Linux Learning Guide¶

Introduction¶

This folder contains materials for systematic learning of the Linux operating system, from basics to server administration.

Target Audience: Linux beginners ~ server administrators
Distributions: Ubuntu/Debian and CentOS/RHEL both covered
Goal: From command usage to server operations

Learning Roadmap¶

[Beginner]            [Intermediate]         [Advanced]
  │                     │                      │
  ▼                     ▼                      ▼
Linux Basics ──────▶ Text Processing ──────▶ Shell Scripting
  │                     │                      │
  ▼                     ▼                      ▼
Filesystem ────────▶ Permissions ───────────▶ Network Basics
  │                     │                      │
  ▼                     ▼                      ▼
File Mgmt ─────────▶ User Mgmt ─────────────▶ System Monitoring
                        │                      │
                        ▼                      ▼
                  Process Mgmt ──────────▶ Security & Firewall
                        │
                        ▼
                  Package Mgmt

Prerequisites¶

Basic computer skills
Understanding of terminal/command prompt concepts
English command reading (not required)

File List¶

File	Difficulty	Key Topics
01_Linux_Basics.md	⭐	Linux concepts, distributions, terminal, basic commands
02_Filesystem_Navigation.md	⭐	Directory structure, paths, ls, cd, find
03_File_Directory_Management.md	⭐	touch, mkdir, cp, mv, rm, tar
04_Text_Processing.md	⭐⭐	grep, sed, awk, pipes, redirection
05_Permissions_Ownership.md	⭐⭐	chmod, chown, special permissions, umask
06_User_Group_Management.md	⭐⭐	useradd, sudo, user/group management
07_Process_Management.md	⭐⭐	ps, top, kill, systemctl
08_Package_Management.md	⭐⭐	apt, yum/dnf, repository management
09_Shell_Scripting.md	⭐⭐⭐	variables, conditionals, loops, practical scripts
10_Network_Basics.md	⭐⭐⭐	ip, ssh, port checking, remote access
11_System_Monitoring.md	⭐⭐⭐	df, free, logs, cron
12_Security_and_Firewall.md	⭐⭐⭐⭐	SSH security, ufw, firewalld, fail2ban
13_Systemd_Advanced.md	⭐⭐⭐⭐	service units, timers, sockets, journald
14_Performance_Tuning.md	⭐⭐⭐⭐	sysctl, kernel parameters, perf, flamegraph
15_Container_Internals.md	⭐⭐⭐⭐	cgroups, namespaces, container runtime
16_Storage_Management.md	⭐⭐⭐⭐	LVM, RAID, filesystems, LUKS encryption
17_SELinux_AppArmor.md	⭐⭐⭐⭐	SELinux policies, AppArmor profiles, troubleshooting
18_Log_Management.md	⭐⭐⭐	journald, rsyslog, logrotate, remote logging
19_Backup_Recovery.md	⭐⭐⭐⭐	rsync, Borg Backup, disaster recovery strategies
20_Kernel_Management.md	⭐⭐⭐⭐	kernel compilation, modules, DKMS, GRUB
21_Virtualization_KVM.md	⭐⭐⭐⭐	libvirt, virsh, VM management, snapshots
22_Ansible_Basics.md	⭐⭐⭐	inventory, playbooks, roles, Vault
23_Advanced_Networking.md	⭐⭐⭐⭐	VLAN, bonding, iptables/nftables
24_Cloud_Integration.md	⭐⭐⭐	cloud-init, AWS CLI, metadata
25_High_Availability_Cluster.md	⭐⭐⭐⭐⭐	Pacemaker, Corosync, DRBD
26_Troubleshooting_Guide.md	⭐⭐⭐	boot, network, disk, performance troubleshooting

Recommended Learning Path¶

Stage 1: Linux Introduction (Beginner)¶

01_Linux_Basics → 02_Filesystem_Navigation → 03_File_Directory_Management

Learn terminal usage and basic commands.

Stage 2: Practical Usage (Intermediate)¶

04_Text_Processing → 05_Permissions_Ownership → 06_User_Group_Management
    → 07_Process_Management → 08_Package_Management

Learn file processing, permission management, and system operations basics.

Stage 3: Server Administration (Advanced)¶

09_Shell_Scripting → 10_Network_Basics → 11_System_Monitoring → 12_Security_and_Firewall

Cover all aspects of server management including automation, networking, monitoring, and security.

Stage 4: System Deep Dive (Expert)¶

13_Systemd_Advanced → 14_Performance_Tuning → 15_Container_Internals → 16_Storage_Management

Study systemd, performance optimization, container internals, and storage management.

Stage 5: Enterprise Operations (Expert)¶

17_SELinux_AppArmor → 18_Log_Management → 19_Backup_Recovery → 20_Kernel_Management

Cover security modules, log management, backup strategies, and kernel management.

Stage 6: Infrastructure Engineering (Expert)¶

21_Virtualization_KVM → 22_Ansible_Basics → 23_Advanced_Networking → 24_Cloud_Integration
    → 25_High_Availability_Cluster → 26_Troubleshooting_Guide

Master virtualization, automation, advanced networking, cloud, HA, and troubleshooting.

Practice Environment¶

Ubuntu (Recommended)¶

# Quick start with Docker
docker run -it ubuntu:22.04 bash

# Or use VM/WSL
# - VirtualBox + Ubuntu ISO
# - Windows WSL2

CentOS/RHEL¶

# Start with Docker
docker run -it rockylinux:9 bash

# Or use VM
# - VirtualBox + Rocky Linux ISO

Cloud (for practice)¶

AWS EC2 Free Tier
Google Cloud Free Tier
DigitalOcean (paid)

Distribution Comparison¶

Item	Ubuntu/Debian	CentOS/RHEL
Package Management	APT (`apt`)	YUM/DNF (`dnf`)
Package Format	.deb	.rpm
Firewall	UFW	firewalld
Security Module	AppArmor	SELinux
Service Management	systemctl	systemctl
Main Use	Desktop, server	Enterprise server

Docker/ - Using Linux in container environments
Git/ - Version control on Linux
PostgreSQL/ - Database operations on Linux servers