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Module 00 - Introduction to Linux

Overview

Linux is one of the most widely used operating systems in the world.

It powers:

  • Web servers
  • Cloud platforms
  • Network devices
  • Supercomputers
  • Mobile devices
  • Embedded systems
  • Enterprise applications

This module introduces the Linux operating system, its history, common distributions, and the basic concepts required before beginning Linux administration.

Learning Objectives

By the end of this module, you should understand:

  • What Linux is
  • How Linux differs from other operating systems
  • The history of Linux
  • What Linux distributions are
  • The difference between Linux desktop and server environments
  • Common Linux terminology
  • How Linux is used in modern IT environments
  • How Linux systems are accessed

What is Linux?

Linux is an open-source operating system based on the Linux kernel.

An operating system provides the interface between:

+----------------------+
|   Applications       |
+----------------------+
|   Operating System   |
+----------------------+
|   Hardware           |
+----------------------+

Linux manages:

  • CPU resources
  • Memory
  • Storage
  • Network interfaces
  • User accounts
  • Security controls
  • Running applications

Linux Components

A Linux system is made up of several key components.

+--------------------------------+
| Applications                   |
+--------------------------------+
| Shell / Command Line           |
+--------------------------------+
| System Libraries               |
+--------------------------------+
| Linux Kernel                   |
+--------------------------------+
| Hardware                       |
+--------------------------------+

Kernel

The kernel is the core component of Linux.

It manages communication between software and hardware.

Examples:

  • CPU scheduling
  • Memory management
  • Device drivers
  • Network communication

The kernel is responsible for allowing applications to communicate with the underlying hardware.

Check your kernel version:

uname -r

Example output:

6.18.34+rpt-rpi-v8

Linux History

Linux has its roots in earlier operating systems and open-source projects.

Understanding the history helps explain why Linux is designed the way it is today.

UNIX

Linux was heavily influenced by UNIX.

UNIX was developed in the 1970s and introduced many concepts still used today:

  • Multi-user systems
  • File permissions
  • Command-line administration
  • Small tools working together

Many Linux concepts originated from UNIX design principles.

GNU Project

The GNU Project began in 1983 with the goal of creating a free UNIX-like operating system.

Many Linux systems include GNU tools such as:

  • Bash
  • Core utilities
  • Compilers
  • System libraries

Linux Kernel

In 1991, Linus Torvalds created the first Linux kernel.

The project grew rapidly because:

  • The source code was freely available
  • Developers worldwide contributed
  • Organisations adopted Linux

Today Linux is maintained by thousands of contributors and is used across many industries.

What is a Linux Distribution?

A Linux distribution combines several components into a complete operating system.

A distribution normally includes:

  • Linux kernel
  • System tools
  • Package manager
  • Applications
  • Configuration tools

Examples:

Distribution Common Use
Ubuntu Servers, cloud, desktop
Debian Stable servers
Rocky Linux Enterprise systems
Fedora Development/testing
Arch Linux Advanced users

Popular Linux Families

Linux distributions are commonly grouped into families.

Debian Family

Examples:

  • Debian
  • Ubuntu
  • Linux Mint

Package manager:

apt

Example:

sudo apt update

Red Hat Family

Examples:

  • Red Hat Enterprise Linux
  • Rocky Linux
  • AlmaLinux

Package manager:

dnf

Example:

sudo dnf install nginx

Linux Server vs Desktop

Linux can be used in many different environments.

Desktop Operating System

Linux desktops are used for:

  • Web browsing
  • Office applications
  • Development
  • Personal computing

Examples:

  • Ubuntu Desktop
  • Fedora Workstation

Server Operating System

Linux servers are commonly used for:

  • Websites
  • Databases
  • Cloud workloads
  • Virtualisation
  • Containers
  • Enterprise applications

Servers often:

  • Run continuously
  • Have no graphical interface
  • Are managed remotely
  • Support automation

Example:

Administrator

      |
      |
      v

Linux Server

+----------------+
| Applications   |
| Databases      |
| Services       |
+----------------+

Accessing Linux Systems

Linux systems can be accessed in several different ways depending on where they are running.

Common access methods include:

  • Local console access
  • Remote SSH access
  • Virtual machine console access
  • Cloud provider console access

Local Console Access

A local console provides direct access to a Linux system.

Examples:

  • Physical server
  • Raspberry Pi
  • Linux workstation

A user authenticates using:

  • Username
  • Password

After login, Linux provides access to a command-line environment called the shell.

Example:

james@linux-server:~$

Remote Access Using SSH

Linux servers are commonly managed remotely using SSH.

SSH means:

Secure Shell

SSH provides an encrypted connection between an administrator and a Linux system.

Example:

ssh username@hostname

Example:

ssh james@server01

SSH is widely used for:

  • Cloud servers
  • Enterprise servers
  • Remote administration

SSH administration will be covered in more detail in later modules.

Virtual Machine and Cloud Access

Linux systems may also be accessed through:

  • Virtual machine consoles
  • Cloud provider management consoles
  • Remote management platforms

Examples:

  • AWS virtual machines
  • Microsoft Azure virtual machines
  • VMware environments

Why Linux is Important in Modern IT

Linux skills are important because Linux runs many of the technologies used in modern infrastructure.

Cloud Platforms

Examples:

  • AWS
  • Azure
  • Google Cloud

Containers

Examples:

  • Docker
  • Kubernetes

Automation

Examples:

  • Ansible
  • Terraform workflows

Enterprise Systems

Examples:

  • Web servers
  • Databases
  • Monitoring systems
  • Application platforms

Practical Exercise

Task 1 - Identify Your System

Run:

hostname

Record:

Hostname:

Run:

uname -r

Record:

Kernel:

Run:

cat /etc/os-release

Record:

Distribution:

Task 2 - Explore Your Environment

Identify:

  • What Linux distribution you are using
  • Whether the system is physical, virtual, cloud-based, or a Raspberry Pi
  • How you access the system

Record:

Linux Distribution:

Environment:

Access Method:

Knowledge Check

  1. What component of Linux communicates with hardware?

  2. What year was the first Linux kernel released?

  3. What is a Linux distribution?

  4. Name two Linux distributions.

  5. What is the difference between a Linux desktop and a Linux server?

  6. What technology is commonly used to remotely access Linux servers?

  7. Why is Linux widely used in cloud environments?

Summary

In this module you learned:

✓ Linux is an open-source operating system
✓ The Linux kernel manages communication between software and hardware
✓ Linux has roots in UNIX and the GNU Project
✓ Linux distributions package the kernel with tools and applications
✓ Linux is widely used for servers, cloud platforms and containers
✓ Linux systems can be accessed locally or remotely using tools such as SSH

Next Module

Continue your learning with:

Module 01 - Command Line Fundamentals