1GIT-FILTER-BRANCH(1) Git Manual GIT-FILTER-BRANCH(1)
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6 git-filter-branch - Rewrite branches
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9 git filter-branch [--setup <command>] [--subdirectory-filter <directory>]
10 [--env-filter <command>] [--tree-filter <command>]
11 [--index-filter <command>] [--parent-filter <command>]
12 [--msg-filter <command>] [--commit-filter <command>]
13 [--tag-name-filter <command>] [--prune-empty]
14 [--original <namespace>] [-d <directory>] [-f | --force]
15 [--state-branch <branch>] [--] [<rev-list options>...]
16
19 git filter-branch has a plethora of pitfalls that can produce
20 non-obvious manglings of the intended history rewrite (and can leave
21 you with little time to investigate such problems since it has such
22 abysmal performance). These safety and performance issues cannot be
23 backward compatibly fixed and as such, its use is not recommended.
24 Please use an alternative history filtering tool such as git
25 filter-repo[1]. If you still need to use git filter-branch, please
26 carefully read the section called “SAFETY” (and the section called
27 “PERFORMANCE”) to learn about the land mines of filter-branch, and then
28 vigilantly avoid as many of the hazards listed there as reasonably
29 possible.
30
32 Lets you rewrite Git revision history by rewriting the branches
33 mentioned in the <rev-list options>, applying custom filters on each
34 revision. Those filters can modify each tree (e.g. removing a file or
35 running a perl rewrite on all files) or information about each commit.
36 Otherwise, all information (including original commit times or merge
37 information) will be preserved.
38 The command will only rewrite the positive refs mentioned in the
40 command line (e.g. if you pass a..b, only b will be rewritten). If you
41 specify no filters, the commits will be recommitted without any
42 changes, which would normally have no effect. Nevertheless, this may be
43 useful in the future for compensating for some Git bugs or such,
44 therefore such a usage is permitted.
45 NOTE: This command honors .git/info/grafts file and refs in the
47 refs/replace/ namespace. If you have any grafts or replacement refs
48 defined, running this command will make them permanent.
49 WARNING! The rewritten history will have different object names for all
51 the objects and will not converge with the original branch. You will
52 not be able to easily push and distribute the rewritten branch on top
53 of the original branch. Please do not use this command if you do not
54 know the full implications, and avoid using it anyway, if a simple
55 single commit would suffice to fix your problem. (See the "RECOVERING
56 FROM UPSTREAM REBASE" section in git-rebase(1) for further information
57 about rewriting published history.)
58 Always verify that the rewritten version is correct: The original refs,
60 if different from the rewritten ones, will be stored in the namespace
61 refs/original/.
62 Note that since this operation is very I/O expensive, it might be a
64 good idea to redirect the temporary directory off-disk with the -d
65 option, e.g. on tmpfs. Reportedly the speedup is very noticeable.
66 Filters
68 The filters are applied in the order as listed below. The <command>
69 argument is always evaluated in the shell context using the eval
70 command (with the notable exception of the commit filter, for technical
71 reasons). Prior to that, the $GIT_COMMIT environment variable will be
72 set to contain the id of the commit being rewritten. Also,
73 GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, GIT_AUTHOR_DATE, GIT_COMMITTER_NAME,
74 GIT_COMMITTER_EMAIL, and GIT_COMMITTER_DATE are taken from the current
75 commit and exported to the environment, in order to affect the author
76 and committer identities of the replacement commit created by git-
77 commit-tree(1) after the filters have run.
78 If any evaluation of <command> returns a non-zero exit status, the
80 whole operation will be aborted.
81 A map function is available that takes an "original sha1 id" argument
83 and outputs a "rewritten sha1 id" if the commit has been already
84 rewritten, and "original sha1 id" otherwise; the map function can
85 return several ids on separate lines if your commit filter emitted
86 multiple commits.
87
89 --setup <command>
90 This is not a real filter executed for each commit but a one time
91 setup just before the loop. Therefore no commit-specific variables
92 are defined yet. Functions or variables defined here can be used or
93 modified in the following filter steps except the commit filter,
94 for technical reasons.
95 --subdirectory-filter <directory>
97 Only look at the history which touches the given subdirectory. The
98 result will contain that directory (and only that) as its project
99 root. Implies the section called “Remap to ancestor”.
100 --env-filter <command>
102 This filter may be used if you only need to modify the environment
103 in which the commit will be performed. Specifically, you might want
104 to rewrite the author/committer name/email/time environment
105 variables (see git-commit-tree(1) for details).
106 --tree-filter <command>
108 This is the filter for rewriting the tree and its contents. The
109 argument is evaluated in shell with the working directory set to
110 the root of the checked out tree. The new tree is then used as-is
111 (new files are auto-added, disappeared files are auto-removed -
112 neither .gitignore files nor any other ignore rules HAVE ANY
113 EFFECT!).
114 --index-filter <command>
116 This is the filter for rewriting the index. It is similar to the
117 tree filter but does not check out the tree, which makes it much
118 faster. Frequently used with git rm --cached --ignore-unmatch ...,
119 see EXAMPLES below. For hairy cases, see git-update-index(1).
120 --parent-filter <command>
122 This is the filter for rewriting the commit’s parent list. It will
123 receive the parent string on stdin and shall output the new parent
124 string on stdout. The parent string is in the format described in
125 git-commit-tree(1): empty for the initial commit, "-p parent" for a
126 normal commit and "-p parent1 -p parent2 -p parent3 ..." for a
127 merge commit.
128 --msg-filter <command>
130 This is the filter for rewriting the commit messages. The argument
131 is evaluated in the shell with the original commit message on
132 standard input; its standard output is used as the new commit
133 message.
134 --commit-filter <command>
136 This is the filter for performing the commit. If this filter is
137 specified, it will be called instead of the git commit-tree
138 command, with arguments of the form "<TREE_ID> [(-p
139 <PARENT_COMMIT_ID>)...]" and the log message on stdin. The commit
140 id is expected on stdout.
141 As a special extension, the commit filter may emit multiple commit
143 ids; in that case, the rewritten children of the original commit
144 will have all of them as parents.
145 You can use the map convenience function in this filter, and other
147 convenience functions, too. For example, calling skip_commit "$@"
148 will leave out the current commit (but not its changes! If you want
149 that, use git rebase instead).
150 You can also use the git_commit_non_empty_tree "$@" instead of git
152 commit-tree "$@" if you don’t wish to keep commits with a single
153 parent and that makes no change to the tree.
154 --tag-name-filter <command>
156 This is the filter for rewriting tag names. When passed, it will be
157 called for every tag ref that points to a rewritten object (or to a
158 tag object which points to a rewritten object). The original tag
159 name is passed via standard input, and the new tag name is expected
160 on standard output.
161 The original tags are not deleted, but can be overwritten; use
163 "--tag-name-filter cat" to simply update the tags. In this case, be
164 very careful and make sure you have the old tags backed up in case
165 the conversion has run afoul.
166 Nearly proper rewriting of tag objects is supported. If the tag has
168 a message attached, a new tag object will be created with the same
169 message, author, and timestamp. If the tag has a signature
170 attached, the signature will be stripped. It is by definition
171 impossible to preserve signatures. The reason this is "nearly"
172 proper, is because ideally if the tag did not change (points to the
173 same object, has the same name, etc.) it should retain any
174 signature. That is not the case, signatures will always be removed,
175 buyer beware. There is also no support for changing the author or
176 timestamp (or the tag message for that matter). Tags which point to
177 other tags will be rewritten to point to the underlying commit.
178 --prune-empty
180 Some filters will generate empty commits that leave the tree
181 untouched. This option instructs git-filter-branch to remove such
182 commits if they have exactly one or zero non-pruned parents; merge
183 commits will therefore remain intact. This option cannot be used
184 together with --commit-filter, though the same effect can be
185 achieved by using the provided git_commit_non_empty_tree function
186 in a commit filter.
187 --original <namespace>
189 Use this option to set the namespace where the original commits
190 will be stored. The default value is refs/original.
191 -d <directory>
193 Use this option to set the path to the temporary directory used for
194 rewriting. When applying a tree filter, the command needs to
195 temporarily check out the tree to some directory, which may consume
196 considerable space in case of large projects. By default it does
197 this in the .git-rewrite/ directory but you can override that
198 choice by this parameter.
199 -f, --force
201 git filter-branch refuses to start with an existing temporary
202 directory or when there are already refs starting with
203 refs/original/, unless forced.
204 --state-branch <branch>
206 This option will cause the mapping from old to new objects to be
207 loaded from named branch upon startup and saved as a new commit to
208 that branch upon exit, enabling incremental of large trees. If
209 <branch> does not exist it will be created.
210 <rev-list options>...
212 Arguments for git rev-list. All positive refs included by these
213 options are rewritten. You may also specify options such as --all,
214 but you must use -- to separate them from the git filter-branch
215 options. Implies the section called “Remap to ancestor”.
216 Remap to ancestor
218 By using git-rev-list(1) arguments, e.g., path limiters, you can limit
219 the set of revisions which get rewritten. However, positive refs on the
220 command line are distinguished: we don’t let them be excluded by such
221 limiters. For this purpose, they are instead rewritten to point at the
222 nearest ancestor that was not excluded.
223
225 On success, the exit status is 0. If the filter can’t find any commits
226 to rewrite, the exit status is 2. On any other error, the exit status
227 may be any other non-zero value.
228
230 Suppose you want to remove a file (containing confidential information
231 or copyright violation) from all commits:
232 git filter-branch --tree-filter 'rm filename' HEAD
234 However, if the file is absent from the tree of some commit, a simple
237 rm filename will fail for that tree and commit. Thus you may instead
238 want to use rm -f filename as the script.
239 Using --index-filter with git rm yields a significantly faster version.
241 Like with using rm filename, git rm --cached filename will fail if the
242 file is absent from the tree of a commit. If you want to "completely
243 forget" a file, it does not matter when it entered history, so we also
244 add --ignore-unmatch:
245 git filter-branch --index-filter 'git rm --cached --ignore-unmatch filename' HEAD
247 Now, you will get the rewritten history saved in HEAD.
250 To rewrite the repository to look as if foodir/ had been its project
252 root, and discard all other history:
253 git filter-branch --subdirectory-filter foodir -- --all
255 Thus you can, e.g., turn a library subdirectory into a repository of
258 its own. Note the -- that separates filter-branch options from revision
259 options, and the --all to rewrite all branches and tags.
260 To set a commit (which typically is at the tip of another history) to
262 be the parent of the current initial commit, in order to paste the
263 other history behind the current history:
264 git filter-branch --parent-filter 'sed "s/^\$/-p <graft-id>/"' HEAD
266 (if the parent string is empty - which happens when we are dealing with
269 the initial commit - add graftcommit as a parent). Note that this
270 assumes history with a single root (that is, no merge without common
271 ancestors happened). If this is not the case, use:
272 git filter-branch --parent-filter \
274 'test $GIT_COMMIT = <commit-id> && echo "-p <graft-id>" || cat' HEAD
275 or even simpler:
278 git replace --graft $commit-id $graft-id
280 git filter-branch $graft-id..HEAD
281 To remove commits authored by "Darl McBribe" from the history:
284 git filter-branch --commit-filter '
286 if [ "$GIT_AUTHOR_NAME" = "Darl McBribe" ];
287 then
288 skip_commit "$@";
289 else
290 git commit-tree "$@";
291 fi' HEAD
292 The function skip_commit is defined as follows:
295 skip_commit()
297 {
298 shift;
299 while [ -n "$1" ];
300 do
301 shift;
302 map "$1";
303 shift;
304 done;
305 }
306 The shift magic first throws away the tree id and then the -p
309 parameters. Note that this handles merges properly! In case Darl
310 committed a merge between P1 and P2, it will be propagated properly and
311 all children of the merge will become merge commits with P1,P2 as their
312 parents instead of the merge commit.
313 NOTE the changes introduced by the commits, and which are not reverted
315 by subsequent commits, will still be in the rewritten branch. If you
316 want to throw out changes together with the commits, you should use the
317 interactive mode of git rebase.
318 You can rewrite the commit log messages using --msg-filter. For
320 example, git svn-id strings in a repository created by git svn can be
321 removed this way:
322 git filter-branch --msg-filter '
324 sed -e "/^git-svn-id:/d"
325 '
326 If you need to add Acked-by lines to, say, the last 10 commits (none of
329 which is a merge), use this command:
330 git filter-branch --msg-filter '
332 cat &&
333 echo "Acked-by: Bugs Bunny <bunny@bugzilla.org>"
334 ' HEAD~10..HEAD
335 The --env-filter option can be used to modify committer and/or author
338 identity. For example, if you found out that your commits have the
339 wrong identity due to a misconfigured user.email, you can make a
340 correction, before publishing the project, like this:
341 git filter-branch --env-filter '
343 if test "$GIT_AUTHOR_EMAIL" = "root@localhost"
344 then
345 GIT_AUTHOR_EMAIL=john@example.com
346 fi
347 if test "$GIT_COMMITTER_EMAIL" = "root@localhost"
348 then
349 GIT_COMMITTER_EMAIL=john@example.com
350 fi
351 ' -- --all
352 To restrict rewriting to only part of the history, specify a revision
355 range in addition to the new branch name. The new branch name will
356 point to the top-most revision that a git rev-list of this range will
357 print.
358 Consider this history:
360 D--E--F--G--H
362 / /
363 A--B-----C
364 To rewrite only commits D,E,F,G,H, but leave A, B and C alone, use:
367 git filter-branch ... C..H
369 To rewrite commits E,F,G,H, use one of these:
372 git filter-branch ... C..H --not D
374 git filter-branch ... D..H --not C
375 To move the whole tree into a subdirectory, or remove it from there:
378 git filter-branch --index-filter \
380 'git ls-files -s | sed "s-\t\"*-&newsubdir/-" |
381 GIT_INDEX_FILE=$GIT_INDEX_FILE.new \
382 git update-index --index-info &&
383 mv "$GIT_INDEX_FILE.new" "$GIT_INDEX_FILE"' HEAD
384
387 git-filter-branch can be used to get rid of a subset of files, usually
388 with some combination of --index-filter and --subdirectory-filter.
389 People expect the resulting repository to be smaller than the original,
390 but you need a few more steps to actually make it smaller, because Git
391 tries hard not to lose your objects until you tell it to. First make
392 sure that:
393 · You really removed all variants of a filename, if a blob was moved
395 over its lifetime. git log --name-only --follow --all -- filename
396 can help you find renames.
397 · You really filtered all refs: use --tag-name-filter cat -- --all
399 when calling git-filter-branch.
400 Then there are two ways to get a smaller repository. A safer way is to
402 clone, that keeps your original intact.
403 · Clone it with git clone file:///path/to/repo. The clone will not
405 have the removed objects. See git-clone(1). (Note that cloning with
406 a plain path just hardlinks everything!)
407 If you really don’t want to clone it, for whatever reasons, check the
409 following points instead (in this order). This is a very destructive
410 approach, so make a backup or go back to cloning it. You have been
411 warned.
412 · Remove the original refs backed up by git-filter-branch: say git
414 for-each-ref --format="%(refname)" refs/original/ | xargs -n 1 git
415 update-ref -d.
416 · Expire all reflogs with git reflog expire --expire=now --all.
418 · Garbage collect all unreferenced objects with git gc --prune=now
420 (or if your git-gc is not new enough to support arguments to
421 --prune, use git repack -ad; git prune instead).
422
424 The performance of git-filter-branch is glacially slow; its design
425 makes it impossible for a backward-compatible implementation to ever be
426 fast:
427 · In editing files, git-filter-branch by design checks out each and
429 every commit as it existed in the original repo. If your repo has
430 10^5 files and 10^5 commits, but each commit only modifies 5 files,
431 then git-filter-branch will make you do 10^10 modifications,
432 despite only having (at most) 5*10^5 unique blobs.
433 · If you try and cheat and try to make git-filter-branch only work on
435 files modified in a commit, then two things happen
436 · you run into problems with deletions whenever the user is
438 simply trying to rename files (because attempting to delete
439 files that don’t exist looks like a no-op; it takes some
440 chicanery to remap deletes across file renames when the renames
441 happen via arbitrary user-provided shell)
442 · even if you succeed at the map-deletes-for-renames chicanery,
444 you still technically violate backward compatibility because
445 users are allowed to filter files in ways that depend upon
446 topology of commits instead of filtering solely based on file
447 contents or names (though this has not been observed in the
448 wild).
449 · Even if you don’t need to edit files but only want to e.g. rename
451 or remove some and thus can avoid checking out each file (i.e. you
452 can use --index-filter), you still are passing shell snippets for
453 your filters. This means that for every commit, you have to have a
454 prepared git repo where those filters can be run. That’s a
455 significant setup.
456 · Further, several additional files are created or updated per commit
458 by git-filter-branch. Some of these are for supporting the
459 convenience functions provided by git-filter-branch (such as
460 map()), while others are for keeping track of internal state (but
461 could have also been accessed by user filters; one of
462 git-filter-branch’s regression tests does so). This essentially
463 amounts to using the filesystem as an IPC mechanism between
464 git-filter-branch and the user-provided filters. Disks tend to be a
465 slow IPC mechanism, and writing these files also effectively
466 represents a forced synchronization point between separate
467 processes that we hit with every commit.
468 · The user-provided shell commands will likely involve a pipeline of
470 commands, resulting in the creation of many processes per commit.
471 Creating and running another process takes a widely varying amount
472 of time between operating systems, but on any platform it is very
473 slow relative to invoking a function.
474 · git-filter-branch itself is written in shell, which is kind of
476 slow. This is the one performance issue that could be
477 backward-compatibly fixed, but compared to the above problems that
478 are intrinsic to the design of git-filter-branch, the language of
479 the tool itself is a relatively minor issue.
480 · Side note: Unfortunately, people tend to fixate on the
482 written-in-shell aspect and periodically ask if
483 git-filter-branch could be rewritten in another language to fix
484 the performance issues. Not only does that ignore the bigger
485 intrinsic problems with the design, it’d help less than you’d
486 expect: if git-filter-branch itself were not shell, then the
487 convenience functions (map(), skip_commit(), etc) and the
488 --setup argument could no longer be executed once at the
489 beginning of the program but would instead need to be prepended
490 to every user filter (and thus re-executed with every commit).
491 The git filter-repo[1] tool is an alternative to git-filter-branch
493 which does not suffer from these performance problems or the safety
494 problems (mentioned below). For those with existing tooling which
495 relies upon git-filter-branch, git repo-filter also provides
496 filter-lamely[2], a drop-in git-filter-branch replacement (with a few
497 caveats). While filter-lamely suffers from all the same safety issues
498 as git-filter-branch, it at least ameloriates the performance issues a
499 little.
500
502 git-filter-branch is riddled with gotchas resulting in various ways to
503 easily corrupt repos or end up with a mess worse than what you started
504 with:
505 · Someone can have a set of "working and tested filters" which they
507 document or provide to a coworker, who then runs them on a
508 different OS where the same commands are not working/tested (some
509 examples in the git-filter-branch manpage are also affected by
510 this). BSD vs. GNU userland differences can really bite. If lucky,
511 error messages are spewed. But just as likely, the commands either
512 don’t do the filtering requested, or silently corrupt by making
513 some unwanted change. The unwanted change may only affect a few
514 commits, so it’s not necessarily obvious either. (The fact that
515 problems won’t necessarily be obvious means they are likely to go
516 unnoticed until the rewritten history is in use for quite a while,
517 at which point it’s really hard to justify another flag-day for
518 another rewrite.)
519 · Filenames with spaces are often mishandled by shell snippets since
521 they cause problems for shell pipelines. Not everyone is familiar
522 with find -print0, xargs -0, git-ls-files -z, etc. Even people who
523 are familiar with these may assume such flags are not relevant
524 because someone else renamed any such files in their repo back
525 before the person doing the filtering joined the project. And
526 often, even those familiar with handling arguments with spaces may
527 not do so just because they aren’t in the mindset of thinking about
528 everything that could possibly go wrong.
529 · Non-ascii filenames can be silently removed despite being in a
531 desired directory. Keeping only wanted paths is often done using
532 pipelines like git ls-files | grep -v ^WANTED_DIR/ | xargs git rm.
533 ls-files will only quote filenames if needed, so folks may not
534 notice that one of the files didn’t match the regex (at least not
535 until it’s much too late). Yes, someone who knows about
536 core.quotePath can avoid this (unless they have other special
537 characters like \t, \n, or "), and people who use ls-files -z with
538 something other than grep can avoid this, but that doesn’t mean
539 they will.
540 · Similarly, when moving files around, one can find that filenames
542 with non-ascii or special characters end up in a different
543 directory, one that includes a double quote character. (This is
544 technically the same issue as above with quoting, but perhaps an
545 interesting different way that it can and has manifested as a
546 problem.)
547 · It’s far too easy to accidentally mix up old and new history. It’s
549 still possible with any tool, but git-filter-branch almost invites
550 it. If lucky, the only downside is users getting frustrated that
551 they don’t know how to shrink their repo and remove the old stuff.
552 If unlucky, they merge old and new history and end up with multiple
553 "copies" of each commit, some of which have unwanted or sensitive
554 files and others which don’t. This comes about in multiple
555 different ways:
556 · the default to only doing a partial history rewrite (--all is
558 not the default and few examples show it)
559 · the fact that there’s no automatic post-run cleanup
561 · the fact that --tag-name-filter (when used to rename tags)
563 doesn’t remove the old tags but just adds new ones with the new
564 name
565 · the fact that little educational information is provided to
567 inform users of the ramifications of a rewrite and how to avoid
568 mixing old and new history. For example, this man page
569 discusses how users need to understand that they need to rebase
570 their changes for all their branches on top of new history (or
571 delete and reclone), but that’s only one of multiple concerns
572 to consider. See the "DISCUSSION" section of the git
573 filter-repo manual page for more details.
574 · Annotated tags can be accidentally converted to lightweight tags,
576 due to either of two issues:
577 · Someone can do a history rewrite, realize they messed up,
579 restore from the backups in refs/original/, and then redo their
580 git-filter-branch command. (The backup in refs/original/ is not
581 a real backup; it dereferences tags first.)
582 · Running git-filter-branch with either --tags or --all in your
584 <rev-list options>. In order to retain annotated tags as
585 annotated, you must use --tag-name-filter (and must not have
586 restored from refs/original/ in a previously botched rewrite).
587 · Any commit messages that specify an encoding will become corrupted
589 by the rewrite; git-filter-branch ignores the encoding, takes the
590 original bytes, and feeds it to commit-tree without telling it the
591 proper encoding. (This happens whether or not --msg-filter is
592 used.)
593 · Commit messages (even if they are all UTF-8) by default become
595 corrupted due to not being updated — any references to other commit
596 hashes in commit messages will now refer to no-longer-extant
597 commits.
598 · There are no facilities for helping users find what unwanted crud
600 they should delete, which means they are much more likely to have
601 incomplete or partial cleanups that sometimes result in confusion
602 and people wasting time trying to understand. (For example, folks
603 tend to just look for big files to delete instead of big
604 directories or extensions, and once they do so, then sometime later
605 folks using the new repository who are going through history will
606 notice a build artifact directory that has some files but not
607 others, or a cache of dependencies (node_modules or similar) which
608 couldn’t have ever been functional since it’s missing some files.)
609 · If --prune-empty isn’t specified, then the filtering process can
611 create hoards of confusing empty commits
612 · If --prune-empty is specified, then intentionally placed empty
614 commits from before the filtering operation are also pruned instead
615 of just pruning commits that became empty due to filtering rules.
616 · If --prune empty is specified, sometimes empty commits are missed
618 and left around anyway (a somewhat rare bug, but it happens...)
619 · A minor issue, but users who have a goal to update all names and
621 emails in a repository may be led to --env-filter which will only
622 update authors and committers, missing taggers.
623 · If the user provides a --tag-name-filter that maps multiple tags to
625 the same name, no warning or error is provided; git-filter-branch
626 simply overwrites each tag in some undocumented pre-defined order
627 resulting in only one tag at the end. (A git-filter-branch
628 regression test requires this surprising behavior.)
629 Also, the poor performance of git-filter-branch often leads to safety
631 issues:
632 · Coming up with the correct shell snippet to do the filtering you
634 want is sometimes difficult unless you’re just doing a trivial
635 modification such as deleting a couple files. Unfortunately, people
636 often learn if the snippet is right or wrong by trying it out, but
637 the rightness or wrongness can vary depending on special
638 circumstances (spaces in filenames, non-ascii filenames, funny
639 author names or emails, invalid timezones, presence of grafts or
640 replace objects, etc.), meaning they may have to wait a long time,
641 hit an error, then restart. The performance of git-filter-branch is
642 so bad that this cycle is painful, reducing the time available to
643 carefully re-check (to say nothing about what it does to the
644 patience of the person doing the rewrite even if they do
645 technically have more time available). This problem is extra
646 compounded because errors from broken filters may not be shown for
647 a long time and/or get lost in a sea of output. Even worse, broken
648 filters often just result in silent incorrect rewrites.
649 · To top it all off, even when users finally find working commands,
651 they naturally want to share them. But they may be unaware that
652 their repo didn’t have some special cases that someone else’s does.
653 So, when someone else with a different repository runs the same
654 commands, they get hit by the problems above. Or, the user just
655 runs commands that really were vetted for special cases, but they
656 run it on a different OS where it doesn’t work, as noted above.
657
659 Part of the git(1) suite
660
662 1. git filter-repo
663 https://github.com/newren/git-filter-repo/
664 2. filter-lamely
666 https://github.com/newren/git-filter-repo/blob/master/contrib/filter-repo-demos/filter-lamely
667Git 2.24.1 12/10/2019 GIT-FILTER-BRANCH(1)