Book Image

Linux for System Administrators

By : Viorel Rudareanu, Daniil Baturin
Book Image

Linux for System Administrators

By: Viorel Rudareanu, Daniil Baturin

Overview of this book

Linux system administration is an essential aspect of maintaining and managing Linux servers within an organization. The role of a Linux system administrator is pivotal in ensuring the smooth functioning and security of these servers, making it a critical job function for any company that relies on Linux infrastructure. This book is a comprehensive guide designed to help you build a solid foundation in Linux system administration. It takes you from the fundamentals of Linux to more advanced topics, encompassing key areas such as Linux system installation, managing user accounts and filesystems, networking fundamentals, and Linux security techniques. Additionally, the book delves into the automation of applications and infrastructure using Chef, enabling you to streamline and optimize your operations. For both newcomers getting started with Linux and professionals looking to enhance their skills, this book is an invaluable hands-on guide with a structured approach and concise explanations that make it an effective resource for quickly acquiring and reinforcing Linux system administration skills. With the help of this Linux book, you’ll be able to navigate the world of Linux administration confidently to meet the demands of your role.
Table of Contents (21 chapters)
Part 1: Linux Basics
Part 2: Configuring and Modifying Linux Systems
Part 3: Linux as a Part of a Larger System

The process tree

We’ve seen that the shell knows the PIDs of the commands you run and can send them signals to terminate when you press Ctrl + C. That implies that it has certain control over the processes you ask it to launch. Indeed, everything you launch from your shell becomes a child process of that shell process.

The shell itself is a child process — either of your terminal emulator if you are on a Linux desktop, or of the OpenSSH daemon if you connect remotely over SSH. However, is there a parent of all processes, or can there be multiple processes without parents?

In fact, there is a parent of all processes, and all running process relationships form a tree with a single root (PID = 1). For historical reasons, the parent of all processes is often called the init process. For a long time in general-purpose Linux distributions, that process was System V init, hence the term.

The PID=1 process can be anything. When you boot a Linux system, you can tell it...