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<!DOCTYPE sect2 SYSTEM "../../../dtd/dblite.dtd">

<sect2 lang="en" id="gitrepository-layout(5)">
    <title>gitrepository-layout(5)</title>
    <date>2024-07-02</date>
<revhistory><revision><date>2024-07-02</date></revision></revhistory>
<indexterm>
<primary>gitrepository-layout(5)</primary>
</indexterm>
<simplesect id="gitrepository-layout(5)__name">
<title>NAME</title>
<simpara>gitrepository-layout - Git Repository Layout</simpara>
</simplesect>
<simplesect id="gitrepository-layout(5)__synopsis">
<title>SYNOPSIS</title>
<simpara>$GIT_DIR/*</simpara>
</simplesect>
<simplesect id="gitrepository-layout(5)__description">
<title>DESCRIPTION</title>
<simpara>A Git repository comes in two different flavours:</simpara>
<itemizedlist>
<listitem>
<simpara>
a <emphasis>.git</emphasis> directory at the root of the working tree;
</simpara>
</listitem>
<listitem>
<simpara>
a <emphasis>&lt;project&gt;.git</emphasis> directory that is a <emphasis>bare</emphasis> 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.
</simpara>
</listitem>
</itemizedlist>
<simpara><emphasis role="strong">Note</emphasis>: Also you can have a plain text file <emphasis>.git</emphasis> at the root of
your working tree, containing <emphasis>gitdir: &lt;path&gt;</emphasis> to point at the real
directory that has the repository.
This mechanism is called a <emphasis>gitfile</emphasis> and is usually managed via the
<emphasis>git submodule</emphasis> and <emphasis>git worktree</emphasis> commands. It is often used for
a working tree of a submodule checkout, to allow you in the
containing superproject to <emphasis>git checkout</emphasis> a branch that does not
have the submodule.  The <emphasis>checkout</emphasis> has to remove the entire
submodule working tree, without losing the submodule repository.</simpara>
<simpara>These things may exist in a Git repository.</simpara>
<variablelist>
<varlistentry>
<term>
objects
</term>
<listitem>
<simpara>
        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.
</simpara>
<orderedlist numeration="arabic">
<listitem>
<simpara>
You could have an incomplete but locally usable repository
by creating a shallow clone.  See <xref linkend="git-clone(1)" />.
</simpara>
</listitem>
<listitem>
<simpara>
You could be using the <emphasis>objects/info/alternates</emphasis> or
<emphasis>$GIT_ALTERNATE_OBJECT_DIRECTORIES</emphasis> mechanisms to <emphasis>borrow</emphasis>
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
<emphasis>objects/info/alternates</emphasis> points at the object stores it
borrows from.
</simpara>
<simpara>This directory is ignored if $GIT_COMMON_DIR is set and
"$GIT_COMMON_DIR/objects" will be used instead.</simpara>
</listitem>
</orderedlist>
</listitem>
</varlistentry>
<varlistentry>
<term>
objects/[0-9a-f][0-9a-f]
</term>
<listitem>
<simpara>
        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 <emphasis>objects</emphasis>
        itself to a manageable number. Objects found
        here are often called <emphasis>unpacked</emphasis> (or <emphasis>loose</emphasis>) objects.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
objects/pack
</term>
<listitem>
<simpara>
        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.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
objects/info
</term>
<listitem>
<simpara>
        Additional information about the object store is
        recorded in this directory.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
objects/info/packs
</term>
<listitem>
<simpara>
        This file is to help dumb transports discover what packs
        are available in this object store.  Whenever a pack is
        added or removed, <emphasis>git update-server-info</emphasis> should be run
        to keep this file up to date if the repository is
        published for dumb transports.  <emphasis>git repack</emphasis> does this
        by default.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
objects/info/alternates
</term>
<listitem>
<simpara>
        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 <emphasis>objects/info/http-alternates</emphasis>.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
objects/info/http-alternates
</term>
<listitem>
<simpara>
        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.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
refs
</term>
<listitem>
<simpara>
        References are stored in subdirectories of this
        directory.  The <emphasis>git prune</emphasis> 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.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
refs/heads/<emphasis>name</emphasis>
</term>
<listitem>
<simpara>
        records tip-of-the-tree commit objects of branch <emphasis>name</emphasis>
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
refs/tags/<emphasis>name</emphasis>
</term>
<listitem>
<simpara>
        records any object name (not necessarily a commit
        object, or a tag object that points at a commit object).
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
refs/remotes/<emphasis>name</emphasis>
</term>
<listitem>
<simpara>
        records tip-of-the-tree commit objects of branches copied
        from a remote repository.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
refs/replace/<emphasis>&lt;obj-sha1&gt;</emphasis>
</term>
<listitem>
<simpara>
        records the SHA-1 of the object that replaces <emphasis>&lt;obj-sha1&gt;</emphasis>.
        This is similar to info/grafts and is internally used and
        maintained by <xref linkend="git-replace(1)" />. Such refs can be exchanged
        between repositories while grafts are not.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
packed-refs
</term>
<listitem>
<simpara>
        records the same information as refs/heads/, refs/tags/,
        and friends record in a more efficient way.  See
        <xref linkend="git-pack-refs(1)" />. This file is ignored if $GIT_COMMON_DIR
        is set and "$GIT_COMMON_DIR/packed-refs" will be used instead.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
HEAD
</term>
<listitem>
<simpara>
        A symref (see glossary) to the <emphasis>refs/heads/</emphasis> namespace
        describing the currently active branch.  It does not mean
        much if the repository is not associated with any working tree
        (i.e. a <emphasis>bare</emphasis> repository), but a valid Git repository
        <emphasis role="strong">must</emphasis> have the HEAD file; some porcelains may use it to
        guess the designated "default" branch of the repository
        (usually <emphasis>master</emphasis>).  It is legal if the named branch
        <emphasis>name</emphasis> does not (yet) exist.  In some legacy setups, it is
        a symbolic link instead of a symref that points at the current
        branch.
</simpara>
<simpara>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 <emphasis>detached HEAD.</emphasis>  See <xref linkend="git-checkout(1)" />
for details.</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
config
</term>
<listitem>
<simpara>
        Repository specific configuration file. This file is ignored
        if $GIT_COMMON_DIR is set and "$GIT_COMMON_DIR/config" will be
        used instead.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
config.worktree
</term>
<listitem>
<simpara>
        Working directory specific configuration file for the main
        working directory in multiple working directory setup (see
        <xref linkend="git-worktree(1)" />).
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
branches
</term>
<listitem>
<simpara>
        A slightly deprecated way to store shorthands to be used
        to specify a URL to <emphasis>git fetch</emphasis>, <emphasis>git pull</emphasis> and <emphasis>git push</emphasis>.
        A file can be stored as <emphasis>branches/&lt;name&gt;</emphasis> and then
        <emphasis>name</emphasis> can be given to these commands in place of
        <emphasis>repository</emphasis> argument.  See the REMOTES section in
        <xref linkend="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.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
hooks
</term>
<listitem>
<simpara>
        Hooks are customization scripts used by various Git
        commands.  A handful of sample hooks are installed when
        <emphasis>git init</emphasis> is run, but all of them are disabled by
        default.  To enable, the <emphasis>.sample</emphasis> suffix has to be
        removed from the filename by renaming.
        Read <xref linkend="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.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
common
</term>
<listitem>
<simpara>
        When multiple working trees are used, most of files in
        $GIT_DIR are per-worktree with a few known exceptions. All
        files under <emphasis>common</emphasis> however will be shared between all
        working trees.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
index
</term>
<listitem>
<simpara>
        The current index file for the repository.  It is
        usually not found in a bare repository.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
sharedindex.&lt;SHA-1&gt;
</term>
<listitem>
<simpara>
        The shared index part, to be referenced by $GIT_DIR/index and
        other temporary index files. Only valid in split index mode.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
info
</term>
<listitem>
<simpara>
        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.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
info/refs
</term>
<listitem>
<simpara>
        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 <emphasis>git update-server-info</emphasis> every time a tag
        or branch is created or modified.  This is normally done
        from the <emphasis>hooks/update</emphasis> hook, which is run by the
        <emphasis>git-receive-pack</emphasis> command when you <emphasis>git push</emphasis> into the
        repository.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
info/grafts
</term>
<listitem>
<simpara>
        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.
</simpara>
<simpara>Note that the grafts mechanism is outdated and can lead to problems
transferring objects between repositories; see <xref linkend="git-replace(1)" />
for a more flexible and robust system to do the same thing.</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
info/exclude
</term>
<listitem>
<simpara>
        This file, by convention among Porcelains, stores the
        exclude pattern list. <emphasis>.gitignore</emphasis> is the per-directory
        ignore file.  <emphasis>git status</emphasis>, <emphasis>git add</emphasis>, <emphasis>git rm</emphasis> and
        <emphasis>git clean</emphasis> look at it but the core Git commands do not look
        at it.  See also: <xref linkend="gitignore(5)" />.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
info/attributes
</term>
<listitem>
<simpara>
        Defines which attributes to assign to a path, similar to per-directory
        <emphasis>.gitattributes</emphasis> files.   See also: <xref linkend="gitattributes(5)" />.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
info/sparse-checkout
</term>
<listitem>
<simpara>
        This file stores sparse checkout patterns.
        See also: <xref linkend="git-read-tree(1)" />.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
remotes
</term>
<listitem>
<simpara>
        Stores shorthands for URL and default refnames for use
        when interacting with remote repositories via <emphasis>git fetch</emphasis>,
        <emphasis>git pull</emphasis> and <emphasis>git push</emphasis> commands.  See the REMOTES section
        in <xref linkend="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.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
logs
</term>
<listitem>
<simpara>
        Records of changes made to refs are stored in this directory.
        See <xref linkend="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.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
logs/refs/heads/<emphasis>name</emphasis>
</term>
<listitem>
<simpara>
        Records all changes made to the branch tip named <emphasis>name</emphasis>.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
logs/refs/tags/<emphasis>name</emphasis>
</term>
<listitem>
<simpara>
        Records all changes made to the tag named <emphasis>name</emphasis>.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
shallow
</term>
<listitem>
<simpara>
        This is similar to <emphasis>info/grafts</emphasis> but is internally used
        and maintained by shallow clone mechanism.  See <emphasis>--depth</emphasis>
        option to <xref linkend="git-clone(1)" /> and <xref linkend="git-fetch(1)" />. This
        file is ignored if $GIT_COMMON_DIR is set and
        "$GIT_COMMON_DIR/shallow" will be used instead.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
commondir
</term>
<listitem>
<simpara>
        If this file exists, $GIT_COMMON_DIR (see <xref linkend="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".
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
modules
</term>
<listitem>
<simpara>
        Contains the git-repositories of the submodules.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
worktrees
</term>
<listitem>
<simpara>
        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.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
worktrees/&lt;id&gt;/gitdir
</term>
<listitem>
<simpara>
        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.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
worktrees/&lt;id&gt;/locked
</term>
<listitem>
<simpara>
        If this file exists, the linked working tree may be on a
        portable device and not available. The presence of this file
        prevents <emphasis>worktrees/&lt;id&gt;</emphasis> from being pruned either automatically
        or manually by <emphasis>git worktree prune</emphasis>. The file may contain a string
        explaining why the repository is locked.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>
worktrees/&lt;id&gt;/config.worktree
</term>
<listitem>
<simpara>
        Working directory specific configuration file.
</simpara>
</listitem>
</varlistentry>
</variablelist>
</simplesect>
<simplesect id="gitrepository-layout(5)__git_repository_format_versions">
<title>Git Repository Format Versions</title>
<simpara>Every git repository is marked with a numeric version in the
<emphasis>core.repositoryformatversion</emphasis> key of its <emphasis>config</emphasis> 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.</simpara>
<simpara>Because of this rule, version bumps should be kept to an absolute
minimum. Instead, we generally prefer these strategies:</simpara>
<itemizedlist>
<listitem>
<simpara>
bumping format version numbers of individual data files (e.g.,
    index, packfiles, etc). This restricts the incompatibilities only to
    those files.
</simpara>
</listitem>
<listitem>
<simpara>
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).
</simpara>
</listitem>
</itemizedlist>
<simpara>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.</simpara>
<simpara>Note that this applies only to accessing the repository's disk contents
directly. An older client which understands only format <emphasis>0</emphasis> may still
connect via <emphasis>git://</emphasis> to a repository using format <emphasis>1</emphasis>, as long as the
server process understands format <emphasis>1</emphasis>.</simpara>
<simpara>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.</simpara>
<simpara>The currently defined format versions are:</simpara>
<section id="gitrepository-layout(5)__version_emphasis_0_emphasis">
<title>Version <emphasis>0</emphasis></title>
<simpara>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.</simpara>
</section>
<section id="gitrepository-layout(5)__version_emphasis_1_emphasis">
<title>Version <emphasis>1</emphasis></title>
<simpara>This format is identical to version <emphasis>0</emphasis>, with the following exceptions:</simpara>
<orderedlist numeration="arabic">
<listitem>
<simpara>
When reading the <emphasis>core.repositoryformatversion</emphasis> variable, a git
     implementation which supports version 1 MUST also read any
     configuration keys found in the <emphasis>extensions</emphasis> section of the
     configuration file.
</simpara>
</listitem>
<listitem>
<simpara>
If a version-1 repository specifies any <emphasis>extensions.*</emphasis> 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.
</simpara>
</listitem>
</orderedlist>
<simpara>Note that if no extensions are specified in the config file, then
<emphasis>core.repositoryformatversion</emphasis> SHOULD be set to <emphasis>0</emphasis> (setting it to <emphasis>1</emphasis>
provides no benefit, and makes the repository incompatible with older
implementations of git).</simpara>
<simpara>This document will serve as the master list for extensions. Any
implementation wishing to define a new extension should make a note of
it here, in order to claim the name.</simpara>
<simpara>The defined extensions are:</simpara>
<section id="gitrepository-layout(5)__emphasis_noop_emphasis">
<title><emphasis>noop</emphasis></title>
<simpara>This extension does not change git's behavior at all. It is useful only
for testing format-1 compatibility.</simpara>
</section>
<section id="gitrepository-layout(5)__emphasis_preciousobjects_emphasis">
<title><emphasis>preciousObjects</emphasis></title>
<simpara>When the config key <emphasis>extensions.preciousObjects</emphasis> is set to <emphasis>true</emphasis>,
objects in the repository MUST NOT be deleted (e.g., by <emphasis>git-prune</emphasis> or
<emphasis>git repack -d</emphasis>).</simpara>
</section>
<section id="gitrepository-layout(5)__emphasis_partialclone_emphasis">
<title><emphasis>partialClone</emphasis></title>
<simpara>When the config key <emphasis>extensions.partialClone</emphasis> is set, it indicates
that the repo was created with a partial clone (or later performed
a partial fetch) and that the remote may have omitted sending
certain unwanted objects.  Such a remote is called a "promisor remote"
and it promises that all such omitted objects can be fetched from it
in the future.</simpara>
<simpara>The value of this key is the name of the promisor remote.</simpara>
</section>
<section id="gitrepository-layout(5)__emphasis_worktreeconfig_emphasis">
<title><emphasis>worktreeConfig</emphasis></title>
<simpara>If set, by default "git config" reads from both "config" and
"config.worktree" files from GIT_DIR in that order. In
multiple working directory mode, "config" file is shared while
"config.worktree" is per-working directory (i.e., it's in
GIT_COMMON_DIR/worktrees/&lt;id&gt;/config.worktree)</simpara>
</section>
<section id="gitrepository-layout(5)__emphasis_refstorage_emphasis">
<title><emphasis>refStorage</emphasis></title>
<simpara>Specifies the file format for the ref database. The valid values are
<emphasis>files</emphasis> (loose references with a packed-refs file) and <emphasis>reftable</emphasis> (see
Documentation/technical/reftable.txt).</simpara>
</section>
</section>
</simplesect>
<simplesect id="gitrepository-layout(5)__see_also">
<title>SEE ALSO</title>
<simpara><xref linkend="git-init(1)" />,
<xref linkend="git-clone(1)" />,
<xref linkend="git-fetch(1)" />,
<xref linkend="git-pack-refs(1)" />,
<xref linkend="git-gc(1)" />,
<xref linkend="git-checkout(1)" />,
<xref linkend="gitglossary(7)" />,
<ulink url="https://www.kernel.org/pub/software/scm/git/docs/user-manual.html"><citetitle>The Git User's Manual</citetitle></ulink></simpara>
</simplesect>
<simplesect id="gitrepository-layout(5)__git">
<title>GIT</title>
<simpara>Part of the <xref linkend="git(1)" /> suite</simpara>
</simplesect>
</sect2>
