defaults is a
command line utility that manipulates
plist files. defaults is present in the
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.