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)

Working with awk

In this section, we will show you what the command awk is all about and why it can be important for us. We will also show you how to use it for text file manipulation and processing. awk is another very important tool for text processing and manipulation. It can be used as a complete scripting language to work on text files or streams. It contains some very powerful programming constructs, including variables: if...else, while, do while and for loops; arrays; functions; and mathematical operations. awk also works on a line-by-line basis, as sed does. One of the key features of awk and the main difference to sed is that it splits input lines into fields automatically. But how does it work and why is it so helpful?

awk enables you to create rule and action pairs, and, for each record that matches this rule or condition, the action will fire. The rules are also called...