usermod change username problem

[Zhengquan Zhang <zhang.zhengquan@gmail.com>]

Dear Debian community:
I have got a specific problem using usermod to change my previous
username olduser to newuser.

This is what I use:
sudo usermod -l newuser -md  /home/newuser olduser[:w

newuser is the new login name and -md use /home/newuser as the new
home directory and moves /home/olduser to /home/newuser.

The problem is after I did all this I found that in /home/newuser
the file ownership becomes newuser:olduser. So the group
ownership is still olduser. I know I can use chgrp to change
group owner olduser to newuser. But I guess there are simpler ways to do
that.

So basically I don't want to use olduser as my username again and want
to change 'everything' associated with olduser to become newuser. such
the home directory, spoolfile, cron, etc... and I dont want the olduser
appear again.

Thanks for any suggestions.

-- 
Zhengquan