+
+
+Git specific extention to diff format
+-------------------------------------
+
+What -p option produces is slightly different from the
+traditional diff format.
+
+ (1) It is preceeded with a "git diff" header, that looks like
+ this:
+
+ diff --git a/file1 b/file2
+
+ The a/ and b/ filenames are the same unless rename/copy is
+ involved. Especially, even for a creation or a deletion,
+ /dev/null is _not_ used in place of a/ or b/ filename.
+
+ When rename/copy is involved, file1 and file2 shows the
+ name of the source file of the rename/copy and the name of
+ the file that rename/copy produces, respectively.
+
+ (2) It is followed by extended header lines that are one or
+ more of:
+
+ old mode <mode>
+ new mode <mode>
+ deleted file mode <mode>
+ new file mode <mode>
+ copy from <path>
+ copy to <path>
+ rename from <path>
+ rename to <path>
+ similarity index <number>
+ dissimilarity index <number>