Show diff when writing commit messages during an interactive rebase

You can do:

git -c commit.verbose=true rebase --continue

If you get tired copying that command you can create an alias in your ~/.gitconfig:

    myrebasecontinue = "!git -c commit.verbose=true rebase --continue"

And now just do:

git myrebasecontinue

To show the diff:

git -c commit.verbose=true rebase --continue

To make all commits verbose without having to specify -c commit.verbose=true every time, add this to ~/.gitconfig:

    verbose = true

Reference: man git-config.