Merge branch 'jc/update-index-doc'
[git/git.git] / Documentation / git-update-index.txt
1 git-update-index(1)
2 ===================
3
4 NAME
5 ----
6 git-update-index - Register file contents in the working tree to the index
7
8
9 SYNOPSIS
10 --------
11 [verse]
12 'git update-index'
13 [--add] [--remove | --force-remove] [--replace]
14 [--refresh] [-q] [--unmerged] [--ignore-missing]
15 [(--cacheinfo <mode>,<object>,<file>)...]
16 [--chmod=(+|-)x]
17 [--[no-]assume-unchanged]
18 [--[no-]skip-worktree]
19 [--[no-]fsmonitor-valid]
20 [--ignore-submodules]
21 [--[no-]split-index]
22 [--[no-|test-|force-]untracked-cache]
23 [--[no-]fsmonitor]
24 [--really-refresh] [--unresolve] [--again | -g]
25 [--info-only] [--index-info]
26 [-z] [--stdin] [--index-version <n>]
27 [--verbose]
28 [--] [<file>...]
29
30 DESCRIPTION
31 -----------
32 Modifies the index or directory cache. Each file mentioned is updated
33 into the index and any 'unmerged' or 'needs updating' state is
34 cleared.
35
36 See also linkgit:git-add[1] for a more user-friendly way to do some of
37 the most common operations on the index.
38
39 The way 'git update-index' handles files it is told about can be modified
40 using the various options:
41
42 OPTIONS
43 -------
44 --add::
45 If a specified file isn't in the index already then it's
46 added.
47 Default behaviour is to ignore new files.
48
49 --remove::
50 If a specified file is in the index but is missing then it's
51 removed.
52 Default behavior is to ignore removed file.
53
54 --refresh::
55 Looks at the current index and checks to see if merges or
56 updates are needed by checking stat() information.
57
58 -q::
59 Quiet. If --refresh finds that the index needs an update, the
60 default behavior is to error out. This option makes
61 'git update-index' continue anyway.
62
63 --ignore-submodules::
64 Do not try to update submodules. This option is only respected
65 when passed before --refresh.
66
67 --unmerged::
68 If --refresh finds unmerged changes in the index, the default
69 behavior is to error out. This option makes 'git update-index'
70 continue anyway.
71
72 --ignore-missing::
73 Ignores missing files during a --refresh
74
75 --cacheinfo <mode>,<object>,<path>::
76 --cacheinfo <mode> <object> <path>::
77 Directly insert the specified info into the index. For
78 backward compatibility, you can also give these three
79 arguments as three separate parameters, but new users are
80 encouraged to use a single-parameter form.
81
82 --index-info::
83 Read index information from stdin.
84
85 --chmod=(+|-)x::
86 Set the execute permissions on the updated files.
87
88 --[no-]assume-unchanged::
89 When this flag is specified, the object names recorded
90 for the paths are not updated. Instead, this option
91 sets/unsets the "assume unchanged" bit for the
92 paths. When the "assume unchanged" bit is on, the user
93 promises not to change the file and allows Git to assume
94 that the working tree file matches what is recorded in
95 the index. If you want to change the working tree file,
96 you need to unset the bit to tell Git. This is
97 sometimes helpful when working with a big project on a
98 filesystem that has very slow lstat(2) system call
99 (e.g. cifs).
100 +
101 Git will fail (gracefully) in case it needs to modify this file
102 in the index e.g. when merging in a commit;
103 thus, in case the assumed-untracked file is changed upstream,
104 you will need to handle the situation manually.
105
106 --really-refresh::
107 Like `--refresh`, but checks stat information unconditionally,
108 without regard to the "assume unchanged" setting.
109
110 --[no-]skip-worktree::
111 When one of these flags is specified, the object name recorded
112 for the paths are not updated. Instead, these options
113 set and unset the "skip-worktree" bit for the paths. See
114 section "Skip-worktree bit" below for more information.
115
116 --[no-]fsmonitor-valid::
117 When one of these flags is specified, the object name recorded
118 for the paths are not updated. Instead, these options
119 set and unset the "fsmonitor valid" bit for the paths. See
120 section "File System Monitor" below for more information.
121
122 -g::
123 --again::
124 Runs 'git update-index' itself on the paths whose index
125 entries are different from those from the `HEAD` commit.
126
127 --unresolve::
128 Restores the 'unmerged' or 'needs updating' state of a
129 file during a merge if it was cleared by accident.
130
131 --info-only::
132 Do not create objects in the object database for all
133 <file> arguments that follow this flag; just insert
134 their object IDs into the index.
135
136 --force-remove::
137 Remove the file from the index even when the working directory
138 still has such a file. (Implies --remove.)
139
140 --replace::
141 By default, when a file `path` exists in the index,
142 'git update-index' refuses an attempt to add `path/file`.
143 Similarly if a file `path/file` exists, a file `path`
144 cannot be added. With --replace flag, existing entries
145 that conflict with the entry being added are
146 automatically removed with warning messages.
147
148 --stdin::
149 Instead of taking list of paths from the command line,
150 read list of paths from the standard input. Paths are
151 separated by LF (i.e. one path per line) by default.
152
153 --verbose::
154 Report what is being added and removed from index.
155
156 --index-version <n>::
157 Write the resulting index out in the named on-disk format version.
158 Supported versions are 2, 3 and 4. The current default version is 2
159 or 3, depending on whether extra features are used, such as
160 `git add -N`.
161 +
162 Version 4 performs a simple pathname compression that reduces index
163 size by 30%-50% on large repositories, which results in faster load
164 time. Version 4 is relatively young (first released in 1.8.0 in
165 October 2012). Other Git implementations such as JGit and libgit2
166 may not support it yet.
167
168 -z::
169 Only meaningful with `--stdin` or `--index-info`; paths are
170 separated with NUL character instead of LF.
171
172 --split-index::
173 --no-split-index::
174 Enable or disable split index mode. If split-index mode is
175 already enabled and `--split-index` is given again, all
176 changes in $GIT_DIR/index are pushed back to the shared index
177 file.
178 +
179 These options take effect whatever the value of the `core.splitIndex`
180 configuration variable (see linkgit:git-config[1]). But a warning is
181 emitted when the change goes against the configured value, as the
182 configured value will take effect next time the index is read and this
183 will remove the intended effect of the option.
184
185 --untracked-cache::
186 --no-untracked-cache::
187 Enable or disable untracked cache feature. Please use
188 `--test-untracked-cache` before enabling it.
189 +
190 These options take effect whatever the value of the `core.untrackedCache`
191 configuration variable (see linkgit:git-config[1]). But a warning is
192 emitted when the change goes against the configured value, as the
193 configured value will take effect next time the index is read and this
194 will remove the intended effect of the option.
195
196 --test-untracked-cache::
197 Only perform tests on the working directory to make sure
198 untracked cache can be used. You have to manually enable
199 untracked cache using `--untracked-cache` or
200 `--force-untracked-cache` or the `core.untrackedCache`
201 configuration variable afterwards if you really want to use
202 it. If a test fails the exit code is 1 and a message
203 explains what is not working as needed, otherwise the exit
204 code is 0 and OK is printed.
205
206 --force-untracked-cache::
207 Same as `--untracked-cache`. Provided for backwards
208 compatibility with older versions of Git where
209 `--untracked-cache` used to imply `--test-untracked-cache` but
210 this option would enable the extension unconditionally.
211
212 --fsmonitor::
213 --no-fsmonitor::
214 Enable or disable files system monitor feature. These options
215 take effect whatever the value of the `core.fsmonitor`
216 configuration variable (see linkgit:git-config[1]). But a warning
217 is emitted when the change goes against the configured value, as
218 the configured value will take effect next time the index is
219 read and this will remove the intended effect of the option.
220
221 \--::
222 Do not interpret any more arguments as options.
223
224 <file>::
225 Files to act on.
226 Note that files beginning with '.' are discarded. This includes
227 `./file` and `dir/./file`. If you don't want this, then use
228 cleaner names.
229 The same applies to directories ending '/' and paths with '//'
230
231 USING --REFRESH
232 ---------------
233 `--refresh` does not calculate a new sha1 file or bring the index
234 up to date for mode/content changes. But what it *does* do is to
235 "re-match" the stat information of a file with the index, so that you
236 can refresh the index for a file that hasn't been changed but where
237 the stat entry is out of date.
238
239 For example, you'd want to do this after doing a 'git read-tree', to link
240 up the stat index details with the proper files.
241
242 USING --CACHEINFO OR --INFO-ONLY
243 --------------------------------
244 `--cacheinfo` is used to register a file that is not in the
245 current working directory. This is useful for minimum-checkout
246 merging.
247
248 To pretend you have a file at path with mode and sha1, say:
249
250 ----------------
251 $ git update-index --add --cacheinfo <mode>,<sha1>,<path>
252 ----------------
253
254 `--info-only` is used to register files without placing them in the object
255 database. This is useful for status-only repositories.
256
257 Both `--cacheinfo` and `--info-only` behave similarly: the index is updated
258 but the object database isn't. `--cacheinfo` is useful when the object is
259 in the database but the file isn't available locally. `--info-only` is
260 useful when the file is available, but you do not wish to update the
261 object database.
262
263
264 USING --INDEX-INFO
265 ------------------
266
267 `--index-info` is a more powerful mechanism that lets you feed
268 multiple entry definitions from the standard input, and designed
269 specifically for scripts. It can take inputs of three formats:
270
271 . mode SP type SP sha1 TAB path
272 +
273 This format is to stuff `git ls-tree` output into the index.
274
275 . mode SP sha1 SP stage TAB path
276 +
277 This format is to put higher order stages into the
278 index file and matches 'git ls-files --stage' output.
279
280 . mode SP sha1 TAB path
281 +
282 This format is no longer produced by any Git command, but is
283 and will continue to be supported by `update-index --index-info`.
284
285 To place a higher stage entry to the index, the path should
286 first be removed by feeding a mode=0 entry for the path, and
287 then feeding necessary input lines in the third format.
288
289 For example, starting with this index:
290
291 ------------
292 $ git ls-files -s
293 100644 8a1218a1024a212bb3db30becd860315f9f3ac52 0 frotz
294 ------------
295
296 you can feed the following input to `--index-info`:
297
298 ------------
299 $ git update-index --index-info
300 0 0000000000000000000000000000000000000000 frotz
301 100644 8a1218a1024a212bb3db30becd860315f9f3ac52 1 frotz
302 100755 8a1218a1024a212bb3db30becd860315f9f3ac52 2 frotz
303 ------------
304
305 The first line of the input feeds 0 as the mode to remove the
306 path; the SHA-1 does not matter as long as it is well formatted.
307 Then the second and third line feeds stage 1 and stage 2 entries
308 for that path. After the above, we would end up with this:
309
310 ------------
311 $ git ls-files -s
312 100644 8a1218a1024a212bb3db30becd860315f9f3ac52 1 frotz
313 100755 8a1218a1024a212bb3db30becd860315f9f3ac52 2 frotz
314 ------------
315
316
317 USING ``ASSUME UNCHANGED'' BIT
318 ------------------------------
319
320 Many operations in Git depend on your filesystem to have an
321 efficient `lstat(2)` implementation, so that `st_mtime`
322 information for working tree files can be cheaply checked to see
323 if the file contents have changed from the version recorded in
324 the index file. Unfortunately, some filesystems have
325 inefficient `lstat(2)`. If your filesystem is one of them, you
326 can set "assume unchanged" bit to paths you have not changed to
327 cause Git not to do this check. Note that setting this bit on a
328 path does not mean Git will check the contents of the file to
329 see if it has changed -- it makes Git to omit any checking and
330 assume it has *not* changed. When you make changes to working
331 tree files, you have to explicitly tell Git about it by dropping
332 "assume unchanged" bit, either before or after you modify them.
333
334 In order to set "assume unchanged" bit, use `--assume-unchanged`
335 option. To unset, use `--no-assume-unchanged`. To see which files
336 have the "assume unchanged" bit set, use `git ls-files -v`
337 (see linkgit:git-ls-files[1]).
338
339 The command looks at `core.ignorestat` configuration variable. When
340 this is true, paths updated with `git update-index paths...` and
341 paths updated with other Git commands that update both index and
342 working tree (e.g. 'git apply --index', 'git checkout-index -u',
343 and 'git read-tree -u') are automatically marked as "assume
344 unchanged". Note that "assume unchanged" bit is *not* set if
345 `git update-index --refresh` finds the working tree file matches
346 the index (use `git update-index --really-refresh` if you want
347 to mark them as "assume unchanged").
348
349
350 EXAMPLES
351 --------
352 To update and refresh only the files already checked out:
353
354 ----------------
355 $ git checkout-index -n -f -a && git update-index --ignore-missing --refresh
356 ----------------
357
358 On an inefficient filesystem with `core.ignorestat` set::
359 +
360 ------------
361 $ git update-index --really-refresh <1>
362 $ git update-index --no-assume-unchanged foo.c <2>
363 $ git diff --name-only <3>
364 $ edit foo.c
365 $ git diff --name-only <4>
366 M foo.c
367 $ git update-index foo.c <5>
368 $ git diff --name-only <6>
369 $ edit foo.c
370 $ git diff --name-only <7>
371 $ git update-index --no-assume-unchanged foo.c <8>
372 $ git diff --name-only <9>
373 M foo.c
374 ------------
375 +
376 <1> forces lstat(2) to set "assume unchanged" bits for paths that match index.
377 <2> mark the path to be edited.
378 <3> this does lstat(2) and finds index matches the path.
379 <4> this does lstat(2) and finds index does *not* match the path.
380 <5> registering the new version to index sets "assume unchanged" bit.
381 <6> and it is assumed unchanged.
382 <7> even after you edit it.
383 <8> you can tell about the change after the fact.
384 <9> now it checks with lstat(2) and finds it has been changed.
385
386
387 SKIP-WORKTREE BIT
388 -----------------
389
390 Skip-worktree bit can be defined in one (long) sentence: When reading
391 an entry, if it is marked as skip-worktree, then Git pretends its
392 working directory version is up to date and read the index version
393 instead.
394
395 To elaborate, "reading" means checking for file existence, reading
396 file attributes or file content. The working directory version may be
397 present or absent. If present, its content may match against the index
398 version or not. Writing is not affected by this bit, content safety
399 is still first priority. Note that Git _can_ update working directory
400 file, that is marked skip-worktree, if it is safe to do so (i.e.
401 working directory version matches index version)
402
403 Although this bit looks similar to assume-unchanged bit, its goal is
404 different from assume-unchanged bit's. Skip-worktree also takes
405 precedence over assume-unchanged bit when both are set.
406
407 SPLIT INDEX
408 -----------
409
410 This mode is designed for repositories with very large indexes, and
411 aims at reducing the time it takes to repeatedly write these indexes.
412
413 In this mode, the index is split into two files, $GIT_DIR/index and
414 $GIT_DIR/sharedindex.<SHA-1>. Changes are accumulated in
415 $GIT_DIR/index, the split index, while the shared index file contains
416 all index entries and stays unchanged.
417
418 All changes in the split index are pushed back to the shared index
419 file when the number of entries in the split index reaches a level
420 specified by the splitIndex.maxPercentChange config variable (see
421 linkgit:git-config[1]).
422
423 Each time a new shared index file is created, the old shared index
424 files are deleted if their modification time is older than what is
425 specified by the splitIndex.sharedIndexExpire config variable (see
426 linkgit:git-config[1]).
427
428 To avoid deleting a shared index file that is still used, its
429 modification time is updated to the current time everytime a new split
430 index based on the shared index file is either created or read from.
431
432 UNTRACKED CACHE
433 ---------------
434
435 This cache is meant to speed up commands that involve determining
436 untracked files such as `git status`.
437
438 This feature works by recording the mtime of the working tree
439 directories and then omitting reading directories and stat calls
440 against files in those directories whose mtime hasn't changed. For
441 this to work the underlying operating system and file system must
442 change the `st_mtime` field of directories if files in the directory
443 are added, modified or deleted.
444
445 You can test whether the filesystem supports that with the
446 `--test-untracked-cache` option. The `--untracked-cache` option used
447 to implicitly perform that test in older versions of Git, but that's
448 no longer the case.
449
450 If you want to enable (or disable) this feature, it is easier to use
451 the `core.untrackedCache` configuration variable (see
452 linkgit:git-config[1]) than using the `--untracked-cache` option to
453 `git update-index` in each repository, especially if you want to do so
454 across all repositories you use, because you can set the configuration
455 variable to `true` (or `false`) in your `$HOME/.gitconfig` just once
456 and have it affect all repositories you touch.
457
458 When the `core.untrackedCache` configuration variable is changed, the
459 untracked cache is added to or removed from the index the next time a
460 command reads the index; while when `--[no-|force-]untracked-cache`
461 are used, the untracked cache is immediately added to or removed from
462 the index.
463
464 Before 2.17, the untracked cache had a bug where replacing a directory
465 with a symlink to another directory could cause it to incorrectly show
466 files tracked by git as untracked. See the "status: add a failing test
467 showing a core.untrackedCache bug" commit to git.git. A workaround for
468 that is (and this might work for other undiscovered bugs in the
469 future):
470
471 ----------------
472 $ git -c core.untrackedCache=false status
473 ----------------
474
475 This bug has also been shown to affect non-symlink cases of replacing
476 a directory with a file when it comes to the internal structures of
477 the untracked cache, but no case has been reported where this resulted in
478 wrong "git status" output.
479
480 There are also cases where existing indexes written by git versions
481 before 2.17 will reference directories that don't exist anymore,
482 potentially causing many "could not open directory" warnings to be
483 printed on "git status". These are new warnings for existing issues
484 that were previously silently discarded.
485
486 As with the bug described above the solution is to one-off do a "git
487 status" run with `core.untrackedCache=false` to flush out the leftover
488 bad data.
489
490 FILE SYSTEM MONITOR
491 -------------------
492
493 This feature is intended to speed up git operations for repos that have
494 large working directories.
495
496 It enables git to work together with a file system monitor (see the
497 "fsmonitor-watchman" section of linkgit:githooks[5]) that can
498 inform it as to what files have been modified. This enables git to avoid
499 having to lstat() every file to find modified files.
500
501 When used in conjunction with the untracked cache, it can further improve
502 performance by avoiding the cost of scanning the entire working directory
503 looking for new files.
504
505 If you want to enable (or disable) this feature, it is easier to use
506 the `core.fsmonitor` configuration variable (see
507 linkgit:git-config[1]) than using the `--fsmonitor` option to
508 `git update-index` in each repository, especially if you want to do so
509 across all repositories you use, because you can set the configuration
510 variable in your `$HOME/.gitconfig` just once and have it affect all
511 repositories you touch.
512
513 When the `core.fsmonitor` configuration variable is changed, the
514 file system monitor is added to or removed from the index the next time
515 a command reads the index. When `--[no-]fsmonitor` are used, the file
516 system monitor is immediately added to or removed from the index.
517
518 CONFIGURATION
519 -------------
520
521 The command honors `core.filemode` configuration variable. If
522 your repository is on a filesystem whose executable bits are
523 unreliable, this should be set to 'false' (see linkgit:git-config[1]).
524 This causes the command to ignore differences in file modes recorded
525 in the index and the file mode on the filesystem if they differ only on
526 executable bit. On such an unfortunate filesystem, you may
527 need to use 'git update-index --chmod='.
528
529 Quite similarly, if `core.symlinks` configuration variable is set
530 to 'false' (see linkgit:git-config[1]), symbolic links are checked out
531 as plain files, and this command does not modify a recorded file mode
532 from symbolic link to regular file.
533
534 The command looks at `core.ignorestat` configuration variable. See
535 'Using "assume unchanged" bit' section above.
536
537 The command also looks at `core.trustctime` configuration variable.
538 It can be useful when the inode change time is regularly modified by
539 something outside Git (file system crawlers and backup systems use
540 ctime for marking files processed) (see linkgit:git-config[1]).
541
542 The untracked cache extension can be enabled by the
543 `core.untrackedCache` configuration variable (see
544 linkgit:git-config[1]).
545
546 SEE ALSO
547 --------
548 linkgit:git-config[1],
549 linkgit:git-add[1],
550 linkgit:git-ls-files[1]
551
552 GIT
553 ---
554 Part of the linkgit:git[1] suite