Book Image

Linux Command Line and Shell Scripting Techniques

By : Vedran Dakic, Jasmin Redzepagic
Book Image

Linux Command Line and Shell Scripting Techniques

By: Vedran Dakic, Jasmin Redzepagic

Overview of this book

Linux Command Line and Shell Scripting Techniques begins by taking you through the basics of the shell and command-line utilities. You’ll start by exploring shell commands for file, directory, service, package, and process management. Next, you’ll learn about networking - network, firewall and DNS client configuration, ssh, scp, rsync, and vsftpd, as well as some network troubleshooting tools. You’ll also focus on using the command line to find and manipulate text content, via commands such as cut, egrep, and sed. As you progress, you'll learn how to use shell scripting. You’ll understand the basics - input and output, along with various programming concepts such as loops, variables, arguments, functions, and arrays. Later, you’ll learn about shell script interaction and troubleshooting, before covering a wide range of examples of complete shell scripts, varying from network and firewall configuration, through to backup and concepts for creating live environments. This includes examples of performing scripted virtual machine installation and administration, LAMP (Linux, Apache, MySQL, PHP) stack provisioning and bulk user creation for testing environments. By the end of this Linux book, you’ll have gained the knowledge and confidence you need to use shell and command-line scripts.
Table of Contents (19 chapters)

Chapter 9: An Introduction to Shell Scripting

We have come to the part that defines one of the things that Unix (or Linux) is known for – its scripting. When it comes to the so-called Unix philosophy, being able not only to use tools that the command line offers to you but also being able to create your own is an amazing ability, using shell tools that do one thing really well.

Scripting is exactly that – the ability to create simple (and complex) tools that, at their core, are a set of commands performing a certain task. We need to clear one thing up before everything else – there is a distinction that some people make between programming and scripting. Strictly speaking, all scripting is programming, but not all programming is scripting. We are talking about disciplines that follow the exact same premises, logic, and ways of thinking, but at the same time, there are major differences between the two. When we talk about scripting, we are in reality creating...