Understanding where Linux came from helps you make sense of why there are hundreds of distributions, why some commands differ between systems, and why certain tools are the standard in cloud environments.
A Brief History
The story of Linux starts in the early 1970s with Unix, an operating system developed at Bell Labs. Unix introduced concepts still used today — hierarchical filesystems, pipes, user permissions, and portable C code. It was powerful but expensive and proprietary.
In 1983, Richard Stallman launched the GNU Project to create a free Unix-like system. By the early 1990s GNU had most of the pieces — compilers, utilities, shell — but lacked a working kernel.
In 1991, Linus Torvalds, a 21-year-old student in Helsinki, wrote his own kernel as a hobby project and released it on the internet. Combined with the GNU tools, this became what we call Linux. The open-source licence meant anyone could use, modify, and redistribute it — which led to an explosion of development.
What is a Linux Distribution?
The Linux kernel alone isn't an operating system you can use directly. A distribution (or distro) packages the kernel together with:
- A package manager to install software
- A init system (like systemd) to manage services
- A set of core utilities (ls, cp, grep, etc.)
- Optionally, a desktop environment
- Default configuration and security policies
Today there are thousands of Linux distributions. They mostly fall into a few family trees, each with a different package manager and design philosophy.
The Major Distribution Families
Debian / Ubuntu
Debian is one of the oldest community-driven distros, known for stability. Ubuntu, built on Debian, is the most popular Linux for cloud VMs and developer workstations. It uses the apt package manager. Most AWS, GCP, and Azure documentation uses Ubuntu examples.
Red Hat / RHEL family
Red Hat Enterprise Linux (RHEL) dominates corporate data centers. It uses the dnf (formerly yum) package manager and .rpm packages. AlmaLinux and Rocky Linux are free RHEL clones widely used in enterprise environments. Fedora is Red Hat's community testing ground.
SUSE family
SUSE Linux Enterprise is popular in European enterprise environments. openSUSE is its community version. Uses the zypper package manager.
Alpine Linux
Alpine Linux is a minimal, security-focused distro. It weighs just 5 MB and is the default base image for most Docker containers. Uses the apk package manager. If you work with containers, you will encounter Alpine constantly.
Arch Linux
Arch is a rolling-release distro for advanced users who want full control. Uses pacman. Popular with developers but rarely seen in cloud or enterprise production environments.
Which Distro Should You Learn On?
For cloud certification study:
- Ubuntu LTS (latest Long Term Support release) is the best choice. It's widely documented, free, and available everywhere.
- For RHEL-based exam prep (such as RHCSA or any Red Hat certification), use AlmaLinux 9 — it's free and nearly identical to RHEL 9.
- For container work, get comfortable with Alpine's minimal shell and
apk add.
Practical Takeaway
When you're on an unfamiliar Linux system, the first thing to check is which distribution you're running. Use any of these commands:
cat /etc/os-release
lsb_release -a
uname -rThe output tells you the distro name, version, and kernel version — essential context before you troubleshoot anything or install software. In the next lesson, you'll explore how Linux organises its files and directories.