Get System Info from the Mac OS X Login Screen

Whenever you log in to your Mac, you’re greeted by the familiar login screen with the Mac OS X logo, the computer name, and a list of users. You can actually get useful system information from this login screen by clicking on the computer name, which cycles through a series of statistics and info on your Mac, ranging from build version to IP address. This is particularly useful for System Administrators, but it’s a good feature to know of for all Mac users.

• One click: Your OS X version number (e.g. Version 10.4.8)
• Two clicks: Your OS X build number (e.g. Build 8L2127)
• Three clicks: Your mac’s serial number (e.g. WN1511LHKNW)
• Four clicks: Your mac’s IP address (e.g. 196.254.0.1)
• Five clicks: The status of any networked account
• Six clicks: The date and time (e.g. Saturday, January 20 2007 4:02:31 AM GMT)
• Seven clicks: Back to where you started, the name of your computer.

Say you wanted to display one of these instead of the default computer name, well you can do so by launching the Terminal and typing the following (be sure to change info_name):

defaults write /Library/Preferences/com.apple.loginwindow AdminHostInfo info_name

Where info_name is one of the following options:

• SystemVersion
• SystemBuild
• SerialNumber
• IPAddress
• DSStatus
• Time

For example, we’ll prefer the IP address to be displayed at login, so here is the syntax:
defaults write /Library/Preferences/com.apple.loginwindow AdminHostInfo IPAddress


The results you can see below:

Source: MacOSXTips