git-fetch(1)

NAME#

git-fetch - Download objects and refs from another repository

SYNOPSIS#

git fetch\n [<options>] [<repository> [<refspec>...]]
\ngit fetch\n [<options>] <group>
\ngit fetch\n --multiple [<options>] [(<repository> | <group>)...]
\ngit fetch\n --all [<options>]

DESCRIPTION#

Fetch branches and/or tags (collectively, "refs") from one or more other repositories, along with the objects necessary to complete their histories. Remote-tracking branches are updated (see the description of <refspec> below for ways to control this behavior).

By default, any tag that points into the histories being fetched is also fetched; the effect is to fetch tags that point at branches that you are interested in. This default behavior can be changed by using the --tags or --no-tags options or by configuring remote.<name>.tagOpt. By using a refspec that fetches tags explicitly, you can fetch tags that do not point into branches you are interested in as well.

git fetch can fetch from either a single named repository or URL, or from several repositories at once if <group> is given and there is a remotes.<group> entry in the configuration file. (See git-config(1)).

When no remote is specified, by default the origin remote will be used, unless there’s an upstream branch configured for the current branch.

The names of refs that are fetched, together with the object names they point at, are written to .git/FETCH_HEAD. This information may be used by scripts or other git commands, such as git-pull(1).

OPTIONS#

--[no-]all

-a, --append

--atomic

--depth=<depth>

--deepen=<depth>

--shallow-since=<date>

--shallow-exclude=<revision>

--unshallow

If the source repository is shallow, fetch as much as possible so that the current repository has the same history as the source repository.

--update-shallow

--negotiation-tip=<commit|glob>

This option may be specified more than once; if so, Git will report commits reachable from any of the given commits.

The argument to this option may be a glob on ref names, a ref, or the (possibly abbreviated) SHA-1 of a commit. Specifying a glob is equivalent to specifying this option multiple times, one for each matching ref name.

See also the fetch.negotiationAlgorithm and push.negotiate configuration variables documented in git-config(1), and the --negotiate-only option below.

--negotiate-only

This is incompatible with --recurse-submodules=[yes|on-demand]. Internally this is used to implement the push.negotiate option, see git-config(1).

--dry-run

--porcelain

This is incompatible with --recurse-submodules=[yes|on-demand] and takes precedence over the fetch.output config option.

--[no-]write-fetch-head

-f, --force

-k, --keep

--multiple

--[no-]auto-maintenance, --[no-]auto-gc

--[no-]write-commit-graph

--prefetch

-p, --prune

See the PRUNING section below for more details.

-P, --prune-tags

See the PRUNING section below for more details.

-n, --no-tags

--refetch

--refmap=<refspec>

-t, --tags

--recurse-submodules[=(yes|on-demand|no)]

When set to on-demand, only changed submodules are fetched. When set to yes, all populated submodules are fetched and submodules that are both unpopulated and changed are fetched. When set to no, submodules are never fetched.

When unspecified, this uses the value of fetch.recurseSubmodules if it is set (see git-config(1)), defaulting to on-demand if unset. When this option is used without any value, it defaults to yes.

-j, --jobs=<n>

If the --multiple option was specified, the different remotes will be fetched in parallel. If multiple submodules are fetched, they will be fetched in parallel. To control them independently, use the config settings fetch.parallel and submodule.fetchJobs (see git-config(1)).

Typically, parallel recursive and multi-remote fetches will be faster. By default fetches are performed sequentially, not in parallel.

--no-recurse-submodules

--set-upstream

--submodule-prefix=<path>

--recurse-submodules-default=[yes|on-demand]

-u, --update-head-ok

--upload-pack <upload-pack>

-q, --quiet

-v, --verbose

--progress

-o <option>, --server-option=<option>

--show-forced-updates

--no-show-forced-updates

-4, --ipv4

-6, --ipv6

<repository>

<group>

<refspec>

The format of a <refspec> parameter is an optional plus +, followed by the source <src>, followed by a colon :, followed by the destination <dst>. The colon can be omitted when <dst> is empty. <src> is typically a ref, or a glob pattern with a single * that is used to match a set of refs, but it can also be a fully spelled hex object name.

A <refspec> may contain a * in its <src> to indicate a simple pattern match. Such a refspec functions like a glob that matches any ref with the pattern. A pattern <refspec> must have one and only one * in both the <src> and <dst>. It will map refs to the destination by replacing the * with the contents matched from the source.

If a refspec is prefixed by ^, it will be interpreted as a negative refspec. Rather than specifying which refs to fetch or which local refs to update, such a refspec will instead specify refs to exclude. A ref will be considered to match if it matches at least one positive refspec, and does not match any negative refspec. Negative refspecs can be useful to restrict the scope of a pattern refspec so that it will not include specific refs. Negative refspecs can themselves be pattern refspecs. However, they may only contain a <src> and do not specify a <dst>. Fully spelled out hex object names are also not supported.

tag <tag> means the same as refs/tags/<tag>:refs/tags/<tag>; it requests fetching everything up to the given tag.

The remote ref that matches <src> is fetched, and if <dst> is not an empty string, an attempt is made to update the local ref that matches it.

Whether that update is allowed without --force depends on the ref namespace it’s being fetched to, the type of object being fetched, and whether the update is considered to be a fast-forward. Generally, the same rules apply for fetching as when pushing, see the <refspec>... section of git-push(1) for what those are. Exceptions to those rules particular to git fetch are noted below.

Until Git version 2.20, and unlike when pushing with git-push(1), any updates to refs/tags/* would be accepted without + in the refspec (or --force). When fetching, we promiscuously considered all tag updates from a remote to be forced fetches. Since Git version 2.20, fetching to update refs/tags/* works the same way as when pushing. I.e. any updates will be rejected without + in the refspec (or --force).

Unlike when pushing with git-push(1), any updates outside of refs/{tags,heads}/* will be accepted without + in the refspec (or --force), whether that’s swapping e.g. a tree object for a blob, or a commit for another commit that doesn’t have the previous commit as an ancestor etc.

Unlike when pushing with git-push(1), there is no configuration which’ll amend these rules, and nothing like a pre-fetch hook analogous to the pre-receive hook.

As with pushing with git-push(1), all of the rules described above about what’s not allowed as an update can be overridden by adding an optional leading + to a refspec (or using the --force command line option). The only exception to this is that no amount of forcing will make the refs/heads/* namespace accept a non-commit object.

--stdin

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:

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

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:

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

These two syntaxes are mostly equivalent, except when cloning, when the former implies --local option. See git-clone(1) for details.

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:

where <address> may be a path, a server and path, or an arbitrary URL-like string recognized by the specific remote helper being invoked. See gitremote-helpers(7) for details.

If there are a large number of similarly-named remote repositories and you want to use a different format for them (such that the URLs you use will be rewritten into URLs that work), you can create a configuration section of the form:

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

For example, with this:

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

a URL like "work:repo.git" or like "host.xz:/path/to/repo.git" will be rewritten in any context that takes a URL to be "git://git.host.xz/repo.git".

If you want to rewrite URLs for push only, you can create a configuration section of the form:

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

For example, with this:

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

a URL like "git://example.org/path/to/repo.git" will be rewritten to "ssh://example.org/path/to/repo.git" for pushes, but pulls will still use the original URL.

REMOTES#

The name of one of the following can be used instead of a URL as <repository> argument:

All of these also allow you to omit the refspec from the command line because they each contain a refspec which git will use by default.

Named remote in configuration file#

You can choose to provide the name of a remote which you had previously configured using git-remote(1), git-config(1) or even by a manual edit to the $GIT_DIR/config file. The URL of this remote will be used to access the repository. The refspec of this remote will be used by default when you do not provide a refspec on the command line. The entry in the config file would appear like this:

\n
        [remote "<name>"]
\n
                url = <URL>
\n
                pushurl = <pushurl>
\n
                push = <refspec>
\n
                fetch = <refspec>

The <pushurl> is used for pushes only. It is optional and defaults to <URL>. Pushing to a remote affects all defined pushurls or all defined urls if no pushurls are defined. Fetch, however, will only fetch from the first defined url if multiple urls are defined.

Named file in $GIT_DIR/remotes#

You can choose to provide the name of a file in $GIT_DIR/remotes. The URL in this file will be used to access the repository. The refspec in this file will be used as default when you do not provide a refspec on the command line. This file should have the following format:

\n
        URL: one of the above URL formats
\n
        Push: <refspec>
\n
        Pull: <refspec>

Push: lines are used by git push and Pull: lines are used by git pull and git fetch. Multiple Push: and Pull: lines may be specified for additional branch mappings.

Named file in $GIT_DIR/branches#

You can choose to provide the name of a file in $GIT_DIR/branches. The URL in this file will be used to access the repository. This file should have the following format:

\n
        <URL>#<head>

<URL> is required; #<head> is optional.

Depending on the operation, git will use one of the following refspecs, if you don’t provide one on the command line. <branch> is the name of this file in $GIT_DIR/branches and <head> defaults to master.

git fetch uses:

\n
        refs/heads/<head>:refs/heads/<branch>

git push uses:

\n
        HEAD:refs/heads/<head>

CONFIGURED REMOTE-TRACKING BRANCHES#

You often interact with the same remote repository by regularly and repeatedly fetching from it. In order to keep track of the progress of such a remote repository, git fetch allows you to configure remote.<repository>.fetch configuration variables.

Typically such a variable may look like this:

[remote "origin"]
\n
        fetch = +refs/heads/*:refs/remotes/origin/*

This configuration is used in two ways:

The latter use of the remote.<repository>.fetch values can be overridden by giving the --refmap=<refspec> parameter(s) on the command line.

PRUNING#

Git has a default disposition of keeping data unless it’s explicitly thrown away; this extends to holding onto local references to branches on remotes that have themselves deleted those branches.

If left to accumulate, these stale references might make performance worse on big and busy repos that have a lot of branch churn, and e.g. make the output of commands like git branch -a --contains <commit> needlessly verbose, as well as impacting anything else that’ll work with the complete set of known references.

These remote-tracking references can be deleted as a one-off with either of:

# While fetching
$ git fetch --prune <name>
# Only prune, don't fetch
$ git remote prune <name>

To prune references as part of your normal workflow without needing to remember to run that, set fetch.prune globally, or remote.<name>.prune per-remote in the config. See git-config(1).

Here’s where things get tricky and more specific. The pruning feature doesn’t actually care about branches, instead it’ll prune local ←→ remote-references as a function of the refspec of the remote (see <refspec> and CONFIGURED REMOTE-TRACKING BRANCHES above).

Therefore if the refspec for the remote includes e.g. refs/tags/*:refs/tags/*, or you manually run e.g. git fetch --prune <name> "refs/tags/*:refs/tags/*" it won’t be stale remote tracking branches that are deleted, but any local tag that doesn’t exist on the remote.

This might not be what you expect, i.e. you want to prune remote <name>, but also explicitly fetch tags from it, so when you fetch from it you delete all your local tags, most of which may not have come from the <name> remote in the first place.

So be careful when using this with a refspec like refs/tags/*:refs/tags/*, or any other refspec which might map references from multiple remotes to the same local namespace.

Since keeping up-to-date with both branches and tags on the remote is a common use-case the --prune-tags option can be supplied along with --prune to prune local tags that don’t exist on the remote, and force-update those tags that differ. Tag pruning can also be enabled with fetch.pruneTags or remote.<name>.pruneTags in the config. See git-config(1).

The --prune-tags option is equivalent to having refs/tags/*:refs/tags/* declared in the refspecs of the remote. This can lead to some seemingly strange interactions:

# These both fetch tags
$ git fetch --no-tags origin 'refs/tags/*:refs/tags/*'
$ git fetch --no-tags --prune-tags origin

The reason it doesn’t error out when provided without --prune or its config versions is for flexibility of the configured versions, and to maintain a 1=1 mapping between what the command line flags do, and what the configuration versions do.

It’s reasonable to e.g. configure fetch.pruneTags=true in ~/.gitconfig to have tags pruned whenever git fetch --prune is run, without making every invocation of git fetch without --prune an error.

Pruning tags with --prune-tags also works when fetching a URL instead of a named remote. These will all prune tags not found on origin:

$ git fetch origin --prune --prune-tags
$ git fetch origin --prune 'refs/tags/*:refs/tags/*'
$ git fetch <url-of-origin> --prune --prune-tags
$ git fetch <url-of-origin> --prune 'refs/tags/*:refs/tags/*'

OUTPUT#

The output of "git fetch" depends on the transport method used; this section describes the output when fetching over the Git protocol (either locally or via ssh) and Smart HTTP protocol.

The status of the fetch is output in tabular form, with each line representing the status of a single ref. Each line is of the form:

\n
 <flag> <summary> <from> -> <to> [<reason>]

When using --porcelain, the output format is intended to be machine-parseable. In contrast to the human-readable output formats it thus prints to standard output instead of standard error. Each line is of the form:

<flag> <old-object-id> <new-object-id> <local-reference>

The status of up-to-date refs is shown only if the --verbose option is used.

In compact output mode, specified with configuration variable fetch.output, if either entire <from> or <to> is found in the other string, it will be substituted with * in the other string. For example, master -> origin/master becomes master -> origin/*.

flag

(space)

+

-

t

*

!

=

summary

from

to

reason

EXAMPLES#

$ git fetch origin

The above command copies all branches from the remote refs/heads/ namespace and stores them to the local refs/remotes/origin/ namespace, unless the remote.<repository>.fetch option is used to specify a non-default refspec.

$ git fetch origin +seen:seen maint:tmp

This updates (or creates, as necessary) branches seen and tmp in the local repository by fetching from the branches (respectively) seen and maint from the remote repository.

The seen branch will be updated even if it does not fast-forward, because it is prefixed with a plus sign; tmp will not be.

$ git fetch git://git.kernel.org/pub/scm/git/git.git maint
$ git log FETCH_HEAD

The first command fetches the maint branch from the repository at git://git.kernel.org/pub/scm/git/git.git and the second command uses FETCH_HEAD to examine the branch with git-log(1). The fetched objects will eventually be removed by git’s built-in housekeeping (see git-gc(1)).

SECURITY#

The fetch and push protocols are not designed to prevent one side from stealing data from the other repository that was not intended to be shared. If you have private data that you need to protect from a malicious peer, your best option is to store it in another repository. This applies to both clients and servers. In particular, namespaces on a server are not effective for read access control; you should only grant read access to a namespace to clients that you would trust with read access to the entire repository.

The known attack vectors are as follows:

CONFIGURATION#

Everything below this line in this section is selectively included from the git-config(1) documentation. The content is the same as what’s found there:

fetch.recurseSubmodules

fetch.fsckObjects

fetch.fsck.<msg-id>

fetch.fsck.skipList

fetch.unpackLimit

fetch.prune

fetch.pruneTags

fetch.all

fetch.output

fetch.negotiationAlgorithm

See also the --negotiate-only and --negotiation-tip options to git-fetch(1).

fetch.showForcedUpdates

fetch.parallel

A value of 0 will give some reasonable default. If unset, it defaults to 1.

For submodules, this setting can be overridden using the submodule.fetchJobs config setting.

fetch.writeCommitGraph

fetch.bundleURI

If you modify this value and your repository has a fetch.bundleCreationToken value, then remove that fetch.bundleCreationToken value before fetching from the new bundle URI.

fetch.bundleCreationToken

The creation token values are chosen by the provider serving the specific bundle URI. If you modify the URI at fetch.bundleURI, then be sure to remove the value for the fetch.bundleCreationToken value before fetching.

BUGS#

Using --recurse-submodules can only fetch new commits in submodules that are present locally e.g. in $GIT_DIR/modules/. If the upstream adds a new submodule, that submodule cannot be fetched until it is cloned e.g. by git submodule update. This is expected to be fixed in a future Git version.

SEE ALSO#

git-pull(1)

GIT#

Part of the git(1) suite