Linux

🌳 Linux RHCSA → RHCE Learning Tree

1. Linux Fundamentals

• 1.1 What is Linux?

  • Linux = Kernel + GNU tools + Shell
  • Multi-user, multitasking OS
  • Open-source and community driven
• 📘 Topic 1.2 – Linux vs Windows

  • Linux is free and open-source
  • Uses / (root) filesystem instead of C:\
  • Case-sensitive file paths
  • Text-based configuration files
  • Native remote access using SSH
• 1.3 Linux Architecture

  • User → Shell → Kernel → Hardware
  • Kernel manages CPU, memory, devices
• 1.4 Linux Security Basics

  • User & group permission model
  • No default administrator login
  • Strong isolation between users
• 1.5 SELinux Introduction

  • Security-Enhanced Linux
  • Mandatory Access Control
  • Modes: Enforcing, Permissive, Disabled
  • getenforce command
• 1.6 Package Management (RPM)

  • RPM = Red Hat Package Manager
  • Used in RHEL-based systems
  • rpm -qa to list packages

2. Bash & Shell

• What is Bash
• Shell Prompt (# / $)
• Command Structure
• Pipes ( | )
• Command Chaining ( ; )
• History & Shortcuts
• Wildcards & Globbing

3. Accessing the System

• TTY & PTS
• GUI vs CLI
• Switching Terminals
• Login & Logout
• SSH Basics

4. Linux File System Hierarchy

• / , /boot , /root , /home
• /bin , /sbin , /usr
• /etc , /var , /dev
• /opt , /tmp , /run
• Absolute vs Relative Paths

5. File & Directory Management

• pwd , cd
• ls (all options)
• touch
• cp , mv
• rm , rmdir
• df , du

6. File Types & Links

• Regular, Directory, Block, Character
• Symbolic Links
• Hard Links
• Inodes

7. Users & Groups

• Root vs Regular User
• useradd, usermod, userdel
• groupadd, groupdel
• passwd, chage
• /etc/passwd, /etc/shadow

8. Permissions & Security

• chmod (numeric & symbolic)
• chown, chgrp
• umask
• SELinux modes
• Contexts & restorecon

9. Process Management

• ps, top
• kill, killall
• nice, renice
• jobs, fg, bg

10. Boot & Services

• Boot Process
• GRUB
• systemctl
• Targets
• Root Password Recovery

11. Networking

• IP Addressing
• nmcli
• ip a / ip r
• hostnamectl
• SSH Server

12. Storage Management

• Partitions
• File Systems (ext4, xfs)
• mount, umount
• /etc/fstab
• Swap
• LVM (PV, VG, LV)

13. Archiving & Transfer

• tar
• gzip / gunzip
• zip / unzip
• scp
• rsync

14. Logs & Monitoring

• /var/log
• journalctl
• log rotation

🚀 RHCE (EX294) – Automation with Ansible

• Ansible Architecture
• Inventory
• Playbooks
• Modules
• Variables & Facts
• Loops & Conditionals
• Roles & Collections
• Jinja2 Templates
• Ansible Vault
• Automating Services, Users, Storage

📘 Topic 1.3 – Linux Architecture

• User interacts with Shell (Bash)
• Shell sends commands to Kernel
• Kernel communicates with hardware

📘 Topic 1.4 – Linux Security Basics

• User and group permission model
• SELinux provides mandatory access control
• No default administrator login

📘 Topic 1.5 – SELinux Introduction

• Security-Enhanced Linux (SELinux)
• Developed by NSA
• Modes: Enforcing, Permissive, Disabled
• getenforce command to check mode

📘 Topic 1.6 – Package Management (RPM)

• RPM = Red Hat Package Manager
• Used in RHEL-based distributions
• rpm -qa lists installed packages

RHCSA (EX200) → RHCE (EX294) | Tree-style Linux Learning