Determine if you need to stop, suspend, or change the priority of a user process. If you terminate or change the priority of a user process, contact the process owner and explain what you have done. Stop the process using the kill command. Use the ps command to determine the PID number of commands. In a background process, the shell does not wait for the command to complete before returning the shell prompt.
Jobs running in the background appear in the normal ps command.
The renice command alters the scheduling priority of one or more running processes. The higher the number, the lower the priority with 20 being the lowest priority. In the previous example, renice reschedules process number 1883 to the lowest priority. It will run when there is a small amount of unused processor time available.