[CentOS] dovecot/procmail w/maildir format?

--On Friday, February 22, 2008 9:48 PM +0000 Anne Wilson 
<cannewilson at googlemail.com> wrote:

> I don't know of any convenient way if you are talking huge amounts.  I
> simply  created maildir folders to match each of the mbox ones, just
> slightly  modifying the name, and moved the messages into the new boxes.
> Finally I  deleted the old boxes and renamed the new ones.

What did you use to "move" the message?