t4034: abstract away SHA-1-specific constants

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

git-bundle(1)
=============

NAME
----
git-bundle - Move objects and refs by archive


SYNOPSIS
--------
[verse]
'git bundle' create <file> <git-rev-list-args>
'git bundle' verify <file>
'git bundle' list-heads <file> [<refname>...]
'git bundle' unbundle <file> [<refname>...]

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

Some workflows require that one or more branches of development on one
machine be replicated on another machine, but the two machines cannot
be directly connected, and therefore the interactive Git protocols (git,
ssh, http) cannot be used.  This command provides support for
'git fetch' and 'git pull' to operate by packaging objects and references
in an archive at the originating machine, then importing those into
another repository using 'git fetch' and 'git pull'
after moving the archive by some means (e.g., by sneakernet).  As no
direct connection between the repositories exists, the user must specify a
basis for the bundle that is held by the destination repository: the
bundle assumes that all objects in the basis are already in the
destination repository.

OPTIONS
-------

create <file>::
	Used to create a bundle named 'file'.  This requires the
	'git-rev-list-args' arguments to define the bundle contents.

verify <file>::
	Used to check that a bundle file is valid and will apply
	cleanly to the current repository.  This includes checks on the
	bundle format itself as well as checking that the prerequisite
	commits exist and are fully linked in the current repository.
	'git bundle' prints a list of missing commits, if any, and exits
	with a non-zero status.

list-heads <file>::
	Lists the references defined in the bundle.  If followed by a
	list of references, only references matching those given are
	printed out.

unbundle <file>::
	Passes the objects in the bundle to 'git index-pack'
	for storage in the repository, then prints the names of all
	defined references. If a list of references is given, only
	references matching those in the list are printed. This command is
	really plumbing, intended to be called only by 'git fetch'.

<git-rev-list-args>::
	A list of arguments, acceptable to 'git rev-parse' and
	'git rev-list' (and containing a named ref, see SPECIFYING REFERENCES
	below), that specifies the specific objects and references
	to transport.  For example, `master~10..master` causes the
	current master reference to be packaged along with all objects
	added since its 10th ancestor commit.  There is no explicit
	limit to the number of references and objects that may be
	packaged.


[<refname>...]::
	A list of references used to limit the references reported as
	available. This is principally of use to 'git fetch', which
	expects to receive only those references asked for and not
	necessarily everything in the pack (in this case, 'git bundle' acts
	like 'git fetch-pack').

SPECIFYING REFERENCES
---------------------

'git bundle' will only package references that are shown by
'git show-ref': this includes heads, tags, and remote heads.  References
such as `master~1` cannot be packaged, but are perfectly suitable for
defining the basis.  More than one reference may be packaged, and more
than one basis can be specified.  The objects packaged are those not
contained in the union of the given bases.  Each basis can be
specified explicitly (e.g. `^master~10`), or implicitly (e.g.
`master~10..master`, `--since=10.days.ago master`).

It is very important that the basis used be held by the destination.
It is okay to err on the side of caution, causing the bundle file
to contain objects already in the destination, as these are ignored
when unpacking at the destination.

EXAMPLES
--------

Assume you want to transfer the history from a repository R1 on machine A
to another repository R2 on machine B.
For whatever reason, direct connection between A and B is not allowed,
but we can move data from A to B via some mechanism (CD, email, etc.).
We want to update R2 with development made on the branch master in R1.

To bootstrap the process, you can first create a bundle that does not have
any basis. You can use a tag to remember up to what commit you last
processed, in order to make it easy to later update the other repository
with an incremental bundle:

----------------
machineA$ cd R1
machineA$ git bundle create file.bundle master
machineA$ git tag -f lastR2bundle master
----------------

Then you transfer file.bundle to the target machine B. Because this
bundle does not require any existing object to be extracted, you can
create a new repository on machine B by cloning from it:

----------------
machineB$ git clone -b master /home/me/tmp/file.bundle R2
----------------

This will define a remote called "origin" in the resulting repository that
lets you fetch and pull from the bundle. The $GIT_DIR/config file in R2 will
have an entry like this:

------------------------
[remote "origin"]
    url = /home/me/tmp/file.bundle
    fetch = refs/heads/*:refs/remotes/origin/*
------------------------

To update the resulting mine.git repository, you can fetch or pull after
replacing the bundle stored at /home/me/tmp/file.bundle with incremental
updates.

After working some more in the original repository, you can create an
incremental bundle to update the other repository:

----------------
machineA$ cd R1
machineA$ git bundle create file.bundle lastR2bundle..master
machineA$ git tag -f lastR2bundle master
----------------

You then transfer the bundle to the other machine to replace
/home/me/tmp/file.bundle, and pull from it.

----------------
machineB$ cd R2
machineB$ git pull
----------------

If you know up to what commit the intended recipient repository should
have the necessary objects, you can use that knowledge to specify the
basis, giving a cut-off point to limit the revisions and objects that go
in the resulting bundle. The previous example used the lastR2bundle tag
for this purpose, but you can use any other options that you would give to
the linkgit:git-log[1] command. Here are more examples:

You can use a tag that is present in both:

----------------
$ git bundle create mybundle v1.0.0..master
----------------

You can use a basis based on time:

----------------
$ git bundle create mybundle --since=10.days master
----------------

You can use the number of commits:

----------------
$ git bundle create mybundle -10 master
----------------

You can run `git-bundle verify` to see if you can extract from a bundle
that was created with a basis:

----------------
$ git bundle verify mybundle
----------------

This will list what commits you must have in order to extract from the
bundle and will error out if you do not have them.

A bundle from a recipient repository's point of view is just like a
regular repository which it fetches or pulls from. You can, for example, map
references when fetching:

----------------
$ git fetch mybundle master:localRef
----------------

You can also see what references it offers:

----------------
$ git ls-remote mybundle
----------------

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