The Linux file system hierarchy is a logical and standardized structure that organizes all files and directories within a single unified directory tree. This structure, defined by the Filesystem Hierarchy Standard (FHS), ensures consistency and predictability across different Linux distributions.
Understanding the Root Directory
At the very top of the Linux file system is the root directory, denoted by a single forward slash /. All files and directories branch off from this root, regardless of their actual physical location on disk or partitions. There are no "drive letters" as in Windows; everything in Linux exists within this one tree structure.
Major Top-Level Directories and Their Purposes
Each main directory under / plays a specific role. The table below summarizes the most important ones:
Key Features and Practical Uses
Each major Linux directory is designed for a specific operational purpose. Below are essential directories and their practical applications.
1. /etc: Critical for holding configuration files; for example, /etc/passwd holds user accounts, /etc/network/interfaces manages network setup.
2. /var: Used for files that can change in size (log files, emails, print jobs) and can grow substantially over time.
3. /home: Each user has a private workspace—great for separating user data from system files.
4. /proc and /sys: Pseudo-files; essential for administrators to monitor and configure kernel parameters and processes in real time.
Examples of Directory Structure
/
├── bin/
├── boot/
├── dev/
├── etc/
│ └── passwd
├── home/
│ ├── user1/
│ └── user2/
├── lib/
├── media/
├── opt/
├── proc/
├── root/
├── run/
├── sbin/
├── srv/
├── sys/
├── tmp/
├── usr/
└── var/Notes on Navigation and Permissions
1. Only the root user can make system-level changes outside /home or /tmp.
2. Mounting new storage devices temporarily uses /mnt or /media, not inside /home.
3. /bin and /sbin contain only essential programs needed for booting or repairing the system.
4. Files in /tmp may be deleted between reboots; never store important data there.
Filesystem Hierarchy Standard (FHS)
The FHS is a widely accepted convention that all major Linux distributions follow. It ensures programs and administrators know where system files, binaries, configurations, and user data are located for consistency and ease of use.
