You're going to need a computer. If you intend to work along with the examples, the easiest way to do so is by utilizing Vagrant, which is software for building portable development environments programmatically.

At the start of each chapter with working code, you'll find a Vagrantfile entry. This can be downloaded from the links provided later in this preface, but it can also be typed out if you prefer.

For the best experience, I'd recommend a computer with at least four cores and preferably 8 GB of RAM, though you might be able to tweak each entry for your own purposes.

This book assumes basic knowledge of moving around a Linux filesystem using the command line.

You can download the example code files for this book from your account at www.packt.com. If you purchased this book elsewhere, you can visit www.packt.com/support and register to have the files emailed directly to you.

You can download the code files by following these steps:

1. Log in or register at www.packt.com.
2. Select the SUPPORT tab.
3. Click on Code Downloads & Errata.
4. Enter the name of the book in the Search box and follow the onscreen instructions.

Once the file is downloaded, please make sure that you unzip or extract the folder using the latest version of:

• WinRAR/7-Zip for Windows
• Zipeg/iZip/UnRarX for Mac
• 7-Zip/PeaZip for Linux

The code bundle for the book is also hosted on GitHub at https://github.com/PacktPublishing/Linux-Administration-Cookbook. In case there's an update to the code, it will be updated on the existing GitHub repository.

We also have other code bundles from our rich catalog of books and videos available at https://github.com/PacktPublishing/. Check them out!

We also provide a PDF file that has color images of the screenshots/diagrams used in this book. You can download it here: https://www.packtpub.com/sites/default/files/downloads/9781789342529_ColorImages.pdf.

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "I've put together the following Vagrantfile for use in this chapter."

A block of code is set as follows:

# -*- mode: ruby -*-
# vi: set ft=ruby :

$provisionScript = <<-SCRIPT
sed -i 's#PasswordAuthentication no#PasswordAuthentication yes#g' /etc/ssh/sshd_config
systemctl restart sshd
SCRIPT

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

[vagrant@centos2 ~]$ ip a
<SNIP>
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 08:00:27:56:c5:a7 brd ff:ff:ff:ff:ff:ff
    inet 192.168.33.11/24 brd 192.168.33.255 scope global noprefixroute eth1
       valid_lft forever preferred_lft forever
    inet6 fe80::a00:27ff:fe56:c5a7/64 scope link 
       valid_lft forever preferred_lft forever

Any command-line input or output is written as follows:

[vagrant@centos1 ~]$ ssh centos2 -X

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "The last thing to do from the main screen is set our INSTALLATION DESTINATION."