Documentation/gitrepository-layout.txt

   1 gitrepository-layout(5)
   2 =======================
   3
   4 NAME
   5 ----
   6 gitrepository-layout - Git Repository Layout
   7
   8 SYNOPSIS
   9 --------
  10 $GIT_DIR/*
  11
  12 DESCRIPTION
  13 -----------
  14
  15 A Git repository comes in two different flavours:
  16
  17  * a `.git` directory at the root of the working tree;
  18
  19  * a `<project>.git` directory that is a 'bare' repository
  20    (i.e. without its own working tree), that is typically used for
  21    exchanging histories with others by pushing into it and fetching
  22    from it.
  23
  24 *Note*: Also you can have a plain text file `.git` at the root of
  25 your working tree, containing `gitdir: <path>` to point at the real
  26 directory that has the repository.  This mechanism is often used for
  27 a working tree of a submodule checkout, to allow you in the
  28 containing superproject to `git checkout` a branch that does not
  29 have the submodule.  The `checkout` has to remove the entire
  30 submodule working tree, without losing the submodule repository.
  31
  32 These things may exist in a Git repository.
  33
  34 objects::
  35         Object store associated with this repository.  Usually
  36         an object store is self sufficient (i.e. all the objects
  37         that are referred to by an object found in it are also
  38         found in it), but there are a few ways to violate it.
  39 +
  40 . You could have an incomplete but locally usable repository
  41 by creating a shallow clone.  See linkgit:git-clone[1].
  42 . You could be using the `objects/info/alternates` or
  43 `$GIT_ALTERNATE_OBJECT_DIRECTORIES` mechanisms to 'borrow'
  44 objects from other object stores.  A repository with this kind
  45 of incomplete object store is not suitable to be published for
  46 use with dumb transports but otherwise is OK as long as
  47 `objects/info/alternates` points at the object stores it
  48 borrows from.
  49
  50 objects/[0-9a-f][0-9a-f]::
  51         A newly created object is stored in its own file.
  52         The objects are splayed over 256 subdirectories using
  53         the first two characters of the sha1 object name to
  54         keep the number of directory entries in `objects`
  55         itself to a manageable number. Objects found
  56         here are often called 'unpacked' (or 'loose') objects.
  57
  58 objects/pack::
  59         Packs (files that store many object in compressed form,
  60         along with index files to allow them to be randomly
  61         accessed) are found in this directory.
  62
  63 objects/info::
  64         Additional information about the object store is
  65         recorded in this directory.
  66
  67 objects/info/packs::
  68         This file is to help dumb transports discover what packs
  69         are available in this object store.  Whenever a pack is
  70         added or removed, `git update-server-info` should be run
  71         to keep this file up-to-date if the repository is
  72         published for dumb transports.  'git repack' does this
  73         by default.
  74
  75 objects/info/alternates::
  76         This file records paths to alternate object stores that
  77         this object store borrows objects from, one pathname per
  78         line. Note that not only native Git tools use it locally,
  79         but the HTTP fetcher also tries to use it remotely; this
  80         will usually work if you have relative paths (relative
  81         to the object database, not to the repository!) in your
  82         alternates file, but it will not work if you use absolute
  83         paths unless the absolute path in filesystem and web URL
  84         is the same. See also 'objects/info/http-alternates'.
  85
  86 objects/info/http-alternates::
  87         This file records URLs to alternate object stores that
  88         this object store borrows objects from, to be used when
  89         the repository is fetched over HTTP.
  90
  91 refs::
  92         References are stored in subdirectories of this
  93         directory.  The 'git prune' command knows to preserve
  94         objects reachable from refs found in this directory and
  95         its subdirectories.
  96
  97 refs/heads/`name`::
  98         records tip-of-the-tree commit objects of branch `name`
  99
 100 refs/tags/`name`::
 101         records any object name (not necessarily a commit
 102         object, or a tag object that points at a commit object).
 103
 104 refs/remotes/`name`::
 105         records tip-of-the-tree commit objects of branches copied
 106         from a remote repository.
 107
 108 refs/replace/`<obj-sha1>`::
 109         records the SHA-1 of the object that replaces `<obj-sha1>`.
 110         This is similar to info/grafts and is internally used and
 111         maintained by linkgit:git-replace[1]. Such refs can be exchanged
 112         between repositories while grafts are not.
 113
 114 packed-refs::
 115         records the same information as refs/heads/, refs/tags/,
 116         and friends record in a more efficient way.  See
 117         linkgit:git-pack-refs[1].
 118
 119 HEAD::
 120         A symref (see glossary) to the `refs/heads/` namespace
 121         describing the currently active branch.  It does not mean
 122         much if the repository is not associated with any working tree
 123         (i.e. a 'bare' repository), but a valid Git repository
 124         *must* have the HEAD file; some porcelains may use it to
 125         guess the designated "default" branch of the repository
 126         (usually 'master').  It is legal if the named branch
 127         'name' does not (yet) exist.  In some legacy setups, it is
 128         a symbolic link instead of a symref that points at the current
 129         branch.
 130 +
 131 HEAD can also record a specific commit directly, instead of
 132 being a symref to point at the current branch.  Such a state
 133 is often called 'detached HEAD.'  See linkgit:git-checkout[1]
 134 for details.
 135
 136 branches::
 137         A slightly deprecated way to store shorthands to be used
 138         to specify a URL to 'git fetch', 'git pull' and 'git push'.
 139         A file can be stored as `branches/<name>` and then
 140         'name' can be given to these commands in place of
 141         'repository' argument.  See the REMOTES section in
 142         linkgit:git-fetch[1] for details.  This mechanism is legacy
 143         and not likely to be found in modern repositories.
 144
 145 hooks::
 146         Hooks are customization scripts used by various Git
 147         commands.  A handful of sample hooks are installed when
 148         'git init' is run, but all of them are disabled by
 149         default.  To enable, the `.sample` suffix has to be
 150         removed from the filename by renaming.
 151         Read linkgit:githooks[5] for more details about
 152         each hook.
 153
 154 index::
 155         The current index file for the repository.  It is
 156         usually not found in a bare repository.
 157
 158 info::
 159         Additional information about the repository is recorded
 160         in this directory.
 161
 162 info/refs::
 163         This file helps dumb transports discover what refs are
 164         available in this repository.  If the repository is
 165         published for dumb transports, this file should be
 166         regenerated by 'git update-server-info' every time a tag
 167         or branch is created or modified.  This is normally done
 168         from the `hooks/update` hook, which is run by the
 169         'git-receive-pack' command when you 'git push' into the
 170         repository.
 171
 172 info/grafts::
 173         This file records fake commit ancestry information, to
 174         pretend the set of parents a commit has is different
 175         from how the commit was actually created.  One record
 176         per line describes a commit and its fake parents by
 177         listing their 40-byte hexadecimal object names separated
 178         by a space and terminated by a newline.
 179 +
 180 Note that the grafts mechanism is outdated and can lead to problems
 181 transferring objects between repositories; see linkgit:git-replace[1]
 182 for a more flexible and robust system to do the same thing.
 183
 184 info/exclude::
 185         This file, by convention among Porcelains, stores the
 186         exclude pattern list. `.gitignore` is the per-directory
 187         ignore file.  'git status', 'git add', 'git rm' and
 188         'git clean' look at it but the core Git commands do not look
 189         at it.  See also: linkgit:gitignore[5].
 190
 191 info/sparse-checkout::
 192         This file stores sparse checkout patterns.
 193         See also: linkgit:git-read-tree[1].
 194
 195 remotes::
 196         Stores shorthands for URL and default refnames for use
 197         when interacting with remote repositories via 'git fetch',
 198         'git pull' and 'git push' commands.  See the REMOTES section
 199         in linkgit:git-fetch[1] for details.  This mechanism is legacy
 200         and not likely to be found in modern repositories.
 201
 202 logs::
 203         Records of changes made to refs are stored in this
 204         directory.  See linkgit:git-update-ref[1]
 205         for more information.
 206
 207 logs/refs/heads/`name`::
 208         Records all changes made to the branch tip named `name`.
 209
 210 logs/refs/tags/`name`::
 211         Records all changes made to the tag named `name`.
 212
 213 shallow::
 214         This is similar to `info/grafts` but is internally used
 215         and maintained by shallow clone mechanism.  See `--depth`
 216         option to linkgit:git-clone[1] and linkgit:git-fetch[1].
 217
 218 modules::
 219         Contains the git-repositories of the submodules.
 220
 221 SEE ALSO
 222 --------
 223 linkgit:git-init[1],
 224 linkgit:git-clone[1],
 225 linkgit:git-fetch[1],
 226 linkgit:git-pack-refs[1],
 227 linkgit:git-gc[1],
 228 linkgit:git-checkout[1],
 229 linkgit:gitglossary[7],
 230 link:user-manual.html[The Git User's Manual]
 231
 232 GIT
 233 ---
 234 Part of the linkgit:git[1] suite.