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HTML rendering created 2025-02-02 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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NAME | SYNOPSIS | DESCRIPTION | GIT REPOSITORY FORMAT VERSIONS | SEE ALSO | GIT | NOTES | COLOPHON |
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GITREPOSITORY-LAYOUT(5) Git Manual GITREPOSITORY-LAYOUT(5)
gitrepository-layout - Git Repository Layout
$GIT_DIR/*
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 slightly 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.
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.
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.
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.
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]
Part of the git(1) suite
1. The Git User’s Manual
file:///home/mtk/share/doc/git-doc/user-manual.html
This page is part of the git (Git distributed version control
system) project. Information about the project can be found at
⟨http://git-scm.com/⟩. If you have a bug report for this manual
page, see ⟨http://git-scm.com/community⟩. This page was obtained
from the project's upstream Git repository
⟨https://github.com/git/git.git⟩ on 2025-02-02. (At that time,
the date of the most recent commit that was found in the
repository was 2025-01-31.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
Git 2.48.1.166.g58b580 2025-01-31 GITREPOSITORY-LAYOUT(5)
Pages that refer to this page: git(1), git-config(1), git-gc(1), git-help(1), git-repack(1), git-show-ref(1), git-update-server-info(1), git-worktree(1), gitignore(5), gitcore-tutorial(7), gitglossary(7)
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HTML rendering created 2025-02-02 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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