Book Image

Mastering Ubuntu Server

By : Jay LaCroix
Book Image

Mastering Ubuntu Server

By: Jay LaCroix

Overview of this book

Ubuntu is a Debian-based Linux operating system, and has various versions targeted at servers, desktops, phones, tablets and televisions. The Ubuntu Server Edition, also called Ubuntu Server, offers support for several common configurations, and also simplifies common Linux server deployment processes. With this book as their guide, readers will be able to configure and deploy Ubuntu Servers using Ubuntu Server 16.04, with all the skills necessary to manage real servers. The book begins with the concept of user management, group management, as well as file-system permissions. To manage your storage on Ubuntu Server systems, you will learn how to add and format storage and view disk usage. Later, you will also learn how to configure network interfaces, manage IP addresses, deploy Network Manager in order to connect to networks, and manage network interfaces. Furthermore, you will understand how to start and stop services so that you can manage running processes on Linux servers. The book will then demonstrate how to access and share files to or from Ubuntu Servers. You will learn how to create and manage databases using MariaDB and share web content with Apache. To virtualize hosts and applications, you will be shown how to set up KVM/Qemu and Docker and manage virtual machines with virt-manager. Lastly, you will explore best practices and troubleshooting techniques when working with Ubuntu Servers. By the end of the book, you will be an expert Ubuntu Server user well-versed in its advanced concepts.
Table of Contents (22 chapters)
Mastering Ubuntu Server
Credits
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
Index

Understanding the /etc/passwd and /etc/shadow files


Now that we know how to create (and delete) user accounts on our server, we are well on our way to being able to manage our users. But where exactly is this information stored? We know that users store their personal files in /home, but is there some kind of database somewhere that keeps track of which user accounts are on our system? Actually, user account information is stored in two special text files: /etc/passwd and /etc/shadow.

You can display the contents of each of those two files with the following commands. Take note that any user can look at the contents of /etc/passwd, while only root has access to /etc/shadow:

# cat /etc/passwd
# cat /etc/shadow

Go ahead and take a look at these two files (just don't make any changes), and I will help you understand them. First, let's go over the /etc/passwd file. What follows is example output from this file on my test server. For brevity, I limited the output to the last seven lines:

testuser...