resetting admin password on a Mac

I had a client with a Mac where we did not have the admin credentials for the sole administrator on the laptop.  I was luckily able to find this option to tell the mac to set itself up from scratch by removing the file that tells the Mac it has already gone through the initial setup process so it goes through the initial setup process again on the next reboot.  That is described here:

http://osxdaily.com/2010/08/10/forgot-mac-password-how-to-reset-mac-password/

In case this that post is ever removed, here are the steps:

Restart the Mac holding down the Command+S keys, this will take you into Single User Mode and its Terminal interface

type:
mount -uw /

type:
rm /var/db/.applesetupdone

type:
reboot

This worked very well for me and allowed me to create a new account on the Mac and did *not* delete the existing data already on the Mac on the user whose password we did not know.