git-annex/doc/git-annex-export.mdwn

# NAME

git-annex export - export content to a remote

# SYNOPSIS

git annex export `treeish --to remote`

git annex export `--tracking treeish --to remote`

# DESCRIPTION

Use this command to export a tree of files from a git-annex repository.

Normally files are stored on a git-annex special remote named by their
keys. That is great for reliable data storage, but your filenames are
obscured. Exporting replicates the tree to the special remote as-is.

Mixing key/value storage and exports in the same remote would be a mess and
so is not allowed. You have to configure a special remote with
`exporttree=yes` when initially setting it up with
[[git-annex-initremote]](1).

The treeish to export can be the name of a git branch, or a tag, or any
other treeish accepted by git, including eg master:subdir to only export a
subdirectory from a branch.

Repeated exports are done efficiently, by diffing the old and new tree,
and transferring only the changed files, and renaming files as necessary.

Exports can be interrupted and resumed. However, partially uploaded files
will be re-started from the beginning in most cases.

Once content has been exported to a remote, commands like `git annex get`
can download content from there the same as from other remotes. However,
since an export is not a key/value store, git-annex has to do more
verification of content downloaded from an export. Some types of keys,
that are not based on checksums, cannot be downloaded from an export.
And, git-annex will never trust an export to retain the content of a key.

However, some special remotes, notably S3, support keeping track of old
versions of files stored in them. If a special remote is set up to do 
that, it can be used as a key/value store and the limitations in the above
paragraph do not apply. Note that dropping content from such a remote is
not supported. See individual special remotes' documentation for
details of how to enable such versioning.

# OPTIONS

* `--to=remote`

  Specify the special remote to export to.

* `--tracking`

  This makes the export track changes that are committed to
  the branch. `git annex sync --content` and the git-annex assistant
  will update exports with commits made to the branch.

  This is a local configuration setting, similar to a git remote's tracking
  branch. You'll need to run `git annex export --tracking` in each
  repository you want the export to track.

* `--fast`

  This sets up an export of a tree, but avoids any expensive file uploads to
  the remote. You can later run `git annex sync --content` to upload
  the files to the export.

# EXAMPLE

	git annex initremote myexport type=directory directory=/mnt/myexport \
		exporttree=yes encryption=none
	git annex export master --to myexport

After that, /mnt/myexport will contain the same tree of files as the master
branch does.

	git mv myfile subdir/myfile
	git commit -m renamed
	git annex export master --to myexport

That updates /mnt/myexport to reflect the renamed file.

	git annex export master:subdir --to myexport

That updates /mnt/myexport, to contain only the files in the "subdir"
directory of the master branch.

	git annex export --tracking master --to myexport

That makes myexport track changes that are committed to the master branch.

# EXPORT CONFLICTS

If two different git-annex repositories are both exporting different trees
to the same special remote, it's possible for an export conflict to occur.
This leaves the special remote with some files from one tree, and some
files from the other. Files in the special remote may have entirely the
wrong content as well.

It's not possible for git-annex to detect when making an export will result
in an export conflict. The best way to avoid export conflicts is to either
only ever export to a special remote from a single repository, or to have a
rule about the tree that you export to the special remote. For example, if
you always export origin/master after pushing to origin, then an export
conflict can't happen.

An export conflict can only be detected after the two git repositories
that produced it get back in sync. Then the next time you run `git annex
export`, it will detect the export conflict, and resolve it.

# SEE ALSO

[[git-annex]](1)

[[git-annex-initremote]](1)

[[git-annex-sync]](1)

# HISTORY

The `export` command was introduced in git-annex version 6.20170925.

# AUTHOR

Joey Hess <id@joeyh.name>

Warning: Automatically converted into a man page by mdwn2man. Edit with care.