Interacting with the system
Programs and scripts lying on a hard drive are just files. The moment they get mapped to the memory and start performing their function, they become processes. At this stage, you can safely assume that anything running in the system is some kind of a process.
Process this
Processes in Linux have several characteristics that you need to be aware of:
- Process ID (PID): A system-wide unique numerical identifier.
- Parent process ID (PPID): Every single process in the Linux system, except process number 1, has a parent. Process number 1 is an init process. It is the program responsible for starting all the system services. A program that starts another program is known as a parent. A program started by another program is known as a child. When you log in to the system, your shell is a process too, and it has its PID. When you start a program in that shell, your command-line PID will become the parent ID of that program. If a process loses its...
