DEV Community: Swayamprava Sahoo

Linux from Scratch #2: Is Linux an Operating System or Just a Kernel?

Swayamprava Sahoo — Wed, 14 Oct 2026 08:28:18 +0000

When I first started learning Linux, I constantly heard two different statements:

"Linux is an operating system."
"Linux is just a kernel."

At first, I thought one of them had to be wrong. After learning how Linux actually works, I realized both statements make sense depending on the context.

Let's understand why.

What Is an Operating System?

An operating system (OS) is the software that acts as a bridge between users, applications, and the computer's hardware.

Without an operating system, applications wouldn't know how to communicate with the CPU, memory, keyboard, display, storage devices, or network hardware.

An operating system provides services such as:

Process management
Memory management
File management
Device management
Security and permissions
Networking

These services allow applications to run without worrying about the underlying hardware.

What Is a Kernel?

The kernel is the core component of an operating system.

Think of it as the manager that is always running in the background. Every program that needs hardware access must go through the kernel.

The kernel is responsible for:

Scheduling CPU time
Allocating memory
Managing devices using drivers
Handling filesystems
Managing processes
Enforcing permissions
Providing system calls

Applications cannot directly control hardware. Instead, they request services from the kernel.

Application
      │
System Calls
      │
Linux Kernel
      │
Hardware

Then What Is Linux?

Technically, Linux refers to the Linux kernel created by Linus Torvalds in 1991.

The kernel alone cannot provide a complete user experience.

For example, the kernel cannot:

Let you type commands
Display directories with ls
Copy files using cp
Edit files
Browse the web

It simply provides the core functionality needed for these programs to work.

So Where Do Commands Come From?

Commands like:

ls
cp
mv
mkdir
grep
cat

are not part of the Linux kernel.

Most of these commands come from the GNU Project, which provides many of the utilities we use every day.

The shell (such as Bash) is also a separate program that lets us interact with the kernel.

When you type:

ls

the shell starts the ls program, which eventually makes system calls to the Linux kernel. The kernel retrieves the directory information from the filesystem and returns it to the program, which displays it on your screen.

What Is a Linux Distribution?

A Linux distribution combines everything needed to create a usable operating system.

A typical distribution includes:

Linux kernel
GNU utilities
Shell (Bash, Zsh, etc.)
Package manager
System libraries
Desktop environment (optional)
Applications

Examples include:

Ubuntu
Debian
Fedora
Arch Linux
Linux Mint

Each distribution uses the Linux kernel but packages it with different software and tools.

Why Do Some People Say GNU/Linux?

Richard Stallman and the GNU Project argue that most of the user-space tools come from GNU, while Linux is only the kernel.

Because of this, some people prefer calling the complete operating system GNU/Linux instead of simply Linux.

Others use the shorter name "Linux" because it is more common.

Both terms are widely used today, depending on the context.

How Everything Fits Together

+-----------------------------+
| Applications                |
+-----------------------------+
| Shell (Bash)                |
+-----------------------------+
| GNU Utilities               |
+-----------------------------+
| System Libraries            |
+-----------------------------+
| Linux Kernel                |
+-----------------------------+
| Hardware                    |
+-----------------------------+

What I Learned

Before learning Linux, I assumed Linux itself contained every command I used.

Now I understand that the Linux kernel is only the core of the operating system. The commands, shell, libraries, and applications are separate software that work together with the kernel to create the complete Linux experience.

This also explains why different Linux distributions look and behave differently while sharing the same Linux kernel.

Conclusion

Linux is technically a kernel, not a complete operating system by itself. However, in everyday conversation, people often use the word Linux to refer to the complete operating system provided by Linux distributions.

Understanding this distinction helped me better understand how Linux works internally and why different distributions can share the same kernel while offering different user experiences.

In the next article, we'll explore how a Linux system boots—from pressing the power button to seeing the login prompt.

See you in Linux from Scratch #3!

Linux from Scratch #1: What is Unix? Why Was It Created?

Swayamprava Sahoo — Wed, 14 Oct 2026 08:26:50 +0000

Before understanding Linux, I realized I first needed to understand Unix.
In my previous article, I shared how installing Ubuntu completely changed the way I thought about operating systems.

As I started learning Linux, one word kept appearing everywhere:

Unix.

People would say things like:

"Linux is Unix-like."

"macOS is based on Unix."

That made me wonder:

If Unix already existed, why was Linux created?

To answer that question, I had to go back more than 50 years.

Computing Before Unix

In the 1960s, computers were very different from what we use today.

A computer was a huge machine shared by many users, and every manufacturer had its own operating system.

Programs written for one computer often wouldn't run on another.

There was no common way to interact with computers.

The Birth of Unix

In 1969, researchers at Bell Labs, including Ken Thompson and later Dennis Ritchie, started building a new operating system.

Their goal wasn't to create something complicated.

They wanted an operating system that was:

Simple

Reliable

Portable

Easy for programmers to use

That operating system became Unix.

Many ideas introduced by Unix are still part of modern operating systems today.

Ideas That Changed Computing

Unix wasn't just another operating system.

It introduced ideas that have survived for decades.

For example:

Everything is treated like a file.

Programs should do one job well.

Programs should work together using pipes (|).

Multi-user systems.

Multi-tasking.

A command-line shell.

When I learned Linux commands like grep, sort, cat, and pipes, I realized these ideas actually came from Unix.

Then Why Didn't Everyone Use Unix?

This was my next question.

If Unix was so good, why do we have Linux today?

The answer is licensing.

Unix was owned by AT&T.

Over time, using Unix became expensive because companies had to purchase licenses.

Many universities and developers wanted an operating system they could study, modify, and share freely.

That problem eventually inspired the creation of projects like GNU and later Linux.

We'll talk about those in the next articles.

What I Learned

Before writing this article, I thought Unix was simply an old operating system.

Now I understand something much more important.

Unix wasn't just software.

It introduced ideas that still influence Linux, macOS, Android, and many other operating systems today.

Learning Linux without understanding Unix felt like reading Chapter 2 without reading Chapter 1.

I'm glad I went back to learn the history first.

What's Next?

In the next article, we'll answer one of the questions that confused me the most:

Is Linux an operating system, or is it just a kernel?

See you in Linux from Scratch #2.

Welcome: Why I Started Learning Linux

Swayamprava Sahoo — Wed, 14 Oct 2026 08:04:03 +0000

When I joined MountBlue, one of the first things we were asked to do was dual boot Ubuntu.

Before that, I had always used Windows. I had built several projects on it and, during college, I had only learned a few basic Linux commands like pwd, ls, and cd. To me, Linux was just another operating system that developers talked about.

I also had many misconceptions.

I thought Ubuntu, macOS, Windows, and Android were simply different operating systems with no deeper relationship. I had heard that most software companies preferred developers to use Ubuntu or macOS, but I never really understood why.

Installing Ubuntu made me curious.

I started asking questions like:

Is Linux an operating system or just a kernel?
Why do people keep mentioning Unix and GNU?
Why do developers prefer Linux over Windows?
If Windows already has a terminal, why is Linux so popular among developers?

As I explored further, I realized something interesting.

For most everyday users, the operating system is mainly a way to run applications through a graphical interface. Whether it's browsing the web, watching videos, or editing documents, everything is designed to be accessed through windows, icons, and menus.

Software developers, however, often work in environments that are very different from a typical personal computer. They interact with remote servers, cloud machines, containers, and virtual machines—systems that often don't have a graphical desktop at all. In these environments, the command-line interface (CLI) becomes the primary way to work.

That made me realize learning Linux isn't just about memorizing commands. It's about understanding how operating systems work and why developers rely on them every day.

This series is my attempt to document that journey.

I'm not writing these articles because I know Linux. I'm writing them because I'm learning Linux—and writing is helping me understand it better. If you're beginning your journey too, let's learn together.

Welcome to Linux from Scratch.

In the next article, we'll start from the very beginning.

What exactly is Unix, and why did Linux even exist if Unix was already there?

See you in Part 1.