How to View & Clear the Mac NVRAM Contents from Terminal in Mac OS X
Advanced Mac users may find it necessary to view or directly manipulate firmware variables found within NVRAM on the computer. Typically the NVRAM contains specific system data about things like the system audio level, startup disk details, an active user name, screen backlighting and resolution, and other technical details. While most users have no business interacting with NVRAM, there are times when manually viewing and clearing out NVRAM variables can be beneficial for troubleshooting purposes.
With the help of a command line tool in Mac OS X, Mac users can directly read and adjust firmware in Mac OS without having to reboot the Mac and performing a general NVRAM reset.