Merge http://www.kernel.org/pub/scm/gitk/gitk
[git/git.git] / Documentation / diff-format.txt
1 The output format from "git-diff-index", "git-diff-tree" and
2 "git-diff-files" are very similar.
3
4 These commands all compare two sets of things; what is
5 compared differs:
6
7 git-diff-index <tree-ish>::
8 compares the <tree-ish> and the files on the filesystem.
9
10 git-diff-index --cached <tree-ish>::
11 compares the <tree-ish> and the cache.
12
13 git-diff-tree [-r] <tree-ish-1> <tree-ish-2> [<pattern>...]::
14 compares the trees named by the two arguments.
15
16 git-diff-files [<pattern>...]::
17 compares the cache and the files on the filesystem.
18
19
20 An output line is formatted this way:
21
22 ------------------------------------------------
23 in-place edit :100644 100644 bcd1234... 0123456... M file0
24 copy-edit :100644 100644 abcd123... 1234567... C68 file1 file2
25 rename-edit :100644 100644 abcd123... 1234567... R86 file1 file3
26 create :000000 100644 0000000... 1234567... A file4
27 delete :100644 000000 1234567... 0000000... D file5
28 unmerged :000000 000000 0000000... 0000000... U file6
29 ------------------------------------------------
30
31 That is, from the left to the right:
32
33 . a colon.
34 . mode for "src"; 000000 if creation or unmerged.
35 . a space.
36 . mode for "dst"; 000000 if deletion or unmerged.
37 . a space.
38 . sha1 for "src"; 0\{40\} if creation or unmerged.
39 . a space.
40 . sha1 for "dst"; 0\{40\} if creation, unmerged or "look at work tree".
41 . a space.
42 . status, followed by optional "score" number.
43 . a tab or a NUL when '-z' option is used.
44 . path for "src"
45 . a tab or a NUL when '-z' option is used; only exists for C or R.
46 . path for "dst"; only exists for C or R.
47 . an LF or a NUL when '-z' option is used, to terminate the record.
48
49 <sha1> is shown as all 0's if a file is new on the filesystem
50 and it is out of sync with the cache.
51
52 Example:
53
54 ------------------------------------------------
55 :100644 100644 5be4a4...... 000000...... M file.c
56 ------------------------------------------------
57
58 When `-z` option is not used, TAB, LF, and backslash characters
59 in pathnames are represented as `\t`, `\n`, and `\\`,
60 respectively.
61
62
63 Generating patches with -p
64 --------------------------
65
66 When "git-diff-index", "git-diff-tree", or "git-diff-files" are run
67 with a '-p' option, they do not produce the output described above;
68 instead they produce a patch file.
69
70 The patch generation can be customized at two levels.
71
72 1. When the environment variable 'GIT_EXTERNAL_DIFF' is not set,
73 these commands internally invoke "diff" like this:
74
75 diff -L a/<path> -L b/<path> -pu <old> <new>
76 +
77 For added files, `/dev/null` is used for <old>. For removed
78 files, `/dev/null` is used for <new>
79 +
80 The "diff" formatting options can be customized via the
81 environment variable 'GIT_DIFF_OPTS'. For example, if you
82 prefer context diff:
83
84 GIT_DIFF_OPTS=-c git-diff-index -p $(cat .git/HEAD)
85
86
87 2. When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
88 program named by it is called, instead of the diff invocation
89 described above.
90 +
91 For a path that is added, removed, or modified,
92 'GIT_EXTERNAL_DIFF' is called with 7 parameters:
93
94 path old-file old-hex old-mode new-file new-hex new-mode
95 +
96 where:
97
98 <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
99 contents of <old|new>,
100 <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
101 <old|new>-mode:: are the octal representation of the file modes.
102
103 +
104 The file parameters can point at the user's working file
105 (e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
106 when a new file is added), or a temporary file (e.g. `old-file` in the
107 cache). 'GIT_EXTERNAL_DIFF' should not worry about unlinking the
108 temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
109
110 For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
111 parameter, <path>.
112
113
114 git specific extension to diff format
115 -------------------------------------
116
117 What -p option produces is slightly different from the
118 traditional diff format.
119
120 1. It is preceeded with a "git diff" header, that looks like
121 this:
122
123 diff --git a/file1 b/file2
124 +
125 The `a/` and `b/` filenames are the same unless rename/copy is
126 involved. Especially, even for a creation or a deletion,
127 `/dev/null` is _not_ used in place of `a/` or `b/` filenames.
128 +
129 When rename/copy is involved, `file1` and `file2` show the
130 name of the source file of the rename/copy and the name of
131 the file that rename/copy produces, respectively.
132
133 2. It is followed by one or more extended header lines:
134
135 old mode <mode>
136 new mode <mode>
137 deleted file mode <mode>
138 new file mode <mode>
139 copy from <path>
140 copy to <path>
141 rename from <path>
142 rename to <path>
143 similarity index <number>
144 dissimilarity index <number>
145 index <hash>..<hash> <mode>
146
147 3. TAB, LF, and backslash characters in pathnames are
148 represented as `\t`, `\n`, and `\\`, respectively.