Linux Filesystem Hierarchy: Your Guide to Understanding Its Layout

Introduction

Understanding Linux file system hierarchy can be a difficult task for beginners and even experienced administrators. Unlike some other operating systems, Linux follows a unique directory structure that is both systematic and critical to system management and operation. Understanding this structure is essential for efficient system management, troubleshooting, and software management. In this article, we will explore the Linux file system hierarchy in depth and explore the purpose and significance of each directory.

Root directory (/)

The vertex of the Linux file system hierarchy is the root directory, represented by a single forward slash (/). This directory is the starting point for all other directory branches. Think of it as the bottom of the tree, from which all other directories extend.

The root directory is crucial to the overall structure of the operating system and it lays the foundation for building the entire file system. All files and directories, regardless of their location, can eventually be traced back to the root directory.

Main Directory and Its Uses

Understanding the main directories in Linux file systems is essential for effective navigation and management. Here is a detailed introduction to each important directory:

• /bin

  • Purpose: The /bin directory contains the basic binary executables necessary for the system to function properly, even in single-user mode. These binaries are critical for basic system operation and recovery.
  • Example: Common commands here include ls (list directory contents), CP (copy files), and rm (delete files). These utilities are used by both system administrators and ordinary users.

• /sbin

  • Purpose: Similar to /bin, the /sbin directory contains system binary files, but these are mainly management commands for system maintenance and configuration. These binaries are usually used by the root user or system administrator.
  • Example: Commands such as fsck (file system check), reboot (restart system), and ifconfig (network interface configuration) are located here.

• /etc

  • Purpose: The /etc directory contains system-wide configuration files and shell scripts. This directory contains settings for various services and applications of the system.
  • Example: Key files include passwd (user account information), fstab (file system table), and network (network configuration). The configuration files in /etc usually control how the service runs and how the system is set.

• /dev

  • Purpose: The /dev directory contains device files that represent hardware devices and pseudo-dev on the system. These files are the interface between hardware devices and virtual devices.
  • Example: Files such as tty (terminal device), sda (first SCSI disk), and null (a special file that will discard all data written to it) can be found here. These files are essential for interacting with hardware and virtual devices.

• /proc

  • Purpose: /proc directory is a virtual file system that provides an interface to kernel data structures. It contains information about the system hardware and current status.
  • Example: Here are directories such as cpuinfo (processor information), meminfo (memory usage), and such as /proc/[pid] (process information). These files are generated dynamically and provide real-time information about system performance and configuration.

• /sys

  • Purpose: The /sys directory is another virtual file system that displays a kernel view of the system hardware. It is used to configure and interact with the kernel subsystem.
  • Example: Catals such as devices (hardware devices), class (device class), and bus (bus type) provide detailed hardware information. This directory is critical for hardware management and configuration.

• /var

  • Purpose: The /var directory contains variable data files that change as the system runs. This includes log files, mail storage and temporary files.
  • Example: This is located in subdirectories such as log (system log), mail (user mail storage), and tmp (temporary file). Management /var is very important for system monitoring and cleaning.

• /home

  • Purpose: /home directory contains the personal directory of all users on the system. Each user has their own subdirectory in /home where they can store personal files and settings.
  • Example: For users named john, their home directory will be /home/john. This directory provides workspaces for individual users to separate their files from system files.

• /root

  • Purpose: /root directory is the home directory of the root user (super user). It is different from /home that contains a normal user directory.
  • Example: Common contents of /root include root-specific configuration files, system scripts for administrative purposes, and important logs and documents that may facilitate system management.

• /lib and /lib64

  • Purpose: The /lib and /lib64 directories contain basic shared libraries and kernel modules required for the core functions of the system. Programs and system utilities use these libraries.
  • Example: Libraries such as libc.so (C standard library) and libm.so (mathematics library) can be found here. These directories are critical to executing binary files in /bin and /sbin.

• /opt

  • Purpose: The /opt directory is used to install optional application packages. It provides a location for software that is not part of the core system or distribution.
  • Example: Third-party applications and proprietary software can be installed in /opt. This directory helps separate additional software from standard system directories.

• /tmp

  • Purpose: The /tmp directory is used to store temporary files created by system processes and applications. The files here are usually deleted after a restart or after a period of time.
  • Example: Temporary files from web browsers, installation scripts, and other transient data are stored in /tmp. It is essential for maintaining system performance and managing temporary data.

• /mnt and /media

  • Purpose: The /mnt and /media directories are used to mount temporary file systems and removable media such as CDs, DVDs, and USB drives.
  • Example: External drives may be mounted in /media/usb or /mnt/external. These directories provide a convenient location for accessing and managing removable storage.

Special files and directories

• Symbol link

  • Purpose: Symlink is a special type of file that points to other files or directories. They allow for shortcuts and alternative paths to resources.
  • Example: The symbolic link in /usr/bin may point to an executable file in /opt/bin. Symbol links are useful for simplifying access and managing multiple versions of files.

• mount point

  • Purpose: The mount point is the directory where the attached file system is attached to the main file system. This allows integration of different storage devices and partitions.
  • Example: New file system may be mounted on /mnt/data to provide access to additional storage. Understanding mount points is essential to managing storage and system organization.

Practical Tips for Navigating and Managing File Systems

• Commands to explore file system

  • ls: List the contents of the directory. Use options such as -l (get details) and -a (including hidden files).
  • cd: Change the directory. Use cd .. to move up one level and use cd / to return to the root directory.
  • find: Search files and directories based on conditions. Used to find files and manage directories.

• Best Practices for Managing Files and Directories

  • Logistically organize your files: Separate personal files from system files. Use the appropriate directory for different types of data.
  • Clean temporary files clean up: Monitor and manage /tmp and /var/tmp to prevent unnecessary disk usage.
  • Back up key configuration files: Make sure to regularly back up important files in /etc and /home to prevent data loss.

• Common traps and how to avoid them

  • Accidentally delete key files: Be careful when performing operations to modify or delete files in system directories.
  • Ignore disk usage: Monitor disk space regularly to prevent problems related to file system fullness, especially in /var.

5. Conclusion

Understanding Linux file system hierarchy is a key aspect of system management and user management. By familiarizing yourself with the purpose and structure of each directory, you can navigate the system more effectively, troubleshoot more effectively, and maintain an organized environment. Whether you are a new user or an experienced administrator, a solid grasp of the file system hierarchy will enhance your ability to manage and operate Linux systems.

The above is the detailed content of Linux Filesystem Hierarchy: Your Guide to Understanding Its Layout. For more information, please follow other related articles on the PHP Chinese website!