Book Image

Mastering Bash

By : Giorgio Zarrelli
Book Image

Mastering Bash

By: Giorgio Zarrelli

Overview of this book

System 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. You’ll see how to perform checks on your sites and applications. Moving on, you’ll 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, you’ll 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.
Table of Contents (15 chapters)

Summary

In the previous chapter, we had a look at the variable; now we have just looked at how to correlate them. Assigning values and being able to perform some math or logic operations on them gives us more flexibility, since we do not just collect something, but transform it into something different and new. We also learned that exit codes can sometimes be pitfalls, trapping us with red herrings, and this tells us something important: never take anything as a given, always double-check what you are writing in your code, and always try to catch all the possible outcomes and exceptions. It seems like something obvious, but being such common sense, we tend to overlook this simple but effective code style advice.