How to reset a forgotten password on OSX

My mother recently changed hard ware and a spare imac 2013 was up for grabs, trouble was no one could remember the password to get in. Changing the password from another machine wasn't an option, password hints proved to be useless. So terminal is my friend.

To reset on OSX do the following:

1. Restart the computer
2. Hold down the Command and R keys until you see the Apple logo
3. Select Utilities > Terminal from recovery tools
4. Type the following command and press enter: resetpassword
5. Follow the instructions on screen
6. Restart the computer

You should now be able to log in with the new password.