How do I remove extension for renaming purposes?

Question

I have code that looks like this

%original%-added.txt

So if the original filename is

blue.txt

My code modifies that blue.txt file and the new file is then named

blue.txt-added.txt

How can I remove that first ".txt" so that I only get

blue-added.txt

Answer 1

Try like this :

%original:~0,-4%-added.txt