Linux is a multi-program system. At any given point of time, several processes are running or waiting in a queue on the system, however, a single CPU can actually execute one task at a time. If we have more long process queue, then it might happen that some more important processes spend more time waiting than executing. So, to overcome this problem, Linux allows us to set and modify a processes' priority. Lower-priority processes get less CPU time and higher-priority processes get more CPU time. Using the nice and renice command, we can manage the priority of processes.