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)

ssh_config

On the client side, we have a few ways to configure how a connection will be held:

  • From the command line, passing options to the client while invoking it
  • From the configuration file inside the user's home directory ~/.ssh/config
  • From the system-wide configuration file in /etc/ssh/ssh_config

For the configuration files, we must bear in mind that only the first value obtained for each directive will be used; so if we give the same directive multiple times, only the first one will be evaluated. So, we must keep the more specific options at the beginning of the configuration file while the broader one will be pushed toward the end.

As we will see in the next paragraph, where we will examine a practical use of the client configuration, the file is segmented into sections whose boundaries are delimited by the Host directive: whatever configuration directive is listed...