Giorgio Zarrelli - Mastering Bash

BIRMINGHAM - MUMBAI

Copyright 2017 Packt Publishing

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First published: June 2017

Production reference: 1190617

ISBN 978-1-78439-687-9

www.packtpub.com

Giorgio 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.

Sebastian F. Colomar is a GNU/Linux system engineer specializing in the scripting, installation, configuration, and maintenance of Linux servers for better security and performance.

He is currently an infrastructure architect at Hanscan, having been a consultant for scripting and Linux administration for many companies, such as IBM, Indra, Thales, Accelya, Accenture, AXA, Cetelem, RTVCM, EMT, and ESA.

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Bash is a common tool for everyday tasks that almost every Linux user relies on. Whatever you want to do, you have to log in to a shell, and most of the time, it will be Bash. This book aims to explain how to use this tool to get the most out of it, whether it be programming a plugin or network client or simply explaining why a double dot means what it means, we will dig a bit deeper than usual to become fully confident with our shell. Starting from the basics but with a different point of view, we will climb up step by step, focusing on the programming side of our environment, looking at how to prevent any issues in setting up our recurring tasks and ensure that everything works fine. Make it once, take your time, debug, improve, and then fire and forget; as in old Linux saying states, "If it works, why change it?" So, since we are dealing with sayings, we could stick to the other two cornerstones: "KISS: Keep it simple, stupid" and "Do only one thing, but do it well." These are three principles around which Linux revolves: making something, not everything, and making it simple and reliable and taking your time to make it work well so you do not have to modify it too often over time. When something is focused and simple, it is easy to understand, well maintained, and safe. And that is our approach, since Bash is not only a tool but also the environment we spend a lot of time in, and so understanding it, making the best use of it, and keeping everything clean and tidy should be our daily aim.