# pwd = /var/spool/cyrus/mail/X/user/XX
for mail in ~/Maildir/.Mailbox/cur/*
do
    cp $mail .
done


# convert from \n to \r\n (unix2dos)
# and rename to e.g. 509. from what ever they used to be.
# as far as I can tell the numbering doesn't matter as 
# long as it's unique (within a folder)
c=0
for f in *
do
    if [ -f $f ] ; then
        if ! grep cyrus $f >/dev/null ; then
            perl -pi -e "s/\n/\r\n/;" $f
            mv $f $c.
            let c=c+1
        fi
    fi
done

# set ownership (cyrus owns all mail)
chown cyrus:mail *

# reconstruct mailbox for user.. if you don't specify a
# mailbox, cyrreconstruct will do everything.
su - cyrus -c "/usr/sbin/cyrreconstruct -f -m user/XX"