git-submodule.txt

git-submodule(1)
================

NAME
----
git-submodule - Initialize, update or inspect submodules


SYNOPSIS
--------
[verse]
'git submodule' [--quiet] add [-b branch]
	      [--reference <repository>] [--] <repository> <path>
'git submodule' [--quiet] status [--cached] [--] [<path>...]
'git submodule' [--quiet] init [--] [<path>...]
'git submodule' [--quiet] update [--init] [-N|--no-fetch] [--rebase]
	      [--reference <repository>] [--merge] [--] [<path>...]
'git submodule' [--quiet] summary [--cached] [--summary-limit <n>] [commit] [--] [<path>...]
'git submodule' [--quiet] foreach <command>
'git submodule' [--quiet] sync [--] [<path>...]


DESCRIPTION
-----------
Submodules allow foreign repositories to be embedded within
a dedicated subdirectory of the source tree, always pointed
at a particular commit.

They are not to be confused with remotes, which are meant mainly
for branches of the same project; submodules are meant for
different projects you would like to make part of your source tree,
while the history of the two projects still stays completely
independent and you cannot modify the contents of the submodule
from within the main project.
If you want to merge the project histories and want to treat the
aggregated whole as a single project from then on, you may want to
add a remote for the other project and use the 'subtree' merge strategy,
instead of treating the other project as a submodule. Directories
that come from both projects can be cloned and checked out as a whole
if you choose to go that route.

Submodules are composed from a so-called `gitlink` tree entry
in the main repository that refers to a particular commit object
within the inner repository that is completely separate.
A record in the `.gitmodules` file at the root of the source
tree assigns a logical name to the submodule and describes
the default URL the submodule shall be cloned from.
The logical name can be used for overriding this URL within your
local repository configuration (see 'submodule init').

This command will manage the tree entries and contents of the
gitmodules file for you, as well as inspect the status of your
submodules and update them.
When adding a new submodule to the tree, the 'add' subcommand
is to be used.  However, when pulling a tree containing submodules,
these will not be checked out by default;
the 'init' and 'update' subcommands will maintain submodules
checked out and at appropriate revision in your working tree.
You can briefly inspect the up-to-date status of your submodules
using the 'status' subcommand and get a detailed overview of the
difference between the index and checkouts using the 'summary'
subcommand.


COMMANDS
--------
add::
	Add the given repository as a submodule at the given path
	to the changeset to be committed next to the current
	project: the current project is termed the "superproject".
+
This requires two arguments: <repository> and <path>.
+
<repository> is the URL of the new submodule's origin repository.
This may be either an absolute URL, or (if it begins with ./
or ../), the location relative to the superproject's origin
repository.
+
<path> is the relative location for the cloned submodule to
exist in the superproject. If <path> does not exist, then the
submodule is created by cloning from the named URL. If <path> does
exist and is already a valid git repository, then this is added
to the changeset without cloning. This second form is provided
to ease creating a new submodule from scratch, and presumes
the user will later push the submodule to the given URL.
+
In either case, the given URL is recorded into .gitmodules for
use by subsequent users cloning the superproject. If the URL is
given relative to the superproject's repository, the presumption
is the superproject and submodule repositories will be kept
together in the same relative location, and only the
superproject's URL needs to be provided: git-submodule will correctly
locate the submodule using the relative URL in .gitmodules.

status::
	Show the status of the submodules. This will print the SHA-1 of the
	currently checked out commit for each submodule, along with the
	submodule path and the output of 'git-describe' for the
	SHA-1. Each SHA-1 will be prefixed with `-` if the submodule is not
	initialized and `+` if the currently checked out submodule commit
	does not match the SHA-1 found in the index of the containing
	repository. This command is the default command for 'git-submodule'.

init::
	Initialize the submodules, i.e. register each submodule name
	and url found in .gitmodules into .git/config.
	The key used in .git/config is `submodule.$name.url`.
	This command does not alter existing information in .git/config.
	You can then customize the submodule clone URLs in .git/config
	for your local setup and proceed to 'git submodule update';
	you can also just use 'git submodule update --init' without
	the explicit 'init' step if you do not intend to customize
	any submodule locations.

update::
	Update the registered submodules, i.e. clone missing submodules and
	checkout the commit specified in the index of the containing repository.
	This will make the submodules HEAD be detached unless '--rebase' or
	'--merge' is specified or the key `submodule.$name.update` is set to
	`rebase` or `merge`.
+
If the submodule is not yet initialized, and you just want to use the
setting as stored in .gitmodules, you can automatically initialize the
submodule with the --init option.

summary::
	Show commit summary between the given commit (defaults to HEAD) and
	working tree/index. For a submodule in question, a series of commits
	in the submodule between the given super project commit and the
	index or working tree (switched by --cached) are shown.

foreach::
	Evaluates an arbitrary shell command in each checked out submodule.
	The command has access to the variables $name, $path and $sha1:
	$name is the name of the relevant submodule section in .gitmodules,
	$path is the name of the submodule directory relative to the
	superproject, and $sha1 is the commit as recorded in the superproject.
	Any submodules defined in the superproject but not checked out are
	ignored by this command. Unless given --quiet, foreach prints the name
	of each submodule before evaluating the command.
	A non-zero return from the command in any submodule causes
	the processing to terminate. This can be overridden by adding '|| :'
	to the end of the command.
+
As an example, +git submodule foreach \'echo $path {backtick}git
rev-parse HEAD{backtick}'+ will show the path and currently checked out
commit for each submodule.

sync::
	Synchronizes submodules' remote URL configuration setting
	to the value specified in .gitmodules.  This is useful when
	submodule URLs change upstream and you need to update your local
	repositories accordingly.
+
"git submodule sync" synchronizes all submodules while
"git submodule sync -- A" synchronizes submodule "A" only.

OPTIONS
-------
-q::
--quiet::
	Only print error messages.

-b::
--branch::
	Branch of repository to add as submodule.

--cached::
	This option is only valid for status and summary commands.  These
	commands typically use the commit found in the submodule HEAD, but
	with this option, the commit stored in the index is used instead.

-n::
--summary-limit::
	This option is only valid for the summary command.
	Limit the summary size (number of commits shown in total).
	Giving 0 will disable the summary; a negative number means unlimited
	(the default). This limit only applies to modified submodules. The
	size is always limited to 1 for added/deleted/typechanged submodules.

-N::
--no-fetch::
	This option is only valid for the update command.
	Don't fetch new objects from the remote site.

--merge::
	This option is only valid for the update command.
	Merge the commit recorded in the superproject into the current branch
	of the submodule. If this option is given, the submodule's HEAD will
	not be detached. If a merge failure prevents this process, you will
	have to resolve the resulting conflicts within the submodule with the
	usual conflict resolution tools.
	If the key `submodule.$name.update` is set to `merge`, this option is
	implicit.

--rebase::
	This option is only valid for the update command.
	Rebase the current branch onto the commit recorded in the
	superproject. If this option is given, the submodule's HEAD will not
	be detached. If a a merge failure prevents this process, you will have
	to resolve these failures with linkgit:git-rebase[1].
	If the key `submodule.$name.update` is set to `rebase`, this option is
	implicit.

--reference <repository>::
	This option is only valid for add and update commands.  These
	commands sometimes need to clone a remote repository. In this case,
	this option will be passed to the linkgit:git-clone[1] command.
+
*NOTE*: Do *not* use this option unless you have read the note
for linkgit:git-clone[1]'s --reference and --shared options carefully.

<path>...::
	Paths to submodule(s). When specified this will restrict the command
	to only operate on the submodules found at the specified paths.
	(This argument is required with add).

FILES
-----
When initializing submodules, a .gitmodules file in the top-level directory
of the containing repository is used to find the url of each submodule.
This file should be formatted in the same way as `$GIT_DIR/config`. The key
to each submodule url is "submodule.$name.url".  See linkgit:gitmodules[5]
for details.


AUTHOR
------
Written by Lars Hjemli <hjemli@gmail.com>

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