Rewrite emails in a git history

git-rewrite-email.sh

git filter-branch --commit-filter '
        if [ "$GIT_AUTHOR_EMAIL" = "old.mail@example.com" ];
        then
                GIT_AUTHOR_NAME="username";
                GIT_AUTHOR_EMAIL="new.mail@example.com";
                git commit-tree "$@";
        else
                git commit-tree "$@";
        fi' HEAD