6 git-filter-branch - Rewrite branches
11 'git-filter-branch' [--env-filter <command>] [--tree-filter <command>]
12 [--index-filter <command>] [--parent-filter <command>]
13 [--msg-filter <command>] [--commit-filter <command>]
14 [--tag-name-filter <command>] [--subdirectory-filter <directory>]
15 [-d <directory>] <new-branch-name> [<rev-list options>...]
19 Lets you rewrite git revision history by creating a new branch from
20 your current branch, applying custom filters on each revision.
21 Those filters can modify each tree (e.g. removing a file or running
22 a perl rewrite on all files) or information about each commit.
23 Otherwise, all information (including original commit times or merge
24 information) will be preserved.
26 The command takes the new branch name as a mandatory argument and
27 the filters as optional arguments. If you specify no filters, the
28 commits will be recommitted without any changes, which would normally
29 have no effect and result in the new branch pointing to the same
30 branch as your current branch. Nevertheless, this may be useful in
31 the future for compensating for some git bugs or such, therefore
32 such a usage is permitted.
34 WARNING! The rewritten history will have different object names for all
35 the objects and will not converge with the original branch. You will not
36 be able to easily push and distribute the rewritten branch on top of the
37 original branch. Please do not use this command if you do not know the
38 full implications, and avoid using it anyway, if a simple single commit
39 would suffice to fix your problem.
41 Always verify that the rewritten version is correct before disposing
44 Note that since this operation is extensively I/O expensive, it might
45 be a good idea to redirect the temporary directory off-disk, e.g. on
46 tmpfs. Reportedly the speedup is very noticeable.
52 The filters are applied in the order as listed below. The <command>
53 argument is always evaluated in shell using the 'eval' command.
54 Prior to that, the $GIT_COMMIT environment variable will be set to contain
55 the id of the commit being rewritten. Also, GIT_AUTHOR_NAME,
56 GIT_AUTHOR_EMAIL, GIT_AUTHOR_DATE, GIT_COMMITTER_NAME, GIT_COMMITTER_EMAIL,
57 and GIT_COMMITTER_DATE is set according to the current commit.
59 A 'map' function is available that takes an "original sha1 id" argument
60 and outputs a "rewritten sha1 id" if the commit has been already
61 rewritten, fails otherwise; the 'map' function can return several
62 ids on separate lines if your commit filter emitted multiple commits.
68 --env-filter <command>::
69 This is the filter for modifying the environment in which
70 the commit will be performed. Specifically, you might want
71 to rewrite the author/committer name/email/time environment
72 variables (see gitlink:git-commit[1] for details). Do not forget
73 to re-export the variables.
75 --tree-filter <command>::
76 This is the filter for rewriting the tree and its contents.
77 The argument is evaluated in shell with the working
78 directory set to the root of the checked out tree. The new tree
79 is then used as-is (new files are auto-added, disappeared files
80 are auto-removed - neither .gitignore files nor any other ignore
81 rules HAVE ANY EFFECT!).
83 --index-filter <command>::
84 This is the filter for rewriting the index. It is similar to the
85 tree filter but does not check out the tree, which makes it much
86 faster. For hairy cases, see gitlink:git-update-index[1].
88 --parent-filter <command>::
89 This is the filter for rewriting the commit's parent list.
90 It will receive the parent string on stdin and shall output
91 the new parent string on stdout. The parent string is in
92 a format accepted by gitlink:git-commit-tree[1]: empty for
93 the initial commit, "-p parent" for a normal commit and
94 "-p parent1 -p parent2 -p parent3 ..." for a merge commit.
96 --msg-filter <command>::
97 This is the filter for rewriting the commit messages.
98 The argument is evaluated in the shell with the original
99 commit message on standard input; its standard output is
100 used as the new commit message.
102 --commit-filter <command>::
103 This is the filter for performing the commit.
104 If this filter is specified, it will be called instead of the
105 gitlink:git-commit-tree[1] command, with arguments of the form
106 "<TREE_ID> [-p <PARENT_COMMIT_ID>]..." and the log message on
107 stdin. The commit id is expected on stdout.
109 As a special extension, the commit filter may emit multiple
110 commit ids; in that case, ancestors of the original commit will
111 have all of them as parents.
113 --tag-name-filter <command>::
114 This is the filter for rewriting tag names. When passed,
115 it will be called for every tag ref that points to a rewritten
116 object (or to a tag object which points to a rewritten object).
117 The original tag name is passed via standard input, and the new
118 tag name is expected on standard output.
120 The original tags are not deleted, but can be overwritten;
121 use "--tag-name-filter=cat" to simply update the tags. In this
122 case, be very careful and make sure you have the old tags
123 backed up in case the conversion has run afoul.
125 Note that there is currently no support for proper rewriting of
126 tag objects; in layman terms, if the tag has a message or signature
127 attached, the rewritten tag won't have it. Sorry. (It is by
128 definition impossible to preserve signatures at any rate.)
130 --subdirectory-filter <directory>::
131 Only ever look at the history, which touches the given subdirectory.
132 The result will contain that directory as its project root.
135 Use this option to set the path to the temporary directory used for
136 rewriting. When applying a tree filter, the command needs to
137 temporary checkout the tree to some directory, which may consume
138 considerable space in case of large projects. By default it
139 does this in the '.git-rewrite/' directory but you can override
140 that choice by this parameter.
143 When options are given after the new branch name, they will
144 be passed to gitlink:git-rev-list[1]. Only commits in the resulting
145 output will be filtered, although the filtered commits can still
146 reference parents which are outside of that set.
152 Suppose you want to remove a file (containing confidential information
153 or copyright violation) from all commits:
155 -------------------------------------------------------
156 git filter-branch --tree-filter 'rm filename' newbranch
157 -------------------------------------------------------
159 A significantly faster version:
161 -------------------------------------------------------------------------------
162 git filter-branch --index-filter 'git update-index --remove filename' newbranch
163 -------------------------------------------------------------------------------
165 Now, you will get the rewritten history saved in the branch 'newbranch'
166 (your current branch is left untouched).
168 To "etch-graft" a commit to the revision history (set a commit to be
169 the parent of the current initial commit and propagate that):
171 ----------------------------------------------------------------------
172 git filter-branch --parent-filter sed\ 's/^$/-p <graft-id>/' newbranch
173 ----------------------------------------------------------------------
175 (if the parent string is empty - therefore we are dealing with the
176 initial commit - add graftcommit as a parent). Note that this assumes
177 history with a single root (that is, no merge without common ancestors
178 happened). If this is not the case, use:
180 -------------------------------------------------------------------------------
181 git filter-branch --parent-filter \
182 'cat; test $GIT_COMMIT = <commit-id> && echo "-p <graft-id>"' newbranch
183 -------------------------------------------------------------------------------
185 To remove commits authored by "Darl McBribe" from the history:
187 ------------------------------------------------------------------------------
188 git filter-branch --commit-filter '
189 if [ "$GIT_AUTHOR_NAME" = "Darl McBribe" ];
199 git commit-tree "$@";
201 ------------------------------------------------------------------------------
203 The shift magic first throws away the tree id and then the -p
204 parameters. Note that this handles merges properly! In case Darl
205 committed a merge between P1 and P2, it will be propagated properly
206 and all children of the merge will become merge commits with P1,P2
207 as their parents instead of the merge commit.
209 To restrict rewriting to only part of the history, specify a revision
210 range in addition to the new branch name. The new branch name will
211 point to the top-most revision that a 'git rev-list' of this range
214 Note that the changes introduced by the commits, and not reverted by
215 subsequent commits, will still be in the rewritten branch. If you want
216 to throw out _changes_ together with the commits, you should use the
217 interactive mode of gitlink:git-rebase[1].
219 Consider this history:
227 To rewrite only commits D,E,F,G,H, but leave A, B and C alone, use:
229 --------------------------------
230 git filter-branch ... new-H C..H
231 --------------------------------
233 To rewrite commits E,F,G,H, use one of these:
235 ----------------------------------------
236 git filter-branch ... new-H C..H --not D
237 git filter-branch ... new-H D..H --not C
238 ----------------------------------------
240 To move the whole tree into a subdirectory, or remove it from there:
242 ---------------------------------------------------------------
243 git filter-branch --index-filter \
244 'git ls-files -s | sed "s-\t-&newsubdir/-" |
245 GIT_INDEX_FILE=$GIT_INDEX_FILE.new \
246 git update-index --index-info &&
247 mv $GIT_INDEX_FILE.new $GIT_INDEX_FILE' directorymoved
248 ---------------------------------------------------------------
253 Written by Petr "Pasky" Baudis <pasky@suse.cz>,
254 and the git list <git@vger.kernel.org>
258 Documentation by Petr Baudis and the git list.
262 Part of the gitlink:git[7] suite