NAME
gitrepository-layout - Git Repository LayoutSYNOPSIS
$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.
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.
objects/[0-9a-f][0-9a-f]
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.
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.
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.•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).
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.
SEE ALSO
git-init(1), git-clone(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) suiteNOTES
- 1.
- The Git User’s Manual
file:///usr/share/doc/git/html/user-manual.html
02/28/2023 | Git 2.39.2 |