all parents.
-Generating patches with -p
---------------------------
-
-When "git-diff-index", "git-diff-tree", or "git-diff-files" are run
-with a '-p' option, or "git diff" without the '--raw' option, they
-do not produce the output described above; instead they produce a
-patch file. You can customize the creation of such patches via the
-GIT_EXTERNAL_DIFF and the GIT_DIFF_OPTS environment variables.
-
-What the -p option produces is slightly different from the traditional
-diff format.
-
-1. It is preceded 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/` filenames.
-+
-When rename/copy is involved, `file1` and `file2` show 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 one or more extended header lines:
-
- 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>
- index <hash>..<hash> <mode>
-
-3. TAB, LF, double quote and backslash characters in pathnames
- are represented as `\t`, `\n`, `\"` and `\\`, respectively.
- If there is need for such substitution then the whole
- pathname is put in double quotes.
-
-The similarity index is the percentage of unchanged lines, and
-the dissimilarity index is the percentage of changed lines. It
-is a rounded down integer, followed by a percent sign. The
-similarity index value of 100% is thus reserved for two equal
-files, while 100% dissimilarity means that no line from the old
-file made it into the new one.
-
-
-combined diff format
---------------------
-
-"git-diff-tree", "git-diff-files" and "git-diff" can take '-c' or
-'--cc' option to produce 'combined diff', which looks like this:
-
-------------
-diff --combined describe.c
-index fabadb8,cc95eb0..4866510
---- a/describe.c
-+++ b/describe.c
-@@@ -98,20 -98,12 +98,20 @@@
- return (a_date > b_date) ? -1 : (a_date == b_date) ? 0 : 1;
- }
-
-- static void describe(char *arg)
- -static void describe(struct commit *cmit, int last_one)
-++static void describe(char *arg, int last_one)
- {
- + unsigned char sha1[20];
- + struct commit *cmit;
- struct commit_list *list;
- static int initialized = 0;
- struct commit_name *n;
-
- + if (get_sha1(arg, sha1) < 0)
- + usage(describe_usage);
- + cmit = lookup_commit_reference(sha1);
- + if (!cmit)
- + usage(describe_usage);
- +
- if (!initialized) {
- initialized = 1;
- for_each_ref(get_name);
-------------
-
-1. It is preceded with a "git diff" header, that looks like
- this (when '-c' option is used):
-
- diff --combined file
-+
-or like this (when '--cc' option is used):
-
- diff --c file
-
-2. It is followed by one or more extended header lines
- (this example shows a merge with two parents):
-
- index <hash>,<hash>..<hash>
- mode <mode>,<mode>..<mode>
- new file mode <mode>
- deleted file mode <mode>,<mode>
-+
-The `mode <mode>,<mode>..<mode>` line appears only if at least one of
-the <mode> is different from the rest. Extended headers with
-information about detected contents movement (renames and
-copying detection) are designed to work with diff of two
-<tree-ish> and are not used by combined diff format.
-
-3. It is followed by two-line from-file/to-file header
-
- --- a/file
- +++ b/file
-+
-Similar to two-line header for traditional 'unified' diff
-format, `/dev/null` is used to signal created or deleted
-files.
-
-4. Chunk header format is modified to prevent people from
- accidentally feeding it to `patch -p1`. Combined diff format
- was created for review of merge commit changes, and was not
- meant for apply. The change is similar to the change in the
- extended 'index' header:
-
- @@@ <from-file-range> <from-file-range> <to-file-range> @@@
-+
-There are (number of parents + 1) `@` characters in the chunk
-header for combined diff format.
-
-Unlike the traditional 'unified' diff format, which shows two
-files A and B with a single column that has `-` (minus --
-appears in A but removed in B), `+` (plus -- missing in A but
-added to B), or `" "` (space -- unchanged) prefix, this format
-compares two or more files file1, file2,... with one file X, and
-shows how X differs from each of fileN. One column for each of
-fileN is prepended to the output line to note how X's line is
-different from it.
-
-A `-` character in the column N means that the line appears in
-fileN but it does not appear in the result. A `+` character
-in the column N means that the line appears in the last file,
-and fileN does not have that line (in other words, the line was
-added, from the point of view of that parent).
-
-In the above example output, the function signature was changed
-from both files (hence two `-` removals from both file1 and
-file2, plus `++` to mean one line that was added does not appear
-in either file1 nor file2). Also two other lines are the same
-from file1 but do not appear in file2 (hence prefixed with ` +`).
-
-When shown by `git diff-tree -c`, it compares the parents of a
-merge commit with the merge result (i.e. file1..fileN are the
-parents). When shown by `git diff-files -c`, it compares the
-two unresolved merge parents with the working tree file
-(i.e. file1 is stage 2 aka "our version", file2 is stage 3 aka
-"their version").
+include::diff-generate-patch.txt[]
+
+
+other diff formats
+------------------
+
+The `--summary` option describes newly added, deleted, renamed and
+copied files. The `--stat` option adds diffstat(1) graph to the
+output. These options can be combined with other options, such as
+`-p`, and are meant for human consumption.
+
+When showing a change that involves a rename or a copy, `--stat` output
+formats the pathnames compactly by combining common prefix and suffix of
+the pathnames. For example, a change that moves `arch/i386/Makefile` to
+`arch/x86/Makefile` while modifying 4 lines will be shown like this:
+
+------------------------------------
+arch/{i386 => x86}/Makefile | 4 +--
+------------------------------------
+
+The `--numstat` option gives the diffstat(1) information but is designed
+for easier machine consumption. An entry in `--numstat` output looks
+like this:
+
+----------------------------------------
+1 2 README
+3 1 arch/{i386 => x86}/Makefile
+----------------------------------------
+
+That is, from left to right:
+
+. the number of added lines;
+. a tab;
+. the number of deleted lines;
+. a tab;
+. pathname (possibly with rename/copy information);
+. a newline.
+
+When `-z` output option is in effect, the output is formatted this way:
+
+----------------------------------------
+1 2 README NUL
+3 1 NUL arch/i386/Makefile NUL arch/x86/Makefile NUL
+----------------------------------------
+
+That is:
+
+. the number of added lines;
+. a tab;
+. the number of deleted lines;
+. a tab;
+. a NUL (only exists if renamed/copied);
+. pathname in preimage;
+. a NUL (only exists if renamed/copied);
+. pathname in postimage (only exists if renamed/copied);
+. a NUL.
+
+The extra `NUL` before the preimage path in renamed case is to allow
+scripts that read the output to tell if the current record being read is
+a single-path record or a rename/copy record without reading ahead.
+After reading added and deleted lines, reading up to `NUL` would yield
+the pathname, but if that is `NUL`, the record will show two paths.