How to change author email at commit time with hooks

Question

Question says it all.

I want to give my users some privacy by obfuscating their real email addresses in commits by aliases of my own. Is there a hook that can help m

Answer 1

http://progit.org/book/ch6-4.html explains how to rewrite history. Near the bottom, there ist this command

git filter-branch --commit-filter '
    if [ "$GIT_AUTHOR_EMAIL" = "schacon@localhost" ];
    then
            GIT_AUTHOR_NAME="Scott Chacon";
            GIT_AUTHOR_EMAIL="schacon@example.com";
            git commit-tree "$@";
    else
            git commit-tree "$@";
    fi' HEAD

which changes all commits from schacon@localhost to be from schacon@example.com.

Caveat: this changes ALL commit-ids from the earliest email-change onward.