#!/bin/sh

git filter-branch --env-filter '
        if [ "$GIT_AUTHOR_EMAIL" = "<XXX>" ]; then
                export GIT_AUTHOR_EMAIL="<YYY>";
                export GIT_COMMITTER_EMAIL="<YYY>";
                git commit-tree "$@";
        else
                git commit-tree "$@";
        fi' HEAD~6

$ sh change-name.sh
Rewrite 1caee75b09bc5a360f792e6eb15b633038d8c222 (1/6)usage: git commit-tree <sha1> [-p <sha1>]* < changelog
env filter failed:
        if [ "$GIT_AUTHOR_EMAIL" = "<XXX>" ]; then
                export GIT_AUTHOR_EMAIL="<YYY>";
                export GIT_COMMITTER_EMAIL="<YYY>";
                git commit-tree "$@";
        else
                git commit-tree "$@";
        fi