LFCS — Linux Foundation Certified Systems Administration Preparatory Course by Emmanuel Odenyire

Topic: Understanding the Linux File System Hierarchy

Introduction

Linux is a popular open-source operating system that is widely used for servers, desktops, and embedded systems. Understanding the Linux file system hierarchy is essential for managing files, directories, and other resources on the system. In this blog post, we will provide a detailed analysis of the Linux file system hierarchy in Ubuntu.

File System Hierarchy in Ubuntu

The Linux file system hierarchy in Ubuntu is based on the Filesystem Hierarchy Standard (FHS), which is a set of guidelines for the directory structure of Linux distributions. The FHS defines the location and purpose of each directory in the Linux file system hierarchy. The following is a breakdown of the Linux file system hierarchy in Ubuntu:

/bin

The /bin directory contains essential executable programs that are required for the system to function correctly. These programs are essential for system maintenance and operation, and they can be executed by any user. The programs in this directory are typically single-user utilities and small scripts.

/boot

The /boot directory contains files that are required for the system to boot. These files include the kernel, bootloader configuration files, and initrd files. The bootloader configuration files control how the bootloader loads the kernel and other boot-time parameters.

/dev

The /dev directory contains device files that represent the devices connected to the system. These files allow the system to communicate with the hardware devices connected to it. In Linux, everything is treated as a file, including devices. Therefore, every device on the system has a corresponding device file in the /dev directory.

/etc

The /etc directory contains configuration files for the system and installed applications. These files control how the system and applications operate and can be modified to customize their behavior. The files in this directory are typically text files and can be edited using a text editor.

/home

The /home directory contains the home directories of all users on the system. Each user has a separate directory under /home, where they can store their files and personalize their environment. This directory is where users store their personal files and data.

/lib

The /lib directory contains shared library files that are required for system operation. These files are necessary for the execution of programs and are loaded into memory when a program is executed. The shared library files in this directory are used by the programs in the /bin and /sbin directories.

/mnt

The /mnt directory is used as a mount point for external file systems. When an external file system is mounted, its contents are accessible through the /mnt directory. This directory is typically used for temporary mounts.

/opt

The /opt directory is used for optional software applications installed on the system. These applications are not part of the standard system installation and are installed separately. The applications installed in this directory are typically self-contained and do not have any dependencies on other system libraries.

/proc

The /proc directory contains virtual files that represent system information. These files allow users and applications to access information about the system, such as system memory, CPU usage, and network statistics. The files in this directory are not actual files on disk but are generated dynamically by the kernel.

/root

The /root directory is the home directory of the root user. This directory is not accessible to other users on the system. This directory is where the root user stores their personal files and data.

/run

The /run directory contains runtime files that are created during system operation. These files are temporary and are deleted when the system is shut down. This directory is used to store runtime files such as PID files, sockets, and lock files.

/sbin

The /sbin directory contains essential system executables that are required for system administration and system maintenance and operation. These executables are typically executed by the root user and are not available to regular users. The programs in this directory are typically used for system maintenance and management and are typically system utilities that perform system-level tasks.

/srv

The /srv directory is used to store data for services provided by the system. This directory is typically used by web servers, FTP servers, and other similar services to store their data.

/sys

The /sys directory contains virtual files that represent the system hardware. These files allow users and applications to access information about the hardware devices connected to the system. The files in this directory are not actual files on disk but are generated dynamically by the kernel.

/tmp

The /tmp directory is used to store temporary files that are created by applications and the system. These files are typically deleted when the system is restarted, and they are not meant to be permanent.

/usr

The /usr directory contains user-level programs and data files. This directory is typically the largest directory on the system and contains most of the applications and system libraries. The programs in this directory are typically multi-user utilities and can be executed by any user.

/var

The /var directory contains variable files that change frequently during system operation. These files include log files, spool files, and temporary files. This directory is typically used to store data that is generated by system processes.

Conclusion

Understanding the Linux file system hierarchy is essential for managing a Linux system. The Linux file system hierarchy in Ubuntu is based on the Filesystem Hierarchy Standard (FHS) and defines the location and purpose of each directory in the Linux file system. In this blog post, we have provided a detailed analysis of the Linux file system hierarchy in Ubuntu, and we hope that this information will be useful for managing your Linux system.

References:

1. Filesystem Hierarchy Standard (FHS) — https://refspecs.linuxfoundation.org/fhs.shtml

2. Ubuntu Documentation — https://help.ubuntu.com/lts/serverguide/directory-tree.html