-The output format from "git-diff-cache", "git-diff-tree" and
-"git-diff-files" is very similar.
+Raw output format
+-----------------
-These commands all compare two sets of things; what are
-compared are different:
+The raw output format from "git-diff-index", "git-diff-tree",
+"git-diff-files" and "git diff --raw" are very similar.
-git-diff-cache <tree-ish>::
+These commands all compare two sets of things; what is
+compared differs:
+
+git-diff-index <tree-ish>::
compares the <tree-ish> and the files on the filesystem.
-git-diff-cache --cached <tree-ish>::
- compares the <tree-ish> and the cache.
+git-diff-index --cached <tree-ish>::
+ compares the <tree-ish> and the index.
git-diff-tree [-r] <tree-ish-1> <tree-ish-2> [<pattern>...]::
compares the trees named by the two arguments.
git-diff-files [<pattern>...]::
- compares the cache and the files on the filesystem.
+ compares the index and the files on the filesystem.
+The "git-diff-tree" command begins its output by printing the hash of
+what is being compared. After that, all the commands print one output
+line per changed file.
An output line is formatted this way:
- ':' <mode> ' ' <mode> ' ' <sha1> ' ' <sha1> I <path> I <path> L
-
-By default, I and L are '\t' and '\n' respectively. When '-z'
-flag is in effect, both I and L are '\0'.
-
-In each <mode>, <sha1> and <path> pair, left hand side describes
-the left hand side of what is being compared (<tree-ish> in
-git-diff-cache, <tree-ish-1> in git-diff-tree, cache contents in
-git-diff-files). Non-existence is shown by having 000000 in the
-<mode> column. That is, 000000 appears as the first <mode> for
-newly created files, and as the second <mode> for deleted files.
-
-Usually two <path> are the same. When rename/copy detection is
-used, however, an "create" and another "delete" records can be
-merged into a single record that has two <path>, old name and
-new name.
-
-<sha1> is shown as all 0's if new is a file on the filesystem
-and it is out of sync with the cache. Example:
-
- :100644 100644 5be4a4...... 000000...... file.c file.c
-
-
-Generating patches with -p
---------------------------
-
-When "git-diff-cache", "git-diff-tree", or "git-diff-files" are run
-with a '-p' option, they do not produce the output described above
-instead they produce a patch file.
-
-The patch generation can be customized at two levels. This
-customization also applies to "git-diff-helper".
-
-1. When the environment variable 'GIT_EXTERNAL_DIFF' is not set,
- these commands internally invoke "diff" like this:
-
- diff -L a/<path> -L a/<path> -pu <old> <new>
-+
-For added files, `/dev/null` is used for <old>. For removed
-files, `/dev/null` is used for <new>
-+
-The "diff" formatting options can be customized via the
-environment variable 'GIT_DIFF_OPTS'. For example, if you
-prefer context diff:
-
- GIT_DIFF_OPTS=-c git-diff-cache -p $(cat .git/HEAD)
-
-
-2. When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
- program named by it is called, instead of the diff invocation
- described above.
-+
-For a path that is added, removed, or modified,
-'GIT_EXTERNAL_DIFF' is called with 7 parameters:
-
- path old-file old-hex old-mode new-file new-hex new-mode
-+
-where:
+------------------------------------------------
+in-place edit :100644 100644 bcd1234... 0123456... M file0
+copy-edit :100644 100644 abcd123... 1234567... C68 file1 file2
+rename-edit :100644 100644 abcd123... 1234567... R86 file1 file3
+create :000000 100644 0000000... 1234567... A file4
+delete :100644 000000 1234567... 0000000... D file5
+unmerged :000000 000000 0000000... 0000000... U file6
+------------------------------------------------
+
+That is, from the left to the right:
+
+. a colon.
+. mode for "src"; 000000 if creation or unmerged.
+. a space.
+. mode for "dst"; 000000 if deletion or unmerged.
+. a space.
+. sha1 for "src"; 0\{40\} if creation or unmerged.
+. a space.
+. sha1 for "dst"; 0\{40\} if creation, unmerged or "look at work tree".
+. a space.
+. status, followed by optional "score" number.
+. a tab or a NUL when '-z' option is used.
+. path for "src"
+. a tab or a NUL when '-z' option is used; only exists for C or R.
+. path for "dst"; only exists for C or R.
+. an LF or a NUL when '-z' option is used, to terminate the record.
+
+Possible status letters are:
+
+- A: addition of a file
+- C: copy of a file into a new one
+- D: deletion of a file
+- M: modification of the contents or mode of a file
+- R: renaming of a file
+- T: change in the type of the file
+- U: file is unmerged (you must complete the merge before it can
+be committed)
+- X: "unknown" change type (most probably a bug, please report it)
+
+Status letters C and R are always followed by a score (denoting the
+percentage of similarity between the source and target of the move or
+copy), and are the only ones to be so.
+
+<sha1> is shown as all 0's if a file is new on the filesystem
+and it is out of sync with the index.
+
+Example:
+
+------------------------------------------------
+:100644 100644 5be4a4...... 000000...... M file.c
+------------------------------------------------
+
+When `-z` option is not used, TAB, LF, and backslash characters
+in pathnames are represented as `\t`, `\n`, and `\\`,
+respectively.
+
+diff format for merges
+----------------------
+
+"git-diff-tree", "git-diff-files" and "git-diff --raw"
+can take '-c' or '--cc' option
+to generate diff output also for merge commits. The output differs
+from the format described above in the following way:
+
+. there is a colon for each parent
+. there are more "src" modes and "src" sha1
+. status is concatenated status characters for each parent
+. no optional "score" number
+. single path, only for "dst"
+
+Example:
+
+------------------------------------------------
+::100644 100644 100644 fabadb8... cc95eb0... 4866510... MM describe.c
+------------------------------------------------
+
+Note that 'combined diff' lists only files which were modified from
+all parents.
+
+
+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
+----------------------------------------
- <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
- contents of <old|ne>,
- <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
- <old|new>-mode:: are the octal representation of the file modes.
+That is:
-+
-The file parameters can point at the user's working file
-(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
-when a new file is added), or a temporary file (e.g. `old-file` in the
-cache). 'GIT_EXTERNAL_DIFF' should not worry about unlinking the
-temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
+. 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.
-For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
-parameter, <path>.
+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.