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. Here is the list of information you can get by clicking the computer name at a login screen of OS X:

Revealing Additional Details about a Mac from the Login Screen of OS X

Note this works in OS X 10.3, OS X 10.4, OS X 10.5, and OS X 10.6. From Snow Leopard onward, like Lion, Mavericks, Yosemite, the ability to retrieve this type of information from clicking the computer name is no longer available, as the login screen has changed.

• 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.

Changing the Default Login Screen Display from Computer Name to Other Mac Info

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 to be used with a defaults string:

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

The results you can see below:

While the login screen has changed dramatically in new versions of OS X, similar information can be obtained from the OS X Lion and Mountain Lion boot login screens too with a different method.