Linux File System

The Linux file system is a hierarchical structure that starts from a single root directory /. Unlike Windows (which uses drives like C: or D:), Linux uses one unified directory tree.

/
├── bin
├── boot
├── dev
├── etc
├── home
├── lib
├── proc
├── root
├── sbin
├── tmp
├── usr
└── var

This structure follows the Filesystem Hierarchy Standard (FHS).

Root Directory /

• The starting point of the entire Linux file system

• All other directories are mounted under /

• You cannot delete or rename it

📌 Think of / as the foundation of Linux

Important Linux Directories Explanation :

1. 📂 /bin – Essential User Binaries :

• Contains basic commands used by all users

• Available even in single-user mode

Examples :

ls, cp, mv, rm, cat, echo

2. 📂 /sbin – System Binaries :

• Contains commands mainly used by the root user

• Used for system administration

Examples :

ip, reboot, shutdown, fsck

3. 📂 /etc – Configuration Files :

• Stores system-wide configuration files

• No binaries here

Examples:

• /etc/passwd → User information

• /etc/hosts → Hostname mappings

📌 Editing files here directly impacts system behavior

4. 📂 /home – User Home Directories :

   • Each user gets a personal directory

   • Non-root users store their data here

Examples :

/home/apurv
/home/devops

📌 This is where user-level work happens

5. 📂 /root – Root User’s Home :

• Home directory for the root user

• Different from /home

📌 Keeps admin data isolated from regular users

6. 📂 /var – Variable Data :

   • Stores files that grow over time

Common subdirectories:

• /var/log → System logs

• /var/lib → Application state data

• /var/spool → Mail, cron jobs

📌 Logs are stored here for troubleshooting

7. 📂 /tmp – Temporary Files :

• Used for short-lived files

• Often cleared on reboot

📌 Anyone can write here, so permissions matter

8. 📂 /usr – User System Resources :

• Contains user applications and libraries

• Not user-specific despite the name

Important paths:

• /usr/bin → User commands

• /usr/sbin → Admin commands

• /usr/lib → Libraries

📌 /usr is usually read-only in production systems

9. 📂 /lib & /lib64 – Shared Libraries :

• Libraries required by binaries in /bin and /sbin

• Essential for system boot

10. 📂 /dev – Device Files :

Represents hardware devices as files

Examples :

/dev/sda   → Hard disk
/dev/null → Discards output

📌 Devices are accessed like files in Linux

11. 📂 /proc – Process Information :

• Virtual file system

• Contains runtime system information

• Helps in debugging & performance analysis

• Used by monitoring tools like:

top
ps
htop

12. 📂 /boot – Boot Loader Files

    • Contains kernel and boot-related files

    • Critical for system startup

🔚 Conclusion

Understanding the Linux file system is non-negotiable for anyone working with Linux.
It forms the base for:

• Commands

• Permissions

• Troubleshooting

• Automation