1The output format from "git-diff-index", "git-diff-tree" and 2"git-diff-files" 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" and "git-diff-files" can take '-c' or '--cc' option 66to generate diff output also for merge commits. The output differs 67from the format described above in the following way: 68 69. there is a colon for each parent 70. there are more "src" modes and "src" sha1 71. status is concatenated status characters for each parent 72. no optional "score" number 73. single path, only for "dst" 74 75Example: 76 77------------------------------------------------ 78::100644 100644 100644 fabadb8... cc95eb0... 4866510... MM describe.c 79------------------------------------------------ 80 81Note that 'combined diff' lists only files which were modified from 82all parents. 83 84 85Generating patches with -p 86-------------------------- 87 88When "git-diff-index", "git-diff-tree", or "git-diff-files" are run 89with a '-p' option, they do not produce the output described above; 90instead they produce a patch file. You can customize the creation 91of such patches via the GIT_EXTERNAL_DIFF and the GIT_DIFF_OPTS 92environment variables. 93 94What the -p option produces is slightly different from the traditional 95diff format. 96 971. It is preceded with a "git diff" header, that looks like 98 this: 99 100 diff --git a/file1 b/file2 101+ 102The `a/` and `b/` filenames are the same unless rename/copy is 103involved. Especially, even for a creation or a deletion, 104`/dev/null` is _not_ used in place of `a/` or `b/` filenames. 105+ 106When rename/copy is involved, `file1` and `file2` show the 107name of the source file of the rename/copy and the name of 108the file that rename/copy produces, respectively. 109 1102. It is followed by one or more extended header lines: 111 112 old mode <mode> 113 new mode <mode> 114 deleted file mode <mode> 115 new file mode <mode> 116 copy from <path> 117 copy to <path> 118 rename from <path> 119 rename to <path> 120 similarity index <number> 121 dissimilarity index <number> 122 index <hash>..<hash> <mode> 123 1243. TAB, LF, double quote and backslash characters in pathnames 125 are represented as `\t`, `\n`, `\"` and `\\`, respectively. 126 If there is need for such substitution then the whole 127 pathname is put in double quotes. 128 129 130combined diff format 131-------------------- 132 133git-diff-tree and git-diff-files can take '-c' or '--cc' option 134to produce 'combined diff', which looks like this: 135 136------------ 137diff --combined describe.c 138index fabadb8,cc95eb0..4866510 139--- a/describe.c 140+++ b/describe.c 141@@@ -98,20 -98,12 +98,20 @@@ 142 return (a_date > b_date) ? -1 : (a_date == b_date) ? 0 : 1; 143 } 144 145- static void describe(char *arg) 146 -static void describe(struct commit *cmit, int last_one) 147++static void describe(char *arg, int last_one) 148 { 149 + unsigned char sha1[20]; 150 + struct commit *cmit; 151 struct commit_list *list; 152 static int initialized = 0; 153 struct commit_name *n; 154 155 + if (get_sha1(arg, sha1) < 0) 156 + usage(describe_usage); 157 + cmit = lookup_commit_reference(sha1); 158 + if (!cmit) 159 + usage(describe_usage); 160 + 161 if (!initialized) { 162 initialized = 1; 163 for_each_ref(get_name); 164------------ 165 1661. It is preceded with a "git diff" header, that looks like 167 this (when '-c' option is used): 168 169 diff --combined file 170+ 171or like this (when '--cc' option is used): 172 173 diff --c file 174 1752. It is followed by one or more extended header lines 176 (this example shows a merge with two parents): 177 178 index <hash>,<hash>..<hash> 179 mode <mode>,<mode>..<mode> 180 new file mode <mode> 181 deleted file mode <mode>,<mode> 182+ 183The `mode <mode>,<mode>..<mode>` line appears only if at least one of 184the <mode> is different from the rest. Extended headers with 185information about detected contents movement (renames and 186copying detection) are designed to work with diff of two 187<tree-ish> and are not used by combined diff format. 188 1893. It is followed by two-line from-file/to-file header 190 191 --- a/file 192 +++ b/file 193+ 194Similar to two-line header for traditional 'unified' diff 195format, `/dev/null` is used to signal created or deleted 196files. 197 1984. Chunk header format is modified to prevent people from 199 accidentally feeding it to `patch -p1`. Combined diff format 200 was created for review of merge commit changes, and was not 201 meant for apply. The change is similar to the change in the 202 extended 'index' header: 203 204 @@@ <from-file-range> <from-file-range> <to-file-range> @@@ 205+ 206There are (number of parents + 1) `@` characters in the chunk 207header for combined diff format. 208 209Unlike the traditional 'unified' diff format, which shows two 210files A and B with a single column that has `-` (minus -- 211appears in A but removed in B), `+` (plus -- missing in A but 212added to B), or `" "` (space -- unchanged) prefix, this format 213compares two or more files file1, file2,... with one file X, and 214shows how X differs from each of fileN. One column for each of 215fileN is prepended to the output line to note how X's line is 216different from it. 217 218A `-` character in the column N means that the line appears in 219fileN but it does not appear in the result. A `+` character 220in the column N means that the line appears in the last file, 221and fileN does not have that line (in other words, the line was 222added, from the point of view of that parent). 223 224In the above example output, the function signature was changed 225from both files (hence two `-` removals from both file1 and 226file2, plus `++` to mean one line that was added does not appear 227in either file1 nor file2). Also two other lines are the same 228from file1 but do not appear in file2 (hence prefixed with ` +`). 229 230When shown by `git diff-tree -c`, it compares the parents of a 231merge commit with the merge result (i.e. file1..fileN are the 232parents). When shown by `git diff-files -c`, it compares the 233two unresolved merge parents with the working tree file 234(i.e. file1 is stage 2 aka "our version", file2 is stage 3 aka 235"their version").