Final release of 'trackObjs' - package name changed to 'track' - if using 'trackObjs' please switch to 'track'. Tracking database are the same with 'track' and 'trackObjs'. Automatically stores objects in files on disk so that files are rewritten when objects are changed, and so that objects are accessible but do not occupy memory until they are accessed. Keeps track of times when objects are created and modified, and caches some basic characteristics of objects to allow for fast summaries of objects. Also provides a command history mechanism that saves the last command to a history file after each command completes.