For logins to severs at University of Tasmania your short name must equal your email pop account.

There is a way to change your shortname but any errors can make your system unusable so you shouldn't attempt it light-heartedly.

Although I normally strongly recommend against logging in as root, for this procedure you should activate the root account and log in as root. There are two reasons for this: the first is that if you are logged in as root you can perform the whole operation without using the terminal, the second (and most important) is that if you do somehow corrupt your user's login you will still be able to log into the system as root to repair the damage.

To make it possible to log in as root, you need to do two things: activate the root account and make it possible for root to log in through the login screen.

To activate the root account start the NetInfo Manager, pull down the "Domain" menu to "Security" and select "Enable Root User"; if there is no root password you will have to select and confirm one before you can enable the account. If you have problems activiating the root account through NetInfo Manager, you can activate it by using the Terminal. Open the Terminal and enter the command:

'sudo passwd root'

You will be prompted for your password, and then for the new root password. After entering the new root password you will have to enter it again to confirm it. If you are not able to activate the root account through either of these procedures, stop. Do not try to follow any further instructions. Stop now.

After you have enabled the root account, open System Preferences -> Login and click on the "Login Window" tab. Uncheck the "Automatically log in" box if it is checked. Either select "Name and password entry fields" for the "Display login window as:" selection, or check the 'Show "Other User" in list for network users' box.

Log out.

Login as root, using the password you set for root.

Open NetInfo Manager, click on the lock icon and authenticate.

In the middle column, select "groups". Select "admin" from the third column. Click on the triangle beside the "users" property and expand the list. In the "values" column, click on the user name you want to edit and change it to the new user name.

In the (now) middle column of the top panel, scroll down and select the group "wheel". When prompted, save the changes to the admin directory, and confirm the update. Do the same thing you did for the "admin" group: open the "users" list and edit the user name.

In the left column of the top panel, scroll down and select "users". When prompted, save and confirm. In the right column, select the user you want to edit. In the bottom panel change every instance of the old name to the new name.

Save your changes from the Domain menu, confirm, and quit NetInfo Manager.

In the Finder, select column view and click on "Computer". Click on your boot disk; click on "Users". Select the folder for the user you want to edit and change the old name to the new name.

Log out.

Log in as your new user, using your old password.

If you haven't made any typos or other errors, your account should be exactly as you left it with the exception of the new short name. Double check everything; make sure you still have admin privileges. Leave the root account enabled and the login screen settings as they are (although you can select automatic login if you like) for the next week or two until you are certain everything is working. Then disable the root user using the Domain menu in NetInfo Manager.

If you have made errors and you can't log in as your new shortname or you can log in but you don't have admin privileges you will have to log back in as root and double check every step. If any of the new shortname entries has a typo, there will be something that doesn't work and you'll just have to track it down.