Mastering Bash by Giorgio Zarrelli

Key FeaturesFrom roots to leaves, learn how to program in Bash and automate daily tasks, pouring some spice in your scriptsDaemonize a script and make a real service of it, ensuring its available at any time to process user-fed data or commandsThis book provides functional examples that show you practical applications of commandsBook DescriptionSystem administration is an everyday effort that involves a lot of tedious tasks, and devious pits. Knowing your environment is the key to unleashing the most powerful solution that will make your life easy as an administrator, and show you the path to new heights. Bash is your Swiss army knife to set up your working or home environment as you want, when you want.This book will enable you to customize your system step by step, making your own real, virtual, home out of it. The journey will take you swiftly through the basis of the shell programming in Bash to more interesting and challenging tasks. You will be introduced to one of the most famous open source monitoring systems—Nagios, and write complex programs with it in any languages. Youll see how to perform checks on your sites and applications.Moving on, youll discover how to write your own daemons so you can create your services and take advantage of inter-process communication to let your scripts talk to each other. So, despite these being everyday tasks, youll have a lot of fun on the way. By the end of the book, you will have gained advanced knowledge of Bash that will help you automate routine tasks and manage your systems.What you will learnUnderstand Bash right from the basics and progress to an advanced levelCustomise your environment and automate system routine tasksWrite structured scripts and create a command-line interface for your scriptsUnderstand arrays, menus, and functionsSecurely execute remote commands using sshWrite Nagios plugins to automate your infrastructure checksInteract with web services, and a Slack notification scriptFind out how to execute subshells and take advantage of parallelismExplore inter-process communication and write your own daemonAbout the AuthorGiorgio Zarrelli is a passionate GNU/Linux system administrator and Debian user, but has worked over the years with Windows, Mac, and OpenBSD, writing scripts, programming, installing and configuring services--whatever is required from an IT guy. He started tinkering seriously with servers back in his university days, when he took part in the Computational Philosophy Laboratory and was introduced to the Prolog language. As a young guy, he had fun being paid for playing games and write about them in video game magazines. Then he grew up and worked as an IT journalist and Nagios architect, and recently moved over to the threat intelligence field, where a lot of interesting stuff is happening nowadays.Over the years, he has worked for start-ups and well-established companies, among them In3 incubator and Onebip as a database and systems administrator, IBM as QRadar support, and Anomali as CSO, trying to find the best ways to help companies make the best out of IT.Giorgio has written several books in Italian on different topics related to IT, from Windows security to Linux system administration, covering MySQL DB administration and Bash scripting.Table of ContentsLets Start Programming Operators Testing Quoting and Escaping Menus, Arrays, and Functions Iterations Plug into the Real World We Want to Chat Subshells, Signals, and Job Controls Lets Make a Process Chat Living as a Daemon Remote Connections over SSH Its Time for a Timer Time for Safety