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.
+and GIT_COMMITTER_DATE are taken from the current commit and exported to
+the environment, in order to affect the author and committer identities of
+the replacement commit created by linkgit:git-commit-tree[1] after the
+filters have run.
+
If any evaluation of <command> returns a non-zero exit status, the whole
operation will be aborted.
and all children of the merge will become merge commits with P1,P2
as their parents instead of the merge commit.
+*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'.
+
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:
'
-------------------------------------------------------
-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.
-
If you need to add 'Acked-by' lines to, say, the last 10 commits (none
of which is a merge), use this command:
' HEAD~10..HEAD
--------------------------------------------------------
-*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'.
+The `--env-filter` option can be used to modify committer and/or author
+identity. For example, if you found out that your commits have the wrong
+identity due to a misconfigured user.email, you can make a correction,
+before publishing the project, like this:
+
+--------------------------------------------------------
+git filter-branch --env-filter '
+ if test "$GIT_AUTHOR_EMAIL" = "root@localhost"
+ then
+ GIT_AUTHOR_EMAIL=john@example.com
+ export GIT_AUTHOR_EMAIL
+ fi
+ if test "$GIT_COMMITTER_EMAIL" = "root@localhost"
+ then
+ GIT_COMMITTER_EMAIL=john@example.com
+ export GIT_COMMITTER_EMAIL
+ fi
+' -- --all
+--------------------------------------------------------
+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.
Consider this history: