Documentation/gitrepository-layout.txt - jrn/git - Git at Google

 gitrepository-layout(5)
 =======================

 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 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.
 +
 . You could have an incomplete but locally usable repository
 by creating a shallow clone.  See linkgit:git-clone[1].
 . 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 object 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 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 linkgit: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
 	linkgit: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 linkgit: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.

 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
 	linkgit: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 linkgit: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.


 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/index" 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 linkgit: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: linkgit:gitignore[5].

 info/sparse-checkout::
 	This file stores sparse checkout patterns.
 	See also: linkgit: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 linkgit: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 linkgit: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 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 linkgit:git-clone[1] and linkgit: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 linkgit: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 worktree specific information of linked
 	checkouts. Each subdirectory contains the worktree-related
 	part of a linked checkout. This directory is ignored if
 	$GIT_COMMON_DIR is set and "$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. mtime of this file should be
 	updated every time the linked repository is accessed.

 worktrees/<id>/locked::
 	If this file exists, the linked repository may be on a
 	portable device and not available. It does not mean that the
 	linked repository is gone and `worktrees/<id>` could be
 	removed. The file's content contains a reason string on why
 	the repository is locked.

 worktrees/<id>/link::
 	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.

 SEE ALSO
 --------
 linkgit:git-init[1],
 linkgit:git-clone[1],
 linkgit:git-fetch[1],
 linkgit:git-pack-refs[1],
 linkgit:git-gc[1],
 linkgit:git-checkout[1],
 linkgit:gitglossary[7],
 link:user-manual.html[The Git User's Manual]

 GIT
 ---
 Part of the linkgit:git[1] suite.
	gitrepository-layout(5)
	=======================

	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 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.
	+
	. You could have an incomplete but locally usable repository
	by creating a shallow clone. See linkgit:git-clone[1].
	. 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 object 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 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 linkgit: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
	linkgit: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 linkgit: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.

	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
	linkgit: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 linkgit: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.


	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/index" 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 linkgit: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: linkgit:gitignore[5].

	info/sparse-checkout::
	This file stores sparse checkout patterns.
	See also: linkgit: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 linkgit: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 linkgit: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 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 linkgit:git-clone[1] and linkgit: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 linkgit: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 worktree specific information of linked
	checkouts. Each subdirectory contains the worktree-related
	part of a linked checkout. This directory is ignored if
	$GIT_COMMON_DIR is set and "$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. mtime of this file should be
	updated every time the linked repository is accessed.

	worktrees/<id>/locked::
	If this file exists, the linked repository may be on a
	portable device and not available. It does not mean that the
	linked repository is gone and `worktrees/<id>` could be
	removed. The file's content contains a reason string on why
	the repository is locked.

	worktrees/<id>/link::
	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.

	SEE ALSO
	--------
	linkgit:git-init[1],
	linkgit:git-clone[1],
	linkgit:git-fetch[1],
	linkgit:git-pack-refs[1],
	linkgit:git-gc[1],
	linkgit:git-checkout[1],
	linkgit:gitglossary[7],
	link:user-manual.html[The Git User's Manual]

	GIT
	---
	Part of the linkgit:git[1] suite.