4. Linux File System Structure
🌳 File System Hierarchy Overview
/ (Root Directory)
│
┌───────────────┼───────────────┐
│ │ │
bin etc home
(commands) (configuration) (user dirs)
│ │ │
├─ ls ├─ passwd ├─ alice/
├─ cat ├─ hosts ├─ bob/
└─ grep └─ fstab └─ charlie/
usr var tmp
(programs) (variable) (temporary)
│ │ │
├─ bin/ ├─ log/ └─ (temp files)
├─ lib/ ├─ mail/
└─ share/ └─ spool/
🌍 The Root Directory (/)
🪟 Windows vs 🐧 Linux
| Windows |
Linux |
Multiple roots: C:\, D:\, E:\ |
Single root: / |
| Drive letters |
Everything under one tree |
Key Concept: Linux has a single root directory / that contains everything!
📋 File System Hierarchy Standard (FHS)
🗂️ Directory Tree Visualization
/ ← Root (everything starts here)
├── bin/ ← Essential user commands
│ ├── ls, cat, grep, bash...
├── boot/ ← Boot loader files
├── dev/ ← Device files
│ ├── sda (disk), tty (terminal)...
├── etc/ ← System configuration
│ ├── passwd, hosts, fstab...
├── home/ ← User directories
│ ├── alice/
│ └── bob/
├── lib/ ← Shared libraries
├── media/ ← Removable media mount points
├── mnt/ ← Temporary mount points
├── opt/ ← Optional software
├── proc/ ← Process information (virtual)
├── root/ ← Root user's home
├── run/ ← Runtime data
├── sbin/ ← System administration commands
├── srv/ ← Service data
├── sys/ ← System information (virtual)
├── tmp/ ← Temporary files
├── usr/ ← User programs and data
│ ├── bin/ ← User commands
│ ├── lib/ ← User libraries
│ ├── local/ ← Local software
│ └── share/ ← Shared data
└── var/ ← Variable data
├── log/ ← Log files
├── mail/ ← Mail files
└── spool/ ← Spool directories
🔑 Key Directories
🖥️ System Directories
| Directory |
Purpose |
Examples |
/ |
🌳 Root directory (top level) |
Everything starts here |
/bin |
🔧 Essential user binaries |
ls, cat, cp, mv |
/sbin |
⚙️ System binaries |
ifconfig, reboot, fdisk |
/usr/bin |
📦 User binaries |
Installed programs |
/usr/sbin |
🔐 User system binaries |
Admin tools |
/lib /lib64 |
📚 Shared libraries |
System libraries |
/etc |
⚙️ Configuration files |
System settings |
/var |
📊 Variable data |
Logs, databases |
/tmp |
🗑️ Temporary files |
Cleared on reboot |
👤 User Directories
| Directory |
Purpose |
Who Can Write |
/home |
🏠 User home directories |
Individual users |
/root |
👑 Root user’s home |
Root only |
🔌 Device and Virtual
| Directory |
Purpose |
Type |
/dev |
💾 Device files |
Hardware access |
/proc |
🔄 Process information |
Virtual (kernel) |
/sys |
🖥️ System information |
Virtual (kernel) |
🧭 Path Examples
📍 Absolute Paths (start with /)
┌─────────────────────────────────────────┐
│ /home/alice/documents/report.txt │
│ │ │ │ │ │
│ │ │ │ └─ 📄 filename │
│ │ │ └─ 📁 subdirectory │
│ │ └─ 👤 user directory │
│ └─ 🌳 always starts from root │
└─────────────────────────────────────────┘
🎯 Relative Paths (no leading /)
┌─────────────────────────────────────────┐
│ documents/report.txt │
│ │ │ │
│ │ └─ 📄 filename │
│ └─ 📁 relative to current location │
└─────────────────────────────────────────┘
✨ Special Path Symbols
| Symbol |
Meaning |
Example |
~ |
🏠 Home directory |
/home/username |
. |
📍 Current directory |
./script.sh |
.. |
⬆️ Parent directory |
../file.txt |
/ |
🌳 Root directory |
/etc/hosts |
📊 Directory Purpose Guide
| Category |
Directories |
Purpose |
Icon |
| Essential |
/bin, /sbin |
Critical system commands |
🔧 |
| Configuration |
/etc |
System settings |
⚙️ |
| User Data |
/home, /root |
Personal files |
👤 |
| Programs |
/usr |
Installed software |
📦 |
| Variable Data |
/var |
Logs, mail, databases |
📊 |
| Temporary |
/tmp |
Temporary files |
🗑️ |
| Devices |
/dev |
Hardware access |
💾 |
| Virtual |
/proc, /sys |
Kernel information |
🔄 |
| Mount Points |
/media, /mnt |
External storage |
💿 |
💿 Program Files Location
🪟 Windows vs 🐧 Linux Program Structure
| Component |
Windows |
Linux |
| Executables |
C:\Program Files\App\ |
/bin, /usr/bin |
| Libraries |
C:\Program Files\App\ |
/lib, /usr/lib |
| Configuration |
C:\Program Files\App\ |
/etc |
| Data Files |
C:\Program Files\App\ |
/usr/share |
Key Difference: Windows keeps everything together; Linux distributes program components across the file system by type!
Navigation
Next: → Home Directory Concepts
Previous: ← User Types And Login
Lesson Home: ↑ Lesson 2: The Shell
Course Home: ⌂ Introduction to Linux