Linux Directory Structure

Linux Directory Structure

Prerequisite: Linux File Hierarchy Structure

Introduction

In Linux and Unix operating systems, everything is considered a file, including directories, regular files, and devices like mouse, keyboard, and printers. This document provides an in-depth overview of the Linux directory structure, including types of files and the hierarchy of directories.

Types of Files in Linux

General Files

• General files, also known as ordinary files, can be of various types, such as images, videos, programs, or simple text files. These files can be in ASCII or Binary format and are the most commonly used files in the Linux system.

Directory Files

• Directory files act as a warehouse for other file types. They organize files and may include subdirectories within them, creating a hierarchical structure for file management.

Device Files

• Unlike Windows-like operating systems where devices are represented as drive letters, Linux represents devices as files. For example, /dev/sda1, /dev/sda2 represent different partitions of a hard drive.

Types of Files in Linux

File Types	Description
General Files	Also known as ordinary files, they can be images, videos, programs, or simple text files.
Directory Files	Act as a warehouse for other file types, organizing files and including subdirectories.
Device Files	Represent devices as files, such as /dev/sda1 for partitions of a hard drive.

Linux File System Hierarchy

The Linux file system hierarchy begins with the root directory /. Here are some of the top-level directories and their purposes:

Directory	Description
/bin	Contains binary or executable programs.
/etc	Stores system configuration files.
/home	Default home directory for users.
/opt	Location for optional or third-party software.
/tmp	Temporary space, usually cleared on system reboot.
/usr	Contains user-related programs.
/var	Holds log files and variable data.
Additional Directories
/boot	Boot-related information.
/dev	Device files location.
/lib	Kernel modules and shared libraries.
/lost+found	Used for recovered bits of corrupted files.
/media	Subdirectories for removable media devices.
/mnt	Temporary mount directories.
/proc	Virtual file system containing process information.
/run	Stores volatile runtime data.
/sbin	System binaries for administrators.
/srv	Server-specific files.
/sys	Virtual file system for device information.

Notable Files in Linux

File/Directory	Description
Linux Kernel File	/boot/vmlinux: The Linux kernel file.
Device Files	/dev/hda: Device file for the first IDE HDD.
	/dev/hdc: Pseudo-device for garbage output redirection.
System Config Files	/etc/bashrc: Bash shell system defaults and aliases.
	/etc/crontab: Shell script for scheduled commands.
	/etc/fstab: Disk drive information and mount points.
	/etc/group: Information about security groups.
	/etc/grub.conf: Grub bootloader configuration.
	/etc/init.d: Scripts for service startup.
	/etc/inittab: Initialization process and run levels.
	/etc/passwd: Usernames and passwords.
	/etc/resolv.conf: DNS configuration.
User Files	/usr/bin: Executable files.
	/usr/include: Standard files for C programs.
	/usr/lib: Object files and libraries.
Virtual Files	/proc/cpuinfo: CPU information.
	/proc/filesystems: Information about running processes.
	/proc/ioports: Input and Output addresses used by devices.
	/proc/meminfo: Memory usage information.
Other Important Files	Version Information File: /version - Displays Linux version information.
	Log Files:
	/var/log/lastlog: User's last login information.
	/var/log/messages: Global system messages.
	/var/log/wtmp: Login and logout history.

Conclusion

Understanding the Linux directory structure is essential for efficient system navigation, file management, and access to system resources. While variations may exist across different Linux distributions, the fundamental organization remains consistent.

For detailed explanations and examples, refer to the Linux Directory Structure wiki page.