Provided by: git-man_2.51.0-1ubuntu1_all 
NAME
gitrepository-layout - Git Repository Layout
SYNOPSIS
$GIT_DIR/*
DESCRIPTION
A Git repository comes in two different flavours:
• a .git directory at the root of the working tree;
• a <project>.git directory that is a bare repository (i.e. without its own working tree), that is
typically used for exchanging histories with others by pushing into it and fetching from it.
Note: Also you can have a plain text file .git at the root of your working tree, containing gitdir:
<path> to point at the real directory that has the repository. This mechanism is called a gitfile and is
usually managed via the git submodule and git worktree commands. It is often used for a working tree of a
submodule checkout, to allow you in the containing superproject to git checkout a branch that does not
have the submodule. The checkout has to remove the entire submodule working tree, without losing the
submodule repository.
These things may exist in a Git repository.
objects
Object store associated with this repository. Usually an object store is self sufficient (i.e. all
the objects that are referred to by an object found in it are also found in it), but there are a few
ways to violate it.
1. You could have an incomplete but locally usable repository by creating a shallow clone. See git-
clone(1).
2. You could be using the objects/info/alternates or $GIT_ALTERNATE_OBJECT_DIRECTORIES mechanisms to
borrow objects from other object stores. A repository with this kind of incomplete object store
is not suitable to be published for use with dumb transports but otherwise is OK as long as
objects/info/alternates points at the object stores it borrows from.
This directory is ignored if $GIT_COMMON_DIR is set and "$GIT_COMMON_DIR/objects" will be used
instead.
objects/[0-9a-f][0-9a-f]
A newly created object is stored in its own file. The objects are splayed over 256 subdirectories
using the first two characters of the sha1 object name to keep the number of directory entries in
objects itself to a manageable number. Objects found here are often called unpacked (or loose)
objects.
objects/pack
Packs (files that store many objects in compressed form, along with index files to allow them to be
randomly accessed) are found in this directory.
objects/info
Additional information about the object store is recorded in this directory.
objects/info/packs
This file is to help dumb transports discover what packs are available in this object store. Whenever
a pack is added or removed, git update-server-info should be run to keep this file up to date if the
repository is published for dumb transports. git repack does this by default.
objects/info/alternates
This file records paths to alternate object stores that this object store borrows objects from, one
pathname per line. Note that not only native Git tools use it locally, but the HTTP fetcher also
tries to use it remotely; this will usually work if you have relative paths (relative to the object
database, not to the repository!) in your alternates file, but it will not work if you use absolute
paths unless the absolute path in filesystem and web URL is the same. See also
objects/info/http-alternates.
objects/info/http-alternates
This file records URLs to alternate object stores that this object store borrows objects from, to be
used when the repository is fetched over HTTP.
refs
References are stored in subdirectories of this directory. The git prune command knows to preserve
objects reachable from refs found in this directory and its subdirectories. This directory is ignored
(except refs/bisect, refs/rewritten and refs/worktree) if $GIT_COMMON_DIR is set and
"$GIT_COMMON_DIR/refs" will be used instead.
refs/heads/name
records tip-of-the-tree commit objects of branch name
refs/tags/name
records any object name (not necessarily a commit object, or a tag object that points at a commit
object).
refs/remotes/name
records tip-of-the-tree commit objects of branches copied from a remote repository.
refs/replace/<obj-sha1>
records the SHA-1 of the object that replaces <obj-sha1>. This is similar to info/grafts and is
internally used and maintained by git-replace(1). Such refs can be exchanged between repositories
while grafts are not.
packed-refs
records the same information as refs/heads/, refs/tags/, and friends record in a more efficient way.
See git-pack-refs(1). This file is ignored if $GIT_COMMON_DIR is set and
"$GIT_COMMON_DIR/packed-refs" will be used instead.
HEAD
A symref (see glossary) to the refs/heads/ namespace describing the currently active branch. It does
not mean much if the repository is not associated with any working tree (i.e. a bare repository), but
a valid Git repository must have the HEAD file; some porcelains may use it to guess the designated
"default" branch of the repository (usually master). It is legal if the named branch name does not
(yet) exist. In some legacy setups, it is a symbolic link instead of a symref that points at the
current branch.
HEAD can also record a specific commit directly, instead of being a symref to point at the current
branch. Such a state is often called detached HEAD. See git-checkout(1) for details.
config
Repository specific configuration file. This file is ignored if $GIT_COMMON_DIR is set and
"$GIT_COMMON_DIR/config" will be used instead.
config.worktree
Working directory specific configuration file for the main working directory in multiple working
directory setup (see git-worktree(1)).
branches
A deprecated way to store shorthands to be used to specify a URL to git fetch, git pull and git push.
A file can be stored as branches/<name> and then name can be given to these commands in place of
repository argument. See the REMOTES section in git-fetch(1) for details. This mechanism is legacy
and not likely to be found in modern repositories. This directory is ignored if $GIT_COMMON_DIR is
set and "$GIT_COMMON_DIR/branches" will be used instead.
Git will stop reading remotes from this directory in Git 3.0.
hooks
Hooks are customization scripts used by various Git commands. A handful of sample hooks are installed
when git init is run, but all of them are disabled by default. To enable, the .sample suffix has to
be removed from the filename by renaming. Read githooks(5) for more details about each hook. This
directory is ignored if $GIT_COMMON_DIR is set and "$GIT_COMMON_DIR/hooks" will be used instead.
common
When multiple working trees are used, most of files in $GIT_DIR are per-worktree with a few known
exceptions. All files under common however will be shared between all working trees.
index
The current index file for the repository. It is usually not found in a bare repository.
sharedindex.<SHA-1>
The shared index part, to be referenced by $GIT_DIR/index and other temporary index files. Only valid
in split index mode.
info
Additional information about the repository is recorded in this directory. This directory is ignored
if $GIT_COMMON_DIR is set and "$GIT_COMMON_DIR/info" will be used instead.
info/refs
This file helps dumb transports discover what refs are available in this repository. If the
repository is published for dumb transports, this file should be regenerated by git
update-server-info every time a tag or branch is created or modified. This is normally done from the
hooks/update hook, which is run by the git-receive-pack command when you git push into the
repository.
info/grafts
This file records fake commit ancestry information, to pretend the set of parents a commit has is
different from how the commit was actually created. One record per line describes a commit and its
fake parents by listing their 40-byte hexadecimal object names separated by a space and terminated by
a newline.
Note that the grafts mechanism is outdated and can lead to problems transferring objects between
repositories; see git-replace(1) for a more flexible and robust system to do the same thing.
info/exclude
This file, by convention among Porcelains, stores the exclude pattern list. .gitignore is the
per-directory ignore file. git status, git add, git rm and git clean look at it but the core Git
commands do not look at it. See also: gitignore(5).
info/attributes
Defines which attributes to assign to a path, similar to per-directory .gitattributes files. See
also: gitattributes(5).
info/sparse-checkout
This file stores sparse checkout patterns. See also: git-read-tree(1).
remotes
Stores shorthands for URL and default refnames for use when interacting with remote repositories via
git fetch, git pull and git push commands. See the REMOTES section in git-fetch(1) for details. This
mechanism is legacy and not likely to be found in modern repositories. This directory is ignored if
$GIT_COMMON_DIR is set and "$GIT_COMMON_DIR/remotes" will be used instead.
Git will stop reading remotes from this directory in Git 3.0.
logs
Records of changes made to refs are stored in this directory. See git-update-ref(1) for more
information. This directory is ignored (except logs/HEAD) if $GIT_COMMON_DIR is set and
"$GIT_COMMON_DIR/logs" will be used instead.
logs/refs/heads/name
Records all changes made to the branch tip named name.
logs/refs/tags/name
Records all changes made to the tag named name.
shallow
This is similar to info/grafts but is internally used and maintained by shallow clone mechanism. See
--depth option to git-clone(1) and git-fetch(1). This file is ignored if $GIT_COMMON_DIR is set and
"$GIT_COMMON_DIR/shallow" will be used instead.
commondir
If this file exists, $GIT_COMMON_DIR (see git(1)) will be set to the path specified in this file if
it is not explicitly set. If the specified path is relative, it is relative to $GIT_DIR. The
repository with commondir is incomplete without the repository pointed by "commondir".
modules
Contains the git-repositories of the submodules.
worktrees
Contains administrative data for linked working trees. Each subdirectory contains the working
tree-related part of a linked working tree. This directory is ignored if $GIT_COMMON_DIR is set, in
which case "$GIT_COMMON_DIR/worktrees" will be used instead.
worktrees/<id>/gitdir
A text file containing the absolute path back to the .git file that points to here. This is used to
check if the linked repository has been manually removed and there is no need to keep this directory
any more. The mtime of this file should be updated every time the linked repository is accessed.
worktrees/<id>/locked
If this file exists, the linked working tree may be on a portable device and not available. The
presence of this file prevents worktrees/<id> from being pruned either automatically or manually by
git worktree prune. The file may contain a string explaining why the repository is locked.
worktrees/<id>/config.worktree
Working directory specific configuration file.
GIT REPOSITORY FORMAT VERSIONS
Every git repository is marked with a numeric version in the core.repositoryformatversion key of its
config file. This version specifies the rules for operating on the on-disk repository data. An
implementation of git which does not understand a particular version advertised by an on-disk repository
MUST NOT operate on that repository; doing so risks not only producing wrong results, but actually losing
data.
Because of this rule, version bumps should be kept to an absolute minimum. Instead, we generally prefer
these strategies:
• bumping format version numbers of individual data files (e.g., index, packfiles, etc). This restricts
the incompatibilities only to those files.
• introducing new data that gracefully degrades when used by older clients (e.g., pack bitmap files are
ignored by older clients, which simply do not take advantage of the optimization they provide).
A whole-repository format version bump should only be part of a change that cannot be independently
versioned. For instance, if one were to change the reachability rules for objects, or the rules for
locking refs, that would require a bump of the repository format version.
Note that this applies only to accessing the repository’s disk contents directly. An older client which
understands only format 0 may still connect via git:// to a repository using format 1, as long as the
server process understands format 1.
The preferred strategy for rolling out a version bump (whether whole repository or for a single file) is
to teach git to read the new format, and allow writing the new format with a config switch or command
line option (for experimentation or for those who do not care about backwards compatibility with older
gits). Then after a long period to allow the reading capability to become common, we may switch to
writing the new format by default.
The currently defined format versions are:
Version 0
This is the format defined by the initial version of git, including but not limited to the format of the
repository directory, the repository configuration file, and the object and ref storage. Specifying the
complete behavior of git is beyond the scope of this document.
Version 1
This format is identical to version 0, with the following exceptions:
1. When reading the core.repositoryformatversion variable, a git implementation which supports version 1
MUST also read any configuration keys found in the extensions section of the configuration file.
2. If a version-1 repository specifies any extensions.* keys that the running git has not implemented,
the operation MUST NOT proceed. Similarly, if the value of any known key is not understood by the
implementation, the operation MUST NOT proceed.
Note that if no extensions are specified in the config file, then core.repositoryformatversion SHOULD be
set to 0 (setting it to 1 provides no benefit, and makes the repository incompatible with older
implementations of git).
The defined extensions are given in the extensions.* section of git-config(1). Any implementation wishing
to define a new extension should make a note of it there, in order to claim the name.
SEE ALSO
git-init(1), git-clone(1), git-config(1), git-fetch(1), git-pack-refs(1), git-gc(1), git-checkout(1),
gitglossary(7), The Git User’s Manual[1]
GIT
Part of the git(1) suite
NOTES
1. The Git User’s Manual
file:///usr/share/doc/git/html/user-manual.html
Git 2.51.0 08/28/2025 GITREPOSITORY-LAYOUT(5)