux)

This article will explain how to change the file extension for all files in a directory in Linux using a simple bash shell command.

1. Change from one extension to another

The command below will rename all files with the extension .php4 to .php

for f in *.php4; do mv $f `basename $f .php4`.php; done;

1. Add (append) an extension to all files

The command below add the extension .txt to all files in the directory

for f in *; do mv $f `basename $f `.txt; done;

1. Remove (delete) an extension from all files

The command below remove the extension .txt from all files in the directory

for f in *.txt; do mv $f `basename $f .txt`; done;

OR

This will do the job for you.

rename 's/.m4b$/.m4a/' *.m4b

For a test run you can use this command:

rename 's/.m4b$/.m4a/' *.m4b -vn

-v means "verbose" and it will output the names of the files when it renames them.

-n will do a test run where it won't rename any files, But will show you a list of files that would be renamed.

Straight from Greg's Wiki:

Rename all .txt to .text

for f in *.txt; do 
mv -- "$f" "${f%.txt}.text"
done

Also see the entry on why you shouldn't parse ls.

Edit: if you have to use basename your syntax would be:

for f in *.txt; do
mv "$f" "$(basename "$f" .txt).text"
done