How to parse the output of git status and sent it to another program with a batch file under Windows?

Question

I want to capture the result of git status -s which will output something like this:

 M /path/to/modified/file.py
 M /path/to/another/modified/file2.py

The first 3 characters are to be removed. I want to have this:

/path/to/modified/file.py, /path/to/another/modified/file2.py

(take each line of git status -s, strip the first 3 characters and glue them with a comma on a single line).

I will then send that string to another program (as an argument) who will work on those files.

Is it possible to do that with a batch (.bat) file under Windows?

I saw that you can do a substring with something like set str=%str:~3,10% but I had not found how to capture the output of git and split by lines and get each line length...