1. Linux Introduction
Welcome to the world of Linux! If you've been using Windows or macOS, Linux might seem a bit unfamiliar at first. But don't worry — Linux isn't as difficult as you might think. In fact, it's one of the most powerful and flexible operating systems in the world, found everywhere from smartphones to supercomputers.
1.1 What is Linux?
Linux is an open source operating system kernel, first released by Finnish programmer Linus Torvalds in 1991. Strictly speaking, Linux is just the kernel, while the complete system we use daily is called GNU/Linux, which includes the kernel, system tools, desktop environments, and other components.
In simple terms:
- Kernel: the core program that manages hardware resources (CPU, memory, disk, etc.)
- Shell: the "translator" between the user and the kernel, with Bash being the most common
- Distribution: a complete system that packages the kernel + tools + package manager together
💡 Tip: 💡 Analogy: If the Linux kernel is like a car engine, then a distribution is a complete car from different brands — the engine is the same, but the exterior, interior, and configuration vary.
1.2 Choosing a Mainstream Distribution
| Distribution | Package Manager | Target Audience | Features |
|---|---|---|---|
| Ubuntu | apt | First choice for beginners | Active community, rich software, most documentation |
| Debian | apt | Servers / stability needs | Extremely stable, upstream of Ubuntu |
| CentOS / Rocky | dnf/yum | Enterprise servers | RHEL compatible, long-term support |
| Fedora | dnf | Developers / cutting-edge | Testing ground for new technologies |
| Arch Linux | pacman | Advanced users | Rolling release, highly customizable |
| Kali Linux | apt | Security research | Built-in with numerous penetration testing tools |
💡 Tip: 💡 Beginner's advice: If you're using Linux for the first time, it's highly recommended to start with Ubuntu 22.04 LTS or Ubuntu 24.04 LTS. LTS = Long Term Support, providing 5 years of updates.
1.3 Key Differences Between Linux and Windows
| Comparison | Windows | Linux |
|---|---|---|
| Price | Requires purchasing a license | Free and open source |
| Operation | Primarily GUI-based | Command line is core, GUI is optional |
| File System | Drive letters (C: D: E:) | Single tree structure (/ root directory) |
| File Extensions | Distinguished by extension | Distinguished by file content/permissions |
| Permission Model | Primarily ACL | User/Group/Others + rwx |
| Software Installation | Download .exe installer | One command with package manager |
| Viruses | Relatively common | Rare, but don't be complacent |
| Server Market | About 20% | About 80%+ |