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CHAPTER 1
Getting Started With Linux
This chapter will introduce you to the Linux world with a focus on servers. Therefore, I will not explain about it on desktops. You will see explanations about Linux, why you should know it, its basic concepts, and a lot of commands. I am a technical guy, so brace yourself because you are about to see how to set up your lab hands-on!
Structure
In this chapter, we will discuss the following topics:
- What is Linux
- Setting up your environment
- Installing the VirtualBox
- Installing a Linux system
- Accessing via SSH
- Introduction to Bash
- Useful commands
- Basic files and how to edit them
- Customizing your shell
- Installing packages
Objectives
After studying this unit, you should be able to:
- Understand the basics of Linux
- Choose your favorite distribution
- Install your virtual machine
- Access any remote Linux server
What is Linux?
In my view, if you bought this book, you probably have a basic idea of what is Linux and you already know why you want to learn it. Thus summarizing, Linux is an operating system with an open-source code, and works similar to the famous Windows, but it does not belong to any company. So, how is the code open? Everyone can download the core Linux using this site: https://www.kernel.org/, and if you are interested to give a look around the source code, it can be found on this link https://git.kernel.org/.
Linux has this name because of its creator, Linus Torvalds. The first 3 letters are the initials of Linus, and the last 2 come from another OS, called Minix, created by a man, named Andrew Tanenbaum.
It is common for you to see Linux bound to other initials, like GNU. This happens because when Linus Torvalds was creating Linux, he used many tools that were created by the GNU project, https://www.gnu.org/home.en.html. The GNU project began with Richard Stallman, the creator of the Free Software Foundation, https://www.fsf.org. What does it mean to license an open-source? It means that every software written by the GNU project has its code open for everyone who wants to work on it. Then, how Linus Torvalds used the tools from the GNU project? He decided to use the same philosophy of the open-source and he released the Linux system with the tools from the GNU project. This explains the term GNU/Linux.
Distributions
Since Linux is open-source, a lot of people and companies created their own versions of Linux, which are called distributions. Everyone who has the knowledge in computer programming can make their own Linux distribution. One example is Kurumin Linux, created by a Brazilian programmer, Carlos Morimoto, and can be found on the link, https://distrowatch.com/table.php?distribution=kurumin. Unfortunately, it is discontinued, because maintaining your own distribution is not an easy task. You have to be concerned about updates, new releases, new software, bug correction, and infinite things that are basically impossible for just one person to take all that effort and without being paid for it. So, it is one important topic for you to decide what distribution you are planning to install in your infrastructure. Imagine the situation where you began with one distribution. A year later, it is discontinued and you have to reinstall your whole infrastructure with more than 300 servers. We, as professionals, cannot let this happen.
Regarding the distribution we want to choose for our infrastructure, there exists several of them, but some are the mostly used, because of the reasons I am going to explain further:
- RedHat Enterprise Linux: This is the most famous and corporative distribution because of the RedHat Company. It is one of the most famous companies in the Linux world. It has amazing support, frequent updates, and 100% compatibility with the RedHat software, like JBoss, OpenStack, RedHat Enterprise Virtualization Manager, and a lot of more options. But, for using RHEL, it is required to take a subscription with the company and pay for it. Otherwise, you will neither receive any updates, nor will you be able to access to the repository.
- Community Enterprise Operating System: CentOS is the community version of RHEL. It is the most common distribution among the companies that have chosen to not use the paid version and want to use the community version of the RedHat software.
- SUSE: It is the Novell (Microsoft) distribution and is a good option, because, Microsoft is one of the biggest companies around the world. Therefore, the probability of it being discontinued is zero, and you will always have the updates and new software published by the company. It also has a community version called the OpenSUSE which follows the same features of the CentOS.
- Debian: This is the option for those who are more involved in the community and do not want to be bound to any company, like the distros mentioned previously. Debian is 100% maintained by the community and is one of the oldest distros we have. Also running over a lot of servers, it is very stable and reliable, and is frequently used by the companies and common users.
- Ubuntu: This distro was made in Africa by Canonical that used to distribute CDs over the whole world for people to get to know more about Linux and run it on their desktops. The final users were the target by Canonical in the beginning. So, I believe that for desktops, Ubuntu is the most used distro, and for servers, it is CentOS. Ubuntu has a version for server which is my favorite distribution. That's why I am writing this book using Ubuntu. But the knowledge you will acquire here can be used for all the distributions.
Servers
Servers are nothing more than computers. They are usual...
