GIT-UPDATE-INDEX(1) Git Manual GIT-UPDATE-INDEX(1)
NAME
git-update-index - Register file contents in the working tree to the
index
SYNOPSIS
git update-index
[--add] [--remove | --force-remove] [--replace]
[--refresh] [-q] [--unmerged] [--ignore-missing]
[(--cacheinfo <mode>,<object>,<file>)...]
[--chmod=(+|-)x]
[--[no-]assume-unchanged]
[--[no-]skip-worktree]
[--[no-]ignore-skip-worktree-entries]
[--[no-]fsmonitor-valid]
[--ignore-submodules]
[--[no-]split-index]
[--[no-|test-|force-]untracked-cache]
[--[no-]fsmonitor]
[--really-refresh] [--unresolve] [--again | -g]
[--info-only] [--index-info]
[-z] [--stdin] [--index-version <n>]
[--verbose]
[--] [<file>...]
DESCRIPTION
Modifies the index. Each file mentioned is updated into the index and
any unmerged or needs updating state is cleared.
See also git-add(1) for a more user-friendly way to do some of the most
common operations on the index.
The way git update-index handles files it is told about can be modified
using the various options:
OPTIONS
--add
If a specified file isn't in the index already then it's added.
Default behaviour is to ignore new files.
--remove
If a specified file is in the index but is missing then it's
removed. Default behavior is to ignore removed files.
--refresh
Looks at the current index and checks to see if merges or updates
are needed by checking stat() information.
-q
Quiet. If --refresh finds that the index needs an update, the
default behavior is to error out. This option makes git
update-index continue anyway.
--ignore-submodules
Do not try to update submodules. This option is only respected when
passed before --refresh.
--unmerged
If --refresh finds unmerged changes in the index, the default
behavior is to error out. This option makes git update-index
continue anyway.
--ignore-missing
Ignores missing files during a --refresh
--cacheinfo <mode>,<object>,<path>, --cacheinfo <mode> <object> <path>
Directly insert the specified info into the index. For backward
compatibility, you can also give these three arguments as three
separate parameters, but new users are encouraged to use a
single-parameter form.
--index-info
Read index information from stdin.
--chmod=(+|-)x
Set the execute permissions on the updated files.
--[no-]assume-unchanged
When this flag is specified, the object names recorded for the
paths are not updated. Instead, this option sets/unsets the "assume
unchanged" bit for the paths. When the "assume unchanged" bit is
on, the user promises not to change the file and allows Git to
assume that the working tree file matches what is recorded in the
index. If you want to change the working tree file, you need to
unset the bit to tell Git. This is sometimes helpful when working
with a big project on a filesystem that has a very slow lstat(2)
system call (e.g. cifs).
Git will fail (gracefully) in case it needs to modify this file in
the index e.g. when merging in a commit; thus, in case the
assumed-untracked file is changed upstream, you will need to handle
the situation manually.
--really-refresh
Like --refresh, but checks stat information unconditionally,
without regard to the "assume unchanged" setting.
--[no-]skip-worktree
When one of these flags is specified, the object names recorded for
the paths are not updated. Instead, these options set and unset the
"skip-worktree" bit for the paths. See section "Skip-worktree bit"
below for more information.
--[no-]ignore-skip-worktree-entries
Do not remove skip-worktree (AKA "index-only") entries even when
the --remove option was specified.
--[no-]fsmonitor-valid
When one of these flags is specified, the object names recorded for
the paths are not updated. Instead, these options set and unset the
"fsmonitor valid" bit for the paths. See section "File System
Monitor" below for more information.
-g, --again
Runs git update-index itself on the paths whose index entries are
different from those of the HEAD commit.
--unresolve
Restores the unmerged or needs updating state of a file during a
merge if it was cleared by accident.
--info-only
Do not create objects in the object database for all <file>
arguments that follow this flag; just insert their object IDs into
the index.
--force-remove
Remove the file from the index even when the working directory
still has such a file. (Implies --remove.)
--replace
By default, when a file path exists in the index, git update-index
refuses an attempt to add path/file. Similarly if a file path/file
exists, a file path cannot be added. With --replace flag, existing
entries that conflict with the entry being added are automatically
removed with warning messages.
--stdin
Instead of taking a list of paths from the command line, read a
list of paths from the standard input. Paths are separated by LF
(i.e. one path per line) by default.
--verbose
Report what is being added and removed from the index.
--index-version <n>
Write the resulting index out in the named on-disk format version.
Supported versions are 2, 3, and 4. The current default version is
2 or 3, depending on whether extra features are used, such as git
add -N. With --verbose, also report the version the index file uses
before and after this command.
Version 4 performs a simple pathname compression that reduces index
size by 30%-50% on large repositories, which results in faster load
time. Git supports it since version 1.8.0, released in October
2012, and support for it was added to libgit2 in 2016 and to JGit
in 2020. Older versions of this manual page called it "relatively
young", but it should be considered mature technology these days.
--show-index-version
Report the index format version used by the on-disk index file. See
--index-version above.
-z
Only meaningful with --stdin or --index-info; paths are separated
with NUL character instead of LF.
--split-index, --no-split-index
Enable or disable split index mode. If split-index mode is already
enabled and --split-index is given again, all changes in
$GIT_DIR/index are pushed back to the shared index file.
These options take effect whatever the value of the core.splitIndex
configuration variable (see git-config(1)). But a warning is
emitted when the change goes against the configured value, as the
configured value will take effect next time the index is read and
this will remove the intended effect of the option.
--untracked-cache, --no-untracked-cache
Enable or disable untracked cache feature. Please use
--test-untracked-cache before enabling it.
These options take effect whatever the value of the
core.untrackedCache configuration variable (see git-config(1)). But
a warning is emitted when the change goes against the configured
value, as the configured value will take effect next time the index
is read and this will remove the intended effect of the option.
--test-untracked-cache
Only perform tests on the working directory to make sure untracked
cache can be used. You have to manually enable untracked cache
using --untracked-cache or --force-untracked-cache or the
core.untrackedCache configuration variable afterwards if you really
want to use it. If a test fails the exit code is 1 and a message
explains what is not working as needed, otherwise the exit code is
0 and OK is printed.
--force-untracked-cache
Same as --untracked-cache. Provided for backwards compatibility
with older versions of Git where --untracked-cache used to imply
--test-untracked-cache but this option would enable the extension
unconditionally.
--fsmonitor, --no-fsmonitor
Enable or disable files system monitor feature. These options take
effect whatever the value of the core.fsmonitor configuration
variable (see git-config(1)). But a warning is emitted when the
change goes against the configured value, as the configured value
will take effect next time the index is read and this will remove
the intended effect of the option.
--
Do not interpret any more arguments as options.
<file>
Files to act on. Note that files beginning with . are discarded.
This includes ./file and dir/./file. If you don't want this, then
use cleaner names. The same applies to directories ending / and
paths with //
USING --REFRESH
--refresh does not calculate a new sha1 file or bring the index up to
date for mode/content changes. But what it does do is to "re-match" the
stat information of a file with the index, so that you can refresh the
index for a file that hasn't been changed but where the stat entry is
out of date.
For example, you'd want to do this after doing a git read-tree, to link
up the stat index details with the proper files.
USING --CACHEINFO OR --INFO-ONLY
--cacheinfo is used to register a file that is not in the current
working directory. This is useful for minimum-checkout merging.
To pretend you have a file at path with mode and sha1, say:
$ git update-index --add --cacheinfo <mode>,<sha1>,<path>
--info-only is used to register files without placing them in the
object database. This is useful for status-only repositories.
Both --cacheinfo and --info-only behave similarly: the index is updated
but the object database isn't. --cacheinfo is useful when the object is
in the database but the file isn't available locally. --info-only is
useful when the file is available, but you do not wish to update the
object database.
USING --INDEX-INFO
--index-info is a more powerful mechanism that lets you feed multiple
entry definitions from the standard input, and designed specifically
for scripts. It can take inputs of three formats:
1. mode SP type SP sha1 TAB path
This format is to stuff git ls-tree output into the index.
2. mode SP sha1 SP stage TAB path
This format is to put higher order stages into the index file and
matches git ls-files --stage output.
3. mode SP sha1 TAB path
This format is no longer produced by any Git command, but is and
will continue to be supported by update-index --index-info.
To place a higher stage entry to the index, the path should first be
removed by feeding a mode=0 entry for the path, and then feeding
necessary input lines in the third format.
For example, starting with this index:
$ git ls-files -s
100644 8a1218a1024a212bb3db30becd860315f9f3ac52 0 frotz
you can feed the following input to --index-info:
$ git update-index --index-info
0 0000000000000000000000000000000000000000 frotz
100644 8a1218a1024a212bb3db30becd860315f9f3ac52 1 frotz
100755 8a1218a1024a212bb3db30becd860315f9f3ac52 2 frotz
The first line of the input feeds 0 as the mode to remove the path; the
SHA-1 does not matter as long as it is well formatted. Then the second
and third line feeds stage 1 and stage 2 entries for that path. After
the above, we would end up with this:
$ git ls-files -s
100644 8a1218a1024a212bb3db30becd860315f9f3ac52 1 frotz
100755 8a1218a1024a212bb3db30becd860315f9f3ac52 2 frotz
USING "ASSUME UNCHANGED" BIT
Many operations in Git depend on your filesystem to have an efficient
lstat(2) implementation, so that st_mtime information for working tree
files can be cheaply checked to see if the file contents have changed
from the version recorded in the index file. Unfortunately, some
filesystems have inefficient lstat(2). If your filesystem is one of
them, you can set "assume unchanged" bit to paths you have not changed
to cause Git not to do this check. Note that setting this bit on a path
does not mean Git will check the contents of the file to see if it has
changed -- it makes Git to omit any checking and assume it has not
changed. When you make changes to working tree files, you have to
explicitly tell Git about it by dropping "assume unchanged" bit, either
before or after you modify them.
In order to set "assume unchanged" bit, use --assume-unchanged option.
To unset, use --no-assume-unchanged. To see which files have the
"assume unchanged" bit set, use git ls-files -v (see git-ls-files(1)).
The command looks at core.ignorestat configuration variable. When this
is true, paths updated with git update-index paths... and paths updated
with other Git commands that update both index and working tree (e.g.
git apply --index, git checkout-index -u, and git read-tree -u) are
automatically marked as "assume unchanged". Note that "assume
unchanged" bit is not set if git update-index --refresh finds the
working tree file matches the index (use git update-index
--really-refresh if you want to mark them as "assume unchanged").
Sometimes users confuse the assume-unchanged bit with the skip-worktree
bit. See the final paragraph in the "Skip-worktree bit" section below
for an explanation of the differences.
EXAMPLES
To update and refresh only the files already checked out:
$ git checkout-index -n -f -a && git update-index --ignore-missing --refresh
On an inefficient filesystem with core.ignorestat set
$ git update-index --really-refresh (1)
$ git update-index --no-assume-unchanged foo.c (2)
$ git diff --name-only (3)
$ edit foo.c
$ git diff --name-only (4)
M foo.c
$ git update-index foo.c (5)
$ git diff --name-only (6)
$ edit foo.c
$ git diff --name-only (7)
$ git update-index --no-assume-unchanged foo.c (8)
$ git diff --name-only (9)
M foo.c
1. forces lstat(2) to set "assume unchanged" bits for paths
that match index.
2. mark the path to be edited.
3. this does lstat(2) and finds index matches the path.
4. this does lstat(2) and finds index does not match the
path.
5. registering the new version to index sets "assume
unchanged" bit.
6. and it is assumed unchanged.
7. even after you edit it.
8. you can tell about the change after the fact.
9. now it checks with lstat(2) and finds it has been changed.
SKIP-WORKTREE BIT
Skip-worktree bit can be defined in one (long) sentence: Tell git to
avoid writing the file to the working directory when reasonably
possible, and treat the file as unchanged when it is not present in the
working directory.
Note that not all git commands will pay attention to this bit, and some
only partially support it.
The update-index flags and the read-tree capabilities relating to the
skip-worktree bit predated the introduction of the git-sparse-
checkout(1) command, which provides a much easier way to configure and
handle the skip-worktree bits. If you want to reduce your working tree
to only deal with a subset of the files in the repository, we strongly
encourage the use of git-sparse-checkout(1) in preference to the
low-level update-index and read-tree primitives.
The primary purpose of the skip-worktree bit is to enable sparse
checkouts, i.e. to have working directories with only a subset of paths
present. When the skip-worktree bit is set, Git commands (such as
switch, pull, merge) will avoid writing these files. However, these
commands will sometimes write these files anyway in important cases
such as conflicts during a merge or rebase. Git commands will also
avoid treating the lack of such files as an intentional deletion; for
example git add -u will not stage a deletion for these files and git
commit -a will not make a commit deleting them either.
Although this bit looks similar to assume-unchanged bit, its goal is
different. The assume-unchanged bit is for leaving the file in the
working tree but having Git omit checking it for changes and presuming
that the file has not been changed (though if it can determine without
stat'ing the file that it has changed, it is free to record the
changes). skip-worktree tells Git to ignore the absence of the file,
avoid updating it when possible with commands that normally update much
of the working directory (e.g. checkout, switch, pull, etc.), and not
have its absence be recorded in commits. Note that in sparse checkouts
(setup by git sparse-checkout or by configuring core.sparseCheckout to
true), if a file is marked as skip-worktree in the index but is found
in the working tree, Git will clear the skip-worktree bit for that
file.
SPLIT INDEX
This mode is designed for repositories with very large indexes, and
aims at reducing the time it takes to repeatedly write these indexes.
In this mode, the index is split into two files, $GIT_DIR/index and
$GIT_DIR/sharedindex.<SHA-1>. Changes are accumulated in
$GIT_DIR/index, the split index, while the shared index file contains
all index entries and stays unchanged.
All changes in the split index are pushed back to the shared index file
when the number of entries in the split index reaches a level specified
by the splitIndex.maxPercentChange config variable (see git-config(1)).
Each time a new shared index file is created, the old shared index
files are deleted if their modification time is older than what is
specified by the splitIndex.sharedIndexExpire config variable (see git-
config(1)).
To avoid deleting a shared index file that is still used, its
modification time is updated to the current time every time a new split
index based on the shared index file is either created or read from.
UNTRACKED CACHE
This cache is meant to speed up commands that involve determining
untracked files such as git status.
This feature works by recording the mtime of the working tree
directories and then omitting reading directories and stat calls
against files in those directories whose mtime hasn't changed. For this
to work the underlying operating system and file system must change the
st_mtime field of directories if files in the directory are added,
modified or deleted.
You can test whether the filesystem supports that with the
--test-untracked-cache option. The --untracked-cache option used to
implicitly perform that test in older versions of Git, but that's no
longer the case.
If you want to enable (or disable) this feature, it is easier to use
the core.untrackedCache configuration variable (see git-config(1)) than
using the --untracked-cache option to git update-index in each
repository, especially if you want to do so across all repositories you
use, because you can set the configuration variable to true (or false)
in your $HOME/.gitconfig just once and have it affect all repositories
you touch.
When the core.untrackedCache configuration variable is changed, the
untracked cache is added to or removed from the index the next time a
command reads the index; while when --[no-|force-]untracked-cache are
used, the untracked cache is immediately added to or removed from the
index.
Before 2.17, the untracked cache had a bug where replacing a directory
with a symlink to another directory could cause it to incorrectly show
files tracked by git as untracked. See the "status: add a failing test
showing a core.untrackedCache bug" commit to git.git. A workaround for
that is (and this might work for other undiscovered bugs in the
future):
$ git -c core.untrackedCache=false status
This bug has also been shown to affect non-symlink cases of replacing a
directory with a file when it comes to the internal structures of the
untracked cache, but no case has been reported where this resulted in
wrong "git status" output.
There are also cases where existing indexes written by git versions
before 2.17 will reference directories that don't exist anymore,
potentially causing many "could not open directory" warnings to be
printed on "git status". These are new warnings for existing issues
that were previously silently discarded.
As with the bug described above the solution is to one-off do a "git
status" run with core.untrackedCache=false to flush out the leftover
bad data.
FILE SYSTEM MONITOR
This feature is intended to speed up git operations for repos that have
large working directories.
It enables git to work together with a file system monitor (see git-
fsmonitor--daemon(1) and the "fsmonitor-watchman" section of
githooks(5)) that can inform it as to what files have been modified.
This enables git to avoid having to lstat() every file to find modified
files.
When used in conjunction with the untracked cache, it can further
improve performance by avoiding the cost of scanning the entire working
directory looking for new files.
If you want to enable (or disable) this feature, it is easier to use
the core.fsmonitor configuration variable (see git-config(1)) than
using the --fsmonitor option to git update-index in each repository,
especially if you want to do so across all repositories you use,
because you can set the configuration variable in your $HOME/.gitconfig
just once and have it affect all repositories you touch.
When the core.fsmonitor configuration variable is changed, the file
system monitor is added to or removed from the index the next time a
command reads the index. When --[no-]fsmonitor are used, the file
system monitor is immediately added to or removed from the index.
CONFIGURATION
The command honors core.filemode configuration variable. If your
repository is on a filesystem whose executable bits are unreliable,
this should be set to false (see git-config(1)). This causes the
command to ignore differences in file modes recorded in the index and
the file mode on the filesystem if they differ only on executable bit.
On such an unfortunate filesystem, you may need to use git update-index
--chmod=.
Quite similarly, if core.symlinks configuration variable is set to
false (see git-config(1)), symbolic links are checked out as plain
files, and this command does not modify a recorded file mode from
symbolic link to regular file.
The command looks at core.ignorestat configuration variable. See Using
"assume unchanged" bit section above.
The command also looks at core.trustctime configuration variable. It
can be useful when the inode change time is regularly modified by
something outside Git (file system crawlers and backup systems use
ctime for marking files processed) (see git-config(1)).
The untracked cache extension can be enabled by the core.untrackedCache
configuration variable (see git-config(1)).
NOTES
Users often try to use the assume-unchanged and skip-worktree bits to
tell Git to ignore changes to files that are tracked. This does not
work as expected, since Git may still check working tree files against
the index when performing certain operations. In general, Git does not
provide a way to ignore changes to tracked files, so alternate
solutions are recommended.
For example, if the file you want to change is some sort of config
file, the repository can include a sample config file that can then be
copied into the ignored name and modified. The repository can even
include a script to treat the sample file as a template, modifying and
copying it automatically.
SEE ALSO
git-config(1), git-add(1), git-ls-files(1)
GIT
Part of the git(1) suite
Git 2.43.5 05/31/2024 GIT-UPDATE-INDEX(1)
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