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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 \fIgit\-diff\-index\fR [\-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 Generate patch but keep also the default raw diff output\&.
49 \\0 line termination on output
53 Show only names of changed files\&.
57 Show only names and status of changed files\&.
61 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\&.
65 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>\&.
69 Break complete rewrite changes into pairs of delete and create\&.
77 Detect copies as well as renames\&.
80 \-\-diff\-filter=[ACDMRTUXB*]
81 Select only files that are Added (A), Copied (C), Deleted (D), Modified (M), Renamed (R), have their type (mode) changed (T), are Unmerged (U), are Unknown (X), or have had their pairing Broken (B)\&. Any combination of the filter characters may be used\&. When * (All\-or\-none) is added to the combination, all paths are selected if there is any file that matches other criteria in the comparison; if there is no file that matches other criteria, nothing is selected\&.
84 \-\-find\-copies\-harder
85 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\&.
89 \-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\&.
93 Look for differences that contain the change in <string>\&.
97 When \-S finds a change, show all the changes in that changeset, not just the files that contain the change in <string>\&.
101 Make the <string> not a plain string but an extended POSIX regex to match\&.
105 Output the patch in the order specified in the <orderfile>, which has one shell glob pattern per line\&.
109 Swap two inputs; that is, show differences from index or on\-disk file to tree contents\&.
112 For more detailed explanation on these common options, see also diffcore documentation: \fIdiffcore.html\fR\&.
116 The id of a tree object to diff against\&.
120 do not consider the on\-disk file at all
124 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\&.
129 The output format from "git\-diff\-index", "git\-diff\-tree" and "git\-diff\-files" are very similar\&.
132 These commands all compare two sets of things; what is compared differs:
135 git\-diff\-index <tree\-ish>
136 compares the <tree\-ish> and the files on the filesystem\&.
139 git\-diff\-index \-\-cached <tree\-ish>
140 compares the <tree\-ish> and the index\&.
143 git\-diff\-tree [\-r] <tree\-ish\-1> <tree\-ish\-2> [<pattern>...]
144 compares the trees named by the two arguments\&.
147 git\-diff\-files [<pattern>...]
148 compares the index and the files on the filesystem\&.
151 An output line is formatted this way:
154 in\-place edit :100644 100644 bcd1234\&.\&.\&. 0123456\&.\&.\&. M file0
155 copy\-edit :100644 100644 abcd123\&.\&.\&. 1234567\&.\&.\&. C68 file1 file2
156 rename\-edit :100644 100644 abcd123\&.\&.\&. 1234567\&.\&.\&. R86 file1 file3
157 create :000000 100644 0000000\&.\&.\&. 1234567\&.\&.\&. A file4
158 delete :100644 000000 1234567\&.\&.\&. 0000000\&.\&.\&. D file5
159 unmerged :000000 000000 0000000\&.\&.\&. 0000000\&.\&.\&. U file6
163 That is, from the left to the right:
170 mode for "src"; 000000 if creation or unmerged\&.
176 mode for "dst"; 000000 if deletion or unmerged\&.
182 sha1 for "src"; 0{40} if creation or unmerged\&.
188 sha1 for "dst"; 0{40} if creation, unmerged or "look at work tree"\&.
194 status, followed by optional "score" number\&.
197 a tab or a NUL when \fI\-z\fR option is used\&.
203 a tab or a NUL when \fI\-z\fR option is used; only exists for C or R\&.
206 path for "dst"; only exists for C or R\&.
209 an LF or a NUL when \fI\-z\fR option is used, to terminate the record\&.
213 <sha1> is shown as all 0's if a file is new on the filesystem and it is out of sync with the index\&.
219 :100644 100644 5be4a4\&.\&.\&.\&.\&.\&. 000000\&.\&.\&.\&.\&.\&. M file\&.c
223 When \-z option is not used, TAB, LF, and backslash characters in pathnames are represented as \\t, \\n, and \\\\, respectively\&.
225 .SH "GENERATING PATCHES WITH -P"
228 When "git\-diff\-index", "git\-diff\-tree", or "git\-diff\-files" are run with a \fI\-p\fR option, they do not produce the output described above; instead they produce a patch file\&.
231 The patch generation can be customized at two levels\&.
235 When the environment variable \fIGIT_EXTERNAL_DIFF\fR is not set, these commands internally invoke "diff" like this:
239 diff \-L a/<path> \-L b/<path> \-pu <old> <new>
241 For added files, /dev/null is used for <old>\&. For removed files, /dev/null is used for <new>
243 The "diff" formatting options can be customized via the environment variable \fIGIT_DIFF_OPTS\fR\&. For example, if you prefer context diff:
246 GIT_DIFF_OPTS=\-c git\-diff\-index \-p HEAD
250 When the environment variable \fIGIT_EXTERNAL_DIFF\fR is set, the program named by it is called, instead of the diff invocation described above\&.
252 For a path that is added, removed, or modified, \fIGIT_EXTERNAL_DIFF\fR is called with 7 parameters:
256 path old\-file old\-hex old\-mode new\-file new\-hex new\-mode
262 are files GIT_EXTERNAL_DIFF can use to read the contents of <old|new>,
266 are the 40\-hexdigit SHA1 hashes,
270 are the octal representation of the file modes\&.
272 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)\&. \fIGIT_EXTERNAL_DIFF\fR should not worry about unlinking the temporary file \-\-\- it is removed when \fIGIT_EXTERNAL_DIFF\fR exits\&.
276 For a path that is unmerged, \fIGIT_EXTERNAL_DIFF\fR is called with 1 parameter, <path>\&.
278 .SH "GIT SPECIFIC EXTENSION TO DIFF FORMAT"
281 What \-p option produces is slightly different from the traditional diff format\&.
285 It is preceded with a "git diff" header, that looks like this:
289 diff \-\-git a/file1 b/file2
291 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\&.
293 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\&.
296 It is followed by one or more extended header lines:
301 deleted file mode <mode>
307 similarity index <number>
308 dissimilarity index <number>
309 index <hash>\&.\&.<hash> <mode>
313 TAB, LF, and backslash characters in pathnames are represented as \\t, \\n, and \\\\, respectively\&.
316 .SH "COMBINED DIFF FORMAT"
319 git\-diff\-tree and git\-diff\-files can take \fI\-c\fR or \fI\-\-cc\fR option to produce \fIcombined diff\fR, which looks like this:
322 diff \-\-combined describe\&.c
324 return (a_date > b_date) ? \-1 : (a_date == b_date) ? 0 : 1;
327 \- static void describe(char *arg)
328 \-static void describe(struct commit *cmit, int last_one)
329 ++static void describe(char *arg, int last_one)
331 + unsigned char sha1[20];
332 + struct commit *cmit;
336 Unlike the traditional \fIunified\fR 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\&.
339 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\&.
342 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 +)\&.
345 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")\&.
347 .SH "OPERATING MODES"
350 You can choose whether you want to trust the index file entirely (using the \fI\-\-cached\fR 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\&.
355 If \fI\-\-cached\fR is specified, it allows you to ask:
358 show me the differences between HEAD and the current index
359 contents (the ones I'd write with a "git\-write\-tree")
363 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 \fIwhat\fR 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
366 git\-diff\-index \-\-cached HEAD
370 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:
373 torvalds@ppc970:~/git> git\-diff\-index \-\-cached HEAD
374 \-100644 blob 4161aecc6700a2eb579e842af0b7f22b98443f74 commit\&.c
375 +100644 blob 4161aecc6700a2eb579e842af0b7f22b98443f74 git\-commit\&.c
379 You can trivially see that the above is a rename\&.
382 In fact, "git\-diff\-index \-\-cached" \fIshould\fR 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\&.
385 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"\&.
387 .SH "NON-CACHED MODE"
390 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:
393 show me the differences between HEAD and the currently checked out
394 tree \- index contents _and_ files that aren't up\-to\-date
398 which is obviously a very useful question too, since that tells you what you \fIcould\fR commit\&. Again, the output matches the "git\-diff\-tree \-r" output to a tee, but with a twist\&.
401 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:
404 torvalds@ppc970:~/v2\&.6/linux> git\-diff\-index HEAD
405 *100644\->100664 blob 7476bb\&.\&.\&.\&.\&.\&.\->000000\&.\&.\&.\&.\&.\&. kernel/sched\&.c
409 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\&.
415 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\&.
423 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\&.
430 Written by Linus Torvalds <torvalds@osdl\&.org>
435 Documentation by David Greaves, Junio C Hamano and the git\-list <git@vger\&.kernel\&.org>\&.
440 Part of the \fBgit\fR(7) suite
projects / git.git / blob