About Workspace Services
The NSWorkspace class provides an interface between Cocoa applications and the OS X “workspace,” which consists primarily of the services provided by the Finder.
NSWorkspace provides access to services for files, applications,
devices, user defaults, and a few other system features. Each application
has one shared instance of NSWorkspace, which you access through
NSWorkspace also provides notifications related to its services. Unlike most notifications, all NSWorkspace notifications are posted to NSWorkspace’s own notification center instead of the application’s default notification center.