[--index-filter <command>] [--parent-filter <command>]
[--msg-filter <command>] [--commit-filter <command>]
[--tag-name-filter <command>] [--subdirectory-filter <directory>]
+ [--prune-empty]
[--original <namespace>] [-d <directory>] [-f | --force]
[--] [<rev-list options>...]
useful in the future for compensating for some git bugs or such,
therefore such a usage is permitted.
+*NOTE*: This command honors `.git/info/grafts` and `.git/refs/replace/`.
+If you have any grafts or replacement refs defined, running this command
+will make them permanent.
+
*WARNING*! The rewritten history will have different object names for all
the objects and will not converge with the original branch. You will not
be able to easily push and distribute the rewritten branch on top of the
original branch. Please do not use this command if you do not know the
full implications, and avoid using it anyway, if a simple single commit
-would suffice to fix your problem.
+would suffice to fix your problem. (See the "RECOVERING FROM UPSTREAM
+REBASE" section in linkgit:git-rebase[1] for further information about
+rewriting published history.)
Always verify that the rewritten version is correct: The original refs,
if different from the rewritten ones, will be stored in the namespace
This filter may be used if you only need to modify the environment
in which the commit will be performed. Specifically, you might
want to rewrite the author/committer name/email/time environment
- variables (see linkgit:git-commit[1] for details). Do not forget
+ variables (see linkgit:git-commit-tree[1] for details). Do not forget
to re-export the variables.
--tree-filter <command>::
--index-filter <command>::
This is the filter for rewriting the index. It is similar to the
tree filter but does not check out the tree, which makes it much
- faster. For hairy cases, see linkgit:git-update-index[1].
+ faster. Frequently used with `git rm \--cached
+ \--ignore-unmatch ...`, see EXAMPLES below. For hairy
+ cases, see linkgit:git-update-index[1].
--parent-filter <command>::
This is the filter for rewriting the commit's parent list.
--commit-filter <command>::
This is the filter for performing the commit.
If this filter is specified, it will be called instead of the
- 'git-commit-tree' command, with arguments of the form
- "<TREE_ID> [-p <PARENT_COMMIT_ID>]..." and the log message on
+ 'git commit-tree' command, with arguments of the form
+ "<TREE_ID> [(-p <PARENT_COMMIT_ID>)...]" and the log message on
stdin. The commit id is expected on stdout.
+
As a special extension, the commit filter may emit multiple
You can use the 'map' convenience function in this filter, and other
convenience functions, too. For example, calling 'skip_commit "$@"'
will leave out the current commit (but not its changes! If you want
-that, use 'git-rebase' instead).
+that, use 'git rebase' instead).
++
+You can also use the `git_commit_non_empty_tree "$@"` instead of
+`git commit-tree "$@"` if you don't wish to keep commits with a single parent
+and that makes no change to the tree.
--tag-name-filter <command>::
This is the filter for rewriting tag names. When passed,
--subdirectory-filter <directory>::
Only look at the history which touches the given subdirectory.
The result will contain that directory (and only that) as its
- project root.
+ project root. Implies <<Remap_to_ancestor>>.
+
+--prune-empty::
+ Some kind of filters will generate empty commits, that left the tree
+ untouched. This switch allow git-filter-branch to ignore such
+ commits. Though, this switch only applies for commits that have one
+ and only one parent, it will hence keep merges points. Also, this
+ option is not compatible with the use of '--commit-filter'. Though you
+ just need to use the function 'git_commit_non_empty_tree "$@"' instead
+ of the `git commit-tree "$@"` idiom in your commit filter to make that
+ happen.
--original <namespace>::
Use this option to set the namespace where the original commits
-f::
--force::
- 'git-filter-branch' refuses to start with an existing temporary
+ 'git filter-branch' refuses to start with an existing temporary
directory or when there are already refs starting with
'refs/original/', unless forced.
<rev-list options>...::
- Arguments for 'git-rev-list'. All positive refs included by
+ Arguments for 'git rev-list'. All positive refs included by
these options are rewritten. You may also specify options
such as '--all', but you must use '--' to separate them from
- the 'git-filter-branch' options.
+ the 'git filter-branch' options. Implies <<Remap_to_ancestor>>.
+
+
+[[Remap_to_ancestor]]
+Remap to ancestor
+~~~~~~~~~~~~~~~~~
+
+By using linkgit:rev-list[1] arguments, e.g., path limiters, you can limit the
+set of revisions which get rewritten. However, positive refs on the command
+line are distinguished: we don't let them be excluded by such limiters. For
+this purpose, they are instead rewritten to point at the nearest ancestor that
+was not excluded.
Examples
a simple `rm filename` will fail for that tree and commit.
Thus you may instead want to use `rm -f filename` as the script.
-A significantly faster version:
+Using `\--index-filter` with 'git rm' yields a significantly faster
+version. Like with using `rm filename`, `git rm --cached filename`
+will fail if the file is absent from the tree of a commit. If you
+want to "completely forget" a file, it does not matter when it entered
+history, so we also add `\--ignore-unmatch`:
--------------------------------------------------------------------------
-git filter-branch --index-filter 'git rm --cached filename' HEAD
+git filter-branch --index-filter 'git rm --cached --ignore-unmatch filename' HEAD
--------------------------------------------------------------------------
Now, you will get the rewritten history saved in HEAD.
as their parents instead of the merge commit.
You can rewrite the commit log messages using `--msg-filter`. For
-example, 'git-svn-id' strings in a repository created by 'git-svn' can
+example, 'git svn-id' strings in a repository created by 'git svn' can
be removed this way:
-------------------------------------------------------
To restrict rewriting to only part of the history, specify a revision
range in addition to the new branch name. The new branch name will
-point to the top-most revision that a 'git-rev-list' of this range
+point to the top-most revision that a 'git rev-list' of this range
will print.
+If you need to add 'Acked-by' lines to, say, the last 10 commits (none
+of which is a merge), use this command:
+
+--------------------------------------------------------
+git filter-branch --msg-filter '
+ cat &&
+ echo "Acked-by: Bugs Bunny <bunny@bugzilla.org>"
+' HEAD~10..HEAD
+--------------------------------------------------------
+
*NOTE* the changes introduced by the commits, and which are not reverted
by subsequent commits, will still be in the rewritten branch. If you want
to throw out _changes_ together with the commits, you should use the
-interactive mode of 'git-rebase'.
+interactive mode of 'git rebase'.
Consider this history:
---------------------------------------------------------------
git filter-branch --index-filter \
- 'git ls-files -s | sed "s-\t-&newsubdir/-" |
+ 'git ls-files -s | sed "s-\t\"*-&newsubdir/-" |
GIT_INDEX_FILE=$GIT_INDEX_FILE.new \
git update-index --index-info &&
- mv $GIT_INDEX_FILE.new $GIT_INDEX_FILE' HEAD
+ mv "$GIT_INDEX_FILE.new" "$GIT_INDEX_FILE"' HEAD
---------------------------------------------------------------
-Author
-------
-Written by Petr "Pasky" Baudis <pasky@suse.cz>,
-and the git list <git@vger.kernel.org>
-Documentation
---------------
-Documentation by Petr Baudis and the git list.
+Checklist for Shrinking a Repository
+------------------------------------
+
+git-filter-branch is often used to get rid of a subset of files,
+usually with some combination of `\--index-filter` and
+`\--subdirectory-filter`. People expect the resulting repository to
+be smaller than the original, but you need a few more steps to
+actually make it smaller, because git tries hard not to lose your
+objects until you tell it to. First make sure that:
+
+* You really removed all variants of a filename, if a blob was moved
+ over its lifetime. `git log \--name-only \--follow \--all \--
+ filename` can help you find renames.
+
+* You really filtered all refs: use `\--tag-name-filter cat \--
+ \--all` when calling git-filter-branch.
+
+Then there are two ways to get a smaller repository. A safer way is
+to clone, that keeps your original intact.
+
+* Clone it with `git clone +++file:///path/to/repo+++`. The clone
+ will not have the removed objects. See linkgit:git-clone[1]. (Note
+ that cloning with a plain path just hardlinks everything!)
+
+If you really don't want to clone it, for whatever reasons, check the
+following points instead (in this order). This is a very destructive
+approach, so *make a backup* or go back to cloning it. You have been
+warned.
+
+* Remove the original refs backed up by git-filter-branch: say `git
+ for-each-ref \--format="%(refname)" refs/original/ | xargs -n 1 git
+ update-ref -d`.
+
+* Expire all reflogs with `git reflog expire \--expire=now \--all`.
+
+* Garbage collect all unreferenced objects with `git gc \--prune=now`
+ (or if your git-gc is not new enough to support arguments to
+ `\--prune`, use `git repack -ad; git prune` instead).
GIT
---