The top program provides a dynamic real-time view of a running system. It can display system summary information as well as list of tasks currently being managed by the Linux kernel. The types of system summary information shown and the types, order and size of information displayed for tasks are all user configurable and that configuration can be made persistent across restarts. The program provides a limited interactive interface for process manipulation as well as a much more extensive interface for personal configuration, encompassing every aspect of its operation. It refreshes its output every 3 seconds by default.