Introduction to Linux Operating System – Basics and Common Distributions

Linux System Introduction

What is a Linux system?

How does Linux differ from Windows? Typical use cases?

Major Linux branches and distributions.

Open source: source code is publicly available.

Closed source: proprietary code.

Learning resources:

GitHub – a code repository where developers publish their projects.

Tsinghua mirror: https://mirrors.tuna.tsinghua.edu.cn/centos/

Typical career tracks:

• Linux administration, shell scripting, automation – entry‑level Linux Ops Engineer.

• Python automation – Python Automation Engineer.

• Docker containers and Kubernetes orchestration – Container Cloud Ops Engineer.

• DevOps toolchain integration – DevOps Engineer.

Common Operating Systems

Windows – Microsoft desktop and server OS (e.g., Windows Server 2008, 2019).

macOS – Apple’s desktop and server OS, Unix‑based, paid and requires Apple hardware.

Linux – The foundation of Android phones; a Unix‑like, stable, free, and open‑source server‑grade OS.

What Is Linux?

Linux is a free, freely distributable Unix‑like operating system based on POSIX, supporting multiple users, multitasking, multithreading, and multi‑CPU architectures. It runs major Unix tools, applications, and network protocols on both 32‑bit and 64‑bit hardware, embodying a network‑centric design inherited from Unix.

The Linux kernel was announced by Linus Torvalds on October 5, 1991, on the comp.os.minix newsgroup. Version 1.0 was released in March 1994 with about 170,000 lines of code under a completely free license, later adopting the GPL (GNU General Public License).

System Characteristics

Linux’s core ideas are: 1) Everything is a file. 2) Each application has a specific purpose.

Completely Free

Linux can be obtained freely over the network and its source code can be modified without restriction.

Multi‑User, Multi‑Task

Multiple users can operate simultaneously, each with distinct permissions, ensuring isolation between user environments.

Rich Interface

Linux offers both command‑line and graphical interfaces. The command line allows keyboard‑driven commands, while the X‑Window system provides a graphical desktop similar to Windows.

Cross‑Platform Support

Linux runs on diverse hardware platforms, including x86, 68k, SPARC, Alpha, and many others.

Common Linux Distributions

Red Hat Enterprise Linux – Commercial, subscription‑based enterprise distribution.

CentOS – Community‑driven, free enterprise‑grade distribution.

Ubuntu – Desktop‑focused distribution for personal use.

Technical Certifications

Red Hat offers certifications such as RHCSA, RHCE, and RHCA for validating Linux administration skills.