Managing System Processes
Thus far, you haven't had to worry much about which processes were running and what they were called. At most, you've used the jobs command to manage a list of jobs started from a single shell's command line.
Sometimes, however, you need to list and modify running processes on a systemwide basis. Using the command line, you can list all the running processes on a system, kill processes by their process ID number, or reprioritize processes relative to other processes in the system so that you can control processor time allocation on a busy system.
Because normal users can list all processes but have access to modify only their own processes, management of systemwide processes is often done as the root user so that all ...