Book Image

Fundamentals of Linux

By : Oliver Pelz
Book Image

Fundamentals of Linux

By: Oliver Pelz

Overview of this book

Linux is a Unix-like operating system assembled under the model of free and open source software development and distribution. Fundamentals of Linux will help you learn all the essentials of the Linux command line required to get you started. The book will start by teaching you how to work with virtualization software and install CentOS 7 Linux as a VM. Then, you will get to grips with the workings of various command line operations, such as cursor movement, commands, options, and arguments. As you make your way through the chapters, the book will not only focus on the most essential Linux commands but also give an introduction to Bash shell scripting. Finally, you will explore advanced topics, such as networking and troubleshooting your system, and you will get familiar with the advanced file permissions: ACL, setuid, and setgid. Fundamentals of Linux includes real-world tasks, use cases, and problems that, as a system administrator, you might encounter in your day-to-day activities.
Table of Contents (7 chapters)

Introducing ACLs

In this section, we will give you a brief introduction to how ACLs, or access control lists, work.

Linux has some special file and folder permissions, namely the ACLs, setuid, setgid, and sticky bit. If you look at the file in the filesystem, such as a new file that only the root user has access to, currently we are logged in as olip:

As you can see, the olip user has no write access on that file. Maybe you have already asked yourself this question: how can you give permissions to a file or folder to individual users who are not the file or group owner, in our example root? The only way is to use the others group, but this is not individual as all users who are not the file or group owner fall into this category. But here, we want to set single user permissions; for example, for the olip user.

Access control lists, or ACLs, is a system that extends our normal...