information) will be preserved.
The command will only rewrite the _positive_ refs mentioned in the
-command line (i.e. if you pass 'a..b', only 'b' will be rewritten).
+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,
if different from the rewritten ones, will be stored in the namespace
'refs/original/'.
-Note that since this operation is extensively I/O expensive, it might
+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.
~~~~~~~
The filters are applied in the order as listed below. The <command>
-argument is always evaluated in shell using the 'eval' command (with the
-notable exception of the commit filter, for technical reasons).
+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. If any
-evaluation of <command> returns a non-zero exit status, the whole operation
-will be aborted.
+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
-------
--env-filter <command>::
- This is the filter for modifying the environment in which
- the commit will be performed. Specifically, you might want
- to rewrite the author/committer name/email/time environment
+ 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.
case, be very careful and make sure you have the old tags
backed up in case the conversion has run afoul.
+
-Note that there is currently no support for proper rewriting of
-tag objects; in layman terms, if the tag has a message or signature
-attached, the rewritten tag won't have it. Sorry. (It is by
-definition impossible to preserve signatures at any rate.)
+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.
-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
- temporary checkout the tree to some directory, which may consume
+ 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.
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.
+
A significantly faster version:
--------------------------------------------------------------------------
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 `--message-filter`. For
+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 --message-filter '
+git filter-branch --msg-filter '
sed -e "/^git-svn-id:/d"
'
-------------------------------------------------------