git/Documentation/git-clone.txt
Junio C Hamano fb1d6dabce clone: --dissociate option to mark that reference is only temporary
While use of the --reference option to borrow objects from an
existing local repository of the same project is an effective way to
reduce traffic when cloning a project over the network, it makes the
resulting "borrowing" repository dependent on the "borrowed"
repository.  After running

	git clone --reference=P $URL Q

the resulting repository Q will be broken if the borrowed repository
P disappears.

The way to allow the borrowed repository to be removed is to repack
the borrowing repository (i.e. run "git repack -a -d" in Q); while
power users may know it very well, it is not easily discoverable.

Teach a new "--dissociate" option to "git clone" to run this
repacking for the user.

Helped-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-15 14:34:45 -07:00

276 lines
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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>]
[--dissociate] [--separate-git-dir <git dir>]
[--depth <depth>] [--[no-]single-branch]
[--recursive | --recurse-submodules] [--] <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 is untrue when "--single-branch"
is given; see below).
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.
+
If the repository is specified as a local path (e.g., `/path/to/repo`),
this is the default, and --local is essentially a no-op. If the
repository is specified as a URL, then this flag is ignored (and we
never use the local optimizations). Specifying `--no-local` will
override the default when `/path/to/repo` is given, using the regular
Git transport instead.
--no-hardlinks::
Force the cloning process from a repository on a local
filesystem to copy the files under the `.git/objects`
directory instead of using hardlinks. This may be desirable
if you are trying to make a back-up of your repository.
--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, and also the
`--dissociate` option.
--dissociate::
Borrow the objects from reference repositories specified
with the `--reference` options only to reduce network
transfer and stop borrowing from them after a clone is made
by making necessary local copies of borrowed objects.
--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 source repository. This implies `--bare`.
Compared to `--bare`, `--mirror` not only maps local branches of the
source to local branches of the target, it maps all refs (including
remote-tracking branches, notes etc.) and sets up a refspec configuration such
that all these refs are overwritten by a `git remote update` in the
target repository.
--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.
`--branch` can also take tags and detaches the HEAD at that commit
in the resulting repository.
--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].)
--config <key>=<value>::
-c <key>=<value>::
Set a configuration variable in the newly-created repository;
this takes effect immediately after the repository is
initialized, but before the remote history is fetched or any
files checked out. The key is in the same format as expected by
linkgit:git-config[1] (e.g., `core.eol=true`). If multiple
values are given for the same key, each value will be written to
the config file. This makes it safe, for example, to add
additional fetch refspecs to the origin remote.
--depth <depth>::
Create a 'shallow' clone with a history truncated to the
specified number of revisions.
--[no-]single-branch::
Clone only the history leading to the tip of a single branch,
either specified by the `--branch` option or the primary
branch remote's `HEAD` points at. When creating a shallow
clone with the `--depth` option, this is the default, unless
`--no-single-branch` is given to fetch the histories near the
tips of all branches.
Further fetches into the resulting repository will only update the
remote-tracking branch for the branch this option was used for the
initial cloning. If the HEAD at the remote did not point at any
branch when `--single-branch` clone was made, no remote-tracking
branch is created.
--recursive::
--recurse-submodules::
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)
--separate-git-dir=<git dir>::
Instead of placing the cloned repository where it is supposed
to be, place the cloned repository at the specified directory,
then make a filesystem-agnostic Git symbolic link to there.
The result is Git repository can be separated from working
tree.
<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.git my-linux
$ cd my-linux
$ 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 /git/linux.git \
git://git.kernel.org/pub/scm/.../linux.git \
my-linux
$ cd my-linux
------------
* Create a bare repository to publish your changes to the public:
+
------------
$ git clone --bare -l /home/proj/.git /pub/scm/proj.git
------------
GIT
---
Part of the linkgit:git[1] suite