Linux Fundamentals – Understanding Linux from the Beginning

Lesson 1 of 3 · 10 min · Beginner

When I started learning Linux, the first thing I wanted to understand was what Linux actually is, why companies use it, and how it is different from Windows and Unix.

We use computers every day, but we don't always think about what happens behind the scenes when we open an application, save a file, or connect to the internet. This is where an operating system plays an important role. Let's understand Linux from the basics.

1. What is Linux?

Linux is an open-source, Unix-like operating system kernel. It acts as a bridge between computer hardware and software.

In simple words, Linux helps the computer manage its hardware resources, such as the CPU, RAM, storage, and network devices. It also provides an environment where applications can run.

Linux is widely used in servers, cloud environments, supercomputers, and even embedded devices.

One interesting thing about Linux is that it is open source. This means its source code is available for people to study, modify, and distribute according to its license.

2. Linux vs Unix vs Windows

When learning Linux, one common question is how Linux is different from Unix and Windows. All three are operating system-related technologies, but they have different histories, designs, and uses.

Linux An open-source, Unix-like operating system kernel. Widely used in servers, cloud platforms, and development environments.

Unix An operating system family that originated at Bell Labs. It has influenced many operating systems, including Linux.

Windows An operating system developed by Microsoft. Commonly used on personal computers, in offices, and in enterprise environments.

Let's understand the differences with a simple comparison:

Feature	Linux	Unix	Windows
Kernel / Type	Open-source kernel	Traditional operating system family	Mostly proprietary operating system
Design Origin	Unix-like design	Originated at Bell Labs	Developed by Microsoft
Primary Ecosystem	Widely used in servers and cloud	Used in enterprise environments	Widely used on personal computers
Examples	Ubuntu, Debian, RHEL, Fedora	AIX, Solaris, HP-UX	Windows 10, Windows 11

3. Linux Kernel, Shell and Terminal

When learning Linux, three terms that we frequently come across are kernel, shell, and terminal. They are connected, but they perform different roles.

Linux Kernel

The kernel is the core part of Linux. It manages communication between software and hardware. For example, when an application needs memory to perform an operation, the kernel manages the memory resources required by that application. It also handles processes, CPU scheduling, devices, and networking.

Shell

A shell is an interface that allows users to communicate with the operating system through commands. Think of it as a translator between the user and the system. It understands the commands entered by the user and executes the required programs. bash is one of the commonly used Linux shells.

Terminal

A terminal is the application where we enter commands and see their output. For example, when we open a Linux terminal, we can interact with the shell by typing commands.

Terminal — Interface to enter commands
→
Shell — Interprets and executes commands
→
Kernel — Allocates hardware resources
→
Hardware — CPU, RAM & Disks execute

To understand the relationship:

Kernel Manages hardware and system resources.
Shell Interprets and executes commands.
Terminal Provides the interface where we interact with the shell.

These three components work together to make Linux administration possible.

4. Linux Distributions – Ubuntu, Red Hat, Debian and Fedora

While learning Linux, I came across another important term: Linux distribution.

If Linux is a kernel, then what is Ubuntu or Red Hat? A Linux distribution is a complete operating system built around the Linux kernel. It includes the kernel, system utilities, libraries, applications, and package management tools.

Different distributions are designed for different requirements. Let's understand some commonly used distributions:

Ubuntu A popular Linux distribution based on Debian. Commonly used for personal computers, application servers, cloud environments, and development. It is also a good starting point for beginners who want to learn Linux.

Red Hat Enterprise Linux (RHEL) An enterprise-focused Linux distribution. Widely used by organizations for application hosting, enterprise workloads, and server infrastructure when they need maintenance, security updates, and commercial support.

Debian A community-developed Linux distribution known for its stability. It has a large software repository and is the foundation on which Ubuntu is built.

Fedora Another popular Linux distribution in the Red Hat ecosystem. It generally provides newer technologies and software versions and is used by developers and Linux enthusiasts.

Although these distributions use the Linux kernel, they differ in their software management, release cycles, and intended use cases.

5. Linux Architecture

Linux architecture explains how different parts of the operating system work together.

To understand it simply, imagine a person using a computer to open an application. The application needs resources from the computer, such as CPU, memory, and storage. Linux manages the interaction between the application and the hardware.

Applications (Browsers, Web Servers, Databases)
↓
Shell & System Utilities (bash, coreutils)
↓
System Libraries (glibc, system APIs)
↓
Linux Kernel (Memory, CPU, Process, Device Drivers)
↓
Hardware (CPU, RAM, Hard Disk, Network)

Main Components of Linux Architecture

Hardware Hardware includes the physical components of a computer, such as the CPU, RAM, hard disk, motherboard, and network devices.
Kernel The kernel communicates with the hardware and manages system resources.
System Libraries System libraries provide functions that applications can use to interact with the operating system.
Shell and System Utilities The shell allows users to interact with Linux, while system utilities provide tools to perform different system operations.
Applications Applications are programs that users run to perform their daily tasks, such as browsers, database software, and web servers.

6. Open-Source Concepts in Linux

One of the biggest reasons Linux became popular is its open-source nature.

Open source means the source code of software is available for people to study, modify, and distribute according to the software license.

Unlike proprietary software, where the source code is generally controlled by the vendor, open-source software allows developers around the world to contribute to its development. Linux is a good example of this approach.

However, open source does not always mean that every related service is free. Companies can provide paid support, enterprise subscriptions, and additional services.

Interview Questions and Answers

These are some common interview questions based on the Linux fundamentals covered above: