Linux Directories

Linux organizes system data and programs using a hierarchical tree-like file system. All directories originate from the root / and branch into specialized folders. Learning the purpose of each directory helps users manage configurations, locate files, and understand how Linux operates beneath the surface.

Main Directories in Linux

/ – Root Directory

The starting point of the entire Linux file system hierarchy. Every other directory branches from here.

/bin – Essential Programs

Contains critical executable files needed during boot and for basic system functionality (e.g., ls, cat).

/boot – Kernel and Bootloader

Stores boot-related files including the Linux kernel (vmlinuz) and bootloader configurations (e.g., GRUB).

/dev – Device Files

Linux treats hardware as files. This directory contains device nodes representing disks, input devices, etc.

/etc – System Configuration

Home to global configuration files and startup scripts. Notable files:

• /etc/passwd – User account info
• /etc/fstab – Disk mount points
• /etc/crontab – Scheduled tasks

/home – User Directories

Contains personal directories for each non-root user. Files are stored at /home/username.

/lib – Shared Libraries

Holds library files required by binaries in /bin and /sbin. Comparable to DLLs in Windows.

/media – Auto-mounted External Devices

Temporary mount point for devices like USB drives, DVDs, automatically managed by the system.

/mnt – Manual Mounting

Traditionally used for manually mounting additional storage (e.g., mount /dev/sdb1 /mnt).

/opt – Optional Software

Used for installing third-party or proprietary applications outside the standard Linux package system.

/proc – Kernel Info

A virtual directory that exposes real-time kernel and process data, used by tools like top or ps.

/root – Root User’s Home

Dedicated home directory for the root (admin) user. Isolates root from normal users in /home.

/sbin – System Binaries

Includes administrative tools like shutdown, init, fsck. Often restricted to root access.

/tmp – Temporary Files

Used for temporary file storage. Many systems clear /tmp automatically on reboot.

/usr – User Programs

Typically the largest directory. Contains applications and resources for regular use:

• /usr/bin – Main executables
• /usr/lib – Shared libraries
• /usr/share – Icons, docs, locale files

/var – Variable Data

Stores changing files like system logs, mail spools, databases, and cached content.

/var/log – Log Files

Inside /var, this directory contains log files for debugging and auditing system activity.

Conclusion

Linux structures its file system for maximum clarity and stability. Each directory has a specific purpose, whether it’s storing user data, system binaries, or dynamic content. Familiarity with these directories equips administrators and users to troubleshoot, configure, and interact with the system more effectively.