git-clone详解

NAME

git-clone - Clone a repository into a new directory

SYNOPSIS

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>*] single-branch] [--no-tags]
          [--recurse-submodules[=*<pathspec>*]] shallow-submodules]
          remote-submodules] [--jobs*<n>*] [--sparse] reject-shallow]
          [--filter=*<filter-spec>*] [--also-filter-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 --remotes

), 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

-l

--local

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.

If the repository’s

$GIT_DIR/objects

has symbolic links or is a symbolic link, the clone will fail. This is a security measure to prevent the unintentional copying of files by dereferencing the symbolic links.

NOTE: this operation can race with concurrent modification to the source repository, similar to running

cp -r src dst

while modifying

src

.

--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.

-s

--shared

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 maintenance run --auto

. (See git-maintenance(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

--local

option in a repository cloned with

--shared

will copy objects from the source repository into a pack in the cloned repository, removing the disk space savings of

clone --shared

. It is safe, however, to run

git gc

, which uses the

--local

option by default.

If you want to break the dependency of a repository cloned with

--shared

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

[

-if-able

] <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. When using the

--reference-if-able

, a non existing directory is skipped with a warning instead of aborting the clone.

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. This option can also be used when cloning locally from a repository that already borrows objects from another repository—​the new repository will borrow objects from the same repository, and this option can be used to stop the borrowing.

-q

--quiet

Operate quietly. Progress is not reported to the standard error stream.

-v

--verbose

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

--quiet

is specified. This flag forces progress status even if the standard error stream is not directed to a terminal.

--server-option=

<option>

Transmit the given string to the server when communicating using protocol version 2. The given string must not contain a NUL or LF character. The server’s handling of server options, including unknown ones, is server-specific. When multiple

--server-option=

<option> are given, they are all sent to the other side in the order listed on the command line.

-n

--no-checkout

No checkout of HEAD is performed after the clone is complete.

--

[

no-

]

reject-shallow

Fail if the source repository is a shallow repository. The

clone.rejectShallow

configuration variable can be used to specify the default.

--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

--no-checkout

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.

--sparse

Employ a sparse-checkout, with only files in the toplevel directory initially being present. The git-sparse-checkout(1) command can be used to grow the working directory as needed.

--filter=

<filter-spec>

Use the partial clone feature and request that the server sends a subset of reachable objects according to a given object filter. When using

--filter

, the supplied <filter-spec> is used for the partial clone filter. For example,

--filter=blob:none

will filter out all blobs (file contents) until needed by Git. Also,

--filter=blob:limit=

<size> will filter out all blobs of size at least <size>. For more details on filter specifications, see the

--filter

option in git-rev-list(1).

--also-filter-submodules

Also apply the partial clone filter to any submodules in the repository. Requires

--filter

and

--recurse-submodules

. This can be turned on by default by setting the

clone.filterSubmodules

config option.

--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.

-o

<name>

--origin

<name>

Instead of using the remote name

origin

to keep track of the upstream repository, use <name>. Overrides

clone.defaultRemoteName

from the config.

-b

<name>

--branch

<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.

-u

<upload-pack>

--upload-pack

<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 git-init(1).)

-c

<key>

=

<value>

--config

<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 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.

Due to limitations of the current implementation, some configuration variables do not take effect until after the initial fetch and checkout. Configuration variables known to not take effect are:

remote.

<name>

.mirror

and

remote.

<name>

.tagOpt

. Use the corresponding

--mirror

and

--no-tags

options instead.

--depth

<depth>

Create a shallow clone with a history truncated to the specified number of commits. Implies

--single-branch

unless

--no-single-branch

is given to fetch the histories near the tips of all branches. If you want to clone submodules shallowly, also pass

--shallow-submodules

.

--shallow-since=

<date>

Create a shallow clone with a history after the specified time.

--shallow-exclude=

<revision>

Create a shallow clone with a history, excluding commits reachable from a specified remote branch or tag. This option can be specified multiple times.

--

[

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. 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.

--no-tags

Don’t clone any tags, and set

remote.<remote>.tagOpt=--no-tags

in the config, ensuring that future

git pull

and

git fetch

operations won’t follow any tags. Subsequent explicit tag fetches will still work, (see git-fetch(1)).

Can be used in conjunction with

--single-branch

to clone and maintain a branch with no references other than a single cloned branch. This is useful e.g. to maintain minimal clones of the default branch of some repository for search indexing.

--recurse-submodules

[

=

<pathspec>]

After the clone is created, initialize and clone submodules within based on the provided <pathspec>. If no =<pathspec> is provided, all submodules are initialized and cloned. This option can be given multiple times for pathspecs consisting of multiple entries. The resulting clone has

submodule.active

set to the provided pathspec, or "." (meaning all submodules) if no pathspec is provided.

Submodules are initialized and cloned using their default settings. This is equivalent to running

git submodule update --init --recursive <pathspec>

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)

--

[

no-

]

shallow-submodules

All submodules which are cloned will be shallow with a depth of 1.

--

[

no-

]

remote-submodules

All submodules which are cloned will use the status of the submodule’s remote-tracking branch to update the submodule, rather than the superproject’s recorded SHA-1. Equivalent to passing

--remote

to

git submodule update

.

--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.

--ref-format=

<ref-format>

Specify the given ref storage format for the repository. The valid values are:

• files for loose files with packed-refs. This is the default.
• reftable for the reftable format. This format is experimental and its internals are subject to change.

-j

<n>

--jobs

<n>

The number of submodules fetched at the same time. Defaults to the

submodule.fetchJobs

option.

<repository>

<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.

--bundle-uri=

<uri>

Before fetching from the remote, fetch a bundle from the given <uri> and unbundle the data into the local repository. The refs in the bundle will be stored under the hidden

refs/bundle/*

namespace. This option is incompatible with

--depth

,

--shallow-since

, and

--shallow-exclude

.

GIT URLS

In general, URLs contain information about the transport protocol, the address of the remote server, and the path to the repository. Depending on the transport protocol, some of this information may be absent.

Git supports ssh, git, http, and https protocols (in addition, ftp and ftps can be used for fetching, but this is inefficient and deprecated; do not use them).

The native transport (i.e. git:// URL) does no authentication and should be used with caution on unsecured networks.

The following syntaxes may be used with them:

• ssh://[<user>@]<host>[:<port>]/<path-to-git-repo>
• git://<host>[:<port>]/<path-to-git-repo>
• http[s]://<host>[:<port>]/<path-to-git-repo>
• ftp[s]://<host>[:<port>]/<path-to-git-repo>

An alternative scp-like syntax may also be used with the ssh protocol:

• [<user>@]<host>:/<path-to-git-repo>

This syntax is only recognized if there are no slashes before the first colon. This helps differentiate a local path that contains a colon. For example the local path

foo:bar

could be specified as an absolute path or

./foo:bar

to avoid being misinterpreted as an ssh url.

The ssh and git protocols additionally support

~

<username> expansion:

• ssh://[<user>@]<host>[:<port>]/~<user>/<path-to-git-repo>
• git://<host>[:<port>]/~<user>/<path-to-git-repo>
• [<user>@]<host>:~<user>/<path-to-git-repo>

For local repositories, also supported by Git natively, the following syntaxes may be used:

• /path/to/repo.git/
• file:///path/to/repo.git/

These two syntaxes are mostly equivalent, except the former implies

--local

option.

git clone

,

git fetch

and

git pull

, but not

git push

, will also accept a suitable bundle file. See git-bundle(1).

When Git doesn’t know how to handle a certain transport protocol, it attempts to use the

remote-

<transport> remote helper, if one exists. To explicitly request a remote helper, the following syntax may be used:

• <transport>::

where

        [url "*<actual-url-base>*"]
                insteadOf = *<other-url-base>*

        [url "git://git.host.xz/"]
                insteadOf = host.xz:/path/to/
                insteadOf = work:

        [url "*<actual-url-base>*"]
                pushInsteadOf = *<other-url-base>*

        [url "ssh://example.org/"]
                pushInsteadOf = git://example.org/

init.templateDir

init.defaultBranch

clone.defaultRemoteName

origin

--origin

clone.rejectShallow

--reject-shallow

clone.filterSubmodules

--filter

--recurse-submodules