Comprehensive Linux Learning Roadmaps and Cheat Sheets

Linux Learning Path

Provides a staged roadmap from basic command‑line usage to advanced system administration. The progression typically includes:

Shell fundamentals and basic commands

Package management (apt, yum, dnf, pacman)

Filesystem navigation and permissions

Networking basics (ifconfig/ip, ping, ssh)

Service management with systemd (units, timers)

Scripting with Bash and Python

Performance monitoring (top, htop, vmstat, iostat)

Security hardening and audit

Kernel source exploration and compilation

Linux Desktop Overview

Illustrates the typical components of a Linux desktop environment:

Display server – Xorg or Wayland

Window manager – i3, Mutter, KWin

Desktop environment – GNOME, KDE Plasma, XFCE

Session manager – systemd or loginctl Inter‑process communication – D‑Bus

Supporting services – NetworkManager, polkit, clipboard managers

Filesystem Hierarchy Standard (FHS)

Shows the standard directory layout defined by the FHS. Key top‑level directories: / – Root of the filesystem. /bin – Essential user binaries required for boot and single‑user mode. /sbin – System binaries for administration. /usr – Secondary hierarchy for read‑only user programs and data; includes /usr/bin, /usr/sbin, /usr/lib, /usr/local. /etc – Host‑specific configuration files. /var – Variable data such as logs ( /var/log), caches, spools. /home – User home directories. /tmp – Temporary files. /dev – Device nodes. /proc and /sys – Virtual filesystems exposing kernel and process information.

Directories Requiring Special Attention

Highlights locations that often need monitoring or custom configuration: /etc – Service configuration files (e.g., /etc/ssh/sshd_config, /etc/fstab). /var/log – System and application logs for troubleshooting and security auditing. /var/www – Default web server document root. /home – User data and dotfiles (e.g., ~/.bashrc, ~/.ssh/authorized_keys). /opt – Optional third‑party software installations.

Linux Kernel Learning Roadmap

Outlines a progressive study plan for kernel development:

Set up a build environment (install gcc, make, ncurses-dev, git).

Obtain the source tree:

git clone https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

.

Explore the directory structure ( arch/, drivers/, fs/, kernel/, include/).

Configure the kernel with make menuconfig or make xconfig.

Build and install: make -j$(nproc) && sudo make modules_install install.

Study core subsystems: process scheduler, memory management, file systems, networking stack, device drivers, and security modules (SELinux, AppArmor).

Use debugging and tracing tools ( gdb, kgdb, perf, ftrace).

Follow the kernel contribution workflow: coding style, Signed-off-by, patch submission via git send-email or the web‑based Gerrit system.

Linux Security Coaching

Summarizes essential hardening practices and audit steps:

Apply the principle of least privilege; configure sudo and user groups.

Secure SSH: disable root login, use key‑based authentication, change the default port.

Enable a host‑based firewall (e.g., iptables or nftables) with a default‑deny policy.

Keep the system updated with security patches (e.g., apt update && apt upgrade).

Activate mandatory access control (SELinux or AppArmor) and enforce targeted policies.

Audit logs regularly; employ auditd, logwatch, or fail2ban to detect anomalies.

Disable unnecessary services and remove unused packages.

Implement file‑integrity monitoring (e.g., AIDE or tripwire).

Linux Command Reference

Provides a categorized cheat sheet of frequently used commands:

File operations: ls, cp, mv, rm, find, tar, gzip Process management: ps, top, htop, kill, pkill, nice, renice Networking: ip, ping, ss, curl, wget, ssh, scp Package management: apt, yum, dnf, pacman, dpkg, rpm System monitoring: df, du, free, uptime, dmesg Text processing: grep, sed, awk, cut, sort,

uniq

Linux Command Cheat Sheet

Condensed visual summary for quick lookup, grouping commands by purpose (file, process, network, system, text). Useful for daily terminal work.

Reference URLs (kept as plain text for further lookup):

Kernel source repository: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

Security mind‑map image: https://raw.githubusercontent.com/phith0n/Mind-Map/master/Linux%20Security%20Coaching.png

Command cheat‑sheet article: https://linuxtoy.org/archives/unix-linux-command-cheat-sheet.html