A Git repository comes in two different flavours:
o a .git directory at the root of the working tree;
o 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 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.
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
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.
Packs (files that store many object in compressed form, along with
index files to allow them to be randomly accessed) are found in
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.
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.
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
if $GIT_COMMON_DIR is set and "$GIT_COMMON_DIR/refs" will be used
records tip-of-the-tree commit objects of branch name
records any object name (not necessarily a commit object, or a tag
object that points at a commit object).
records tip-of-the-tree commit objects of branches copied from a
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.
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.
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
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
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
The current index file for the repository. It is usually not found
in a bare repository.
The shared index part, to be referenced by $GIT_DIR/index and other
temporary index files. Only valid in split index mode.
Additional information about the repository is recorded in this
directory. This directory is ignored if $GIT_COMMON_DIR is set and
"$GIT_COMMON_DIR/index" will be used instead.
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
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.
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).
Records of changes made to refs are stored in this directory. See
git-update-ref(1) for more information. This directory is ignored
if $GIT_COMMON_DIR is set and "$GIT_COMMON_DIR/logs" will be used
Records all changes made to the branch tip named name.
Records all changes made to the tag named name.
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.
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".
Contains the git-repositories of the submodules.
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.
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.
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.
If this file exists, it is a hard link to the linked .git file. It
is used to detect if the linked repository is manually removed.
git-init(1), git-clone(1), git-fetch(1), git-pack-refs(1), git-gc(1),
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