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Linux
A complete, practical reference for learning Linux from first principles to professional administration. Every concept is taught with real commands, real output, and real explanations of what is happening underneath.
How to Use This Wiki
Start at Phase 1 if you are new to Linux. Each phase builds on the previous one. If you already know the basics, jump to the phase that matches your current level. Every page follows the same structure: concept, why it matters, how it works, hands-on examples, and common mistakes.
Table of Contents
| Phase | Topic | What You Will Learn |
|---|---|---|
| Phase 1 | Foundations | What Linux is, how it is structured, how to get started |
| Phase 2 | Command Line | Navigate, create, move, copy, delete, read files |
| Phase 3 | Text Processing | Filter, search, transform text from the terminal |
| Phase 4 | Users and Permissions | Control who can access what and how |
| Phase 5 | Processes and Services | Run, monitor, and control programs and background services |
| Phase 6 | Networking | Configure interfaces, test connectivity, secure remote access |
| Phase 7 | Storage and Filesystems | Manage disks, partitions, and how data is stored |
| Phase 8 | Shell Scripting | Automate tasks with Bash scripts |
| Phase 9 | System Administration | Manage packages, logs, performance, and scheduled tasks |
| Phase 10 | Security | Harden a system, control access, audit events |
| Phase 11 | Advanced and DevOps | Containers, virtualization, kernel modules, CI/CD |
Quick Reference Pages
- Essential Commands Cheatsheet
- File Permissions Reference
- Systemd Service Reference
- Networking Commands Reference
- Bash Scripting Patterns
- Troubleshooting Guide
Design Principles of This Wiki
Practical first. Every topic starts with a real command you can run right now, not with theory.
Explain the output. When a command produces output, this wiki explains each field and what it tells you.
Show the errors too. Real learning happens when things go wrong. Common errors and their causes are documented alongside the correct path.
No unnecessary jargon. Technical terms are introduced with a plain-English definition before being used.
Build a mental model. Diagrams and analogies are used to explain how the system works internally, not just how to use it.
Prerequisites
You need a Linux system to follow along. Any of these will work:
- A virtual machine running Ubuntu, Debian, Fedora, or CentOS
- Windows Subsystem for Linux (WSL2) on Windows 10 or 11
- A Raspberry Pi
- Any cloud VPS (DigitalOcean, AWS EC2, or similar free tier)
This wiki uses Ubuntu 22.04 LTS for examples. Commands are noted where they differ on other distributions.
This wiki is structured as a progressive curriculum. Each phase ends with a set of exercises to confirm understanding before moving on.