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1 '\" t
2 .\" Title: git-diff-index
3 .\" Author: [FIXME: author] [see http://www.docbook.org/tdg5/en/html/author]
4 .\" Generator: DocBook XSL Stylesheets v1.79.2 <http://docbook.sf.net/>
5 .\" Date: 2024-11-22
6 .\" Manual: Git Manual
7 .\" Source: Git 2.47.0.318.g04eaff62f2
8 .\" Language: English
9 .\"
10 .TH "GIT\-DIFF\-INDEX" "1" "2024-11-22" "Git 2\&.47\&.0\&.318\&.g04eaff" "Git Manual"
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12 .\" * Define some portability stuff
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15 .\" http://bugs.debian.org/507673
16 .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
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28 .\" * MAIN CONTENT STARTS HERE *
29 .\" -----------------------------------------------------------------
30 .SH "NAME"
31 git-diff-index \- Compare a tree to the working tree or index
32 .SH "SYNOPSIS"
33 .sp
34 .nf
35 \fIgit diff\-index\fR [\-m] [\-\-cached] [\-\-merge\-base] [<common\-diff\-options>] <tree\-ish> [<path>\&...\:]
36 .fi
37 .SH "DESCRIPTION"
38 .sp
39 Compare the content and mode of the blobs found in a tree object with the corresponding tracked files in the working tree, or with the corresponding paths in the index\&. When <path> arguments are present, compare only paths matching those patterns\&. Otherwise all tracked files are compared\&.
40 .SH "OPTIONS"
41 .PP
42 \-p, \-u, \-\-patch
43 .RS 4
44 Generate patch (see
45 the section called \(lqGENERATING PATCH TEXT WITH \-P\(rq)\&.
46 .RE
47 .PP
48 \-s, \-\-no\-patch
49 .RS 4
50 Suppress all output from the diff machinery\&. Useful for commands like
51 \fBgit\fR
52 \fBshow\fR
53 that show the patch by default to squelch their output, or to cancel the effect of options like
54 \fB\-\-patch\fR,
55 \fB\-\-stat\fR
56 earlier on the command line in an alias\&.
57 .RE
58 .PP
59 \-U<n>, \-\-unified=<n>
60 .RS 4
61 Generate diffs with <n> lines of context instead of the usual three\&. Implies
62 \fB\-\-patch\fR\&.
63 .RE
64 .PP
65 \-\-output=<file>
66 .RS 4
67 Output to a specific file instead of stdout\&.
68 .RE
69 .PP
70 \-\-output\-indicator\-new=<char>, \-\-output\-indicator\-old=<char>, \-\-output\-indicator\-context=<char>
71 .RS 4
72 Specify the character used to indicate new, old or context lines in the generated patch\&. Normally they are
73 \fI+\fR,
74 \fI\-\fR
75 and \*(Aq \*(Aq respectively\&.
76 .RE
77 .PP
78 \-\-raw
79 .RS 4
80 Generate the diff in raw format\&. This is the default\&.
81 .RE
82 .PP
83 \-\-patch\-with\-raw
84 .RS 4
85 Synonym for
86 \fB\-p\fR
87 \fB\-\-raw\fR\&.
88 .RE
89 .PP
90 \-\-indent\-heuristic
91 .RS 4
92 Enable the heuristic that shifts diff hunk boundaries to make patches easier to read\&. This is the default\&.
93 .RE
94 .PP
95 \-\-no\-indent\-heuristic
96 .RS 4
97 Disable the indent heuristic\&.
98 .RE
99 .PP
100 \-\-minimal
101 .RS 4
102 Spend extra time to make sure the smallest possible diff is produced\&.
103 .RE
104 .PP
105 \-\-patience
106 .RS 4
107 Generate a diff using the "patience diff" algorithm\&.
108 .RE
109 .PP
110 \-\-histogram
111 .RS 4
112 Generate a diff using the "histogram diff" algorithm\&.
113 .RE
114 .PP
115 \-\-anchored=<text>
116 .RS 4
117 Generate a diff using the "anchored diff" algorithm\&.
118 .sp
119 This option may be specified more than once\&.
120 .sp
121 If a line exists in both the source and destination, exists only once, and starts with this text, this algorithm attempts to prevent it from appearing as a deletion or addition in the output\&. It uses the "patience diff" algorithm internally\&.
122 .RE
123 .PP
124 \-\-diff\-algorithm={patience|minimal|histogram|myers}
125 .RS 4
126 Choose a diff algorithm\&. The variants are as follows:
127 .PP
128 \fBdefault\fR, \fBmyers\fR
129 .RS 4
130 The basic greedy diff algorithm\&. Currently, this is the default\&.
131 .RE
132 .PP
133 \fBminimal\fR
134 .RS 4
135 Spend extra time to make sure the smallest possible diff is produced\&.
136 .RE
137 .PP
138 \fBpatience\fR
139 .RS 4
140 Use "patience diff" algorithm when generating patches\&.
141 .RE
142 .PP
143 \fBhistogram\fR
144 .RS 4
145 This algorithm extends the patience algorithm to "support low\-occurrence common elements"\&.
146 .RE
147 .sp
148 For instance, if you configured the
149 \fBdiff\&.algorithm\fR
150 variable to a non\-default value and want to use the default one, then you have to use
151 \fB\-\-diff\-algorithm=default\fR
152 option\&.
153 .RE
154 .PP
155 \-\-stat[=<width>[,<name\-width>[,<count>]]]
156 .RS 4
157 Generate a diffstat\&. By default, as much space as necessary will be used for the filename part, and the rest for the graph part\&. Maximum width defaults to terminal width, or 80 columns if not connected to a terminal, and can be overridden by
158 \fI<width>\fR\&. The width of the filename part can be limited by giving another width
159 \fI<name\-width>\fR
160 after a comma or by setting
161 \fBdiff\&.statNameWidth=\fR\fI<width>\fR\&. The width of the graph part can be limited by using
162 \fB\-\-stat\-graph\-width=\fR\fI<width>\fR
163 or by setting
164 \fBdiff\&.statGraphWidth=\fR\fI<width>\fR\&. Using
165 \fB\-\-stat\fR
166 or
167 \fB\-\-stat\-graph\-width\fR
168 affects all commands generating a stat graph, while setting
169 \fBdiff\&.statNameWidth\fR
170 or
171 \fBdiff\&.statGraphWidth\fR
172 does not affect
173 \fBgit\fR
174 \fBformat\-patch\fR\&. By giving a third parameter
175 \fI<count>\fR, you can limit the output to the first
176 \fI<count>\fR
177 lines, followed by \&.\&.\&. if there are more\&.
178 .sp
179 These parameters can also be set individually with
180 \fB\-\-stat\-width=\fR\fI<width>\fR,
181 \fB\-\-stat\-name\-width=\fR\fI<name\-width>\fR
182 and
183 \fB\-\-stat\-count=\fR\fI<count>\fR\&.
184 .RE
185 .PP
186 \-\-compact\-summary
187 .RS 4
188 Output a condensed summary of extended header information such as file creations or deletions ("new" or "gone", optionally "+l" if it\(cqs a symlink) and mode changes ("+x" or "\-x" for adding or removing executable bit respectively) in diffstat\&. The information is put between the filename part and the graph part\&. Implies
189 \fB\-\-stat\fR\&.
190 .RE
191 .PP
192 \-\-numstat
193 .RS 4
194 Similar to
195 \fB\-\-stat\fR, but shows number of added and deleted lines in decimal notation and pathname without abbreviation, to make it more machine friendly\&. For binary files, outputs two
196 \fB\-\fR
197 instead of saying
198 \fB0\fR
199 \fB0\fR\&.
200 .RE
201 .PP
202 \-\-shortstat
203 .RS 4
204 Output only the last line of the
205 \fB\-\-stat\fR
206 format containing total number of modified files, as well as number of added and deleted lines\&.
207 .RE
208 .PP
209 \-X[<param1,param2,\&...\:>], \-\-dirstat[=<param1,param2,\&...\:>]
210 .RS 4
211 Output the distribution of relative amount of changes for each sub\-directory\&. The behavior of
212 \fB\-\-dirstat\fR
213 can be customized by passing it a comma separated list of parameters\&. The defaults are controlled by the
214 \fBdiff\&.dirstat\fR
215 configuration variable (see
216 \fBgit-config\fR(1))\&. The following parameters are available:
217 .PP
218 \fBchanges\fR
219 .RS 4
220 Compute the dirstat numbers by counting the lines that have been removed from the source, or added to the destination\&. This ignores the amount of pure code movements within a file\&. In other words, rearranging lines in a file is not counted as much as other changes\&. This is the default behavior when no parameter is given\&.
221 .RE
222 .PP
223 \fBlines\fR
224 .RS 4
225 Compute the dirstat numbers by doing the regular line\-based diff analysis, and summing the removed/added line counts\&. (For binary files, count 64\-byte chunks instead, since binary files have no natural concept of lines)\&. This is a more expensive
226 \fB\-\-dirstat\fR
227 behavior than the
228 \fBchanges\fR
229 behavior, but it does count rearranged lines within a file as much as other changes\&. The resulting output is consistent with what you get from the other
230 \fB\-\-\fR*stat options\&.
231 .RE
232 .PP
233 \fBfiles\fR
234 .RS 4
235 Compute the dirstat numbers by counting the number of files changed\&. Each changed file counts equally in the dirstat analysis\&. This is the computationally cheapest
236 \fB\-\-dirstat\fR
237 behavior, since it does not have to look at the file contents at all\&.
238 .RE
239 .PP
240 \fBcumulative\fR
241 .RS 4
242 Count changes in a child directory for the parent directory as well\&. Note that when using
243 \fBcumulative\fR, the sum of the percentages reported may exceed 100%\&. The default (non\-cumulative) behavior can be specified with the
244 \fBnoncumulative\fR
245 parameter\&.
246 .RE
247 .PP
248 <limit>
249 .RS 4
250 An integer parameter specifies a cut\-off percent (3% by default)\&. Directories contributing less than this percentage of the changes are not shown in the output\&.
251 .RE
252 .sp
253 Example: The following will count changed files, while ignoring directories with less than 10% of the total amount of changed files, and accumulating child directory counts in the parent directories:
254 \fB\-\-dirstat=files,10,cumulative\fR\&.
255 .RE
256 .PP
257 \-\-cumulative
258 .RS 4
259 Synonym for \-\-dirstat=cumulative
260 .RE
261 .PP
262 \-\-dirstat\-by\-file[=<param1,param2>\&...\:]
263 .RS 4
264 Synonym for \-\-dirstat=files,<param1>,<param2>\&...\:
265 .RE
266 .PP
267 \-\-summary
268 .RS 4
269 Output a condensed summary of extended header information such as creations, renames and mode changes\&.
270 .RE
271 .PP
272 \-\-patch\-with\-stat
273 .RS 4
274 Synonym for
275 \fB\-p\fR
276 \fB\-\-stat\fR\&.
277 .RE
278 .PP
279 \-z
280 .RS 4
281 When
282 \fB\-\-raw\fR,
283 \fB\-\-numstat\fR,
284 \fB\-\-name\-only\fR
285 or
286 \fB\-\-name\-status\fR
287 has been given, do not munge pathnames and use NULs as output field terminators\&.
288 .sp
289 Without this option, pathnames with "unusual" characters are quoted as explained for the configuration variable
290 \fBcore\&.quotePath\fR
291 (see
292 \fBgit-config\fR(1))\&.
293 .RE
294 .PP
295 \-\-name\-only
296 .RS 4
297 Show only the name of each changed file in the post\-image tree\&. The file names are often encoded in UTF\-8\&. For more information see the discussion about encoding in the
298 \fBgit-log\fR(1)
299 manual page\&.
300 .RE
301 .PP
302 \-\-name\-status
303 .RS 4
304 Show only the name(s) and status of each changed file\&. See the description of the
305 \fB\-\-diff\-filter\fR
306 option on what the status letters mean\&. Just like
307 \fB\-\-name\-only\fR
308 the file names are often encoded in UTF\-8\&.
309 .RE
310 .PP
311 \-\-submodule[=<format>]
312 .RS 4
313 Specify how differences in submodules are shown\&. When specifying
314 \fB\-\-submodule=short\fR
315 the
316 \fIshort\fR
317 format is used\&. This format just shows the names of the commits at the beginning and end of the range\&. When
318 \fB\-\-submodule\fR
319 or
320 \fB\-\-submodule=log\fR
321 is specified, the
322 \fIlog\fR
323 format is used\&. This format lists the commits in the range like
324 \fBgit-submodule\fR(1)
325 \fBsummary\fR
326 does\&. When
327 \fB\-\-submodule=diff\fR
328 is specified, the
329 \fIdiff\fR
330 format is used\&. This format shows an inline diff of the changes in the submodule contents between the commit range\&. Defaults to
331 \fBdiff\&.submodule\fR
332 or the
333 \fIshort\fR
334 format if the config option is unset\&.
335 .RE
336 .PP
337 \-\-color[=<when>]
338 .RS 4
339 Show colored diff\&.
340 \fB\-\-color\fR
341 (i\&.e\&. without
342 \fI=<when>\fR) is the same as
343 \fB\-\-color=always\fR\&.
344 \fI<when>\fR
345 can be one of
346 \fBalways\fR,
347 \fBnever\fR, or
348 \fBauto\fR\&.
349 .RE
350 .PP
351 \-\-no\-color
352 .RS 4
353 Turn off colored diff\&. It is the same as
354 \fB\-\-color=never\fR\&.
355 .RE
356 .PP
357 \-\-color\-moved[=<mode>]
358 .RS 4
359 Moved lines of code are colored differently\&. The <mode> defaults to
360 \fIno\fR
361 if the option is not given and to
362 \fIzebra\fR
363 if the option with no mode is given\&. The mode must be one of:
364 .PP
365 no
366 .RS 4
367 Moved lines are not highlighted\&.
368 .RE
369 .PP
370 default
371 .RS 4
372 Is a synonym for
373 \fBzebra\fR\&. This may change to a more sensible mode in the future\&.
374 .RE
375 .PP
376 plain
377 .RS 4
378 Any line that is added in one location and was removed in another location will be colored with
379 \fIcolor\&.diff\&.newMoved\fR\&. Similarly
380 \fIcolor\&.diff\&.oldMoved\fR
381 will be used for removed lines that are added somewhere else in the diff\&. This mode picks up any moved line, but it is not very useful in a review to determine if a block of code was moved without permutation\&.
382 .RE
383 .PP
384 blocks
385 .RS 4
386 Blocks of moved text of at least 20 alphanumeric characters are detected greedily\&. The detected blocks are painted using either the
387 \fIcolor\&.diff\&.{old,new}Moved\fR
388 color\&. Adjacent blocks cannot be told apart\&.
389 .RE
390 .PP
391 zebra
392 .RS 4
393 Blocks of moved text are detected as in
394 \fIblocks\fR
395 mode\&. The blocks are painted using either the
396 \fIcolor\&.diff\&.{old,new}Moved\fR
397 color or
398 \fIcolor\&.diff\&.{old,new}MovedAlternative\fR\&. The change between the two colors indicates that a new block was detected\&.
399 .RE
400 .PP
401 dimmed\-zebra
402 .RS 4
403 Similar to
404 \fIzebra\fR, but additional dimming of uninteresting parts of moved code is performed\&. The bordering lines of two adjacent blocks are considered interesting, the rest is uninteresting\&.
405 \fBdimmed_zebra\fR
406 is a deprecated synonym\&.
407 .RE
408 .RE
409 .PP
410 \-\-no\-color\-moved
411 .RS 4
412 Turn off move detection\&. This can be used to override configuration settings\&. It is the same as
413 \fB\-\-color\-moved=no\fR\&.
414 .RE
415 .PP
416 \-\-color\-moved\-ws=<modes>
417 .RS 4
418 This configures how whitespace is ignored when performing the move detection for
419 \fB\-\-color\-moved\fR\&. These modes can be given as a comma separated list:
420 .PP
421 no
422 .RS 4
423 Do not ignore whitespace when performing move detection\&.
424 .RE
425 .PP
426 ignore\-space\-at\-eol
427 .RS 4
428 Ignore changes in whitespace at EOL\&.
429 .RE
430 .PP
431 ignore\-space\-change
432 .RS 4
433 Ignore changes in amount of whitespace\&. This ignores whitespace at line end, and considers all other sequences of one or more whitespace characters to be equivalent\&.
434 .RE
435 .PP
436 ignore\-all\-space
437 .RS 4
438 Ignore whitespace when comparing lines\&. This ignores differences even if one line has whitespace where the other line has none\&.
439 .RE
440 .PP
441 allow\-indentation\-change
442 .RS 4
443 Initially ignore any whitespace in the move detection, then group the moved code blocks only into a block if the change in whitespace is the same per line\&. This is incompatible with the other modes\&.
444 .RE
445 .RE
446 .PP
447 \-\-no\-color\-moved\-ws
448 .RS 4
449 Do not ignore whitespace when performing move detection\&. This can be used to override configuration settings\&. It is the same as
450 \fB\-\-color\-moved\-ws=no\fR\&.
451 .RE
452 .PP
453 \-\-word\-diff[=<mode>]
454 .RS 4
455 Show a word diff, using the <mode> to delimit changed words\&. By default, words are delimited by whitespace; see
456 \fB\-\-word\-diff\-regex\fR
457 below\&. The <mode> defaults to
458 \fIplain\fR, and must be one of:
459 .PP
460 color
461 .RS 4
462 Highlight changed words using only colors\&. Implies
463 \fB\-\-color\fR\&.
464 .RE
465 .PP
466 plain
467 .RS 4
468 Show words as [\fB\-removed\-\fR] and {+added+}\&. Makes no attempts to escape the delimiters if they appear in the input, so the output may be ambiguous\&.
469 .RE
470 .PP
471 porcelain
472 .RS 4
473 Use a special line\-based format intended for script consumption\&. Added/removed/unchanged runs are printed in the usual unified diff format, starting with a
474 \fB+\fR/\fB\-\fR/` ` character at the beginning of the line and extending to the end of the line\&. Newlines in the input are represented by a tilde
475 \fB~\fR
476 on a line of its own\&.
477 .RE
478 .PP
479 none
480 .RS 4
481 Disable word diff again\&.
482 .RE
483 .sp
484 Note that despite the name of the first mode, color is used to highlight the changed parts in all modes if enabled\&.
485 .RE
486 .PP
487 \-\-word\-diff\-regex=<regex>
488 .RS 4
489 Use <regex> to decide what a word is, instead of considering runs of non\-whitespace to be a word\&. Also implies
490 \fB\-\-word\-diff\fR
491 unless it was already enabled\&.
492 .sp
493 Every non\-overlapping match of the <regex> is considered a word\&. Anything between these matches is considered whitespace and ignored(!) for the purposes of finding differences\&. You may want to append |[\fB^\fR[\fB:space:\fR]] to your regular expression to make sure that it matches all non\-whitespace characters\&. A match that contains a newline is silently truncated(!) at the newline\&.
494 .sp
495 For example,
496 \fB\-\-word\-diff\-regex=\&.\fR
497 will treat each character as a word and, correspondingly, show differences character by character\&.
498 .sp
499 The regex can also be set via a diff driver or configuration option, see
500 \fBgitattributes\fR(5)
501 or
502 \fBgit-config\fR(1)\&. Giving it explicitly overrides any diff driver or configuration setting\&. Diff drivers override configuration settings\&.
503 .RE
504 .PP
505 \-\-color\-words[=<regex>]
506 .RS 4
507 Equivalent to
508 \fB\-\-word\-diff=color\fR
509 plus (if a regex was specified)
510 \fB\-\-word\-diff\-regex=\fR\fI<regex>\fR\&.
511 .RE
512 .PP
513 \-\-no\-renames
514 .RS 4
515 Turn off rename detection, even when the configuration file gives the default to do so\&.
516 .RE
517 .PP
518 \-\-[no\-]rename\-empty
519 .RS 4
520 Whether to use empty blobs as rename source\&.
521 .RE
522 .PP
523 \-\-check
524 .RS 4
525 Warn if changes introduce conflict markers or whitespace errors\&. What are considered whitespace errors is controlled by
526 \fBcore\&.whitespace\fR
527 configuration\&. By default, trailing whitespaces (including lines that consist solely of whitespaces) and a space character that is immediately followed by a tab character inside the initial indent of the line are considered whitespace errors\&. Exits with non\-zero status if problems are found\&. Not compatible with \-\-exit\-code\&.
528 .RE
529 .PP
530 \-\-ws\-error\-highlight=<kind>
531 .RS 4
532 Highlight whitespace errors in the
533 \fBcontext\fR,
534 \fBold\fR
535 or
536 \fBnew\fR
537 lines of the diff\&. Multiple values are separated by comma,
538 \fBnone\fR
539 resets previous values,
540 \fBdefault\fR
541 reset the list to
542 \fBnew\fR
543 and
544 \fBall\fR
545 is a shorthand for
546 \fBold,new,context\fR\&. When this option is not given, and the configuration variable
547 \fBdiff\&.wsErrorHighlight\fR
548 is not set, only whitespace errors in
549 \fBnew\fR
550 lines are highlighted\&. The whitespace errors are colored with
551 \fBcolor\&.diff\&.whitespace\fR\&.
552 .RE
553 .PP
554 \-\-full\-index
555 .RS 4
556 Instead of the first handful of characters, show the full pre\- and post\-image blob object names on the "index" line when generating patch format output\&.
557 .RE
558 .PP
559 \-\-binary
560 .RS 4
561 In addition to
562 \fB\-\-full\-index\fR, output a binary diff that can be applied with
563 \fBgit\-apply\fR\&. Implies
564 \fB\-\-patch\fR\&.
565 .RE
566 .PP
567 \-\-abbrev[=<n>]
568 .RS 4
569 Instead of showing the full 40\-byte hexadecimal object name in diff\-raw format output and diff\-tree header lines, show the shortest prefix that is at least
570 \fI<n>\fR
571 hexdigits long that uniquely refers the object\&. In diff\-patch output format,
572 \fB\-\-full\-index\fR
573 takes higher precedence, i\&.e\&. if
574 \fB\-\-full\-index\fR
575 is specified, full blob names will be shown regardless of
576 \fB\-\-abbrev\fR\&. Non default number of digits can be specified with
577 \fB\-\-abbrev=\fR\fI<n>\fR\&.
578 .RE
579 .PP
580 \-B[<n>][/<m>], \-\-break\-rewrites[=[<n>][/<m>]]
581 .RS 4
582 Break complete rewrite changes into pairs of delete and create\&. This serves two purposes:
583 .sp
584 It affects the way a change that amounts to a total rewrite of a file not as a series of deletion and insertion mixed together with a very few lines that happen to match textually as the context, but as a single deletion of everything old followed by a single insertion of everything new, and the number
585 \fBm\fR
586 controls this aspect of the \-B option (defaults to 60%)\&.
587 \fB\-B/70\fR% specifies that less than 30% of the original should remain in the result for Git to consider it a total rewrite (i\&.e\&. otherwise the resulting patch will be a series of deletion and insertion mixed together with context lines)\&.
588 .sp
589 When used with \-M, a totally\-rewritten file is also considered as the source of a rename (usually \-M only considers a file that disappeared as the source of a rename), and the number
590 \fBn\fR
591 controls this aspect of the \-B option (defaults to 50%)\&.
592 \fB\-B20\fR% specifies that a change with addition and deletion compared to 20% or more of the file\(cqs size are eligible for being picked up as a possible source of a rename to another file\&.
593 .RE
594 .PP
595 \-M[<n>], \-\-find\-renames[=<n>]
596 .RS 4
597 Detect renames\&. If
598 \fBn\fR
599 is specified, it is a threshold on the similarity index (i\&.e\&. amount of addition/deletions compared to the file\(cqs size)\&. For example,
600 \fB\-M90\fR% means Git should consider a delete/add pair to be a rename if more than 90% of the file hasn\(cqt changed\&. Without a % sign, the number is to be read as a fraction, with a decimal point before it\&. I\&.e\&.,
601 \fB\-M5\fR
602 becomes 0\&.5, and is thus the same as
603 \fB\-M50\fR%\&. Similarly,
604 \fB\-M05\fR
605 is the same as
606 \fB\-M5\fR%\&. To limit detection to exact renames, use
607 \fB\-M100\fR%\&. The default similarity index is 50%\&.
608 .RE
609 .PP
610 \-C[<n>], \-\-find\-copies[=<n>]
611 .RS 4
612 Detect copies as well as renames\&. See also
613 \fB\-\-find\-copies\-harder\fR\&. If
614 \fBn\fR
615 is specified, it has the same meaning as for
616 \fB\-M\fR\fI<n>\fR\&.
617 .RE
618 .PP
619 \-\-find\-copies\-harder
620 .RS 4
621 For performance reasons, by default,
622 \fB\-C\fR
623 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\&. Giving more than one
624 \fB\-C\fR
625 option has the same effect\&.
626 .RE
627 .PP
628 \-D, \-\-irreversible\-delete
629 .RS 4
630 Omit the preimage for deletes, i\&.e\&. print only the header but not the diff between the preimage and
631 \fB/dev/null\fR\&. The resulting patch is not meant to be applied with
632 \fBpatch\fR
633 or
634 \fBgit\fR
635 \fBapply\fR; this is solely for people who want to just concentrate on reviewing the text after the change\&. In addition, the output obviously lacks enough information to apply such a patch in reverse, even manually, hence the name of the option\&.
636 .sp
637 When used together with
638 \fB\-B\fR, omit also the preimage in the deletion part of a delete/create pair\&.
639 .RE
640 .PP
641 \-l<num>
642 .RS 4
643 The
644 \fB\-M\fR
645 and
646 \fB\-C\fR
647 options involve some preliminary steps that can detect subsets of renames/copies cheaply, followed by an exhaustive fallback portion that compares all remaining unpaired destinations to all relevant sources\&. (For renames, only remaining unpaired sources are relevant; for copies, all original sources are relevant\&.) For N sources and destinations, this exhaustive check is O(N^2)\&. This option prevents the exhaustive portion of rename/copy detection from running if the number of source/destination files involved exceeds the specified number\&. Defaults to diff\&.renameLimit\&. Note that a value of 0 is treated as unlimited\&.
648 .RE
649 .PP
650 \-\-diff\-filter=[(A|C|D|M|R|T|U|X|B)\&...\:[*]]
651 .RS 4
652 Select only files that are Added (\fBA\fR), Copied (\fBC\fR), Deleted (\fBD\fR), Modified (\fBM\fR), Renamed (\fBR\fR), have their type (i\&.e\&. regular file, symlink, submodule, \&...\:) changed (\fBT\fR), are Unmerged (\fBU\fR), are Unknown (\fBX\fR), or have had their pairing Broken (\fBB\fR)\&. Any combination of the filter characters (including none) can 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\&.
653 .sp
654 Also, these upper\-case letters can be downcased to exclude\&. E\&.g\&.
655 \fB\-\-diff\-filter=ad\fR
656 excludes added and deleted paths\&.
657 .sp
658 Note that not all diffs can feature all types\&. For instance, copied and renamed entries cannot appear if detection for those types is disabled\&.
659 .RE
660 .PP
661 \-S<string>
662 .RS 4
663 Look for differences that change the number of occurrences of the specified string (i\&.e\&. addition/deletion) in a file\&. Intended for the scripter\(cqs use\&.
664 .sp
665 It is useful when you\(cqre looking for an exact block of code (like a struct), and want to know the history of that block since it first came into being: use the feature iteratively to feed the interesting block in the preimage back into
666 \fB\-S\fR, and keep going until you get the very first version of the block\&.
667 .sp
668 Binary files are searched as well\&.
669 .RE
670 .PP
671 \-G<regex>
672 .RS 4
673 Look for differences whose patch text contains added/removed lines that match <regex>\&.
674 .sp
675 To illustrate the difference between
676 \fB\-S\fR\fI<regex>\fR
677 \fB\-\-pickaxe\-regex\fR
678 and
679 \fB\-G\fR\fI<regex>\fR, consider a commit with the following diff in the same file:
680 .sp
681 .if n \{\
682 .RS 4
683 .\}
684 .nf
685 + return frotz(nitfol, two\->ptr, 1, 0);
686 \&.\&.\&.
687 \- hit = frotz(nitfol, mf2\&.ptr, 1, 0);
688 .fi
689 .if n \{\
690 .RE
691 .\}
692 .sp
693 While
694 \fBgit\fR
695 \fBlog\fR
696 \fB\-G\fR"frotz\e(\fBnitfol\fR" will show this commit,
697 \fBgit\fR
698 \fBlog\fR
699 \fB\-S\fR"frotz\e(\fBnitfol\fR"
700 \fB\-\-pickaxe\-regex\fR
701 will not (because the number of occurrences of that string did not change)\&.
702 .sp
703 Unless
704 \fB\-\-text\fR
705 is supplied patches of binary files without a textconv filter will be ignored\&.
706 .sp
707 See the
708 \fIpickaxe\fR
709 entry in
710 \fBgitdiffcore\fR(7)
711 for more information\&.
712 .RE
713 .PP
714 \-\-find\-object=<object\-id>
715 .RS 4
716 Look for differences that change the number of occurrences of the specified object\&. Similar to
717 \fB\-S\fR, just the argument is different in that it doesn\(cqt search for a specific string but for a specific object id\&.
718 .sp
719 The object can be a blob or a submodule commit\&. It implies the
720 \fB\-t\fR
721 option in
722 \fBgit\-log\fR
723 to also find trees\&.
724 .RE
725 .PP
726 \-\-pickaxe\-all
727 .RS 4
728 When
729 \fB\-S\fR
730 or
731 \fB\-G\fR
732 finds a change, show all the changes in that changeset, not just the files that contain the change in <string>\&.
733 .RE
734 .PP
735 \-\-pickaxe\-regex
736 .RS 4
737 Treat the <string> given to
738 \fB\-S\fR
739 as an extended POSIX regular expression to match\&.
740 .RE
741 .PP
742 \-O<orderfile>
743 .RS 4
744 Control the order in which files appear in the output\&. This overrides the
745 \fBdiff\&.orderFile\fR
746 configuration variable (see
747 \fBgit-config\fR(1))\&. To cancel
748 \fBdiff\&.orderFile\fR, use
749 \fB\-O/dev/null\fR\&.
750 .sp
751 The output order is determined by the order of glob patterns in <orderfile>\&. All files with pathnames that match the first pattern are output first, all files with pathnames that match the second pattern (but not the first) are output next, and so on\&. All files with pathnames that do not match any pattern are output last, as if there was an implicit match\-all pattern at the end of the file\&. If multiple pathnames have the same rank (they match the same pattern but no earlier patterns), their output order relative to each other is the normal order\&.
752 .sp
753 <orderfile> is parsed as follows:
754 .sp
755 .RS 4
756 .ie n \{\
757 \h'-04'\(bu\h'+03'\c
758 .\}
759 .el \{\
760 .sp -1
761 .IP \(bu 2.3
762 .\}
763 Blank lines are ignored, so they can be used as separators for readability\&.
764 .RE
765 .sp
766 .RS 4
767 .ie n \{\
768 \h'-04'\(bu\h'+03'\c
769 .\}
770 .el \{\
771 .sp -1
772 .IP \(bu 2.3
773 .\}
774 Lines starting with a hash ("#") are ignored, so they can be used for comments\&. Add a backslash ("\e") to the beginning of the pattern if it starts with a hash\&.
775 .RE
776 .sp
777 .RS 4
778 .ie n \{\
779 \h'-04'\(bu\h'+03'\c
780 .\}
781 .el \{\
782 .sp -1
783 .IP \(bu 2.3
784 .\}
785 Each other line contains a single pattern\&.
786 .RE
787 .sp
788 Patterns have the same syntax and semantics as patterns used for fnmatch(3) without the FNM_PATHNAME flag, except a pathname also matches a pattern if removing any number of the final pathname components matches the pattern\&. For example, the pattern "\fBfoo\fR*bar" matches "\fBfooasdfbar\fR" and "\fBfoo/bar/baz/asdf\fR" but not "\fBfoobarx\fR"\&.
789 .RE
790 .PP
791 \-\-skip\-to=<file>, \-\-rotate\-to=<file>
792 .RS 4
793 Discard the files before the named <file> from the output (i\&.e\&.
794 \fIskip to\fR), or move them to the end of the output (i\&.e\&.
795 \fIrotate to\fR)\&. These options were invented primarily for the use of the
796 \fBgit\fR
797 \fBdifftool\fR
798 command, and may not be very useful otherwise\&.
799 .RE
800 .PP
801 \-R
802 .RS 4
803 Swap two inputs; that is, show differences from index or on\-disk file to tree contents\&.
804 .RE
805 .PP
806 \-\-relative[=<path>], \-\-no\-relative
807 .RS 4
808 When run from a subdirectory of the project, it can be told to exclude changes outside the directory and show pathnames relative to it with this option\&. When you are not in a subdirectory (e\&.g\&. in a bare repository), you can name which subdirectory to make the output relative to by giving a <path> as an argument\&.
809 \fB\-\-no\-relative\fR
810 can be used to countermand both
811 \fBdiff\&.relative\fR
812 config option and previous
813 \fB\-\-relative\fR\&.
814 .RE
815 .PP
816 \-a, \-\-text
817 .RS 4
818 Treat all files as text\&.
819 .RE
820 .PP
821 \-\-ignore\-cr\-at\-eol
822 .RS 4
823 Ignore carriage\-return at the end of line when doing a comparison\&.
824 .RE
825 .PP
826 \-\-ignore\-space\-at\-eol
827 .RS 4
828 Ignore changes in whitespace at EOL\&.
829 .RE
830 .PP
831 \-b, \-\-ignore\-space\-change
832 .RS 4
833 Ignore changes in amount of whitespace\&. This ignores whitespace at line end, and considers all other sequences of one or more whitespace characters to be equivalent\&.
834 .RE
835 .PP
836 \-w, \-\-ignore\-all\-space
837 .RS 4
838 Ignore whitespace when comparing lines\&. This ignores differences even if one line has whitespace where the other line has none\&.
839 .RE
840 .PP
841 \-\-ignore\-blank\-lines
842 .RS 4
843 Ignore changes whose lines are all blank\&.
844 .RE
845 .PP
846 \-I<regex>, \-\-ignore\-matching\-lines=<regex>
847 .RS 4
848 Ignore changes whose all lines match <regex>\&. This option may be specified more than once\&.
849 .RE
850 .PP
851 \-\-inter\-hunk\-context=<lines>
852 .RS 4
853 Show the context between diff hunks, up to the specified number of lines, thereby fusing hunks that are close to each other\&. Defaults to
854 \fBdiff\&.interHunkContext\fR
855 or 0 if the config option is unset\&.
856 .RE
857 .PP
858 \-W, \-\-function\-context
859 .RS 4
860 Show whole function as context lines for each change\&. The function names are determined in the same way as
861 \fBgit\fR
862 \fBdiff\fR
863 works out patch hunk headers (see
864 \fIDefining a custom hunk\-header\fR
865 in
866 \fBgitattributes\fR(5))\&.
867 .RE
868 .PP
869 \-\-exit\-code
870 .RS 4
871 Make the program exit with codes similar to diff(1)\&. That is, it exits with 1 if there were differences and 0 means no differences\&.
872 .RE
873 .PP
874 \-\-quiet
875 .RS 4
876 Disable all output of the program\&. Implies
877 \fB\-\-exit\-code\fR\&. Disables execution of external diff helpers whose exit code is not trusted, i\&.e\&. their respective configuration option
878 \fBdiff\&.trustExitCode\fR
879 or
880 \fBdiff\&.\fR\fI<driver>\fR\fB\&.trustExitCode\fR
881 or environment variable
882 \fBGIT_EXTERNAL_DIFF_TRUST_EXIT_CODE\fR
883 is false\&.
884 .RE
885 .PP
886 \-\-ext\-diff
887 .RS 4
888 Allow an external diff helper to be executed\&. If you set an external diff driver with
889 \fBgitattributes\fR(5), you need to use this option with
890 \fBgit-log\fR(1)
891 and friends\&.
892 .RE
893 .PP
894 \-\-no\-ext\-diff
895 .RS 4
896 Disallow external diff drivers\&.
897 .RE
898 .PP
899 \-\-textconv, \-\-no\-textconv
900 .RS 4
901 Allow (or disallow) external text conversion filters to be run when comparing binary files\&. See
902 \fBgitattributes\fR(5)
903 for details\&. Because textconv filters are typically a one\-way conversion, the resulting diff is suitable for human consumption, but cannot be applied\&. For this reason, textconv filters are enabled by default only for
904 \fBgit-diff\fR(1)
905 and
906 \fBgit-log\fR(1), but not for
907 \fBgit-format-patch\fR(1)
908 or diff plumbing commands\&.
909 .RE
910 .PP
911 \-\-ignore\-submodules[=<when>]
912 .RS 4
913 Ignore changes to submodules in the diff generation\&. <when> can be either "none", "untracked", "dirty" or "all", which is the default\&. Using "none" will consider the submodule modified when it either contains untracked or modified files or its HEAD differs from the commit recorded in the superproject and can be used to override any settings of the
914 \fIignore\fR
915 option in
916 \fBgit-config\fR(1)
917 or
918 \fBgitmodules\fR(5)\&. When "untracked" is used submodules are not considered dirty when they only contain untracked content (but they are still scanned for modified content)\&. Using "dirty" ignores all changes to the work tree of submodules, only changes to the commits stored in the superproject are shown (this was the behavior until 1\&.7\&.0)\&. Using "all" hides all changes to submodules\&.
919 .RE
920 .PP
921 \-\-src\-prefix=<prefix>
922 .RS 4
923 Show the given source prefix instead of "a/"\&.
924 .RE
925 .PP
926 \-\-dst\-prefix=<prefix>
927 .RS 4
928 Show the given destination prefix instead of "b/"\&.
929 .RE
930 .PP
931 \-\-no\-prefix
932 .RS 4
933 Do not show any source or destination prefix\&.
934 .RE
935 .PP
936 \-\-default\-prefix
937 .RS 4
938 Use the default source and destination prefixes ("a/" and "b/")\&. This overrides configuration variables such as
939 \fBdiff\&.noprefix\fR,
940 \fBdiff\&.srcPrefix\fR,
941 \fBdiff\&.dstPrefix\fR, and
942 \fBdiff\&.mnemonicPrefix\fR
943 (see
944 \fBgit\-config\fR(1))\&.
945 .RE
946 .PP
947 \-\-line\-prefix=<prefix>
948 .RS 4
949 Prepend an additional prefix to every line of output\&.
950 .RE
951 .PP
952 \-\-ita\-invisible\-in\-index
953 .RS 4
954 By default entries added by "git add \-N" appear as an existing empty file in "git diff" and a new file in "git diff \-\-cached"\&. This option makes the entry appear as a new file in "git diff" and non\-existent in "git diff \-\-cached"\&. This option could be reverted with
955 \fB\-\-ita\-visible\-in\-index\fR\&. Both options are experimental and could be removed in future\&.
956 .RE
957 .sp
958 For more detailed explanation on these common options, see also \fBgitdiffcore\fR(7)\&.
959 .PP
960 <tree\-ish>
961 .RS 4
962 The id of a tree object to diff against\&.
963 .RE
964 .PP
965 \-\-cached
966 .RS 4
967 Do not consider the on\-disk file at all\&.
968 .RE
969 .PP
970 \-\-merge\-base
971 .RS 4
972 Instead of comparing <tree\-ish> directly, use the merge base between <tree\-ish> and HEAD instead\&. <tree\-ish> must be a commit\&.
973 .RE
974 .PP
975 \-m
976 .RS 4
977 By default, files recorded in the index but not checked out are reported as deleted\&. This flag makes
978 \fIgit diff\-index\fR
979 say that all non\-checked\-out files are up to date\&.
980 .RE
981 .SH "RAW OUTPUT FORMAT"
982 .sp
983 The raw output format from "git\-diff\-index", "git\-diff\-tree", "git\-diff\-files" and "git diff \-\-raw" are very similar\&.
984 .sp
985 These commands all compare two sets of things; what is compared differs:
986 .PP
987 git\-diff\-index <tree\-ish>
988 .RS 4
989 compares the <tree\-ish> and the files on the filesystem\&.
990 .RE
991 .PP
992 git\-diff\-index \-\-cached <tree\-ish>
993 .RS 4
994 compares the <tree\-ish> and the index\&.
995 .RE
996 .PP
997 git\-diff\-tree [\-r] <tree\-ish\-1> <tree\-ish\-2> [<pattern>\&...\:]
998 .RS 4
999 compares the trees named by the two arguments\&.
1000 .RE
1001 .PP
1002 git\-diff\-files [<pattern>\&...\:]
1003 .RS 4
1004 compares the index and the files on the filesystem\&.
1005 .RE
1006 .sp
1007 The "git\-diff\-tree" command begins its output by printing the hash of what is being compared\&. After that, all the commands print one output line per changed file\&.
1008 .sp
1009 An output line is formatted this way:
1010 .sp
1011 .if n \{\
1012 .RS 4
1013 .\}
1014 .nf
1015 in\-place edit :100644 100644 bcd1234 0123456 M file0
1016 copy\-edit :100644 100644 abcd123 1234567 C68 file1 file2
1017 rename\-edit :100644 100644 abcd123 1234567 R86 file1 file3
1018 create :000000 100644 0000000 1234567 A file4
1019 delete :100644 000000 1234567 0000000 D file5
1020 unmerged :000000 000000 0000000 0000000 U file6
1021 .fi
1022 .if n \{\
1023 .RE
1024 .\}
1025 .sp
1026 That is, from the left to the right:
1027 .sp
1028 .RS 4
1029 .ie n \{\
1030 \h'-04' 1.\h'+01'\c
1031 .\}
1032 .el \{\
1033 .sp -1
1034 .IP " 1." 4.2
1035 .\}
1036 a colon\&.
1037 .RE
1038 .sp
1039 .RS 4
1040 .ie n \{\
1041 \h'-04' 2.\h'+01'\c
1042 .\}
1043 .el \{\
1044 .sp -1
1045 .IP " 2." 4.2
1046 .\}
1047 mode for "src"; 000000 if creation or unmerged\&.
1048 .RE
1049 .sp
1050 .RS 4
1051 .ie n \{\
1052 \h'-04' 3.\h'+01'\c
1053 .\}
1054 .el \{\
1055 .sp -1
1056 .IP " 3." 4.2
1057 .\}
1058 a space\&.
1059 .RE
1060 .sp
1061 .RS 4
1062 .ie n \{\
1063 \h'-04' 4.\h'+01'\c
1064 .\}
1065 .el \{\
1066 .sp -1
1067 .IP " 4." 4.2
1068 .\}
1069 mode for "dst"; 000000 if deletion or unmerged\&.
1070 .RE
1071 .sp
1072 .RS 4
1073 .ie n \{\
1074 \h'-04' 5.\h'+01'\c
1075 .\}
1076 .el \{\
1077 .sp -1
1078 .IP " 5." 4.2
1079 .\}
1080 a space\&.
1081 .RE
1082 .sp
1083 .RS 4
1084 .ie n \{\
1085 \h'-04' 6.\h'+01'\c
1086 .\}
1087 .el \{\
1088 .sp -1
1089 .IP " 6." 4.2
1090 .\}
1091 sha1 for "src"; 0{40} if creation or unmerged\&.
1092 .RE
1093 .sp
1094 .RS 4
1095 .ie n \{\
1096 \h'-04' 7.\h'+01'\c
1097 .\}
1098 .el \{\
1099 .sp -1
1100 .IP " 7." 4.2
1101 .\}
1102 a space\&.
1103 .RE
1104 .sp
1105 .RS 4
1106 .ie n \{\
1107 \h'-04' 8.\h'+01'\c
1108 .\}
1109 .el \{\
1110 .sp -1
1111 .IP " 8." 4.2
1112 .\}
1113 sha1 for "dst"; 0{40} if deletion, unmerged or "work tree out of sync with the index"\&.
1114 .RE
1115 .sp
1116 .RS 4
1117 .ie n \{\
1118 \h'-04' 9.\h'+01'\c
1119 .\}
1120 .el \{\
1121 .sp -1
1122 .IP " 9." 4.2
1123 .\}
1124 a space\&.
1125 .RE
1126 .sp
1127 .RS 4
1128 .ie n \{\
1129 \h'-04'10.\h'+01'\c
1130 .\}
1131 .el \{\
1132 .sp -1
1133 .IP "10." 4.2
1134 .\}
1135 status, followed by optional "score" number\&.
1136 .RE
1137 .sp
1138 .RS 4
1139 .ie n \{\
1140 \h'-04'11.\h'+01'\c
1141 .\}
1142 .el \{\
1143 .sp -1
1144 .IP "11." 4.2
1145 .\}
1146 a tab or a NUL when
1147 \fB\-z\fR
1148 option is used\&.
1149 .RE
1150 .sp
1151 .RS 4
1152 .ie n \{\
1153 \h'-04'12.\h'+01'\c
1154 .\}
1155 .el \{\
1156 .sp -1
1157 .IP "12." 4.2
1158 .\}
1159 path for "src"
1160 .RE
1161 .sp
1162 .RS 4
1163 .ie n \{\
1164 \h'-04'13.\h'+01'\c
1165 .\}
1166 .el \{\
1167 .sp -1
1168 .IP "13." 4.2
1169 .\}
1170 a tab or a NUL when
1171 \fB\-z\fR
1172 option is used; only exists for C or R\&.
1173 .RE
1174 .sp
1175 .RS 4
1176 .ie n \{\
1177 \h'-04'14.\h'+01'\c
1178 .\}
1179 .el \{\
1180 .sp -1
1181 .IP "14." 4.2
1182 .\}
1183 path for "dst"; only exists for C or R\&.
1184 .RE
1185 .sp
1186 .RS 4
1187 .ie n \{\
1188 \h'-04'15.\h'+01'\c
1189 .\}
1190 .el \{\
1191 .sp -1
1192 .IP "15." 4.2
1193 .\}
1194 an LF or a NUL when
1195 \fB\-z\fR
1196 option is used, to terminate the record\&.
1197 .RE
1198 .sp
1199 Possible status letters are:
1200 .sp
1201 .RS 4
1202 .ie n \{\
1203 \h'-04'\(bu\h'+03'\c
1204 .\}
1205 .el \{\
1206 .sp -1
1207 .IP \(bu 2.3
1208 .\}
1209 A: addition of a file
1210 .RE
1211 .sp
1212 .RS 4
1213 .ie n \{\
1214 \h'-04'\(bu\h'+03'\c
1215 .\}
1216 .el \{\
1217 .sp -1
1218 .IP \(bu 2.3
1219 .\}
1220 C: copy of a file into a new one
1221 .RE
1222 .sp
1223 .RS 4
1224 .ie n \{\
1225 \h'-04'\(bu\h'+03'\c
1226 .\}
1227 .el \{\
1228 .sp -1
1229 .IP \(bu 2.3
1230 .\}
1231 D: deletion of a file
1232 .RE
1233 .sp
1234 .RS 4
1235 .ie n \{\
1236 \h'-04'\(bu\h'+03'\c
1237 .\}
1238 .el \{\
1239 .sp -1
1240 .IP \(bu 2.3
1241 .\}
1242 M: modification of the contents or mode of a file
1243 .RE
1244 .sp
1245 .RS 4
1246 .ie n \{\
1247 \h'-04'\(bu\h'+03'\c
1248 .\}
1249 .el \{\
1250 .sp -1
1251 .IP \(bu 2.3
1252 .\}
1253 R: renaming of a file
1254 .RE
1255 .sp
1256 .RS 4
1257 .ie n \{\
1258 \h'-04'\(bu\h'+03'\c
1259 .\}
1260 .el \{\
1261 .sp -1
1262 .IP \(bu 2.3
1263 .\}
1264 T: change in the type of the file (regular file, symbolic link or submodule)
1265 .RE
1266 .sp
1267 .RS 4
1268 .ie n \{\
1269 \h'-04'\(bu\h'+03'\c
1270 .\}
1271 .el \{\
1272 .sp -1
1273 .IP \(bu 2.3
1274 .\}
1275 U: file is unmerged (you must complete the merge before it can be committed)
1276 .RE
1277 .sp
1278 .RS 4
1279 .ie n \{\
1280 \h'-04'\(bu\h'+03'\c
1281 .\}
1282 .el \{\
1283 .sp -1
1284 .IP \(bu 2.3
1285 .\}
1286 X: "unknown" change type (most probably a bug, please report it)
1287 .RE
1288 .sp
1289 Status letters C and R are always followed by a score (denoting the percentage of similarity between the source and target of the move or copy)\&. Status letter M may be followed by a score (denoting the percentage of dissimilarity) for file rewrites\&.
1290 .sp
1291 The sha1 for "dst" is shown as all 0\(cqs if a file on the filesystem is out of sync with the index\&.
1292 .sp
1293 Example:
1294 .sp
1295 .if n \{\
1296 .RS 4
1297 .\}
1298 .nf
1299 :100644 100644 5be4a4a 0000000 M file\&.c
1300 .fi
1301 .if n \{\
1302 .RE
1303 .\}
1304 .sp
1305 Without the \fB\-z\fR option, pathnames with "unusual" characters are quoted as explained for the configuration variable \fBcore\&.quotePath\fR (see \fBgit-config\fR(1))\&. Using \fB\-z\fR the filename is output verbatim and the line is terminated by a NUL byte\&.
1306 .SH "DIFF FORMAT FOR MERGES"
1307 .sp
1308 "git\-diff\-tree", "git\-diff\-files" and "git\-diff \-\-raw" can take \fB\-c\fR or \fB\-\-cc\fR option to generate diff output also for merge commits\&. The output differs from the format described above in the following way:
1309 .sp
1310 .RS 4
1311 .ie n \{\
1312 \h'-04' 1.\h'+01'\c
1313 .\}
1314 .el \{\
1315 .sp -1
1316 .IP " 1." 4.2
1317 .\}
1318 there is a colon for each parent
1319 .RE
1320 .sp
1321 .RS 4
1322 .ie n \{\
1323 \h'-04' 2.\h'+01'\c
1324 .\}
1325 .el \{\
1326 .sp -1
1327 .IP " 2." 4.2
1328 .\}
1329 there are more "src" modes and "src" sha1
1330 .RE
1331 .sp
1332 .RS 4
1333 .ie n \{\
1334 \h'-04' 3.\h'+01'\c
1335 .\}
1336 .el \{\
1337 .sp -1
1338 .IP " 3." 4.2
1339 .\}
1340 status is concatenated status characters for each parent
1341 .RE
1342 .sp
1343 .RS 4
1344 .ie n \{\
1345 \h'-04' 4.\h'+01'\c
1346 .\}
1347 .el \{\
1348 .sp -1
1349 .IP " 4." 4.2
1350 .\}
1351 no optional "score" number
1352 .RE
1353 .sp
1354 .RS 4
1355 .ie n \{\
1356 \h'-04' 5.\h'+01'\c
1357 .\}
1358 .el \{\
1359 .sp -1
1360 .IP " 5." 4.2
1361 .\}
1362 tab\-separated pathname(s) of the file
1363 .RE
1364 .sp
1365 For \fB\-c\fR and \fB\-\-cc\fR, only the destination or final path is shown even if the file was renamed on any side of history\&. With \fB\-\-combined\-all\-paths\fR, the name of the path in each parent is shown followed by the name of the path in the merge commit\&.
1366 .sp
1367 Examples for \fB\-c\fR and \fB\-\-cc\fR without \fB\-\-combined\-all\-paths\fR:
1368 .sp
1369 .if n \{\
1370 .RS 4
1371 .\}
1372 .nf
1373 ::100644 100644 100644 fabadb8 cc95eb0 4866510 MM desc\&.c
1374 ::100755 100755 100755 52b7a2d 6d1ac04 d2ac7d7 RM bar\&.sh
1375 ::100644 100644 100644 e07d6c5 9042e82 ee91881 RR phooey\&.c
1376 .fi
1377 .if n \{\
1378 .RE
1379 .\}
1380 .sp
1381 Examples when \fB\-\-combined\-all\-paths\fR added to either \fB\-c\fR or \fB\-\-cc\fR:
1382 .sp
1383 .if n \{\
1384 .RS 4
1385 .\}
1386 .nf
1387 ::100644 100644 100644 fabadb8 cc95eb0 4866510 MM desc\&.c desc\&.c desc\&.c
1388 ::100755 100755 100755 52b7a2d 6d1ac04 d2ac7d7 RM foo\&.sh bar\&.sh bar\&.sh
1389 ::100644 100644 100644 e07d6c5 9042e82 ee91881 RR fooey\&.c fuey\&.c phooey\&.c
1390 .fi
1391 .if n \{\
1392 .RE
1393 .\}
1394 .sp
1395 Note that \fIcombined diff\fR lists only files which were modified from all parents\&.
1396 .SH "GENERATING PATCH TEXT WITH \-P"
1397 .sp
1398 Running \fBgit-diff\fR(1), \fBgit-log\fR(1), \fBgit-show\fR(1), \fBgit-diff-index\fR(1), \fBgit-diff-tree\fR(1), or \fBgit-diff-files\fR(1) with the \fB\-p\fR option produces patch text\&. You can customize the creation of patch text via the \fBGIT_EXTERNAL_DIFF\fR and the \fBGIT_DIFF_OPTS\fR environment variables (see \fBgit\fR(1)), and the \fBdiff\fR attribute (see \fBgitattributes\fR(5))\&.
1399 .sp
1400 What the \-p option produces is slightly different from the traditional diff format:
1401 .sp
1402 .RS 4
1403 .ie n \{\
1404 \h'-04' 1.\h'+01'\c
1405 .\}
1406 .el \{\
1407 .sp -1
1408 .IP " 1." 4.2
1409 .\}
1410 It is preceded by a "git diff" header that looks like this:
1411 .sp
1412 .if n \{\
1413 .RS 4
1414 .\}
1415 .nf
1416 diff \-\-git a/file1 b/file2
1417 .fi
1418 .if n \{\
1419 .RE
1420 .\}
1421 .sp
1422 The
1423 \fBa/\fR
1424 and
1425 \fBb/\fR
1426 filenames are the same unless rename/copy is involved\&. Especially, even for a creation or a deletion,
1427 \fB/dev/null\fR
1428 is
1429 \fInot\fR
1430 used in place of the
1431 \fBa/\fR
1432 or
1433 \fBb/\fR
1434 filenames\&.
1435 .sp
1436 When a rename/copy is involved,
1437 \fBfile1\fR
1438 and
1439 \fBfile2\fR
1440 show the name of the source file of the rename/copy and the name of the file that the rename/copy produces, respectively\&.
1441 .RE
1442 .sp
1443 .RS 4
1444 .ie n \{\
1445 \h'-04' 2.\h'+01'\c
1446 .\}
1447 .el \{\
1448 .sp -1
1449 .IP " 2." 4.2
1450 .\}
1451 It is followed by one or more extended header lines:
1452 .sp
1453 .if n \{\
1454 .RS 4
1455 .\}
1456 .nf
1457 old mode <mode>
1458 new mode <mode>
1459 deleted file mode <mode>
1460 new file mode <mode>
1461 copy from <path>
1462 copy to <path>
1463 rename from <path>
1464 rename to <path>
1465 similarity index <number>
1466 dissimilarity index <number>
1467 index <hash>\&.\&.<hash> <mode>
1468 .fi
1469 .if n \{\
1470 .RE
1471 .\}
1472 .sp
1473 File modes are printed as 6\-digit octal numbers including the file type and file permission bits\&.
1474 .sp
1475 Path names in extended headers do not include the
1476 \fBa/\fR
1477 and
1478 \fBb/\fR
1479 prefixes\&.
1480 .sp
1481 The similarity index is the percentage of unchanged lines, and the dissimilarity index is the percentage of changed lines\&. It is a rounded down integer, followed by a percent sign\&. The similarity index value of 100% is thus reserved for two equal files, while 100% dissimilarity means that no line from the old file made it into the new one\&.
1482 .sp
1483 The index line includes the blob object names before and after the change\&. The <mode> is included if the file mode does not change; otherwise, separate lines indicate the old and the new mode\&.
1484 .RE
1485 .sp
1486 .RS 4
1487 .ie n \{\
1488 \h'-04' 3.\h'+01'\c
1489 .\}
1490 .el \{\
1491 .sp -1
1492 .IP " 3." 4.2
1493 .\}
1494 Pathnames with "unusual" characters are quoted as explained for the configuration variable
1495 \fBcore\&.quotePath\fR
1496 (see
1497 \fBgit-config\fR(1))\&.
1498 .RE
1499 .sp
1500 .RS 4
1501 .ie n \{\
1502 \h'-04' 4.\h'+01'\c
1503 .\}
1504 .el \{\
1505 .sp -1
1506 .IP " 4." 4.2
1507 .\}
1508 All the
1509 \fBfile1\fR
1510 files in the output refer to files before the commit, and all the
1511 \fBfile2\fR
1512 files refer to files after the commit\&. It is incorrect to apply each change to each file sequentially\&. For example, this patch will swap a and b:
1513 .sp
1514 .if n \{\
1515 .RS 4
1516 .\}
1517 .nf
1518 diff \-\-git a/a b/b
1519 rename from a
1520 rename to b
1521 diff \-\-git a/b b/a
1522 rename from b
1523 rename to a
1524 .fi
1525 .if n \{\
1526 .RE
1527 .\}
1528 .RE
1529 .sp
1530 .RS 4
1531 .ie n \{\
1532 \h'-04' 5.\h'+01'\c
1533 .\}
1534 .el \{\
1535 .sp -1
1536 .IP " 5." 4.2
1537 .\}
1538 Hunk headers mention the name of the function to which the hunk applies\&. See "Defining a custom hunk\-header" in
1539 \fBgitattributes\fR(5)
1540 for details of how to tailor this to specific languages\&.
1541 .RE
1542 .SH "COMBINED DIFF FORMAT"
1543 .sp
1544 Any diff\-generating command can take the \fB\-c\fR or \fB\-\-cc\fR option to produce a \fIcombined diff\fR when showing a merge\&. This is the default format when showing merges with \fBgit-diff\fR(1) or \fBgit-show\fR(1)\&. Note also that you can give suitable \fB\-\-diff\-merges\fR option to any of these commands to force generation of diffs in a specific format\&.
1545 .sp
1546 A "combined diff" format looks like this:
1547 .sp
1548 .if n \{\
1549 .RS 4
1550 .\}
1551 .nf
1552 diff \-\-combined describe\&.c
1553 index fabadb8,cc95eb0\&.\&.4866510
1554 \-\-\- a/describe\&.c
1555 +++ b/describe\&.c
1556 @@@ \-98,20 \-98,12 +98,20 @@@
1557 return (a_date > b_date) ? \-1 : (a_date == b_date) ? 0 : 1;
1558 }
1560 \- static void describe(char *arg)
1561 \-static void describe(struct commit *cmit, int last_one)
1562 ++static void describe(char *arg, int last_one)
1563 {
1564 + unsigned char sha1[20];
1565 + struct commit *cmit;
1566 struct commit_list *list;
1567 static int initialized = 0;
1568 struct commit_name *n;
1570 + if (get_sha1(arg, sha1) < 0)
1571 + usage(describe_usage);
1572 + cmit = lookup_commit_reference(sha1);
1573 + if (!cmit)
1574 + usage(describe_usage);
1575 +
1576 if (!initialized) {
1577 initialized = 1;
1578 for_each_ref(get_name);
1579 .fi
1580 .if n \{\
1581 .RE
1582 .\}
1583 .sp
1584 .RS 4
1585 .ie n \{\
1586 \h'-04' 1.\h'+01'\c
1587 .\}
1588 .el \{\
1589 .sp -1
1590 .IP " 1." 4.2
1591 .\}
1592 It is preceded by a "git diff" header, that looks like this (when the
1593 \fB\-c\fR
1594 option is used):
1595 .sp
1596 .if n \{\
1597 .RS 4
1598 .\}
1599 .nf
1600 diff \-\-combined file
1601 .fi
1602 .if n \{\
1603 .RE
1604 .\}
1605 .sp
1606 or like this (when the
1607 \fB\-\-cc\fR
1608 option is used):
1609 .sp
1610 .if n \{\
1611 .RS 4
1612 .\}
1613 .nf
1614 diff \-\-cc file
1615 .fi
1616 .if n \{\
1617 .RE
1618 .\}
1619 .RE
1620 .sp
1621 .RS 4
1622 .ie n \{\
1623 \h'-04' 2.\h'+01'\c
1624 .\}
1625 .el \{\
1626 .sp -1
1627 .IP " 2." 4.2
1628 .\}
1629 It is followed by one or more extended header lines (this example shows a merge with two parents):
1630 .sp
1631 .if n \{\
1632 .RS 4
1633 .\}
1634 .nf
1635 index <hash>,<hash>\&.\&.<hash>
1636 mode <mode>,<mode>\&.\&.<mode>
1637 new file mode <mode>
1638 deleted file mode <mode>,<mode>
1639 .fi
1640 .if n \{\
1641 .RE
1642 .\}
1643 .sp
1644 The
1645 \fBmode\fR
1646 \fI<mode>\fR\fB,\fR\fI<mode>\fR\fB\&.\&.\fR\fI<mode>\fR
1647 line appears only if at least one of the <mode> is different from the rest\&. Extended headers with information about detected content movement (renames and copying detection) are designed to work with the diff of two <tree\-ish> and are not used by combined diff format\&.
1648 .RE
1649 .sp
1650 .RS 4
1651 .ie n \{\
1652 \h'-04' 3.\h'+01'\c
1653 .\}
1654 .el \{\
1655 .sp -1
1656 .IP " 3." 4.2
1657 .\}
1658 It is followed by a two\-line from\-file/to\-file header:
1659 .sp
1660 .if n \{\
1661 .RS 4
1662 .\}
1663 .nf
1664 \-\-\- a/file
1665 +++ b/file
1666 .fi
1667 .if n \{\
1668 .RE
1669 .\}
1670 .sp
1671 Similar to the two\-line header for the traditional
1672 \fIunified\fR
1673 diff format,
1674 \fB/dev/null\fR
1675 is used to signal created or deleted files\&.
1676 .sp
1677 However, if the \-\-combined\-all\-paths option is provided, instead of a two\-line from\-file/to\-file, you get an N+1 line from\-file/to\-file header, where N is the number of parents in the merge commit:
1678 .sp
1679 .if n \{\
1680 .RS 4
1681 .\}
1682 .nf
1683 \-\-\- a/file
1684 \-\-\- a/file
1685 \-\-\- a/file
1686 +++ b/file
1687 .fi
1688 .if n \{\
1689 .RE
1690 .\}
1691 .sp
1692 This extended format can be useful if rename or copy detection is active, to allow you to see the original name of the file in different parents\&.
1693 .RE
1694 .sp
1695 .RS 4
1696 .ie n \{\
1697 \h'-04' 4.\h'+01'\c
1698 .\}
1699 .el \{\
1700 .sp -1
1701 .IP " 4." 4.2
1702 .\}
1703 Chunk header format is modified to prevent people from accidentally feeding it to
1704 \fBpatch\fR
1705 \fB\-p1\fR\&. Combined diff format was created for review of merge commit changes, and was not meant to be applied\&. The change is similar to the change in the extended
1706 \fIindex\fR
1707 header:
1708 .sp
1709 .if n \{\
1710 .RS 4
1711 .\}
1712 .nf
1713 @@@ <from\-file\-range> <from\-file\-range> <to\-file\-range> @@@
1714 .fi
1715 .if n \{\
1716 .RE
1717 .\}
1718 .sp
1719 There are (number of parents + 1)
1720 \fB@\fR
1721 characters in the chunk header for combined diff format\&.
1722 .RE
1723 .sp
1724 Unlike the traditional \fIunified\fR diff format, which shows two files A and B with a single column that has \fB\-\fR (minus \(em appears in A but removed in B), \fB+\fR (plus \(em missing in A but added to B), or " " (space \(em 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\(cqs line is different from it\&.
1725 .sp
1726 A \fB\-\fR character in the column N means that the line appears in fileN but it does not appear in the result\&. A \fB+\fR character in the column N means that the line appears in the result, and fileN does not have that line (in other words, the line was added, from the point of view of that parent)\&.
1727 .sp
1728 In the above example output, the function signature was changed from both files (hence two \fB\-\fR removals from both file1 and file2, plus \fB++\fR to mean one line that was added does not appear in either file1 or file2)\&. Also, eight other lines are the same from file1 but do not appear in file2 (hence prefixed with \fB+\fR)\&.
1729 .sp
1730 When shown by \fBgit\fR \fBdiff\-tree\fR \fB\-c\fR, it compares the parents of a merge commit with the merge result (i\&.e\&. file1\&.\&.fileN are the parents)\&. When shown by \fBgit\fR \fBdiff\-files\fR \fB\-c\fR, 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")\&.
1731 .SH "OTHER DIFF FORMATS"
1732 .sp
1733 The \fB\-\-summary\fR option describes newly added, deleted, renamed and copied files\&. The \fB\-\-stat\fR option adds diffstat(1) graph to the output\&. These options can be combined with other options, such as \fB\-p\fR, and are meant for human consumption\&.
1734 .sp
1735 When showing a change that involves a rename or a copy, \fB\-\-stat\fR output formats the pathnames compactly by combining common prefix and suffix of the pathnames\&. For example, a change that moves \fBarch/i386/Makefile\fR to \fBarch/x86/Makefile\fR while modifying 4 lines will be shown like this:
1736 .sp
1737 .if n \{\
1738 .RS 4
1739 .\}
1740 .nf
1741 arch/{i386 => x86}/Makefile | 4 +\-\-
1742 .fi
1743 .if n \{\
1744 .RE
1745 .\}
1746 .sp
1747 The \fB\-\-numstat\fR option gives the diffstat(1) information but is designed for easier machine consumption\&. An entry in \fB\-\-numstat\fR output looks like this:
1748 .sp
1749 .if n \{\
1750 .RS 4
1751 .\}
1752 .nf
1753 1 2 README
1754 3 1 arch/{i386 => x86}/Makefile
1755 .fi
1756 .if n \{\
1757 .RE
1758 .\}
1759 .sp
1760 That is, from left to right:
1761 .sp
1762 .RS 4
1763 .ie n \{\
1764 \h'-04' 1.\h'+01'\c
1765 .\}
1766 .el \{\
1767 .sp -1
1768 .IP " 1." 4.2
1769 .\}
1770 the number of added lines;
1771 .RE
1772 .sp
1773 .RS 4
1774 .ie n \{\
1775 \h'-04' 2.\h'+01'\c
1776 .\}
1777 .el \{\
1778 .sp -1
1779 .IP " 2." 4.2
1780 .\}
1781 a tab;
1782 .RE
1783 .sp
1784 .RS 4
1785 .ie n \{\
1786 \h'-04' 3.\h'+01'\c
1787 .\}
1788 .el \{\
1789 .sp -1
1790 .IP " 3." 4.2
1791 .\}
1792 the number of deleted lines;
1793 .RE
1794 .sp
1795 .RS 4
1796 .ie n \{\
1797 \h'-04' 4.\h'+01'\c
1798 .\}
1799 .el \{\
1800 .sp -1
1801 .IP " 4." 4.2
1802 .\}
1803 a tab;
1804 .RE
1805 .sp
1806 .RS 4
1807 .ie n \{\
1808 \h'-04' 5.\h'+01'\c
1809 .\}
1810 .el \{\
1811 .sp -1
1812 .IP " 5." 4.2
1813 .\}
1814 pathname (possibly with rename/copy information);
1815 .RE
1816 .sp
1817 .RS 4
1818 .ie n \{\
1819 \h'-04' 6.\h'+01'\c
1820 .\}
1821 .el \{\
1822 .sp -1
1823 .IP " 6." 4.2
1824 .\}
1825 a newline\&.
1826 .RE
1827 .sp
1828 When \fB\-z\fR output option is in effect, the output is formatted this way:
1829 .sp
1830 .if n \{\
1831 .RS 4
1832 .\}
1833 .nf
1834 1 2 README NUL
1835 3 1 NUL arch/i386/Makefile NUL arch/x86/Makefile NUL
1836 .fi
1837 .if n \{\
1838 .RE
1839 .\}
1840 .sp
1841 That is:
1842 .sp
1843 .RS 4
1844 .ie n \{\
1845 \h'-04' 1.\h'+01'\c
1846 .\}
1847 .el \{\
1848 .sp -1
1849 .IP " 1." 4.2
1850 .\}
1851 the number of added lines;
1852 .RE
1853 .sp
1854 .RS 4
1855 .ie n \{\
1856 \h'-04' 2.\h'+01'\c
1857 .\}
1858 .el \{\
1859 .sp -1
1860 .IP " 2." 4.2
1861 .\}
1862 a tab;
1863 .RE
1864 .sp
1865 .RS 4
1866 .ie n \{\
1867 \h'-04' 3.\h'+01'\c
1868 .\}
1869 .el \{\
1870 .sp -1
1871 .IP " 3." 4.2
1872 .\}
1873 the number of deleted lines;
1874 .RE
1875 .sp
1876 .RS 4
1877 .ie n \{\
1878 \h'-04' 4.\h'+01'\c
1879 .\}
1880 .el \{\
1881 .sp -1
1882 .IP " 4." 4.2
1883 .\}
1884 a tab;
1885 .RE
1886 .sp
1887 .RS 4
1888 .ie n \{\
1889 \h'-04' 5.\h'+01'\c
1890 .\}
1891 .el \{\
1892 .sp -1
1893 .IP " 5." 4.2
1894 .\}
1895 a NUL (only exists if renamed/copied);
1896 .RE
1897 .sp
1898 .RS 4
1899 .ie n \{\
1900 \h'-04' 6.\h'+01'\c
1901 .\}
1902 .el \{\
1903 .sp -1
1904 .IP " 6." 4.2
1905 .\}
1906 pathname in preimage;
1907 .RE
1908 .sp
1909 .RS 4
1910 .ie n \{\
1911 \h'-04' 7.\h'+01'\c
1912 .\}
1913 .el \{\
1914 .sp -1
1915 .IP " 7." 4.2
1916 .\}
1917 a NUL (only exists if renamed/copied);
1918 .RE
1919 .sp
1920 .RS 4
1921 .ie n \{\
1922 \h'-04' 8.\h'+01'\c
1923 .\}
1924 .el \{\
1925 .sp -1
1926 .IP " 8." 4.2
1927 .\}
1928 pathname in postimage (only exists if renamed/copied);
1929 .RE
1930 .sp
1931 .RS 4
1932 .ie n \{\
1933 \h'-04' 9.\h'+01'\c
1934 .\}
1935 .el \{\
1936 .sp -1
1937 .IP " 9." 4.2
1938 .\}
1939 a NUL\&.
1940 .RE
1941 .sp
1942 The extra \fBNUL\fR before the preimage path in renamed case is to allow scripts that read the output to tell if the current record being read is a single\-path record or a rename/copy record without reading ahead\&. After reading added and deleted lines, reading up to \fBNUL\fR would yield the pathname, but if that is \fBNUL\fR, the record will show two paths\&.
1943 .SH "OPERATING MODES"
1944 .sp
1945 You can choose whether you want to trust the index file entirely (using the \fB\-\-cached\fR flag) or ask the diff logic to show any files that don\(cqt match the stat state as being "tentatively changed"\&. Both of these operations are very useful indeed\&.
1946 .SH "CACHED MODE"
1947 .sp
1948 If \fB\-\-cached\fR is specified, it allows you to ask:
1949 .sp
1950 .if n \{\
1951 .RS 4
1952 .\}
1953 .nf
1954 show me the differences between HEAD and the current index
1955 contents (the ones I\*(Aqd write using \*(Aqgit write\-tree\*(Aq)
1956 .fi
1957 .if n \{\
1958 .RE
1959 .\}
1960 .sp
1961 For example, let\(cqs 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 \fBwhat\fR you are going to commit, without having to write a new tree object and compare it that way, and to do that, you just do
1962 .sp
1963 .if n \{\
1964 .RS 4
1965 .\}
1966 .nf
1967 git diff\-index \-\-cached HEAD
1968 .fi
1969 .if n \{\
1970 .RE
1971 .\}
1972 .sp
1973 Example: let\(cqs say I had renamed \fBcommit\&.c\fR to \fBgit\-commit\&.c\fR, and I had done an \fBupdate\-index\fR to make that effective in the index file\&. \fBgit\fR \fBdiff\-files\fR wouldn\(cqt show anything at all, since the index file matches my working directory\&. But doing a \fIgit diff\-index\fR does:
1974 .sp
1975 .if n \{\
1976 .RS 4
1977 .\}
1978 .nf
1979 torvalds@ppc970:~/git> git diff\-index \-\-cached HEAD
1980 :100644 000000 4161aecc6700a2eb579e842af0b7f22b98443f74 0000000000000000000000000000000000000000 D commit\&.c
1981 :000000 100644 0000000000000000000000000000000000000000 4161aecc6700a2eb579e842af0b7f22b98443f74 A git\-commit\&.c
1982 .fi
1983 .if n \{\
1984 .RE
1985 .\}
1986 .sp
1987 You can see easily that the above is a rename\&.
1988 .sp
1989 In fact, \fBgit\fR \fBdiff\-index\fR \fB\-\-cached\fR \fBshould\fR always be entirely equivalent to actually doing a \fIgit write\-tree\fR and comparing that\&. Except this one is much nicer for the case where you just want to check where you are\&.
1990 .sp
1991 So doing a \fBgit\fR \fBdiff\-index\fR \fB\-\-cached\fR is basically very useful when you are asking yourself "what have I already marked for being committed, and what\(cqs the difference to a previous tree"\&.
1992 .SH "NON\-CACHED MODE"
1993 .sp
1994 The "non\-cached" mode takes a different approach, and is potentially the more useful of the two in that what it does can\(cqt be emulated with a \fIgit write\-tree\fR + \fIgit diff\-tree\fR\&. Thus that\(cqs the default mode\&. The non\-cached version asks the question:
1995 .sp
1996 .if n \{\
1997 .RS 4
1998 .\}
1999 .nf
2000 show me the differences between HEAD and the currently checked out
2001 tree \- index contents _and_ files that aren\*(Aqt up to date
2002 .fi
2003 .if n \{\
2004 .RE
2005 .\}
2006 .sp
2007 which is obviously a very useful question too, since that tells you what you \fBcould\fR commit\&. Again, the output matches the \fIgit diff\-tree \-r\fR output to a tee, but with a twist\&.
2008 .sp
2009 The twist is that if some file doesn\(cqt match the index, we don\(cqt have a backing store thing for it, and we use the magic "all\-zero" sha1 to show that\&. So let\(cqs say that you have edited \fBkernel/sched\&.c\fR, but have not actually done a \fIgit update\-index\fR on it yet \- there is no "object" associated with the new state, and you get:
2010 .sp
2011 .if n \{\
2012 .RS 4
2013 .\}
2014 .nf
2015 torvalds@ppc970:~/v2\&.6/linux> git diff\-index \-\-abbrev HEAD
2016 :100644 100644 7476bb5ba 000000000 M kernel/sched\&.c
2017 .fi
2018 .if n \{\
2019 .RE
2020 .\}
2021 .sp
2022 i\&.e\&., it shows that the tree has changed, and that \fBkernel/sched\&.c\fR 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\&.
2023 .if n \{\
2024 .sp
2025 .\}
2026 .RS 4
2027 .it 1 an-trap
2028 .nr an-no-space-flag 1
2029 .nr an-break-flag 1
2030 .br
2031 .ps +1
2032 \fBNote\fR
2033 .ps -1
2034 .br
2035 .sp
2036 As with other commands of this type, \fIgit diff\-index\fR does not actually look at the contents of the file at all\&. So maybe \fBkernel/sched\&.c\fR hasn\(cqt actually changed, and it\(cqs just that you touched it\&. In either case, it\(cqs a note that you need to \fIgit update\-index\fR it to make the index be in sync\&.
2037 .sp .5v
2038 .RE
2039 .if n \{\
2040 .sp
2041 .\}
2042 .RS 4
2043 .it 1 an-trap
2044 .nr an-no-space-flag 1
2045 .nr an-break-flag 1
2046 .br
2047 .ps +1
2048 \fBNote\fR
2049 .ps -1
2050 .br
2051 .sp
2052 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\&.
2053 .sp .5v
2054 .RE
2055 .SH "GIT"
2056 .sp
2057 Part of the \fBgit\fR(1) suite