You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
395 lines
15 KiB
395 lines
15 KiB
git-filter-branch(1) |
|
==================== |
|
|
|
NAME |
|
---- |
|
git-filter-branch - Rewrite branches |
|
|
|
SYNOPSIS |
|
-------- |
|
[verse] |
|
'git filter-branch' [--env-filter <command>] [--tree-filter <command>] |
|
[--index-filter <command>] [--parent-filter <command>] |
|
[--msg-filter <command>] [--commit-filter <command>] |
|
[--tag-name-filter <command>] [--subdirectory-filter <directory>] |
|
[--original <namespace>] [-d <directory>] [-f | --force] |
|
[--] [<rev-list options>...] |
|
|
|
DESCRIPTION |
|
----------- |
|
Lets you rewrite git revision history by rewriting the branches mentioned |
|
in the <rev-list options>, applying custom filters on each revision. |
|
Those filters can modify each tree (e.g. removing a file or running |
|
a perl rewrite on all files) or information about each commit. |
|
Otherwise, all information (including original commit times or merge |
|
information) will be preserved. |
|
|
|
The command will only rewrite the _positive_ refs mentioned in the |
|
command line (e.g. if you pass 'a..b', only 'b' will be rewritten). |
|
If you specify no filters, the commits will be recommitted without any |
|
changes, which would normally have no effect. Nevertheless, this may be |
|
useful in the future for compensating for some git bugs or such, |
|
therefore such a usage is permitted. |
|
|
|
*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. (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 |
|
'refs/original/'. |
|
|
|
Note that since this operation is very I/O expensive, it might |
|
be a good idea to redirect the temporary directory off-disk with the |
|
'-d' option, e.g. on tmpfs. Reportedly the speedup is very noticeable. |
|
|
|
|
|
Filters |
|
~~~~~~~ |
|
|
|
The filters are applied in the order as listed below. The <command> |
|
argument is always evaluated in the shell context using the 'eval' command |
|
(with the notable exception of the commit filter, for technical reasons). |
|
Prior to that, the $GIT_COMMIT environment variable will be set to contain |
|
the id of the commit being rewritten. Also, GIT_AUTHOR_NAME, |
|
GIT_AUTHOR_EMAIL, GIT_AUTHOR_DATE, GIT_COMMITTER_NAME, GIT_COMMITTER_EMAIL, |
|
and GIT_COMMITTER_DATE are set according to the current commit. The values |
|
of these variables after the filters have run, are used for the new commit. |
|
If any evaluation of <command> returns a non-zero exit status, the whole |
|
operation will be aborted. |
|
|
|
A 'map' function is available that takes an "original sha1 id" argument |
|
and outputs a "rewritten sha1 id" if the commit has been already |
|
rewritten, and "original sha1 id" otherwise; the 'map' function can |
|
return several ids on separate lines if your commit filter emitted |
|
multiple commits. |
|
|
|
|
|
OPTIONS |
|
------- |
|
|
|
--env-filter <command>:: |
|
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 |
|
to re-export the variables. |
|
|
|
--tree-filter <command>:: |
|
This is the filter for rewriting the tree and its contents. |
|
The argument is evaluated in shell with the working |
|
directory set to the root of the checked out tree. The new tree |
|
is then used as-is (new files are auto-added, disappeared files |
|
are auto-removed - neither .gitignore files nor any other ignore |
|
rules *HAVE ANY EFFECT*!). |
|
|
|
--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. 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. |
|
It will receive the parent string on stdin and shall output |
|
the new parent string on stdout. The parent string is in |
|
the format described in linkgit:git-commit-tree[1]: empty for |
|
the initial commit, "-p parent" for a normal commit and |
|
"-p parent1 -p parent2 -p parent3 ..." for a merge commit. |
|
|
|
--msg-filter <command>:: |
|
This is the filter for rewriting the commit messages. |
|
The argument is evaluated in the shell with the original |
|
commit message on standard input; its standard output is |
|
used as the new commit message. |
|
|
|
--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 |
|
stdin. The commit id is expected on stdout. |
|
+ |
|
As a special extension, the commit filter may emit multiple |
|
commit ids; in that case, the rewritten children of the original commit will |
|
have all of them as parents. |
|
+ |
|
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). |
|
+ |
|
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, |
|
it will be called for every tag ref that points to a rewritten |
|
object (or to a tag object which points to a rewritten object). |
|
The original tag name is passed via standard input, and the new |
|
tag name is expected on standard output. |
|
+ |
|
The original tags are not deleted, but can be overwritten; |
|
use "--tag-name-filter cat" to simply update the tags. In this |
|
case, be very careful and make sure you have the old tags |
|
backed up in case the conversion has run afoul. |
|
+ |
|
Nearly proper rewriting of tag objects is supported. If the tag has |
|
a message attached, a new tag object will be created with the same message, |
|
author, and timestamp. If the tag has a signature attached, the |
|
signature will be stripped. It is by definition impossible to preserve |
|
signatures. The reason this is "nearly" proper, is because ideally if |
|
the tag did not change (points to the same object, has the same name, etc.) |
|
it should retain any signature. That is not the case, signatures will always |
|
be removed, buyer beware. There is also no support for changing the |
|
author or timestamp (or the tag message for that matter). Tags which point |
|
to other tags will be rewritten to point to the underlying commit. |
|
|
|
--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. |
|
|
|
--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 |
|
will be stored. The default value is 'refs/original'. |
|
|
|
-d <directory>:: |
|
Use this option to set the path to the temporary directory used for |
|
rewriting. When applying a tree filter, the command needs to |
|
temporarily check out the tree to some directory, which may consume |
|
considerable space in case of large projects. By default it |
|
does this in the '.git-rewrite/' directory but you can override |
|
that choice by this parameter. |
|
|
|
-f:: |
|
--force:: |
|
'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 |
|
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. |
|
|
|
|
|
Examples |
|
-------- |
|
|
|
Suppose you want to remove a file (containing confidential information |
|
or copyright violation) from all commits: |
|
|
|
------------------------------------------------------- |
|
git filter-branch --tree-filter 'rm filename' HEAD |
|
------------------------------------------------------- |
|
|
|
However, if the file is absent from the tree of some commit, |
|
a simple `rm filename` will fail for that tree and commit. |
|
Thus you may instead want to use `rm -f filename` as the script. |
|
|
|
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 --ignore-unmatch filename' HEAD |
|
-------------------------------------------------------------------------- |
|
|
|
Now, you will get the rewritten history saved in HEAD. |
|
|
|
To rewrite the repository to look as if `foodir/` had been its project |
|
root, and discard all other history: |
|
|
|
------------------------------------------------------- |
|
git filter-branch --subdirectory-filter foodir -- --all |
|
------------------------------------------------------- |
|
|
|
Thus you can, e.g., turn a library subdirectory into a repository of |
|
its own. Note the `\--` that separates 'filter-branch' options from |
|
revision options, and the `\--all` to rewrite all branches and tags. |
|
|
|
To set a commit (which typically is at the tip of another |
|
history) to be the parent of the current initial commit, in |
|
order to paste the other history behind the current history: |
|
|
|
------------------------------------------------------------------- |
|
git filter-branch --parent-filter 'sed "s/^\$/-p <graft-id>/"' HEAD |
|
------------------------------------------------------------------- |
|
|
|
(if the parent string is empty - which happens when we are dealing with |
|
the initial commit - add graftcommit as a parent). Note that this assumes |
|
history with a single root (that is, no merge without common ancestors |
|
happened). If this is not the case, use: |
|
|
|
-------------------------------------------------------------------------- |
|
git filter-branch --parent-filter \ |
|
'test $GIT_COMMIT = <commit-id> && echo "-p <graft-id>" || cat' HEAD |
|
-------------------------------------------------------------------------- |
|
|
|
or even simpler: |
|
|
|
----------------------------------------------- |
|
echo "$commit-id $graft-id" >> .git/info/grafts |
|
git filter-branch $graft-id..HEAD |
|
----------------------------------------------- |
|
|
|
To remove commits authored by "Darl McBribe" from the history: |
|
|
|
------------------------------------------------------------------------------ |
|
git filter-branch --commit-filter ' |
|
if [ "$GIT_AUTHOR_NAME" = "Darl McBribe" ]; |
|
then |
|
skip_commit "$@"; |
|
else |
|
git commit-tree "$@"; |
|
fi' HEAD |
|
------------------------------------------------------------------------------ |
|
|
|
The function 'skip_commit' is defined as follows: |
|
|
|
-------------------------- |
|
skip_commit() |
|
{ |
|
shift; |
|
while [ -n "$1" ]; |
|
do |
|
shift; |
|
map "$1"; |
|
shift; |
|
done; |
|
} |
|
-------------------------- |
|
|
|
The shift magic first throws away the tree id and then the -p |
|
parameters. Note that this handles merges properly! In case Darl |
|
committed a merge between P1 and P2, it will be propagated properly |
|
and all children of the merge will become merge commits with P1,P2 |
|
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 |
|
be removed this way: |
|
|
|
------------------------------------------------------- |
|
git filter-branch --msg-filter ' |
|
sed -e "/^git-svn-id:/d" |
|
' |
|
------------------------------------------------------- |
|
|
|
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 |
|
will print. |
|
|
|
*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'. |
|
|
|
|
|
Consider this history: |
|
|
|
------------------ |
|
D--E--F--G--H |
|
/ / |
|
A--B-----C |
|
------------------ |
|
|
|
To rewrite only commits D,E,F,G,H, but leave A, B and C alone, use: |
|
|
|
-------------------------------- |
|
git filter-branch ... C..H |
|
-------------------------------- |
|
|
|
To rewrite commits E,F,G,H, use one of these: |
|
|
|
---------------------------------------- |
|
git filter-branch ... C..H --not D |
|
git filter-branch ... D..H --not C |
|
---------------------------------------- |
|
|
|
To move the whole tree into a subdirectory, or remove it from there: |
|
|
|
--------------------------------------------------------------- |
|
git filter-branch --index-filter \ |
|
'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 |
|
--------------------------------------------------------------- |
|
|
|
|
|
|
|
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). |
|
|
|
|
|
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. |
|
|
|
GIT |
|
--- |
|
Part of the linkgit:git[1] suite
|
|
|