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20 .TH "GIT-DIFF-INDEX" 1 "" "" ""
22 git-diff-index \- Compares content and mode of blobs between the index and repository
26 git\-diff\-index [\-m] [\-\-cached] [<common diff options>] <tree\-ish> [<path>...]
31 Compares the content and mode of the blobs found via a tree object with the content of the current index and, optionally ignoring the stat state of the file on disk\&. When paths are specified, compares only those named paths\&. Otherwise all entries in the index are compared\&.
37 Generate patch (see section on generating patches)
45 \\0 line termination on output
49 Show only names of changed files\&.
53 Show only names and status of changed files\&.
57 Instead of the first handful characters, show full object name of pre\- and post\-image blob on the "index" line when generating a patch format output\&.
61 Instead of showing the full 40\-byte hexadecimal object name in diff\-raw format output and diff\-tree header lines, show only handful hexdigits prefix\&. This is independent of \-\-full\-index option above, which controls the diff\-patch output format\&. Non default number of digits can be specified with \-\-abbrev=<n>\&.
65 Break complete rewrite changes into pairs of delete and create\&.
73 Detect copies as well as renames\&.
76 \-\-find\-copies\-harder
77 For performance reasons, by default, \-C option finds copies only if the original file of the copy was modified in the same changeset\&. This flag makes the command inspect unmodified files as candidates for the source of copy\&. This is a very expensive operation for large projects, so use it with caution\&.
81 \-M and \-C options require O(n^2) processing time where n is the number of potential rename/copy targets\&. This option prevents rename/copy detection from running if the number of rename/copy targets exceeds the specified number\&.
85 Look for differences that contain the change in <string>\&.
89 When \-S finds a change, show all the changes in that changeset, not just the files that contain the change in <string>\&.
93 Output the patch in the order specified in the <orderfile>, which has one shell glob pattern per line\&.
97 Swap two inputs; that is, show differences from index or on\-disk file to tree contents\&.
100 For more detailed explanation on these common options, see also diffcore documentation: \fIdiffcore.html\fR\&.
104 The id of a tree object to diff against\&.
108 do not consider the on\-disk file at all
112 By default, files recorded in the index but not checked out are reported as deleted\&. This flag makes "git\-diff\-index" say that all non\-checked\-out files are up to date\&.
117 The output format from "git\-diff\-index", "git\-diff\-tree" and "git\-diff\-files" are very similar\&.
120 These commands all compare two sets of things; what is compared differs:
123 git\-diff\-index <tree\-ish>
124 compares the <tree\-ish> and the files on the filesystem\&.
127 git\-diff\-index \-\-cached <tree\-ish>
128 compares the <tree\-ish> and the index\&.
131 git\-diff\-tree [\-r] <tree\-ish\-1> <tree\-ish\-2> [<pattern>...]
132 compares the trees named by the two arguments\&.
135 git\-diff\-files [<pattern>...]
136 compares the index and the files on the filesystem\&.
139 An output line is formatted this way:
142 in\-place edit :100644 100644 bcd1234\&.\&.\&. 0123456\&.\&.\&. M file0
143 copy\-edit :100644 100644 abcd123\&.\&.\&. 1234567\&.\&.\&. C68 file1 file2
144 rename\-edit :100644 100644 abcd123\&.\&.\&. 1234567\&.\&.\&. R86 file1 file3
145 create :000000 100644 0000000\&.\&.\&. 1234567\&.\&.\&. A file4
146 delete :100644 000000 1234567\&.\&.\&. 0000000\&.\&.\&. D file5
147 unmerged :000000 000000 0000000\&.\&.\&. 0000000\&.\&.\&. U file6
149 That is, from the left to the right:
156 mode for "src"; 000000 if creation or unmerged\&.
162 mode for "dst"; 000000 if deletion or unmerged\&.
168 sha1 for "src"; 0{40} if creation or unmerged\&.
174 sha1 for "dst"; 0{40} if creation, unmerged or "look at work tree"\&.
180 status, followed by optional "score" number\&.
183 a tab or a NUL when \-z option is used\&.
189 a tab or a NUL when \-z option is used; only exists for C or R\&.
192 path for "dst"; only exists for C or R\&.
195 an LF or a NUL when \-z option is used, to terminate the record\&.
199 <sha1> is shown as all 0's if a file is new on the filesystem and it is out of sync with the index\&.
205 :100644 100644 5be4a4\&.\&.\&.\&.\&.\&. 000000\&.\&.\&.\&.\&.\&. M file\&.c
207 When \-z option is not used, TAB, LF, and backslash characters in pathnames are represented as \\t, \\n, and \\\\, respectively\&.
209 .SH "GENERATING PATCHES WITH -P"
212 When "git\-diff\-index", "git\-diff\-tree", or "git\-diff\-files" are run with a \-p option, they do not produce the output described above; instead they produce a patch file\&.
215 The patch generation can be customized at two levels\&.
219 When the environment variable GIT_EXTERNAL_DIFF is not set, these commands internally invoke "diff" like this:
223 diff \-L a/<path> \-L b/<path> \-pu <old> <new>
225 For added files, /dev/null is used for <old>\&. For removed files, /dev/null is used for <new>
227 The "diff" formatting options can be customized via the environment variable GIT_DIFF_OPTS\&. For example, if you prefer context diff:
230 GIT_DIFF_OPTS=\-c git\-diff\-index \-p HEAD
234 When the environment variable GIT_EXTERNAL_DIFF is set, the program named by it is called, instead of the diff invocation described above\&.
236 For a path that is added, removed, or modified, GIT_EXTERNAL_DIFF is called with 7 parameters:
240 path old\-file old\-hex old\-mode new\-file new\-hex new\-mode
245 are files GIT_EXTERNAL_DIFF can use to read the contents of <old|new>,
247 are the 40\-hexdigit SHA1 hashes,
249 are the octal representation of the file modes\&.
250 The file parameters can point at the user's working file (e\&.g\&. new\-file in "git\-diff\-files"), /dev/null (e\&.g\&. old\-file when a new file is added), or a temporary file (e\&.g\&. old\-file in the index)\&. GIT_EXTERNAL_DIFF should not worry about unlinking the temporary file \-\-\- it is removed when GIT_EXTERNAL_DIFF exits\&.
254 For a path that is unmerged, GIT_EXTERNAL_DIFF is called with 1 parameter, <path>\&.
256 .SH "GIT SPECIFIC EXTENSION TO DIFF FORMAT"
259 What \-p option produces is slightly different from the traditional diff format\&.
263 It is preceded with a "git diff" header, that looks like this:
267 diff \-\-git a/file1 b/file2
269 The a/ and b/ filenames are the same unless rename/copy is involved\&. Especially, even for a creation or a deletion, /dev/null is _not_ used in place of a/ or b/ filenames\&.
271 When rename/copy is involved, file1 and file2 show the name of the source file of the rename/copy and the name of the file that rename/copy produces, respectively\&.
274 It is followed by one or more extended header lines:
279 deleted file mode <mode>
285 similarity index <number>
286 dissimilarity index <number>
287 index <hash>\&.\&.<hash> <mode>
291 TAB, LF, and backslash characters in pathnames are represented as \\t, \\n, and \\\\, respectively\&.
294 .SH "COMBINED DIFF FORMAT"
297 git\-diff\-tree and git\-diff\-files can take \-c or \-\-cc option to produce combined diff, which looks like this:
300 diff \-\-combined describe\&.c
302 return (a_date > b_date) ? \-1 : (a_date == b_date) ? 0 : 1;
305 \- static void describe(char *arg)
306 \-static void describe(struct commit *cmit, int last_one)
307 ++static void describe(char *arg, int last_one)
309 + unsigned char sha1[20];
310 + struct commit *cmit;
312 Unlike the traditional unified diff format, which shows two files A and B with a single column that has \- (minus -- appears in A but removed in B), + (plus -- missing in A but added to B), or (space -- unchanged) prefix, this format compares two or more files file1, file2,... with one file X, and shows how X differs from each of fileN\&. One column for each of fileN is prepended to the output line to note how X's line is different from it\&.
315 A \- character in the column N means that the line appears in fileN but it does not appear in the last file\&. A + character in the column N means that the line appears in the last file, and fileN does not have that line\&.
318 In the above example output, the function signature was changed from both files (hence two \- removals from both file1 and file2, plus ++ to mean one line that was added does not appear in either file1 nor file2)\&. Also two other lines are the same from file1 but do not appear in file2 (hence prefixed with +)\&.
321 When shown by git diff\-tree \-c, it compares the parents of a merge commit with the merge result (i\&.e\&. file1\&.\&.fileN are the parents)\&. When shown by git diff\-files \-c, it compares the two unresolved merge parents with the working tree file (i\&.e\&. file1 is stage 2 aka "our version", file2 is stage 3 aka "their version")\&.
323 .SH "OPERATING MODES"
326 You can choose whether you want to trust the index file entirely (using the \-\-cached flag) or ask the diff logic to show any files that don't match the stat state as being "tentatively changed"\&. Both of these operations are very useful indeed\&.
331 If \-\-cached is specified, it allows you to ask:
334 show me the differences between HEAD and the current index
335 contents (the ones I'd write with a "git\-write\-tree")
339 For example, let's say that you have worked on your working directory, updated some files in the index and are ready to commit\&. You want to see exactly what you are going to commit is without having to write a new tree object and compare it that way, and to do that, you just do
342 git\-diff\-index \-\-cached HEAD
346 Example: let's say I had renamed commit\&.c to git\-commit\&.c, and I had done an "git\-update\-index" to make that effective in the index file\&. "git\-diff\-files" wouldn't show anything at all, since the index file matches my working directory\&. But doing a "git\-diff\-index" does:
349 torvalds@ppc970:~/git> git\-diff\-index \-\-cached HEAD
350 \-100644 blob 4161aecc6700a2eb579e842af0b7f22b98443f74 commit\&.c
351 +100644 blob 4161aecc6700a2eb579e842af0b7f22b98443f74 git\-commit\&.c
355 You can trivially see that the above is a rename\&.
358 In fact, "git\-diff\-index \-\-cached" should always be entirely equivalent to actually doing a "git\-write\-tree" and comparing that\&. Except this one is much nicer for the case where you just want to check where you are\&.
361 So doing a "git\-diff\-index \-\-cached" is basically very useful when you are asking yourself "what have I already marked for being committed, and what's the difference to a previous tree"\&.
363 .SH "NON-CACHED MODE"
366 The "non\-cached" mode takes a different approach, and is potentially the more useful of the two in that what it does can't be emulated with a "git\-write\-tree" + "git\-diff\-tree"\&. Thus that's the default mode\&. The non\-cached version asks the question:
369 show me the differences between HEAD and the currently checked out
370 tree \- index contents _and_ files that aren't up\-to\-date
374 which is obviously a very useful question too, since that tells you what you could commit\&. Again, the output matches the "git\-diff\-tree \-r" output to a tee, but with a twist\&.
377 The twist is that if some file doesn't match the index, we don't have a backing store thing for it, and we use the magic "all\-zero" sha1 to show that\&. So let's say that you have edited kernel/sched\&.c, but have not actually done a "git\-update\-index" on it yet \- there is no "object" associated with the new state, and you get:
380 torvalds@ppc970:~/v2\&.6/linux> git\-diff\-index HEAD
381 *100644\->100664 blob 7476bb\&.\&.\&.\&.\&.\&.\->000000\&.\&.\&.\&.\&.\&. kernel/sched\&.c
385 ie it shows that the tree has changed, and that kernel/sched\&.c has is not up\-to\-date and may contain new stuff\&. The all\-zero sha1 means that to get the real diff, you need to look at the object in the working directory directly rather than do an object\-to\-object diff\&.
391 As with other commands of this type, "git\-diff\-index" does not actually look at the contents of the file at all\&. So maybe kernel/sched\&.c hasn't actually changed, and it's just that you touched it\&. In either case, it's a note that you need to "git\-update\-index" it to make the index be in sync\&.
399 You can have a mixture of files show up as "has been updated" and "is still dirty in the working directory" together\&. You can always tell which file is in which state, since the "has been updated" ones show a valid sha1, and the "not in sync with the index" ones will always have the special all\-zero sha1\&.
406 Written by Linus Torvalds <torvalds@osdl\&.org>
411 Documentation by David Greaves, Junio C Hamano and the git\-list <git@vger\&.kernel\&.org>\&.
416 Part of the \fBgit\fR(7) suite
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