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: "Download the installation .iso files for Ubuntu Server 18.04, CentOS 7, and CentOS 8."

A block of code is set as follows:

//Unattended-Upgrade::Automatic-Reboot "false";
  Unattended-Upgrade::Automatic-Reboot "true";

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

sudo apt update
sudo apt dist-upgrade

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: "Spend some time perusing the Common Vulnerabilities and Exposures database, and you'll soon see why it's so important to keep your systems updated."