path: root/Documentation/diff-format.txt
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authorDavid Greaves <>2005-05-08 17:22:48 (GMT)
committerJunio C Hamano <>2005-05-08 21:44:20 (GMT)
commit03ea2802495df568690760906e26dda753f75e1d (patch)
tree81166cf3defd293ddb64e7c3de0089ad1efa5770 /Documentation/diff-format.txt
parentaa575f815e2350e46a1895a6905fd8ad548c946a (diff)
[PATCH 2/2] core-git documentation update
Reformat core-git.txt to asciidoc format. Includes to create individual txt, html and man pages. <JC> Editorial note. I've updated to add git-diff-cache -m and git-update-cache --replace description on top of the version David posted to the GIT list and got his OK. Signed-off-by: David Greaves <> Signed-off-by: Junio C Hamano <>
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+The output format from "git-diff-cache", "git-diff-tree" and
+"git-diff-files" is very similar.
+These commands all compare two sets of things; what are
+compared are different:
+git-diff-cache <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-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.
+The following desription uses "old" and "new" to mean those
+compared entities.
+For files in old but not in new (i.e. removed):
+ -<mode> \t <type> \t <object> \t <path>
+For files not in old but in new (i.e. added):
+ +<mode> \t <type> \t <object> \t <path>
+For files that differ:
+ *<old-mode>-><new-mode> \t <type> \t <old-sha1>-><new-sha1> \t <path>
+<new-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 blob 5be4a4.......->000000....... 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-tree-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
+ <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.
+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.
+For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
+parameter, <path>.