desktop Linux distributions). But two major distributions rose to become the foundation for many other distributions: Red Hat Linux and Debian.
Choosing a Red Hat distribution
When Red Hat Linux appeared in the late 1990s, it quickly became the most popular Linux distribution for several reasons:
RPM package management: Tarballs are fine for dropping software on your computer, but they don't work as well when you want to update, remove, or even find out about that software. Red Hat created the RPM packaging format so that a software package could contain not only the files to be shared but also information about the package version, who created it, which files were documentation or configuration files, and when it was created. By installing software packaged in RPM format, you could store that information about each software package in a local RPM database. It became easy to find what was installed, update it, or remove it.
Simple installation: The Anaconda installer made it much simpler to install Linux. As a user, you could step through some simple questions, in most cases accepting defaults, to install Red Hat Linux.
Graphical administration: Red Hat added simple graphical tools to configure printers, add users, set time and date, and do other basic administrative tasks. As a result, desktop users could use a Linux system without even having to run commands.
For years, Red Hat Linux was the preferred Linux distribution for both Linux professionals and enthusiasts. Red Hat, Inc., gave away the source code, as well as the compiled, ready-to-run versions of Red Hat Linux (referred to as the binaries). But as the needs of its Linux community users and big-ticket customers began to move further apart, Red Hat abandoned Red Hat Linux and began developing two operating systems instead: Red Hat Enterprise Linux and Fedora.
Using Red Hat Enterprise Linux
In March 2012, Red Hat, Inc., became the first open source software company to bring in more than $1 billion in yearly revenue. It achieved that goal by building a set of products around Red Hat Enterprise Linux (RHEL) that would suit the needs of the most demanding enterprise computing environments. After expanding its product line to include many components of hybrid cloud computing, Red Hat was purchased by IBM in July 2019 for $34 billion.
While other Linux distributions focused on desktop systems or small business computing, RHEL worked on those features needed to handle mission-critical applications for big business and government. It built systems that could speed transactions for the world's largest financial exchanges and be deployed as clusters and virtual hosts.
Instead of just selling RHEL, Red Hat offers an ecosystem of benefits upon which Linux customers could draw. To use RHEL, customers buy subscriptions that they can use to deploy any version of RHEL that they desire. If they decommission a RHEL system, they can use the subscription to deploy another system.
Different levels of support are available for RHEL, depending on customer needs. Customers can be assured that, along with support, they can get hardware and third-party software that is certified to work with RHEL. They can get Red Hat consultants and engineers to help them put together the computing environments they need. They can also get training and certification exams for their employees (see the discussion of RHCE certification later in this chapter).
Red Hat has also added other products as natural extensions to Red Hat Enterprise Linux. JBoss is a middleware product for deploying Java-based applications to the Internet or company intranets. Red Hat Virtualization comprises the virtualization hosts, managers, and guest computers that allow you to install, run, manage, migrate, and decommission huge virtual computing environments.
In recent years, Red Hat has extended its portfolio into cloud computing. Red Hat OpenStack Platform and Red Hat Virtualization offer complete platforms for running and managing virtual machines. However, the technology with the biggest impact in recent years is Red Hat OpenShift, which provides a hybrid cloud suite of software that has Kubernetes, the most popular container orchestration platform project, as its foundation. With the Red Hat acquisition, IBM has set a goal to containerize most of its applications to run on OpenShift.
There are those who have tried to clone RHEL, using the freely available RHEL source code, rebuilding and rebranding it. Oracle Linux is built from source code for RHEL but currently offers an incompatible kernel. CentOS is a community-sponsored Linux distribution that is built from RHEL source code. Recently, Red Hat took over support of the CentOS project.
I've chosen to use Red Hat Enterprise Linux for many of the examples in this book because, if you want a career working on Linux systems, there is a huge demand for those who can administer RHEL systems. If you are starting out with Linux, however, Fedora can provide an excellent entry point to the same skills that you need to use and administer RHEL systems.
Using Fedora
While RHEL is the commercial, stable, supported Linux distribution, Fedora is the free, cutting-edge Linux distribution that is sponsored by Red Hat, Inc. Fedora is the Linux system that Red Hat uses to engage the Linux development community and encourage those who want a free Linux for personal use and rapid development.
Fedora includes tens of thousands of software packages, many of which keep up with the latest available open source technology. As a user, you can try the latest Linux desktop, server, and administrative interfaces in Fedora for free. As a software developer, you can create and test your applications using the latest Linux kernel and development tools.
Because the focus of Fedora is on the latest technology, it focuses less on stability. So, expect that you might need to do some extra work to get everything working and that not all the software will be fully baked.
I recommend that you use Fedora or RHEL for most of the examples in this book for the following reasons:
Fedora is used as a proving ground for Red Hat Enterprise Linux. Red Hat tests many new applications in Fedora before committing them to RHEL. By using Fedora, you will learn the skills you need to work with features as they are being developed for Red Hat Enterprise Linux.
For learning, Fedora is more convenient than RHEL, yet still includes many of the more advanced, enterprise-ready tools that are in RHEL.
Fedora is free, not only as in “freedom,” but also as in “you don't have to pay for it.”
Fedora is extremely popular with those who develop open source software. However, in the past few years, another Linux distribution has captured the attention of many people starting out with Linux: Ubuntu.
Choosing Ubuntu or another Debian distribution
Like Red Hat Linux, the Debian GNU/Linux distribution was an early Linux distribution that excelled at packaging and managing software. Debian uses the deb packaging format and tools to manage all of the software packages on its systems. Debian also has a reputation for stability.
Many Linux distributions can trace their roots back to Debian. According to DistroWatch (https://distrowatch.com), more than 130 active Linux distributions can be traced back to Debian. Popular Debian-based distributions include Linux Mint, elementary OS, Zorin OS, LXLE, Kali Linux, and many others. However, the Debian derivative that has achieved the most success is Ubuntu (https://ubuntu.com).
By relying on stable Debian software development and packaging, the Ubuntu Linux distribution (sponsored by Canonical Ltd.) was able to come along and add those features that Debian lacked. In pursuit of bringing new users to Linux, the Ubuntu project added a simple graphical installer and easy-to-use graphical tools. It also focused on full-featured desktop systems while still offering popular server packages.
Ubuntu was also an innovator in creating new ways to run Linux. Using live CDs or live USB drives offered by Ubuntu, you could have Ubuntu up and running in just a few minutes. Often included on live CDs were open source applications, such as web browsers and word processors,