To find the process ID and parent process ID of the current shell, run: $ echo $$įind Linux Parent Process ID Starting a Process in Linux You can use the pidof command to find the ID of a process: # pidof systemd It functions as an adoptive parent for all orphaned processes. The init process always has process ID of 1. It is started by the kernel itself, so in principle it does not have a parent process. Init process is the mother (parent) of all processes on the system, it’s the first program that is executed when the Linux system boots up it manages all other processes on the system. Child processes – these processes are created by other processes during run-time.Parent processes – these are processes that create other processes during run-time.Using fork() and exec() Function – this technique is a little advanced but offers greater flexibility, speed, together with security.īecause Linux is a multi-user system, meaning different users can be running various programs on the system, each running instance of a program must be identified uniquely by the kernel.Īnd a program is identified by its process ID ( PID) as well as it’s parent processes ID ( PPID), therefore processes can further be categorized into:.Using The System() Function – this method is relatively simple, however, it’s inefficient and has significantly certain security risks.There are two conventional ways used for creating a new process in Linux: The child process will have the same environment as its parent, but only the process ID number is different. Linux Process State Creation of a Processes in LinuxĪ new process is normally created when an existing process makes an exact copy of itself in memory. However, they can be controlled by a user via the init process. They are started as system tasks (run as services), spontaneously. These are special types of background processes that start at system startup and keep running forever as a service they don’t die. Background processes (also referred to as non-interactive/automatic processes) – are processes not connected to a terminal they don’t expect any user input.In other words, there has to be a user connected to the system to start such processes they haven’t started automatically as part of the system functions/services. Foreground processes (also referred to as interactive processes) – these are initialized and controlled through a terminal session.There are fundamentally two types of processes in Linux: It is made up of the program instruction, data read from files, other programs or input from a system user. In this article, we will walk through a basic understanding of processes and briefly look at how to manage processes in Linux using certain commands.Ī process refers to a program in execution it’s a running instance of a program.
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