This will move messages from one IMAP system to another
php ./imap-move.php \
--source imap-ssl://userA:secret-password@imap.example.com:993/ \
--target imap-ssl://userB:secret-passwrod@imap.example.com:993/sub-folder \
[ --wipe --fake --copy ]
--fake to just list what would be copied
--wipe to remove messages after they are copied (move)
--copy to store copies of the messages in a path
Included is a shell wrapper to make life a bit easier, see imap-move.sh