How to change or remove file extensions in Windows

Say you have a bunch of files and you want to quickly change or remove the file extension of all of them. Turns out that’s very simple to do with the command-line in Windows. I had no idea…


ren *.old *.new

Will change all files with ‘old’ file extension to have the ‘new’ file extension.


ren *.old *.

Will remove the ‘old’ file extension.