What is Linux? A Complete Introduction for Beginners

Beginner 9 min read

What you'll learn

✓What Linux actually is — kernel vs. operating system
✓Where Linux came from and why it matters today
✓How distributions like Ubuntu, Debian, and Fedora differ
✓How Linux compares to Windows and macOS in practice
✓How to try Linux without replacing your current OS

Prerequisites

•Basic familiarity with using a computer — installing software, opening a terminal, etc.

Linux is the operating system that runs most of the modern internet. Almost every public web server, the majority of cloud infrastructure, every Android phone, and a large share of the world’s supercomputers run a Linux kernel. Despite that reach, most people who use Linux every day never see it — it sits underneath the websites, apps, and services they interact with.

If you are learning to program, work with servers, or take a serious step into systems work, Linux is the single most important environment to understand. This post explains what it is, where it came from, and what you actually need to know to start using it.

What Linux actually is

Strictly speaking, Linux is a kernel — the low-level program that talks to your hardware, schedules processes, and manages memory. By itself, the kernel does very little a user can interact with. What most people call “Linux” is really a complete operating system built around the Linux kernel: the kernel plus a shell, a set of command-line tools, system libraries, a package manager, and usually a graphical desktop.

A useful analogy: the kernel is the engine of a car. By itself it is essential but unusable. A distribution is the whole car — engine, transmission, body, dashboard — assembled and ready to drive.

A very short history

Linux was started in 1991 by Linus Torvalds, then a student in Helsinki. He wanted a free, Unix-like kernel he could study and modify on his personal computer. He published the source code on the internet, other developers contributed, and the project grew steadily.

Around the same time, the GNU project — started by Richard Stallman in 1983 — had been producing a set of free, Unix-compatible tools (compilers, editors, shells) but had no usable kernel. The Linux kernel filled exactly that gap. The combination is sometimes written as “GNU/Linux” to acknowledge that both pieces are essential.

Today, the kernel is maintained by thousands of contributors at companies including Intel, Red Hat, Google, and Meta, alongside thousands of independent developers. It is one of the largest and most active open-source projects in existence.

Distributions: the practical units of Linux

You do not install “Linux” directly. You install a distribution (often shortened to distro) — a packaged version of the operating system put together by a particular team. Each distribution chooses a kernel version, a default desktop environment, a package manager, a release cadence, and a philosophy.

The distributions you will encounter most often as a developer:

Ubuntu — by far the most popular desktop and server distribution. Based on Debian, with a polished installer and predictable six-month releases. Long-term support (LTS) releases are supported for five years.
Debian — the upstream project Ubuntu is built on. Conservative, very stable, prized on servers.
Fedora — sponsored by Red Hat. Ships newer software than Ubuntu and is often the first distribution to adopt new technologies.
Arch Linux — a rolling-release distribution that gives you a minimal base and asks you to assemble the rest. Beloved by users who want full control.
Linux Mint, Pop!_OS, elementary OS — desktop-focused distributions built on Ubuntu, each with a different design philosophy.

For everyday learning and development, Ubuntu or Debian is the safest starting point. The rest of this series uses Ubuntu/Debian commands where they differ from macOS, since those two cover the vast majority of beginner setups.

How Linux differs from Windows and macOS

The differences that matter in practice:

Open source. The source code for the kernel and most user-space tools is freely available, modifiable, and redistributable. Windows and macOS are proprietary.

The shell is a first-class citizen. On Linux, the terminal is not an afterthought — it is the primary interface for system administration, package management, networking, and development. Almost everything you can do graphically you can also do from a command line, and very often you will prefer the command line.

Package managers. Software is installed through a central package manager (apt on Ubuntu/Debian, dnf on Fedora, pacman on Arch) rather than by downloading installers from websites. Updates are unified — one command upgrades the entire system.

File system layout. Linux uses a single tree rooted at /, with no drive letters. Everything — disks, devices, network shares — is mounted into that tree. We cover this in detail in the file system post.

Cost. Linux is free. There is no licence to buy, and no activation step.

macOS is closer to Linux than to Windows in many ways — both are Unix-derived, both use a similar shell, and most command-line tools work the same. A developer comfortable on macOS can become comfortable on Linux quickly, and vice versa. Where commands diverge in this series, we will call it out explicitly.

Why developers use Linux

The honest reasons, in rough order of importance:

Servers run Linux. If you deploy a web application, an API, a database, or a machine-learning model, it almost certainly runs on Linux in production. Developing on the same OS removes an entire class of “works on my machine” problems.
The package manager is fast and consistent. Installing Postgres, Redis, Node, Python, and a dozen libraries is one apt install command. No installers, no wizards.
The command line is excellent. Decades of polish on grep, sed, awk, find, ssh, cron, systemd, and the shells (bash, zsh) have produced a development environment that is hard to beat.
Containers, Docker, and Kubernetes are Linux-native. Container technology grew out of Linux kernel features. Running containers on Linux is direct; on other systems it involves a virtual machine.
It does not get in your way. No forced updates that reboot your machine mid-task, no telemetry you cannot turn off, no nag dialogs.

Try it yourself. Open a terminal on whatever system you currently use and run uname -a. On Linux and macOS you will see kernel information including the OS name. On Windows, the same command works inside WSL (more on that below). This single command is the simplest possible peek at the layer beneath your desktop.

Ways to try Linux without committing

You do not need to wipe your existing computer to start learning Linux. In rough order from easiest to most committed:

Windows Subsystem for Linux (WSL). On Windows 10 or 11, open PowerShell as administrator and run wsl --install. After a reboot you will have a real Ubuntu environment running alongside Windows, complete with the same shell and package manager you would get on a dedicated machine. This is the standard recommendation for Windows-based developers.

A virtual machine. Install VirtualBox (free) or VMware and run a Linux distribution inside a window on your existing OS. Good for experimenting with desktop environments without changing your hardware.

A live USB. Most distributions can boot directly from a USB stick without installing anything. You get a full desktop session to explore, and a reboot returns you to your normal OS untouched. Tools like Rufus (Windows) or balenaEtcher (cross-platform) create the USB from a downloaded .iso file.

A cheap cloud server. Providers like DigitalOcean, Hetzner, and Linode rent Linux servers for a few dollars a month. You connect over ssh and get a real production-grade Linux box for the cost of a coffee.

Dual boot. Install Linux alongside your existing OS and pick which one to boot at startup. More involved, but gives Linux full access to your hardware.

For the rest of this series we will assume you have either Ubuntu/Debian (native, WSL, or VM) or macOS open in a terminal. The commands are noted for both where they differ.

Try it yourself. Pick one of the methods above and get a Linux shell open. The fastest paths are WSL on Windows (wsl --install) or the built-in Terminal app on macOS (Cmd+Space → “Terminal”). You do not need a desktop environment to follow this series — a working shell is enough.

A note on “Linux is hard”

Linux had a reputation in the early 2000s for being difficult to install and unfriendly to non-technical users. That reputation is twenty years out of date. Modern Ubuntu installs in fifteen minutes with a graphical wizard, drivers for common hardware are bundled, and the desktop experience is competitive with macOS and Windows.

Where Linux still asks more of you than the alternatives is in the assumption that you can read documentation, type commands, and understand what they do. That is exactly the skill set we are building.

Recap

You now know:

Linux is a kernel; what you install is a distribution that wraps the kernel with tools, a package manager, and a desktop
The kernel was started by Linus Torvalds in 1991 and grew alongside the GNU project’s user-space tools
Ubuntu and Debian are the most common starting distributions; Fedora and Arch are popular alternatives
Linux’s defining traits are its open-source nature, command-line orientation, package-managed software, and unified file system tree
Developers use Linux because servers, containers, and most cloud infrastructure run on it
You can try Linux through WSL, a VM, a live USB, a cheap cloud server, or a dual-boot install

Next steps

The next post is hands-on: opening a terminal, understanding the shell prompt, and running your first commands. By the end of it you will be navigating directories and inspecting files from a keyboard alone.

→ Next: The Linux Terminal: A Beginner’s Guide

Questions or feedback? Email codeloomdevv@gmail.com.