Book Image

Fundamentals of Linux

By : Oliver Pelz
Book Image

Fundamentals of Linux

By: Oliver Pelz

Overview of this book

Linux is a Unix-like operating system assembled under the model of free and open source software development and distribution. Fundamentals of Linux will help you learn all the essentials of the Linux command line required to get you started. The book will start by teaching you how to work with virtualization software and install CentOS 7 Linux as a VM. Then, you will get to grips with the workings of various command line operations, such as cursor movement, commands, options, and arguments. As you make your way through the chapters, the book will not only focus on the most essential Linux commands but also give an introduction to Bash shell scripting. Finally, you will explore advanced topics, such as networking and troubleshooting your system, and you will get familiar with the advanced file permissions: ACL, setuid, and setgid. Fundamentals of Linux includes real-world tasks, use cases, and problems that, as a system administrator, you might encounter in your day-to-day activities.
Table of Contents (7 chapters)

Understanding processes

In this section, we will show you how processes work in Linux. Now, let's discuss everything about processes. Every program in a Linux system that is currently running is called a process. One single program can consist of multiple processes, and the process can start other processes. For example, as we already know, the Bash shell itself is a command, so, when started, it gets a process. Each command you start in this shell is a new process started by the shell process. So, for example, each time we execute the la -al command, the Bash shell process creates a new process in which the ls -al command is running. There are many, processes running all the time on every Linux system. If you have a multiprocessor CPU computer, some of those processes really are physically running in parallel all the time. Other processes, or if you have a single processor...