Re: Retroactively change email signature?

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Jan 2, 2008, 21:24 UTC
Message-ID: <alpine.LFD.1.00.0801021316080.3010@woody.linux-foundation.org>
In-Reply-To: <9b3e2dc20801021237v4d5d236fn3d2643502b9bb78f@mail.gmail.com>

On Wed, 2 Jan 2008, Stephen Sinclair wrote:

Show 5 quoted lines

> 
> Is it possible to retroactively change the author and email of several
> commits?  Perhaps some sort of search-and-replace for the commit
> metadata?  Even for older commits, I'd like to change the email
> addresses to my current address.

See

	man git-filter-branch

and the "--env-filter" flag (and "--msg-filter" if you also want to change things like Sign-off's etc in the message text itself)

BUT! See also the big bold-face warning: using "filter-branch" will not change old commits, it will create a series of *new* commits that bear a striking resemblance to the old ones, but are not the same. So you'll have a totally new history.

That matters for things like
 - if you've already publicised the old history, you need to tell people 
   that they should fetch things anew
 - if you refer to the commit SHA1's elsewhere (like in commit messages 
   that revert previous commits), those SHA1's are still "valid", but they 
   refer to the *old* history, not the new history you created.

(I don't think git-filter-branch even exposes any easy way to remap the "revert commit xyz" messages in the message format. It's not technically hard to use a --msg-filter for it, but it seems a big bother).

		Linus