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c401b33c JS |
1 | git-filter-branch(1) |
2 | ==================== | |
3 | ||
4 | NAME | |
5 | ---- | |
6 | git-filter-branch - Rewrite branches | |
7 | ||
8 | SYNOPSIS | |
9 | -------- | |
10 | [verse] | |
b1889c36 | 11 | 'git filter-branch' [--env-filter <command>] [--tree-filter <command>] |
c401b33c JS |
12 | [--index-filter <command>] [--parent-filter <command>] |
13 | [--msg-filter <command>] [--commit-filter <command>] | |
14 | [--tag-name-filter <command>] [--subdirectory-filter <directory>] | |
e3679ab4 | 15 | [--prune-empty] |
5433235d | 16 | [--original <namespace>] [-d <directory>] [-f | --force] |
8afa4210 | 17 | [--] [<rev-list options>...] |
c401b33c JS |
18 | |
19 | DESCRIPTION | |
20 | ----------- | |
08203668 JS |
21 | Lets you rewrite git revision history by rewriting the branches mentioned |
22 | in the <rev-list options>, applying custom filters on each revision. | |
c401b33c JS |
23 | Those filters can modify each tree (e.g. removing a file or running |
24 | a perl rewrite on all files) or information about each commit. | |
25 | Otherwise, all information (including original commit times or merge | |
26 | information) will be preserved. | |
27 | ||
08203668 | 28 | The command will only rewrite the _positive_ refs mentioned in the |
bf7c9021 | 29 | command line (e.g. if you pass 'a..b', only 'b' will be rewritten). |
08203668 JS |
30 | If you specify no filters, the commits will be recommitted without any |
31 | changes, which would normally have no effect. Nevertheless, this may be | |
32 | useful in the future for compensating for some git bugs or such, | |
33 | therefore such a usage is permitted. | |
c401b33c | 34 | |
c6d8f763 DCS |
35 | *NOTE*: This command honors `.git/info/grafts`. If you have any grafts |
36 | defined, running this command will make them permanent. | |
37 | ||
73616fd3 | 38 | *WARNING*! The rewritten history will have different object names for all |
c401b33c JS |
39 | the objects and will not converge with the original branch. You will not |
40 | be able to easily push and distribute the rewritten branch on top of the | |
41 | original branch. Please do not use this command if you do not know the | |
42 | full implications, and avoid using it anyway, if a simple single commit | |
97c33c65 TR |
43 | would suffice to fix your problem. (See the "RECOVERING FROM UPSTREAM |
44 | REBASE" section in linkgit:git-rebase[1] for further information about | |
45 | rewriting published history.) | |
c401b33c | 46 | |
dfd05e38 JS |
47 | Always verify that the rewritten version is correct: The original refs, |
48 | if different from the rewritten ones, will be stored in the namespace | |
49 | 'refs/original/'. | |
c401b33c | 50 | |
bf7c9021 | 51 | Note that since this operation is very I/O expensive, it might |
08203668 JS |
52 | be a good idea to redirect the temporary directory off-disk with the |
53 | '-d' option, e.g. on tmpfs. Reportedly the speedup is very noticeable. | |
c401b33c JS |
54 | |
55 | ||
56 | Filters | |
57 | ~~~~~~~ | |
58 | ||
59 | The filters are applied in the order as listed below. The <command> | |
bf7c9021 RW |
60 | argument is always evaluated in the shell context using the 'eval' command |
61 | (with the notable exception of the commit filter, for technical reasons). | |
c401b33c JS |
62 | Prior to that, the $GIT_COMMIT environment variable will be set to contain |
63 | the id of the commit being rewritten. Also, GIT_AUTHOR_NAME, | |
64 | GIT_AUTHOR_EMAIL, GIT_AUTHOR_DATE, GIT_COMMITTER_NAME, GIT_COMMITTER_EMAIL, | |
bf7c9021 RW |
65 | and GIT_COMMITTER_DATE are set according to the current commit. The values |
66 | of these variables after the filters have run, are used for the new commit. | |
67 | If any evaluation of <command> returns a non-zero exit status, the whole | |
68 | operation will be aborted. | |
c401b33c JS |
69 | |
70 | A 'map' function is available that takes an "original sha1 id" argument | |
71 | and outputs a "rewritten sha1 id" if the commit has been already | |
32c37c12 JS |
72 | rewritten, and "original sha1 id" otherwise; the 'map' function can |
73 | return several ids on separate lines if your commit filter emitted | |
74 | multiple commits. | |
c401b33c JS |
75 | |
76 | ||
77 | OPTIONS | |
78 | ------- | |
79 | ||
80 | --env-filter <command>:: | |
bf7c9021 RW |
81 | This filter may be used if you only need to modify the environment |
82 | in which the commit will be performed. Specifically, you might | |
83 | want to rewrite the author/committer name/email/time environment | |
5162e697 | 84 | variables (see linkgit:git-commit[1] for details). Do not forget |
c401b33c JS |
85 | to re-export the variables. |
86 | ||
87 | --tree-filter <command>:: | |
88 | This is the filter for rewriting the tree and its contents. | |
89 | The argument is evaluated in shell with the working | |
90 | directory set to the root of the checked out tree. The new tree | |
91 | is then used as-is (new files are auto-added, disappeared files | |
92 | are auto-removed - neither .gitignore files nor any other ignore | |
73616fd3 | 93 | rules *HAVE ANY EFFECT*!). |
c401b33c JS |
94 | |
95 | --index-filter <command>:: | |
96 | This is the filter for rewriting the index. It is similar to the | |
97 | tree filter but does not check out the tree, which makes it much | |
3bc427e0 TR |
98 | faster. Frequently used with `git rm \--cached |
99 | \--ignore-unmatch ...`, see EXAMPLES below. For hairy | |
100 | cases, see linkgit:git-update-index[1]. | |
c401b33c JS |
101 | |
102 | --parent-filter <command>:: | |
103 | This is the filter for rewriting the commit's parent list. | |
104 | It will receive the parent string on stdin and shall output | |
105 | the new parent string on stdout. The parent string is in | |
483bc4f0 | 106 | the format described in linkgit:git-commit-tree[1]: empty for |
c401b33c JS |
107 | the initial commit, "-p parent" for a normal commit and |
108 | "-p parent1 -p parent2 -p parent3 ..." for a merge commit. | |
109 | ||
110 | --msg-filter <command>:: | |
111 | This is the filter for rewriting the commit messages. | |
112 | The argument is evaluated in the shell with the original | |
113 | commit message on standard input; its standard output is | |
114 | used as the new commit message. | |
115 | ||
116 | --commit-filter <command>:: | |
117 | This is the filter for performing the commit. | |
118 | If this filter is specified, it will be called instead of the | |
ba020ef5 | 119 | 'git-commit-tree' command, with arguments of the form |
c401b33c JS |
120 | "<TREE_ID> [-p <PARENT_COMMIT_ID>]..." and the log message on |
121 | stdin. The commit id is expected on stdout. | |
122 | + | |
123 | As a special extension, the commit filter may emit multiple | |
c5833f6e | 124 | commit ids; in that case, the rewritten children of the original commit will |
c401b33c | 125 | have all of them as parents. |
f95eef15 JS |
126 | + |
127 | You can use the 'map' convenience function in this filter, and other | |
128 | convenience functions, too. For example, calling 'skip_commit "$@"' | |
129 | will leave out the current commit (but not its changes! If you want | |
ba020ef5 | 130 | that, use 'git-rebase' instead). |
d3240d93 PH |
131 | + |
132 | You can also use the 'git_commit_non_empty_tree "$@"' instead of | |
133 | 'git commit-tree "$@"' if you don't wish to keep commits with a single parent | |
134 | and that makes no change to the tree. | |
c401b33c JS |
135 | |
136 | --tag-name-filter <command>:: | |
137 | This is the filter for rewriting tag names. When passed, | |
138 | it will be called for every tag ref that points to a rewritten | |
139 | object (or to a tag object which points to a rewritten object). | |
140 | The original tag name is passed via standard input, and the new | |
141 | tag name is expected on standard output. | |
142 | + | |
143 | The original tags are not deleted, but can be overwritten; | |
5876b8ee | 144 | use "--tag-name-filter cat" to simply update the tags. In this |
c401b33c JS |
145 | case, be very careful and make sure you have the old tags |
146 | backed up in case the conversion has run afoul. | |
147 | + | |
1bf6551e BC |
148 | Nearly proper rewriting of tag objects is supported. If the tag has |
149 | a message attached, a new tag object will be created with the same message, | |
150 | author, and timestamp. If the tag has a signature attached, the | |
151 | signature will be stripped. It is by definition impossible to preserve | |
152 | signatures. The reason this is "nearly" proper, is because ideally if | |
153 | the tag did not change (points to the same object, has the same name, etc.) | |
154 | it should retain any signature. That is not the case, signatures will always | |
155 | be removed, buyer beware. There is also no support for changing the | |
156 | author or timestamp (or the tag message for that matter). Tags which point | |
157 | to other tags will be rewritten to point to the underlying commit. | |
c401b33c JS |
158 | |
159 | --subdirectory-filter <directory>:: | |
73616fd3 JS |
160 | Only look at the history which touches the given subdirectory. |
161 | The result will contain that directory (and only that) as its | |
162 | project root. | |
c401b33c | 163 | |
d3240d93 PH |
164 | --prune-empty:: |
165 | Some kind of filters will generate empty commits, that left the tree | |
166 | untouched. This switch allow git-filter-branch to ignore such | |
167 | commits. Though, this switch only applies for commits that have one | |
168 | and only one parent, it will hence keep merges points. Also, this | |
169 | option is not compatible with the use of '--commit-filter'. Though you | |
170 | just need to use the function 'git_commit_non_empty_tree "$@"' instead | |
171 | of the 'git commit-tree "$@"' idiom in your commit filter to make that | |
172 | happen. | |
173 | ||
5433235d GB |
174 | --original <namespace>:: |
175 | Use this option to set the namespace where the original commits | |
176 | will be stored. The default value is 'refs/original'. | |
177 | ||
c401b33c JS |
178 | -d <directory>:: |
179 | Use this option to set the path to the temporary directory used for | |
180 | rewriting. When applying a tree filter, the command needs to | |
bf7c9021 | 181 | temporarily check out the tree to some directory, which may consume |
c401b33c JS |
182 | considerable space in case of large projects. By default it |
183 | does this in the '.git-rewrite/' directory but you can override | |
184 | that choice by this parameter. | |
185 | ||
3240240f SB |
186 | -f:: |
187 | --force:: | |
ba020ef5 | 188 | 'git-filter-branch' refuses to start with an existing temporary |
dfd05e38 JS |
189 | directory or when there are already refs starting with |
190 | 'refs/original/', unless forced. | |
191 | ||
f448e24e | 192 | <rev-list options>...:: |
8afa4210 TR |
193 | Arguments for 'git-rev-list'. All positive refs included by |
194 | these options are rewritten. You may also specify options | |
195 | such as '--all', but you must use '--' to separate them from | |
196 | the 'git-filter-branch' options. | |
c401b33c JS |
197 | |
198 | ||
199 | Examples | |
200 | -------- | |
201 | ||
202 | Suppose you want to remove a file (containing confidential information | |
203 | or copyright violation) from all commits: | |
204 | ||
205 | ------------------------------------------------------- | |
dfd05e38 | 206 | git filter-branch --tree-filter 'rm filename' HEAD |
c401b33c JS |
207 | ------------------------------------------------------- |
208 | ||
e4d594c6 JL |
209 | However, if the file is absent from the tree of some commit, |
210 | a simple `rm filename` will fail for that tree and commit. | |
211 | Thus you may instead want to use `rm -f filename` as the script. | |
212 | ||
3bc427e0 TR |
213 | Using `\--index-filter` with 'git-rm' yields a significantly faster |
214 | version. Like with using `rm filename`, `git rm --cached filename` | |
215 | will fail if the file is absent from the tree of a commit. If you | |
216 | want to "completely forget" a file, it does not matter when it entered | |
217 | history, so we also add `\--ignore-unmatch`: | |
c401b33c | 218 | |
dfd05e38 | 219 | -------------------------------------------------------------------------- |
3bc427e0 | 220 | git filter-branch --index-filter 'git rm --cached --ignore-unmatch filename' HEAD |
dfd05e38 | 221 | -------------------------------------------------------------------------- |
c401b33c | 222 | |
8ef44519 | 223 | Now, you will get the rewritten history saved in HEAD. |
c401b33c | 224 | |
8afa4210 TR |
225 | To rewrite the repository to look as if `foodir/` had been its project |
226 | root, and discard all other history: | |
227 | ||
228 | ------------------------------------------------------- | |
229 | git filter-branch --subdirectory-filter foodir -- --all | |
230 | ------------------------------------------------------- | |
231 | ||
232 | Thus you can, e.g., turn a library subdirectory into a repository of | |
233 | its own. Note the `\--` that separates 'filter-branch' options from | |
234 | revision options, and the `\--all` to rewrite all branches and tags. | |
235 | ||
32c37c12 JS |
236 | To set a commit (which typically is at the tip of another |
237 | history) to be the parent of the current initial commit, in | |
238 | order to paste the other history behind the current history: | |
c401b33c | 239 | |
dfd05e38 JS |
240 | ------------------------------------------------------------------- |
241 | git filter-branch --parent-filter 'sed "s/^\$/-p <graft-id>/"' HEAD | |
242 | ------------------------------------------------------------------- | |
c401b33c | 243 | |
08203668 JS |
244 | (if the parent string is empty - which happens when we are dealing with |
245 | the initial commit - add graftcommit as a parent). Note that this assumes | |
c401b33c JS |
246 | history with a single root (that is, no merge without common ancestors |
247 | happened). If this is not the case, use: | |
248 | ||
dfd05e38 | 249 | -------------------------------------------------------------------------- |
c401b33c | 250 | git filter-branch --parent-filter \ |
41e86a37 | 251 | 'test $GIT_COMMIT = <commit-id> && echo "-p <graft-id>" || cat' HEAD |
dfd05e38 | 252 | -------------------------------------------------------------------------- |
c401b33c | 253 | |
32c37c12 JS |
254 | or even simpler: |
255 | ||
256 | ----------------------------------------------- | |
257 | echo "$commit-id $graft-id" >> .git/info/grafts | |
dfd05e38 | 258 | git filter-branch $graft-id..HEAD |
32c37c12 JS |
259 | ----------------------------------------------- |
260 | ||
c401b33c JS |
261 | To remove commits authored by "Darl McBribe" from the history: |
262 | ||
263 | ------------------------------------------------------------------------------ | |
264 | git filter-branch --commit-filter ' | |
265 | if [ "$GIT_AUTHOR_NAME" = "Darl McBribe" ]; | |
266 | then | |
f95eef15 | 267 | skip_commit "$@"; |
c401b33c JS |
268 | else |
269 | git commit-tree "$@"; | |
dfd05e38 | 270 | fi' HEAD |
c401b33c JS |
271 | ------------------------------------------------------------------------------ |
272 | ||
8451c565 | 273 | The function 'skip_commit' is defined as follows: |
f95eef15 JS |
274 | |
275 | -------------------------- | |
276 | skip_commit() | |
277 | { | |
278 | shift; | |
279 | while [ -n "$1" ]; | |
280 | do | |
281 | shift; | |
282 | map "$1"; | |
283 | shift; | |
284 | done; | |
285 | } | |
286 | -------------------------- | |
287 | ||
c401b33c JS |
288 | The shift magic first throws away the tree id and then the -p |
289 | parameters. Note that this handles merges properly! In case Darl | |
290 | committed a merge between P1 and P2, it will be propagated properly | |
291 | and all children of the merge will become merge commits with P1,P2 | |
292 | as their parents instead of the merge commit. | |
293 | ||
a1748890 | 294 | You can rewrite the commit log messages using `--msg-filter`. For |
ba020ef5 | 295 | example, 'git-svn-id' strings in a repository created by 'git-svn' can |
ed10d9aa MV |
296 | be removed this way: |
297 | ||
298 | ------------------------------------------------------- | |
a1748890 | 299 | git filter-branch --msg-filter ' |
ed10d9aa MV |
300 | sed -e "/^git-svn-id:/d" |
301 | ' | |
302 | ------------------------------------------------------- | |
f95eef15 | 303 | |
c401b33c JS |
304 | To restrict rewriting to only part of the history, specify a revision |
305 | range in addition to the new branch name. The new branch name will | |
ba020ef5 | 306 | point to the top-most revision that a 'git-rev-list' of this range |
c401b33c JS |
307 | will print. |
308 | ||
b8f42332 JS |
309 | If you need to add 'Acked-by' lines to, say, the last 10 commits (none |
310 | of which is a merge), use this command: | |
311 | ||
312 | -------------------------------------------------------- | |
313 | git filter-branch --msg-filter ' | |
314 | cat && | |
315 | echo "Acked-by: Bugs Bunny <bunny@bugzilla.org>" | |
316 | ' HEAD~10..HEAD | |
317 | -------------------------------------------------------- | |
318 | ||
08203668 JS |
319 | *NOTE* the changes introduced by the commits, and which are not reverted |
320 | by subsequent commits, will still be in the rewritten branch. If you want | |
c401b33c | 321 | to throw out _changes_ together with the commits, you should use the |
ba020ef5 | 322 | interactive mode of 'git-rebase'. |
c401b33c | 323 | |
08203668 | 324 | |
c401b33c JS |
325 | Consider this history: |
326 | ||
327 | ------------------ | |
328 | D--E--F--G--H | |
329 | / / | |
330 | A--B-----C | |
331 | ------------------ | |
332 | ||
333 | To rewrite only commits D,E,F,G,H, but leave A, B and C alone, use: | |
334 | ||
335 | -------------------------------- | |
dfd05e38 | 336 | git filter-branch ... C..H |
c401b33c JS |
337 | -------------------------------- |
338 | ||
339 | To rewrite commits E,F,G,H, use one of these: | |
340 | ||
341 | ---------------------------------------- | |
dfd05e38 JS |
342 | git filter-branch ... C..H --not D |
343 | git filter-branch ... D..H --not C | |
c401b33c JS |
344 | ---------------------------------------- |
345 | ||
346 | To move the whole tree into a subdirectory, or remove it from there: | |
347 | ||
348 | --------------------------------------------------------------- | |
349 | git filter-branch --index-filter \ | |
350 | 'git ls-files -s | sed "s-\t-&newsubdir/-" | | |
351 | GIT_INDEX_FILE=$GIT_INDEX_FILE.new \ | |
352 | git update-index --index-info && | |
dfd05e38 | 353 | mv $GIT_INDEX_FILE.new $GIT_INDEX_FILE' HEAD |
c401b33c JS |
354 | --------------------------------------------------------------- |
355 | ||
356 | ||
d0268de6 TR |
357 | |
358 | Checklist for Shrinking a Repository | |
359 | ------------------------------------ | |
360 | ||
361 | git-filter-branch is often used to get rid of a subset of files, | |
362 | usually with some combination of `\--index-filter` and | |
363 | `\--subdirectory-filter`. People expect the resulting repository to | |
364 | be smaller than the original, but you need a few more steps to | |
365 | actually make it smaller, because git tries hard not to lose your | |
366 | objects until you tell it to. First make sure that: | |
367 | ||
368 | * You really removed all variants of a filename, if a blob was moved | |
369 | over its lifetime. `git log \--name-only \--follow \--all \-- | |
370 | filename` can help you find renames. | |
371 | ||
372 | * You really filtered all refs: use `\--tag-name-filter cat \-- | |
373 | \--all` when calling git-filter-branch. | |
374 | ||
375 | Then there are two ways to get a smaller repository. A safer way is | |
376 | to clone, that keeps your original intact. | |
377 | ||
378 | * Clone it with `git clone +++file:///path/to/repo+++`. The clone | |
379 | will not have the removed objects. See linkgit:git-clone[1]. (Note | |
380 | that cloning with a plain path just hardlinks everything!) | |
381 | ||
382 | If you really don't want to clone it, for whatever reasons, check the | |
383 | following points instead (in this order). This is a very destructive | |
384 | approach, so *make a backup* or go back to cloning it. You have been | |
385 | warned. | |
386 | ||
387 | * Remove the original refs backed up by git-filter-branch: say `git | |
388 | for-each-ref \--format="%(refname)" refs/original/ | xargs -n 1 git | |
389 | update-ref -d`. | |
390 | ||
391 | * Expire all reflogs with `git reflog expire \--expire=now \--all`. | |
392 | ||
393 | * Garbage collect all unreferenced objects with `git gc \--prune=now` | |
394 | (or if your git-gc is not new enough to support arguments to | |
395 | `\--prune`, use `git repack -ad; git prune` instead). | |
396 | ||
397 | ||
c401b33c JS |
398 | Author |
399 | ------ | |
400 | Written by Petr "Pasky" Baudis <pasky@suse.cz>, | |
401 | and the git list <git@vger.kernel.org> | |
402 | ||
403 | Documentation | |
404 | -------------- | |
405 | Documentation by Petr Baudis and the git list. | |
406 | ||
407 | GIT | |
408 | --- | |
9e1f0a85 | 409 | Part of the linkgit:git[1] suite |