What is Linux?
A student's hobby project became the operating system that runs the internet. Here's the story — and why it matters to you.
In 1991, a 21-year-old Finnish student named Linus Torvalds posted to an internet forum:
> "I'm doing a (free) operating system — just a hobby, won't be big and professional…"
That hobby was Linux. Three decades later it is quietly everywhere:
- 96% of the world's top web servers run Linux
- Every Android phone runs on the Linux kernel
- Your Wi-Fi router, smart TV, and car infotainment — probably Linux
- All 500 of the world's fastest supercomputers — Linux
You've been using Linux for years. You just haven't talked to it directly yet.
Why did a free hobby project beat billion-dollar companies? One decision: Linus made the code open source.
Open source means the program's source code — the human-readable instructions it's built from — is public. Anyone can read it, improve it, and share their improvements.Thousands of programmers (and later, companies like Google, IBM, and Microsoft) contributed fixes and features. The result is an OS that is:
- Free — no licence fees, install it on a thousand servers for $0
- Reliable — Linux servers routinely run for years without a restart
- Transparent — security problems get found and fixed in the open
What does it mean that Linux is open source?
- AIts source code is public — anyone can read, improve, and share it
- BIt's free to download but the code is secret
- CIt only runs programs that are also free
- DAnyone can change the code running on YOUR computer
Roughly what share of the world's top web servers run Linux?
- A96%
- B50%
- C25%
- D10%
So why should you learn Linux? Because every technical path leads here:
- Backend developers deploy their code to Linux servers
- Data scientists train models on Linux machines in the cloud
- App developers ship to Android — Linux underneath
- DevOps and cloud engineers live in Linux all day
- Docker containers — the standard way to package software — are little Linux worlds
The skills in this course — navigating, managing files, permissions, processes, SSH — are the shared foundation for all of them. Linux is not a detour from your goals; it's the road.
You wrote an app on your Windows laptop and want to put it on the internet for real users. Where will it almost certainly end up running?
- AOn a Linux server in a data center
- BOn your laptop, which must stay on forever
- COn a Windows Phone
- DWebsites don't run on computers
- Linux is a free, open-source operating system started by Linus Torvalds in 1991
- Open source = the source code is public; anyone can read, improve, and share it
- That openness attracted thousands of contributors and made Linux free, reliable, and transparent
- Linux runs ~96% of top web servers, every Android phone, and the entire cloud
- Whatever you want to build — backend, data, apps — your code will end up running on Linux
Next: "Linux" isn't one single download. Let's untangle distributions.