# git-update-index

## 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>]
                        [--show-index-version]
                        [--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.
    


## GIT



           Part of the git(1) suite
    


* * *