I am a little confused by your ultimate goal, but I think I can give an answer anyway.
, , .. , git status --porcelain. ( ) man-. git merge --no-commit, , , (). git diff HEAD --numstat, / .
, git diff-tree:
git diff-tree -c --numstat <commit>
-c , diff merge , --numstat , .
, , -p --numstat, . , gitk, , , / . , , (, '+ ', ' -', , ), , , (--, ++). , . ( , , - --numstat .)