#!/bin/bash

SQL="select email from mail_accounts where enabled=1"

LINES=$( echo $SQL | /usr/bin/mysql -u mail --password=?????????? mail )

for M in $LINES; do
  if [ $M != "email" ]; then
    echo "x GETQUOTAROOT Inbox" | USER=$M /usr/sbin/dovecot --exec-mail imap
  fi
done