mkdir core
git mv includes core/
git mv misc core/
git mv modules core/
git mv scripts core/
git mv themes core/

git mv authorize.php core/
git mv cron.php core/
git mv install.php core/
git mv update.php core/          
git mv xmlrpc.php core/

git mv CHANGELOG.txt core/
git mv COPYRIGHT.txt core/
git mv INSTALL.* core/
git mv LICENSE.txt core/
git mv MAINTAINERS.txt core/
git mv UPGRADE.txt core/

git commit -m "#22336 by [attribution list] Move all core Drupal files under a core subdirectory."