[Dovecot] batch convert mbox to maildir

[Netlink Tech]

Hello,
I have used mb2md for an individual user like this:

su ~username
cd ~
./mb2md -m

This converted /var/spool/mail/username mbox to 
/home/users/username/Maildir just as I expected.

To convert 100s of users the same way would be a chore (su as each user 
for permissions, etc.).

Is there a way to batch process all /var/spool/mail/$USER to 
/home/users/$USER/Maildir with the correct permissions/file owners for 
each user?