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 62 63Generating patches with -p 64-------------------------- 65 66When "git-diff-index", "git-diff-tree", or "git-diff-files" are run 67with a '-p' option, they do not produce the output described above; 68instead they produce a patch file. You can customize the creation 69of such patches via the GIT_EXTERNAL_DIFF and the GIT_DIFF_OPTS 70environment variables. 71 72What the -p option produces is slightly different from the traditional 73diff format. 74 751. It is preceded with a "git diff" header, that looks like 76 this: 77 78 diff --git a/file1 b/file2 79+ 80The `a/` and `b/` filenames are the same unless rename/copy is 81involved. Especially, even for a creation or a deletion, 82`/dev/null` is _not_ used in place of `a/` or `b/` filenames. 83+ 84When rename/copy is involved, `file1` and `file2` show the 85name of the source file of the rename/copy and the name of 86the file that rename/copy produces, respectively. 87 882. It is followed by one or more extended header lines: 89 90 old mode <mode> 91 new mode <mode> 92 deleted file mode <mode> 93 new file mode <mode> 94 copy from <path> 95 copy to <path> 96 rename from <path> 97 rename to <path> 98 similarity index <number> 99 dissimilarity index <number> 100 index <hash>..<hash> <mode> 101 1023. TAB, LF, double quote and backslash characters in pathnames 103 are represented as `\t`, `\n`, `\"` and `\\`, respectively. 104 If there is need for such substitution then the whole 105 pathname is put in double quotes. 106 107 108combined diff format 109-------------------- 110 111git-diff-tree and git-diff-files can take '-c' or '--cc' option 112to produce 'combined diff', which looks like this: 113 114------------ 115diff --combined describe.c 116index fabadb8,cc95eb0..4866510 117--- a/describe.c 118+++ b/describe.c 119@@@ -98,20 -98,12 +98,20 @@@ 120 return (a_date > b_date) ? -1 : (a_date == b_date) ? 0 : 1; 121 } 122 123- static void describe(char *arg) 124 -static void describe(struct commit *cmit, int last_one) 125++static void describe(char *arg, int last_one) 126 { 127 + unsigned char sha1[20]; 128 + struct commit *cmit; 129 struct commit_list *list; 130 static int initialized = 0; 131 struct commit_name *n; 132 133 + if (get_sha1(arg, sha1) < 0) 134 + usage(describe_usage); 135 + cmit = lookup_commit_reference(sha1); 136 + if (!cmit) 137 + usage(describe_usage); 138 + 139 if (!initialized) { 140 initialized = 1; 141 for_each_ref(get_name); 142------------ 143 1441. It is preceded with a "git diff" header, that looks like 145 this (when '-c' option is used): 146 147 diff --combined file 148+ 149or like this (when '--cc' option is used): 150 151 diff --c file 152 1532. It is followed by one or more extended header lines 154 (this example shows a merge with two parents): 155 156 index <hash>,<hash>..<hash> 157 mode <mode>,<mode>..<mode> 158 new file mode <mode> 159 deleted file mode <mode>,<mode> 160+ 161The `mode <mode>,<mode>..<mode>` line appears only if at least one of 162the <mode> is different from the rest. Extended headers with 163information about detected contents movement (renames and 164copying detection) are designed to work with diff of two 165<tree-ish> and are not used by combined diff format. 166 1673. It is followed by two-line from-file/to-file header 168 169 --- a/file 170 +++ b/file 171+ 172Similar to two-line header for traditional 'unified' diff 173format, `/dev/null` is used to signal created or deleted 174files. 175 1764. Chunk header format is modified to prevent people from 177 accidentally feeding it to `patch -p1`. Combined diff format 178 was created for review of merge commit changes, and was not 179 meant for apply. The change is similar to the change in the 180 extended 'index' header: 181 182 @@@ <from-file-range> <from-file-range> <to-file-range> @@@ 183+ 184There are (number of parents + 1) `@` characters in the chunk 185header for combined diff format. 186 187Unlike the traditional 'unified' diff format, which shows two 188files A and B with a single column that has `-` (minus -- 189appears in A but removed in B), `+` (plus -- missing in A but 190added to B), or `" "` (space -- unchanged) prefix, this format 191compares two or more files file1, file2,... with one file X, and 192shows how X differs from each of fileN. One column for each of 193fileN is prepended to the output line to note how X's line is 194different from it. 195 196A `-` character in the column N means that the line appears in 197fileN but it does not appear in the result. A `+` character 198in the column N means that the line appears in the last file, 199and fileN does not have that line (in other words, the line was 200added, from the point of view of that parent). 201 202In the above example output, the function signature was changed 203from both files (hence two `-` removals from both file1 and 204file2, plus `++` to mean one line that was added does not appear 205in either file1 nor file2). Also two other lines are the same 206from file1 but do not appear in file2 (hence prefixed with ` +`). 207 208When shown by `git diff-tree -c`, it compares the parents of a 209merge commit with the merge result (i.e. file1..fileN are the 210parents). When shown by `git diff-files -c`, it compares the 211two unresolved merge parents with the working tree file 212(i.e. file1 is stage 2 aka "our version", file2 is stage 3 aka 213"their version"). 214