What is Linux? A Beginner's Introduction
Understand what Linux is, how it differs from Windows and macOS, why it powers 96% of the world's servers, and how to pick your first distro.
Before you type a single command, it helps to understand what Linux actually is and why it matters. This post gives you the big picture — the mental model you'll carry through every lesson that follows.
What is an Operating System?
An operating system (OS) is the software that sits between your hardware and your applications. Every time you open a browser, save a file, or connect to Wi-Fi, the OS is doing the heavy lifting underneath.
It manages four key resources:
- CPU/Processes — decides which program runs, when, and for how long
- Memory (RAM) — allocates and protects memory space for each program
- Storage — organises data on disk, handles reading and writing
- Devices & Security — drivers for hardware, user accounts, permissions
What is Linux?
Linux is a free, open-source operating system kernel created by Linus Torvalds in 1991 — a Finnish computer science student who posted it online with the message: "I'm doing a (free) operating system (just a hobby, won't be big and professional like GNU)".
He was wrong. Combined with the GNU tools (compilers, shells, utilities), the Linux kernel became a complete OS — today called GNU/Linux — that powers:
- 96%+ of the world's top web servers
- 100% of the world's top 500 supercomputers
- Every major cloud platform (AWS, GCP, Azure all run Linux under the hood)
- Android — 3 billion+ mobile devices
- Smart TVs, routers, cars, and IoT devices
Linux Key Facts
| Fact | Detail |
|---|---|
| Creator | Linus Torvalds (Finland, 1991) |
| License | GNU GPL v2 — free forever |
| Written in | C and Assembly |
| Kernel type | Monolithic (modular) |
| Mascot | Tux 🐧 |
Linux Architecture
Linux is organized in layers. As a user, you interact with the shell (a text-based command interpreter). The shell talks to the kernel through system calls. The kernel talks to the hardware through device drivers.
Understanding this layering explains a lot: why some commands work everywhere (built into the shell), why others need to be installed (external programs on disk), and why you sometimes need sudo (kernel-level operations).
Linux Distributions
The Linux kernel alone isn't an OS you can use — it needs a package manager, desktop environment, and pre-installed software. This bundle is called a distribution (distro).
There are hundreds of distros, but they all trace back to a few family trees:
How to Choose Your First Distro
| I want to… | Use this |
|---|---|
| Try Linux for the first time | Ubuntu or Linux Mint |
| Run a web server | Ubuntu Server or Debian |
| Work at a company (enterprise) | RHEL or Rocky Linux |
| Want the latest packages | Fedora |
| Do security research | Kali Linux |
| Learn deeply / have full control | Arch Linux |
Your First Linux Commands
Open a terminal and try these to confirm you're on Linux and see some basic system info:
# Confirm you're running Linux
uname -s
# Linux
# See your kernel version
uname -r
# 5.15.0-91-generic
# See your distribution name and version
cat /etc/os-release
# NAME="Ubuntu"
# VERSION="22.04.3 LTS (Jammy Jellyfish)"
# Or use lsb_release if available
lsb_release -a
# Distributor ID: Ubuntu
# Release: 22.04Who created the Linux kernel and in what year?
Ubuntu, Linux Mint, and Kali Linux all share the same foundation. Which one?
Run the following on your system and note the output:
uname -a— what does each part of the output mean?cat /etc/os-release— what distro and version are you running?uname -m— what CPU architecture are you on? (x86_64 = 64-bit Intel/AMD, arm64 = Apple Silicon / ARM)