--p::
- Generate patch (see section on generating patches)
-
--r::
- This flag does not mean anything. It is there only to match
- "git-diff-tree". Unlike "git-diff-tree", "git-diff-cache"
- always looks at all the subdirectories.
-
--z::
- \0 line termination on output
-
--M::
- Detect renames; implies -p.
-
--R::
- Output diff in reverse.
-