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git/Documentation/git-fast-export.txt
Geoffrey Irving 79559f27be git fast-export: add --no-data option
When using git fast-export and git fast-import to rewrite the history
of a repository with large binary files, almost all of the time is
spent dealing with blobs.  This is extremely inefficient if all we want
to do is rewrite the commits and tree structure.  --no-data skips the
output of blobs and writes SHA-1s instead of marks, which provides a
massive speedup.

Signed-off-by: Geoffrey Irving <irving@naml.us>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-07-31 07:48:09 -07:00

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git-fast-export(1)
==================
NAME
----
git-fast-export - Git data exporter
SYNOPSIS
--------
'git fast-export [options]' | 'git fast-import'
DESCRIPTION
-----------
This program dumps the given revisions in a form suitable to be piped
into 'git-fast-import'.
You can use it as a human-readable bundle replacement (see
linkgit:git-bundle[1]), or as a kind of an interactive
'git-filter-branch'.
OPTIONS
-------
--progress=<n>::
Insert 'progress' statements every <n> objects, to be shown by
'git-fast-import' during import.
--signed-tags=(verbatim|warn|strip|abort)::
Specify how to handle signed tags. Since any transformation
after the export can change the tag names (which can also happen
when excluding revisions) the signatures will not match.
+
When asking to 'abort' (which is the default), this program will die
when encountering a signed tag. With 'strip', the tags will be made
unsigned, with 'verbatim', they will be silently exported
and with 'warn', they will be exported, but you will see a warning.
--tag-of-filtered-object=(abort|drop|rewrite)::
Specify how to handle tags whose tagged objectis filtered out.
Since revisions and files to export can be limited by path,
tagged objects may be filtered completely.
+
When asking to 'abort' (which is the default), this program will die
when encountering such a tag. With 'drop' it will omit such tags from
the output. With 'rewrite', if the tagged object is a commit, it will
rewrite the tag to tag an ancestor commit (via parent rewriting; see
linkgit:git-rev-list[1])
-M::
-C::
Perform move and/or copy detection, as described in the
linkgit:git-diff[1] manual page, and use it to generate
rename and copy commands in the output dump.
+
Note that earlier versions of this command did not complain and
produced incorrect results if you gave these options.
--export-marks=<file>::
Dumps the internal marks table to <file> when complete.
Marks are written one per line as `:markid SHA-1`. Only marks
for revisions are dumped; marks for blobs are ignored.
Backends can use this file to validate imports after they
have been completed, or to save the marks table across
incremental runs. As <file> is only opened and truncated
at completion, the same path can also be safely given to
\--import-marks.
--import-marks=<file>::
Before processing any input, load the marks specified in
<file>. The input file must exist, must be readable, and
must use the same format as produced by \--export-marks.
+
Any commits that have already been marked will not be exported again.
If the backend uses a similar \--import-marks file, this allows for
incremental bidirectional exporting of the repository by keeping the
marks the same across runs.
--fake-missing-tagger::
Some old repositories have tags without a tagger. The
fast-import protocol was pretty strict about that, and did not
allow that. So fake a tagger to be able to fast-import the
output.
--no-data::
Skip output of blob objects and instead refer to blobs via
their original SHA-1 hash. This is useful when rewriting the
directory structure or history of a repository without
touching the contents of individual files. Note that the
resulting stream can only be used by a repository which
already contains the necessary objects.
[git-rev-list-args...]::
A list of arguments, acceptable to 'git-rev-parse' and
'git-rev-list', that specifies the specific objects and references
to export. For example, `master\~10..master` causes the
current master reference to be exported along with all objects
added since its 10th ancestor commit.
EXAMPLES
--------
-------------------------------------------------------------------
$ git fast-export --all | (cd /empty/repository && git fast-import)
-------------------------------------------------------------------
This will export the whole repository and import it into the existing
empty repository. Except for reencoding commits that are not in
UTF-8, it would be a one-to-one mirror.
-----------------------------------------------------
$ git fast-export master~5..master |
sed "s|refs/heads/master|refs/heads/other|" |
git fast-import
-----------------------------------------------------
This makes a new branch called 'other' from 'master~5..master'
(i.e. if 'master' has linear history, it will take the last 5 commits).
Note that this assumes that none of the blobs and commit messages
referenced by that revision range contains the string
'refs/heads/master'.
Limitations
-----------
Since 'git-fast-import' cannot tag trees, you will not be
able to export the linux-2.6.git repository completely, as it contains
a tag referencing a tree instead of a commit.
Author
------
Written by Johannes E. Schindelin <johannes.schindelin@gmx.de>.
Documentation
--------------
Documentation by Johannes E. Schindelin <johannes.schindelin@gmx.de>.
GIT
---
Part of the linkgit:git[1] suite