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 129The similarity index is the percentage of unchanged lines, and 130the dissimilarity index is the percentage of changed lines. It 131is a rounded down integer, followed by a percent sign. The 132similarity index value of 100% is thus reserved for two equal 133files, while 100% dissimilarity means that no line from the old 134file made it into the new one. 135 136 137combined diff format 138-------------------- 139 140git-diff-tree and git-diff-files can take '-c' or '--cc' option 141to produce 'combined diff', which looks like this: 142 143------------ 144diff --combined describe.c 145index fabadb8,cc95eb0..4866510 146--- a/describe.c 147+++ b/describe.c 148@@@ -98,20 -98,12 +98,20 @@@ 149 return (a_date > b_date) ? -1 : (a_date == b_date) ? 0 : 1; 150 } 151 152- static void describe(char *arg) 153 -static void describe(struct commit *cmit, int last_one) 154++static void describe(char *arg, int last_one) 155 { 156 + unsigned char sha1[20]; 157 + struct commit *cmit; 158 struct commit_list *list; 159 static int initialized = 0; 160 struct commit_name *n; 161 162 + if (get_sha1(arg, sha1) < 0) 163 + usage(describe_usage); 164 + cmit = lookup_commit_reference(sha1); 165 + if (!cmit) 166 + usage(describe_usage); 167 + 168 if (!initialized) { 169 initialized = 1; 170 for_each_ref(get_name); 171------------ 172 1731. It is preceded with a "git diff" header, that looks like 174 this (when '-c' option is used): 175 176 diff --combined file 177+ 178or like this (when '--cc' option is used): 179 180 diff --c file 181 1822. It is followed by one or more extended header lines 183 (this example shows a merge with two parents): 184 185 index <hash>,<hash>..<hash> 186 mode <mode>,<mode>..<mode> 187 new file mode <mode> 188 deleted file mode <mode>,<mode> 189+ 190The `mode <mode>,<mode>..<mode>` line appears only if at least one of 191the <mode> is different from the rest. Extended headers with 192information about detected contents movement (renames and 193copying detection) are designed to work with diff of two 194<tree-ish> and are not used by combined diff format. 195 1963. It is followed by two-line from-file/to-file header 197 198 --- a/file 199 +++ b/file 200+ 201Similar to two-line header for traditional 'unified' diff 202format, `/dev/null` is used to signal created or deleted 203files. 204 2054. Chunk header format is modified to prevent people from 206 accidentally feeding it to `patch -p1`. Combined diff format 207 was created for review of merge commit changes, and was not 208 meant for apply. The change is similar to the change in the 209 extended 'index' header: 210 211 @@@ <from-file-range> <from-file-range> <to-file-range> @@@ 212+ 213There are (number of parents + 1) `@` characters in the chunk 214header for combined diff format. 215 216Unlike the traditional 'unified' diff format, which shows two 217files A and B with a single column that has `-` (minus -- 218appears in A but removed in B), `+` (plus -- missing in A but 219added to B), or `" "` (space -- unchanged) prefix, this format 220compares two or more files file1, file2,... with one file X, and 221shows how X differs from each of fileN. One column for each of 222fileN is prepended to the output line to note how X's line is 223different from it. 224 225A `-` character in the column N means that the line appears in 226fileN but it does not appear in the result. A `+` character 227in the column N means that the line appears in the last file, 228and fileN does not have that line (in other words, the line was 229added, from the point of view of that parent). 230 231In the above example output, the function signature was changed 232from both files (hence two `-` removals from both file1 and 233file2, plus `++` to mean one line that was added does not appear 234in either file1 nor file2). Also two other lines are the same 235from file1 but do not appear in file2 (hence prefixed with ` +`). 236 237When shown by `git diff-tree -c`, it compares the parents of a 238merge commit with the merge result (i.e. file1..fileN are the 239parents). When shown by `git diff-files -c`, it compares the 240two unresolved merge parents with the working tree file 241(i.e. file1 is stage 2 aka "our version", file2 is stage 3 aka 242"their version").