How to view hidden users, add & delete?

Question

I administer eMacs and iBooks in an elementary school setting. Ideally, having hidden users like an administrator, would clean up login page and make the system more secure. The login page would not normally display the hidden login users until required.
How do you view, add & delete hidden users?

Answer 1

For now, I used a Library/Preferences/com.apple.loginwindow.plist file that has a "HideAdminUsers" command in it, and used it by simply replacing the standard com.apple.loginwindow.plist file that displays all users. Conversely, I switched them back when the task was done.
It sounds as if you used this command to modify the .plist file:
sudo defaults write /Library/Preferences/com.apple.loginwindow HideAdminUsers -boolean Yes
As an aside, it can be reversed with
sudo defaults write /Library/Preferences/com.apple.loginwindow HideAdminUsers -boolean No
I don't think there is a keystroke to show the hidden admin usernames, but you can log into a hidden admin account with just a few more keystrokes. At the login screen, press the down-arrow to highlight one of the non-admin accounts, then hold down the option key and press Return. At the next window, enter your admin username (the shortname is fine) and enter your admin password. If there is only one non-admin account in the login window, then click the back button before pressing the down-arrow key.