Fedora Linux

Managing Processes

A process is a running instance of a program. If you run a program twice, two processes are created. In order to manage a Fedora system effectively, you must be able to monitor and control processes.

How Do I Do That?

Fedora provides multiple tools to monitor process activity and resource usage, modify process priority, and terminate processes.

Processes are identified by a Process ID (PID) number, which is sequentially assigned. There is a small set of information associated with each process, including:

nice

A value used to alter a process’s scheduling priority, which determines how much CPU time the process receives. The actual priority assigned to a process is calculated based upon this factor, as well as how much CPU time the process has recently received and how many input/output (I/O) operations it has recently performed. This value is inherited by child processes.

parent process ID

The PID of the process that started the process. If the parent process disappears, this is replaced by 1 (the init process).

real user ID and effective user ID

The numeric user ID of the user actually running the program and the effective user running the program. These can be different only when the suid mechanism is active (see Lab 4.8, “Control Access to Files”), although an effective user ID remains in effect when a suid program calls a non-suid program.

real group ID and effective group ID

The numeric group ID of the group actually running the program and the effective group ...