GIT-FAST-EXPORT(1) Git Manual 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 git-
bundle(1)), or as a format that can be edited before being fed to git
fast-import in order to do history rewrites (an ability relied on by
tools like git filter-repo).

OPTIONS

--progress=<n>
Insert progress statements every <n> objects, to be shown by git
fast-import during import.

--signed-tags=(verbatim|warn|warn-strip|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
silently be made unsigned, with warn-strip they will be made
unsigned but a warning will be displayed, 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 object is 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 git-rev-list(1)).

-M, -C
Perform move and/or copy detection, as described in the 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. The file will not be written if
no new object has been marked/exported.

--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.

--mark-tags
In addition to labelling blobs and commits with mark ids, also
label tags. This is useful in conjunction with --export-marks and
--import-marks, and is also useful (and necessary) for exporting
of nested tags. It does not hurt other cases and would be the
default, but many fast-import frontends are not prepared to
accept tags with mark identifiers.

Any commits (or tags) 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.

--use-done-feature
Start the stream with a feature done stanza, and terminate it
with a done command.

--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.

--full-tree
This option will cause fast-export to issue a "deleteall"
directive for each commit followed by a full list of all files in
the commit (as opposed to just listing the files which are
different from the commit's first parent).

--anonymize
Anonymize the contents of the repository while still retaining
the shape of the history and stored tree. See the section on
ANONYMIZING below.

--anonymize-map=<from>[:<to>]
Convert token <from> to <to> in the anonymized output. If <to> is
omitted, map <from> to itself (i.e., do not anonymize it). See
the section on ANONYMIZING below.

--reference-excluded-parents
By default, running a command such as git fast-export
master~5..master will not include the commit master~5 and will
make master~4 no longer have master~5 as a parent (though both
the old master~4 and new master~4 will have all the same files).
Use --reference-excluded-parents to instead have the stream refer
to commits in the excluded range of history by their sha1sum.
Note that the resulting stream can only be used by a repository
which already contains the necessary parent commits.

--show-original-ids
Add an extra directive to the output for commits and blobs,
original-oid <SHA1SUM>. While such directives will likely be
ignored by importers such as git-fast-import, it may be useful
for intermediary filters (e.g. for rewriting commit messages
which refer to older commits, or for stripping blobs by id).

--reencode=(yes|no|abort)
Specify how to handle encoding header in commit objects. When
asking to abort (which is the default), this program will die
when encountering such a commit object. With yes, the commit
message will be re-encoded into UTF-8. With no, the original
encoding will be preserved.

--refspec
Apply the specified refspec to each ref exported. Multiple of
them can be specified.

[<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 and (unless the --reference-excluded-parents
option is specified) all files common to master~9 and master~10.

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.

ANONYMIZING

If the --anonymize option is given, git will attempt to remove all
identifying information from the repository while still retaining
enough of the original tree and history patterns to reproduce some
bugs. The goal is that a git bug which is found on a private
repository will persist in the anonymized repository, and the latter
can be shared with git developers to help solve the bug.

With this option, git will replace all refnames, paths, blob
contents, commit and tag messages, names, and email addresses in the
output with anonymized data. Two instances of the same string will be
replaced equivalently (e.g., two commits with the same author will
have the same anonymized author in the output, but bear no
resemblance to the original author string). The relationship between
commits, branches, and tags is retained, as well as the commit
timestamps (but the commit messages and refnames bear no resemblance
to the originals). The relative makeup of the tree is retained (e.g.,
if you have a root tree with 10 files and 3 trees, so will the
output), but their names and the contents of the files will be
replaced.

If you think you have found a git bug, you can start by exporting an
anonymized stream of the whole repository:

$ git fast-export --anonymize --all >anon-stream

Then confirm that the bug persists in a repository created from that
stream (many bugs will not, as they really do depend on the exact
repository contents):

$ git init anon-repo
$ cd anon-repo
$ git fast-import <../anon-stream
$ ... test your bug ...

If the anonymized repository shows the bug, it may be worth sharing
anon-stream along with a regular bug report. Note that the anonymized
stream compresses very well, so gzipping it is encouraged. If you
want to examine the stream to see that it does not contain any
private data, you can peruse it directly before sending. You may also
want to try:

$ perl -pe 's/\d+/X/g' <anon-stream | sort -u | less

which shows all of the unique lines (with numbers converted to "X",
to collapse "User 0", "User 1", etc into "User X"). This produces a
much smaller output, and it is usually easy to quickly confirm that
there is no private data in the stream.

Reproducing some bugs may require referencing particular commits or
paths, which becomes challenging after refnames and paths have been
anonymized. You can ask for a particular token to be left as-is or
mapped to a new value. For example, if you have a bug which
reproduces with git rev-list sensitive -- secret.c, you can run:

$ git fast-export --anonymize --all \
--anonymize-map=sensitive:foo \
--anonymize-map=secret.c:bar.c \
>stream

After importing the stream, you can then run git rev-list foo --
bar.c in the anonymized repository.

Note that paths and refnames are split into tokens at slash
boundaries. The command above would anonymize subdir/secret.c as
something like path123/bar.c; you could then search for bar.c in the
anonymized repository to determine the final pathname.

To make referencing the final pathname simpler, you can map each path
component; so if you also anonymize subdir to publicdir, then the
final pathname would be publicdir/bar.c.

LIMITATIONS

Since git fast-import cannot tag trees, you will not be able to
export the linux.git repository completely, as it contains a tag
referencing a tree instead of a commit.

SEE ALSO

git-fast-import(1)

GIT

Part of the git(1) suite

Git 2.48.1 2025-01-13 GIT-FAST-EXPORT(1)