They are little programs designed to complete a function. The function of the UNIX operating system is designed around the concept of processes. To the computer, everything the processor does is a process. As you can imagine, there are many processes that need to be kept track of. UNIX has several ways to manage processes.
Users can manage only the processes that they've started.
One user cannot manage another user's processes, however the super-user has the ability to manage all processes at all times. The process table The UNIX computer keeps track of all of the processes running at any given time by using what's called a process table. You can display information about your own processes or all processes by using the ps command. To examine your own processes, use ps. To examine all processes, type ps -e.