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)

Using set to debug a part of the script

In the previous recipe, we dealt with globally using two options to tell Bash to include a lot of useful information in its output. We mentioned that this offers another way to deal with debugging and troubleshooting how your scripts work. At the same time, we mentioned that this approach is in stark contrast with using commands in the script itself since we can deal with things globally without too many changes to the scripts when debugging.

In this recipe, we are going to cover another way to debug, one that shares a lot of similarities with the ones we introduced before, while also being different.

Getting ready

One very interesting built-in command in Bash is set. What it does is give us the ability to change the options Bash uses. A lot of things can be changed by using set, and by a lot we mean almost every option Bash has. In this recipe, we are using only two of them, but you can turn all of them on or off.

set enables us...