Module 63: Introduction to Linux
What Linux is
🏠The everyday picture
Most of the world's buildings sit on foundations nobody sees. Linux is the foundation under most of the internet: web servers, cloud platforms, Android phones, routers, and even supercomputers.
📘What it really is
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Linux is a free, open-source operating system (Module 2). Strictly, "Linux" is the kernel, the core that manages hardware, memory and processes; a complete system adds tools, a shell and software around it.
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A distribution ("distro") packages the kernel with everything else:
- Ubuntu (and Ubuntu Server): the most common for beginners and cloud servers; LTS versions get five years of updates;
- Debian: stable and conservative; Ubuntu is built on it;
- Red Hat Enterprise Linux, Rocky Linux, AlmaLinux: common in large organisations;
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Alpine: tiny, often used inside containers (Module 69).
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Why servers use Linux: free to run on thousands of machines, stable, secure when maintained, controllable entirely from the terminal over the network, and supported by every cloud and hosting company.
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Your Hostinger hosting runs on Linux; so does almost every VPS you'll ever rent.
- This course uses Ubuntu Server LTS. Commands are very similar on other distributions; package managers differ.
🖱️Try it
Open your hosting control panel (or any VPS provider's site) and find which Linux distributions it offers. Note the newest Ubuntu LTS version, and how long it will receive updates.
✅Quick check
What's the difference between the Linux kernel and a distribution?
Show the answer
The kernel is the core that manages hardware and processes; a distribution bundles it with tools, a shell and software.
Why does an LTS version matter for a server?
Show the answer
It receives security updates for years, so the server can stay safe without major upgrades.