1The output format from "git-diff-index", "git-diff-tree", 2"git-diff-files" and "git diff --raw" are very similar. 3 4These commands all compare two sets of things; what is 5compared differs: 6 7git-diff-index <tree-ish>:: 8 compares the <tree-ish> and the files on the filesystem. 9 10git-diff-index --cached <tree-ish>:: 11 compares the <tree-ish> and the index. 12 13git-diff-tree [-r] <tree-ish-1> <tree-ish-2> [<pattern>...]:: 14 compares the trees named by the two arguments. 15 16git-diff-files [<pattern>...]:: 17 compares the index and the files on the filesystem. 18 19 20An output line is formatted this way: 21 22------------------------------------------------ 23in-place edit :100644 100644 bcd1234... 0123456... M file0 24copy-edit :100644 100644 abcd123... 1234567... C68 file1 file2 25rename-edit :100644 100644 abcd123... 1234567... R86 file1 file3 26create :000000 100644 0000000... 1234567... A file4 27delete :100644 000000 1234567... 0000000... D file5 28unmerged :000000 000000 0000000... 0000000... U file6 29------------------------------------------------ 30 31That 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 50and it is out of sync with the index. 51 52Example: 53 54------------------------------------------------ 55:100644 100644 5be4a4...... 000000...... M file.c 56------------------------------------------------ 57 58When `-z` option is not used, TAB, LF, and backslash characters 59in pathnames are represented as `\t`, `\n`, and `\\`, 60respectively. 61 62diff format for merges 63---------------------- 64 65"git-diff-tree", "git-diff-files" and "git-diff --raw" 66can take '-c' or '--cc' option 67to generate diff output also for merge commits. The output differs 68from the format described above in the following way: 69 70. there is a colon for each parent 71. there are more "src" modes and "src" sha1 72. status is concatenated status characters for each parent 73. no optional "score" number 74. single path, only for "dst" 75 76Example: 77 78------------------------------------------------ 79::100644 100644 100644 fabadb8... cc95eb0... 4866510... MM describe.c 80------------------------------------------------ 81 82Note that 'combined diff' lists only files which were modified from 83all parents. 84 85 86Generating patches with -p 87-------------------------- 88 89When "git-diff-index", "git-diff-tree", or "git-diff-files" are run 90with a '-p' option, or "git diff" without the '--raw' option, they 91do not produce the output described above; instead they produce a 92patch file. You can customize the creation of such patches via the 93GIT_EXTERNAL_DIFF and the GIT_DIFF_OPTS environment variables. 94 95What the -p option produces is slightly different from the traditional 96diff format. 97 981. It is preceded with a "git diff" header, that looks like 99 this: 100 101 diff --git a/file1 b/file2 102+ 103The `a/` and `b/` filenames are the same unless rename/copy is 104involved. Especially, even for a creation or a deletion, 105`/dev/null` is _not_ used in place of `a/` or `b/` filenames. 106+ 107When rename/copy is involved, `file1` and `file2` show the 108name of the source file of the rename/copy and the name of 109the file that rename/copy produces, respectively. 110 1112. It is followed by one or more extended header lines: 112 113 old mode <mode> 114 new mode <mode> 115 deleted file mode <mode> 116 new file mode <mode> 117 copy from <path> 118 copy to <path> 119 rename from <path> 120 rename to <path> 121 similarity index <number> 122 dissimilarity index <number> 123 index <hash>..<hash> <mode> 124 1253. TAB, LF, double quote and backslash characters in pathnames 126 are represented as `\t`, `\n`, `\"` and `\\`, respectively. 127 If there is need for such substitution then the whole 128 pathname is put in double quotes. 129 130The similarity index is the percentage of unchanged lines, and 131the dissimilarity index is the percentage of changed lines. It 132is a rounded down integer, followed by a percent sign. The 133similarity index value of 100% is thus reserved for two equal 134files, while 100% dissimilarity means that no line from the old 135file made it into the new one. 136 137 138combined diff format 139-------------------- 140 141"git-diff-tree", "git-diff-files" and "git-diff" can take '-c' or 142'--cc' option to produce 'combined diff', which looks like this: 143 144------------ 145diff --combined describe.c 146index fabadb8,cc95eb0..4866510 147--- a/describe.c 148+++ b/describe.c 149@@@ -98,20 -98,12 +98,20 @@@ 150 return (a_date > b_date) ? -1 : (a_date == b_date) ? 0 : 1; 151 } 152 153- static void describe(char *arg) 154 -static void describe(struct commit *cmit, int last_one) 155++static void describe(char *arg, int last_one) 156 { 157 + unsigned char sha1[20]; 158 + struct commit *cmit; 159 struct commit_list *list; 160 static int initialized = 0; 161 struct commit_name *n; 162 163 + if (get_sha1(arg, sha1) < 0) 164 + usage(describe_usage); 165 + cmit = lookup_commit_reference(sha1); 166 + if (!cmit) 167 + usage(describe_usage); 168 + 169 if (!initialized) { 170 initialized = 1; 171 for_each_ref(get_name); 172------------ 173 1741. It is preceded with a "git diff" header, that looks like 175 this (when '-c' option is used): 176 177 diff --combined file 178+ 179or like this (when '--cc' option is used): 180 181 diff --c file 182 1832. It is followed by one or more extended header lines 184 (this example shows a merge with two parents): 185 186 index <hash>,<hash>..<hash> 187 mode <mode>,<mode>..<mode> 188 new file mode <mode> 189 deleted file mode <mode>,<mode> 190+ 191The `mode <mode>,<mode>..<mode>` line appears only if at least one of 192the <mode> is different from the rest. Extended headers with 193information about detected contents movement (renames and 194copying detection) are designed to work with diff of two 195<tree-ish> and are not used by combined diff format. 196 1973. It is followed by two-line from-file/to-file header 198 199 --- a/file 200 +++ b/file 201+ 202Similar to two-line header for traditional 'unified' diff 203format, `/dev/null` is used to signal created or deleted 204files. 205 2064. Chunk header format is modified to prevent people from 207 accidentally feeding it to `patch -p1`. Combined diff format 208 was created for review of merge commit changes, and was not 209 meant for apply. The change is similar to the change in the 210 extended 'index' header: 211 212 @@@ <from-file-range> <from-file-range> <to-file-range> @@@ 213+ 214There are (number of parents + 1) `@` characters in the chunk 215header for combined diff format. 216 217Unlike the traditional 'unified' diff format, which shows two 218files A and B with a single column that has `-` (minus -- 219appears in A but removed in B), `+` (plus -- missing in A but 220added to B), or `" "` (space -- unchanged) prefix, this format 221compares two or more files file1, file2,... with one file X, and 222shows how X differs from each of fileN. One column for each of 223fileN is prepended to the output line to note how X's line is 224different from it. 225 226A `-` character in the column N means that the line appears in 227fileN but it does not appear in the result. A `+` character 228in the column N means that the line appears in the last file, 229and fileN does not have that line (in other words, the line was 230added, from the point of view of that parent). 231 232In the above example output, the function signature was changed 233from both files (hence two `-` removals from both file1 and 234file2, plus `++` to mean one line that was added does not appear 235in either file1 nor file2). Also two other lines are the same 236from file1 but do not appear in file2 (hence prefixed with ` +`). 237 238When shown by `git diff-tree -c`, it compares the parents of a 239merge commit with the merge result (i.e. file1..fileN are the 240parents). When shown by `git diff-files -c`, it compares the 241two unresolved merge parents with the working tree file 242(i.e. file1 is stage 2 aka "our version", file2 is stage 3 aka 243"their version").