Linux Shell Scripting Cookbook - Third Edition

Gathering information about processes

The term process in this case means the running instance of a program. Many processes run simultaneously on a computer. Each process is assigned a unique identification number, called a process ID (PID). Multiple instances of the same program with the same name can run at the same time, but they will each have different PIDs and attributes. Process attributes include the user who owns the process, the amount of memory used by the program, the CPU time used by the program, and so on. This recipe shows how to gather information about processes.