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Linux Command Line and Shell Scripting Techniques

Linux Command Line and Shell Scripting Techniques

By : Vedran Dakic, Jasmin Redzepagic
4.4 (5)
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Linux Command Line and Shell Scripting Techniques

Linux Command Line and Shell Scripting Techniques

4.4 (5)
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)
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Simple debugging approach – echoing values during script execution

The first thing you will learn when using Bash is how to regularly use the echo command when running any script. This approach is simple as it gives us an opportunity to follow the workflow of the script and to print the values of the variables as they are in different points of the script. Being able to understand both those things is going to help us to follow all the inputs to our script and to see how they transform into outputs that we expect.

Getting ready

In this recipe, we are going to deal with simple ways we can make our script help us understand what is happening during its run. There are three ways we can use this simple method.

The first thing we can do is use the echo command in every place in the script that we think is helpful. As an example, take a look at one of the scripts from previous chapters (funcglobal.sh) that is already pretty verbose:

Figure 15.13 –...

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