Course 27 - Hacking Web Applications, Penetration Testing, CTF | Episode 2: Linux Fundamentals and Command Injection Basics

In this lesson, you’ll learn about:Linux operating system fundamentals, including its architecture and why command-line proficiency is critical for cybersecurity tasks such as vulnerability discovery and command injection testing.File System Hierarchy Standard (FHS) structure, understanding key root directories like /etc (configuration), /bin (essential binaries), /home (user data), and /var (logs and variable data), along with the difference between absolute vs. relative paths.Core file and directory management commands, including:ls (listing files, including hidden files)cd (navigating directories)pwd (printing the working directory)cp, mv, and rm (copying, moving, and deleting files)Searching and filtering techniques, using:find (searching by name, type, or permissions)grep (matching strings inside files)locate (database-based file indexing)User identity and privilege management, including:whoami (current user identification)su (switching users)sudo (executing commands with elevated privileges)Process monitoring and control, such as:ps -aux (viewing active processes)kill and killall (terminating processes)Understanding signals like SIGTERM (15) for graceful shutdown and SIGKILL (9) for forced terminationCommand control operators, learning how to chain and manipulate commands using:; (sequential execution)&& (execute if previous succeeds)|| (execute if previous fails)| (piping output between commands)Practical lab application, applying navigation, command chaining, and operator behavior to understand how improperly validated input can lead to command injection vulnerabilities in real-world systems.You can listen and download our episodes for free on more than 10 different platforms:https://linktr.ee/cybercode_academy