do not depend on signed integer overflow

[thirdparty/git.git] / Documentation / git-clone.txt

git-clone(1)
============

NAME
----
git-clone - Clone a repository into a new directory


SYNOPSIS
--------
[verse]
'git clone' [--template=<template_directory>]
	  [-l] [-s] [--no-hardlinks] [-q] [-n] [--bare] [--mirror]
	  [-o <name>] [-b <name>] [-u <upload-pack>] [--reference <repository>]
	  [--depth <depth>] [--recursive] [--] <repository> [<directory>]

DESCRIPTION
-----------

Clones a repository into a newly created directory, creates
remote-tracking branches for each branch in the cloned repository
(visible using `git branch -r`), and creates and checks out an
initial branch that is forked from the cloned repository's
currently active branch.

After the clone, a plain `git fetch` without arguments will update
all the remote-tracking branches, and a `git pull` without
arguments will in addition merge the remote master branch into the
current master branch, if any.

This default configuration is achieved by creating references to
the remote branch heads under `refs/remotes/origin` and
by initializing `remote.origin.url` and `remote.origin.fetch`
configuration variables.


OPTIONS
-------
--local::
-l::
	When the repository to clone from is on a local machine,
	this flag bypasses the normal "git aware" transport
	mechanism and clones the repository by making a copy of
	HEAD and everything under objects and refs directories.
	The files under `.git/objects/` directory are hardlinked
	to save space when possible.  This is now the default when
	the source repository is specified with `/path/to/repo`
	syntax, so it essentially is a no-op option.  To force
	copying instead of hardlinking (which may be desirable
	if you are trying to make a back-up of your repository),
	but still avoid the usual "git aware" transport
	mechanism, `--no-hardlinks` can be used.

--no-hardlinks::
	Optimize the cloning process from a repository on a
	local filesystem by copying files under `.git/objects`
	directory.

--shared::
-s::
	When the repository to clone is on the local machine,
	instead of using hard links, automatically setup
	`.git/objects/info/alternates` to share the objects
	with the source repository.  The resulting repository
	starts out without any object of its own.
+
*NOTE*: this is a possibly dangerous operation; do *not* use
it unless you understand what it does. If you clone your
repository using this option and then delete branches (or use any
other git command that makes any existing commit unreferenced) in the
source repository, some objects may become unreferenced (or dangling).
These objects may be removed by normal git operations (such as `git commit`)
which automatically call `git gc --auto`. (See linkgit:git-gc[1].)
If these objects are removed and were referenced by the cloned repository,
then the cloned repository will become corrupt.
+
Note that running `git repack` without the `-l` option in a repository
cloned with `-s` will copy objects from the source repository into a pack
in the cloned repository, removing the disk space savings of `clone -s`.
It is safe, however, to run `git gc`, which uses the `-l` option by
default.
+
If you want to break the dependency of a repository cloned with `-s` on
its source repository, you can simply run `git repack -a` to copy all
objects from the source repository into a pack in the cloned repository.

--reference <repository>::
	If the reference repository is on the local machine,
	automatically setup `.git/objects/info/alternates` to
	obtain objects from the reference repository.  Using
	an already existing repository as an alternate will
	require fewer objects to be copied from the repository
	being cloned, reducing network and local storage costs.
+
*NOTE*: see the NOTE for the `--shared` option.

--quiet::
-q::
	Operate quietly.  Progress is not reported to the standard
	error stream. This flag is also passed to the `rsync'
	command when given.

--verbose::
-v::
	Run verbosely. Does not affect the reporting of progress status
	to the standard error stream.

--progress::
	Progress status is reported on the standard error stream
	by default when it is attached to a terminal, unless -q
	is specified. This flag forces progress status even if the
	standard error stream is not directed to a terminal.

--no-checkout::
-n::
	No checkout of HEAD is performed after the clone is complete.

--bare::
	Make a 'bare' GIT repository.  That is, instead of
	creating `<directory>` and placing the administrative
	files in `<directory>/.git`, make the `<directory>`
	itself the `$GIT_DIR`. This obviously implies the `-n`
	because there is nowhere to check out the working tree.
	Also the branch heads at the remote are copied directly
	to corresponding local branch heads, without mapping
	them to `refs/remotes/origin/`.  When this option is
	used, neither remote-tracking branches nor the related
	configuration variables are created.

--mirror::
	Set up a mirror of the remote repository.  This implies `--bare`.

--origin <name>::
-o <name>::
	Instead of using the remote name `origin` to keep track
	of the upstream repository, use `<name>`.

--branch <name>::
-b <name>::
	Instead of pointing the newly created HEAD to the branch pointed
	to by the cloned repository's HEAD, point to `<name>` branch
	instead. In a non-bare repository, this is the branch that will
	be checked out.

--upload-pack <upload-pack>::
-u <upload-pack>::
	When given, and the repository to clone from is accessed
	via ssh, this specifies a non-default path for the command
	run on the other end.

--template=<template_directory>::
	Specify the directory from which templates will be used;
	(See the "TEMPLATE DIRECTORY" section of linkgit:git-init[1].)

--depth <depth>::
	Create a 'shallow' clone with a history truncated to the
	specified number of revisions.  A shallow repository has a
	number of limitations (you cannot clone or fetch from
	it, nor push from nor into it), but is adequate if you
	are only interested in the recent history of a large project
	with a long history, and would want to send in fixes
	as patches.

--recursive::
	After the clone is created, initialize all submodules within,
	using their default settings. This is equivalent to running
	`git submodule update --init --recursive` immediately after
	the clone is finished. This option is ignored if the cloned
	repository does not have a worktree/checkout (i.e. if any of
	`--no-checkout`/`-n`, `--bare`, or `--mirror` is given)

<repository>::
	The (possibly remote) repository to clone from.  See the
	<<URLS,URLS>> section below for more information on specifying
	repositories.

<directory>::
	The name of a new directory to clone into.  The "humanish"
	part of the source repository is used if no directory is
	explicitly given (`repo` for `/path/to/repo.git` and `foo`
	for `host.xz:foo/.git`).  Cloning into an existing directory
	is only allowed if the directory is empty.

:git-clone: 1
include::urls.txt[]

Examples
--------

* Clone from upstream:
+
------------
$ git clone git://git.kernel.org/pub/scm/.../linux-2.6 my2.6
$ cd my2.6
$ make
------------


* Make a local clone that borrows from the current directory, without checking things out:
+
------------
$ git clone -l -s -n . ../copy
$ cd ../copy
$ git show-branch
------------


* Clone from upstream while borrowing from an existing local directory:
+
------------
$ git clone --reference my2.6 \
	git://git.kernel.org/pub/scm/.../linux-2.7 \
	my2.7
$ cd my2.7
------------


* Create a bare repository to publish your changes to the public:
+
------------
$ git clone --bare -l /home/proj/.git /pub/scm/proj.git
------------


* Create a repository on the kernel.org machine that borrows from Linus:
+
------------
$ git clone --bare -l -s /pub/scm/.../torvalds/linux-2.6.git \
    /pub/scm/.../me/subsys-2.6.git
------------


Author
------
Written by Linus Torvalds <torvalds@osdl.org>


Documentation
--------------
Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.


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