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 index.
  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 index 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 index.
  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 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 index).  '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 preceded 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.