why `git diff` reports no file change after `git add`

Question

 Why is that git diff thinks there are no changes

..even if git status reports them as modified?

$ git status
On bra         


        

Answer 1

git diff diffs against the index, not against your HEAD revision. By running git add, you've put the changes in your index, so of course there are no differences! Use

• git diff HEAD to see the differences between your tree state and the HEAD revision, or
• git diff --cached to see the differences between your index and the HEAD revision.