Linux is a free and open-source operating system kernel that forms the foundation for numerous Linux distributions. Linux is known for its stability, security, and flexibility. It is widely used in various domains, from servers and embedded systems to desktop computers and mobile devices. Linux distributions like Ubuntu, Fedora, and CentOS provide complete operating systems built on top of the Linux kernel. Linux offers a vast array of software packages and utilities, making it suitable for a wide range of applications.

Module 1: Linux Fundamentals

What is Linux?

Linux is a free, open-source operating system based on Unix. It is known for its robustness and flexibility. Linux is used in many different environments, such as servers, desktops, smartphones (Android), and embedded systems.

Understanding Linux distributions

A Linux distribution (or distro) is an operating system made from a software collection, which is based upon the Linux kernel and, often, a package management system. Examples include Ubuntu, CentOS, Debian, Fedora, and many more.

Getting started with the Linux command line

The Linux command line, also known as the terminal or shell, is a powerful tool used by administrators and users to interact with the system. Commands are typed at the prompt, and each command is executed when you press the Enter key.

Filesystem hierarchy

The Linux filesystem is a hierarchical structure. The top of this hierarchy is known as the root directory, denoted as '/'. It includes directories such as /bin (for binary files), /etc (for system configuration files), /home (for user directories), and more.

Module 2: Basic Linux Commands

File management commands

Common file management commands in Linux include `ls` (list directory contents), `cd` (change directory), `pwd` (print working directory), `cp` (copy files and directories), `mv` (move or rename files), and `rm` (remove files or directories).

File permissions and ownership

Linux has a robust system for managing file permissions and ownership. Commands for managing these include `chmod` (change permissions), `chown` (change file owner and group), and `chgrp` (change group ownership).

Process management

Commands for managing system processes include `ps` (show current processes), `top` (display Linux tasks), `kill` (terminate a process), and `shutdown` (shutdown or restart a system).

Package management

Linux distributions use package managers to install, update, and remove software packages. Ubuntu uses `apt`, CentOS and Fedora use `yum` or `dnf`, and Arch Linux uses `pacman`.

Module 3: Intermediate Linux Skills

Shell scripting

Shell scripting allows you to automate tasks in Linux. A shell script is a text file containing one or more commands. `bash` (Bourne Again SHell) is a commonly used shell for scripting.

System monitoring

Commands like `top`, `htop`, `free`, `df`, and `vmstat` provide information about system performance and resource usage. This helps in monitoring the system health and troubleshooting issues.

Text processing

Linux provides powerful text processing commands such as `grep` (search text), `sed` (stream editor for filtering and transforming text), and `awk` (language for text processing).

Networking commands

Networking is a crucial part of Linux administration. Commands such as `ping`, `ifconfig`/`ip`, `netstat`, `ssh`, and `scp` help in network communication and troubleshooting.

Module 4: Advanced Linux Skills

Kernel and system configuration

The Linux kernel can be configured and tuned for different environments using tools like `sysctl` and configuration files in the /etc/sysctl.d/ directory. Services can be managed using system management daemons like systemd or init.

Disk and partition management

Linux provides tools like `fdisk`, `parted`, and `lsblk` for disk and partition management. File systems can be created and modified using `mkfs`, `tune2fs`, and similar tools.

User and group management

Linux system administrators manage user and group accounts using commands like `useradd`, `usermod`, `userdel`, `groupadd`, and `groupdel`. Password management can be done using `passwd`.


Linux offers various security modules like SELinux and AppArmor, and tools like `iptables` for firewall configuration. Regular system updates, minimal installation, least privileges approach, and other best practices also contribute to system security.