Definition and Overview: Linux is a free, open-source operating system based on Unix. It’s known for its stability, security, and flexibility, making it a popular choice for servers, desktops, and embedded systems.
Unlike proprietary operating systems, Linux’s source code is available for anyone to view, modify, and distribute. This openness has led to a vast ecosystem of distributions (distros), catering to various user needs and preferences.
Why Linux Matters: Linux powers a significant portion of the world’s servers, including the infrastructure of major tech companies like Google, Facebook, and Amazon. It’s also the backbone of Android, the most widely used mobile operating system.
2. History of Linux
Origins and Development: Linux was created in 1991 by Linus Torvalds, a Finnish computer science student. He aimed to develop a free, open-source alternative to the proprietary Unix operating system.
Torvalds released the first Linux kernel version, 0.01, in September 1991. The project quickly gained traction, attracting developers worldwide who contributed to its growth and development.
Linus Torvalds and the Kernel: The kernel is the core of any operating system, managing hardware resources and facilitating communication between hardware and software. Linus Torvalds remains the lead maintainer of the Linux kernel, overseeing its development and integration of new features.
The Open Source Movement: Linux’s success is closely tied to the open-source movement, which promotes freely available software that anyone can use, modify, and share. Organizations like the Free Software Foundation (FSF) and the Open Source Initiative (OSI) have been instrumental in advocating for open-source software, including Linux.
3. Linux Distributions
What are Distributions (Distros)? A Linux distribution is a packaged version of the Linux operating system, combining the kernel with various software applications, libraries, and tools to provide a complete user experience.
Popular Distros: Some of the most popular Linux distributions include:
- Ubuntu: Known for its user-friendliness and extensive community support, Ubuntu is a popular choice for beginners and professionals alike.
- Fedora: Sponsored by Red Hat, Fedora is a cutting-edge distro that often introduces new technologies and features before other distros.
- CentOS: Based on Red Hat Enterprise Linux (RHEL), CentOS is a stable, enterprise-grade distro used in server environments.
- Arch Linux: Known for its simplicity and customization, allowing users to build their system from the ground up.
4. Linux Architecture
The Linux Kernel: At the heart of every Linux system is the kernel, which is responsible for managing system resources, including memory, CPU, and peripheral devices.
File System Hierarchy: Linux follows a standardized file system hierarchy, where directories are organized in a tree-like structure starting from the root directory (“/”).
5. Getting Started with Linux
Installation Process: Installing Linux involves downloading an ISO image of a distribution, creating a bootable USB drive, and following the installation prompts.
Basic Command Line Usage: The command line is a powerful tool in Linux, allowing users to perform tasks quickly and efficiently.
6. Core Linux Commands
File and Directory Management: Key commands include:
- ls: Lists files and directories (man page).
- cd: Changes the current directory (man page).
- rm: Removes files or directories (man page).
7. Package Management
Package Managers: Different distros use different package managers:
- APT: Used by Debian-based distros like Ubuntu (Ubuntu Guide).
- YUM/DNF: Used by Red Hat-based distros like Fedora and CentOS (DNF Documentation).
- Pacman: Used by Arch Linux (Arch Wiki).
8. Linux File Permissions
Understanding File Permissions: Linux file permissions determine who can read, write, or execute a file (chmod command).
9. User and Group Management
Managing Users: Linux allows administrators to manage user accounts using commands like:
10. Linux Networking
Networking Commands: Useful networking commands include: