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-rw-r--r--Documentation/gitrepository-layout.txt119
1 files changed, 74 insertions, 45 deletions
diff --git a/Documentation/gitrepository-layout.txt b/Documentation/gitrepository-layout.txt
index 1befca98d4..79653f3134 100644
--- a/Documentation/gitrepository-layout.txt
+++ b/Documentation/gitrepository-layout.txt
@@ -12,43 +12,48 @@ $GIT_DIR/*
DESCRIPTION
-----------
-You may find these things in your git repository (`.git`
-directory for a repository associated with your working tree, or
-`<project>.git` directory for a public 'bare' repository. It is
-also possible to have a working tree where `.git` is a plain
-ascii file containing `gitdir: <path>`, i.e. the path to the
-real git repository).
+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 couple of ways to violate
- it.
+ found in it), but there are a few ways to violate it.
+
-. You could populate the repository by running a commit walker
-without `-a` option. Depending on which options are given, you
-could have only commit objects without associated blobs and
-trees this way, for example. A repository with this kind of
-incomplete object store is not suitable to be published to the
-outside world but sometimes useful for private repository.
-. You also could have an incomplete but locally usable repository
-by cloning shallowly. See linkgit:git-clone[1].
-. You can be using `objects/info/alternates` mechanism, or
-`$GIT_ALTERNATE_OBJECT_DIRECTORIES` mechanism to 'borrow'
+. 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 right object stores
-it borrows from.
+`objects/info/alternates` points at the object stores it
+borrows from.
objects/[0-9a-f][0-9a-f]::
- Traditionally, each object is stored in its own file.
- They are split into 256 subdirectories using the first
- two letters from its object name to keep the number of
- directory entries `objects` directory itself needs to
- hold. Objects found here are often called 'unpacked'
- (or 'loose') objects.
+ 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,
@@ -64,7 +69,7 @@ objects/info/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
+ published for dumb transports. 'git repack' does this
by default.
objects/info/alternates::
@@ -85,7 +90,7 @@ objects/info/http-alternates::
refs::
References are stored in subdirectories of this
- directory. The 'git-prune' command knows to keep
+ directory. The 'git prune' command knows to preserve
objects reachable from refs found in this directory and
its subdirectories.
@@ -100,6 +105,12 @@ 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
@@ -109,7 +120,7 @@ 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
+ (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
@@ -119,21 +130,22 @@ HEAD::
+
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', and almost all commands work
-identically as normal. See linkgit:git-checkout[1] for
-details.
+is often called 'detached HEAD.' See linkgit:git-checkout[1]
+for details.
branches::
A slightly deprecated way to store shorthands to be used
- to specify URL to 'git-fetch', 'git-pull' and 'git-push'
- commands is to store a file in `branches/<name>` and
- give 'name' to these commands in place of 'repository'
- argument.
+ 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.
hooks::
- Hooks are customization scripts used by various git
+ 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
+ '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
@@ -143,6 +155,10 @@ 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.
@@ -151,10 +167,10 @@ 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
+ 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
+ 'git-receive-pack' command when you 'git push' into the
repository.
info/grafts::
@@ -164,18 +180,28 @@ info/grafts::
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
+ 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 to be used to give URL and default
- refnames to interact with remote repository to
- 'git-fetch', 'git-pull' and 'git-push' commands.
+ 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.
logs::
Records of changes made to refs are stored in this
@@ -193,6 +219,9 @@ shallow::
and maintained by shallow clone mechanism. See `--depth`
option to linkgit:git-clone[1] and linkgit:git-fetch[1].
+modules::
+ Contains the git-repositories of the submodules.
+
SEE ALSO
--------
linkgit:git-init[1],