High Quality Content by WIKIPEDIA articles! defaults is a command line utility that manipulates plist files. defaults is present in the Mac OS X and GNUstep operating systems, and it first appeared in the NeXTStep operating system upon which both of the aforementioned systems are based. The system stores each user`s preferences set in a .plist file for each program stored at ~/Library/Preferences for user-specific preferences, and /Library/Preferences/ for global preferences. Either way, the defaults utility writes or reads from these plist files depending on the one given.