Chapter 2 - What is a Linux Distribution Made of?
A Linux distribution comprises the same components that make up any operating system. Every Linux distribution has the following components, many of which can be customized to great effect. This is why there are so many options in Linux. With that in mind, here are the components of Linux:
Bootloader
The bootloader is what boots the machine. There are two types of boot processes for any operating system: EFI and Legacy boot. Most Linux distributions use a package called GRUB to handle this process. However, some newer distributions have started using systemd-boot instead of GRUB.
Display Renderer
For graphical elements to appear on the screen, either Xorg or Wayland is required to render the graphics. Both have their pros and cons. Xorg has been around since the beginning and is feature-rich, but its structure is messy. Wayland is newer and offers cleaner code. Personally, I use Xorg on most distributions because it does everything I need. However, most Linux distributions going forward will package Wayland by default and Xorg will eventually go away. Most servers don't need graphics and omit these packages altogether, relying only on a CLI (Command Line Interface).
Xorg vs Wayland: https://youtu.be/U_MBJcD3SFI
Display Manager
The display manager is essentially the login manager that boots into your desktop environment or window manager.
SDDM
This is the display manager for KDE. There are a lot of themes and support for both Wayland and Xorg.
GDM
This is the display manager for GNOME. Much like SDDM, lots of themes and support for both Wayland and Xorg.
LightDM
This is a more universal display manager that multiple desktop environments use because it is lightweight. Xorg Only, but is very lightweight and still widely used.
LightDM Customization: https://youtu.be/_dYqisDIcC0
None
You technically don't need a display manager, but this means you will boot into a CLI (Command Line Interface) prompt with no graphics. Alternatively, you could set a window manager or desktop environment to auto-launch without requiring a login.
Desktop Environments
Desktop environments are the bread and butter of many distributions. These are typically an assortment of programs that dictate how programs are launched, displayed, and configured. Think of these as the look and feel of Linux.
Overview of Desktop Environments: https://youtu.be/mZa8AMWsYdQ
KDE
This is a Windows-style desktop environment with a start menu, taskbar, and basic floating window management. The workflow is very similar to Microsoft Windows. It has extensive theming capabilities, desktop widgets, and a vast array of built-in tools.
KDE Customization Video: https://youtu.be/nRtyFtpf5yU
GNOME
GNOME has a unique workflow with window animations and extensions to expand its capabilities. It is unlike any other Desktop Environment out there but has great utility. Its strengths include robust system settings and support for scaling and tablet-style computers.
Cinnamon
This is another Windows-style desktop environment, but it is more simplistic than KDE. The menus are more intuitive, and it has everything the user needs without bundling a ton of applications. This is my first recommendation for Windows users converting to Linux.
Cinnamon Customization Video: https://youtu.be/ZWA4F95A0Vc (Note: Cinnamon is made by the Linux Mint team.)
MATE
MATE is based on GNOME 2 from the past. It looks a bit dated out of the box, but its minimal design makes it lightweight and functional. It has a traditional menu system, unlike the latest version of GNOME, and can be tweaked to the user's needs without using many resources.
XFCE
Minimal, simplistic, and modular—that is XFCE's ethos, and it does a good job of it. It is one of my favorites, even though, like MATE, it is very ugly out of the box. After customization, it can look fantastic.
XFCE Customization Video: https://youtu.be/Y_x5svD2sZQ
LXQt / LXDE
LXQt is a very minimal desktop environment with a limited feature set. It is one of the lightest desktop environments on this list and is my recommendation for those using an old PC. Using nearly no resources, it simply gets the job done. LXDE is the older version before it morphed into LXQt.
Deepin
This reminds me of macOS and is my recommendation for mac users coming to Linux who don't like GNOME. It is sleek and has a futuristic look out of the box.
Others
There are many other desktop environments that are less popular than the ones above, and I encourage you to explore them after familiarizing yourself with the ones listed.
Window Managers
Window managers are often a point of confusion for new users, as people often mix them up with desktop environments. What is the difference? Desktop environments include a suite of tools and utilities, while window managers only manage windows.
I could write another book dedicated specifically to window managers, but I'd only recommend them for advanced users who are capable of making system modifications without the assistance of utilities. For example, adjusting your display settings.
Everything is set up by the user, from adjusting volume to launching programs. Depending on the window manager, you might need to edit text files to configure them or create shortcut keys for programs. Each one is unique and not for the faint of heart. In many of my videos, I use a modified version of DWM, which can be found on my GitHub: https://github.com/ChrisTitusTech/dwm-titus
Package Manager
This is probably the biggest factor that separates distributions and also makes many of them similar. There are a variety of package managers, but I will touch on the most popular ones that most distributions are based on.
APT
Debian-based distributions (e.g., Ubuntu, Pop_OS!, Linux Mint, etc.) use APT, which is one of the oldest package managers on this list. It is also the most widely used. A good majority of Linux articles reference APT. The basic syntax is apt install package.
DNF / YUM
RHEL-based distributions (e.g., Fedora, CentOS, Nobara, etc.) use these and dominate the business space. DNF is newer and has better dependency resolution, but you will still see YUM occasionally for legacy systems or older versions. Its basic syntax is dnf install package.
Pacman
This is the oddball of the bunch, as it is used in Arch-based distributions (e.g., Manjaro, Garuda, EndeavourOS, etc.). It has non-standard syntax like pacman -S package to install a package.
Others
There are many other package managers, but these encompass most of the popular Linux installations.
Flatpak / AppImage / SnapD
These are agnostic of any distribution. This means the programs aren't install on the system-level but are self contained. Any dependencies are included with the package which makes them usable on anything Linux. Flatpak and snapd are easy to manage from the command line, but also have lots of files for each package. AppImage is contained within the singular Package.AppImage file. For managing AppImage files, I recommend using gearlever package. For managing permissions on flatpak files, I recommend the flatseal package. I do not recommend using SnapD at all as it is owned and poorly maintained by the company Canonical that distributes Ubuntu.
Misconceptions
It should be noted that most programs can be compiled to work on pretty much any Linux distribution, and all the package manager does is make it easy for you to perform the installation. There are many other ways to install a program, such as building from source. However, most times this isn't needed, as even if a package is not available in your package manager, you can expand it by adding a repository to it, thus giving your package manager access to install even more programs on the fly. Even if this fails or a repository isn't available, you can utilize universal packages like Flatpak, Snap, or AppImage that can install on any system, no matter what package manager you are using.
Types of Linux Installations
There are a variety of ways to install Linux, and I will go over them in depth. These methods are broken into three categories: Beginner, Intermediate, and Expert.
Beginner Installation
This is extremely easy to do and is where a beginner should start. The downside to a beginner install is that it has less customizability, but it is an easier starting place for a novice user.
Intermediate Installation
This method typically involves taking a base distribution from the server level and installing the needed packages as required. It yields a highly customized system with a minimal installation but requires the user to know which packages they want.
Expert Installation
Much like intermediate installation, this method advances to not using desktop environments or bundles that install multiple packages. While this method can be tedious, it results in the most minimal installation, as it avoids installing unnecessary packages. However, it requires an extreme skill level to achieve. Often, the user is building packages or even compiling the base Linux kernel.
Progression
The progression you will go through in Linux is much more than these types of installations, but I wanted to give you a path as you explore and move through these types of installations.
Build What You Want Video: https://youtu.be/fWHKAn5W2CA