📂 Day 1: Linux Directory Structure
- Understanding the Linux File System is like learning the map of a new city. Everything in Linux is a file, and every file has a place.*
🌳 The Linux Directory Tree
In Linux, everything starts from the Root (/). It's the base of the tree from which all other directories branch out.
graph TD
Root["/ (Root)"] --> Home["/home"]
Root --> Etc["/etc"]
Root --> Var["/var"]
Root --> Bin["/bin"]
Root --> Tmp["/tmp"]
Root --> RootHome["/root"]
Home --> User["~ (User Home)"]
style Root fill:#f9f,stroke:#333,stroke-width:2px
style Home fill:#bbf,stroke:#333
style Etc fill:#bfb,stroke:#333
ðŸ—ºï¸ Key Directories Explained
| Directory | Symbol | Description |
|---|---|---|
| Root | / |
The starting point of the filesystem. The "God" directory containing everything. |
| User Home | /home |
Contains personal directories for users (e.g., /home/usman). |
| Home Shortcut | ~ |
A quick shortcut to the current user's home (e.g., cd ~ takes you home). |
| Super User Home | /root |
The private home directory for the System Administrator (Root user). |
| Binaries | /bin |
The Toolbox. Contains essential commands like ls, cp, cat. |
| Variables | /var |
Stores changing data like system logs (/var/log). |
| Temporary | /tmp |
Scratchpad space. Files here are often deleted on reboot. |
âš™ï¸ The Configuration Hub: /etc
ðŸ•µï¸ Hacker's Note: This directory is a goldmine for understanding how a system is configured.
The /etc directory acts as the system's Rule Book. It controls who can do what, network settings, and startup scripts.
🔑 Critical Files in /etc
/etc/passwd
📠List of all users on the system./etc/shadow
🔠Stores hashed passwords (highly sensitive)./etc/sudoers
ðŸ›¡ï¸ The definition of "Who can be Admin". Controlssudoprivileges.