Navigating the Linux file system can often feel overwhelming, especially when faced with a series of obscure directory names. You might find yourself in a rush, unsure of where to save a specific file, and in a moment of panic, you toss it into /usr/share, only to later discover it belonged in /var/local.

Many users have experienced this confusion. The Linux directory structure can appear baffling, leaving one questioning the significance of these names and where files should be placed correctly.

Get ready to demystify Linux directories as we explore their history and purpose, making future file placements stress-free.

This directory serves as the main location for essential executable binaries required by the system, particularly during the boot process. Here, you will find fundamental commands such as ls and top. Sometimes, /bin may be a symbolic link to /usr/bin, ensuring access in case /usr/bin is unavailable at boot.

The /boot directory houses all crucial files necessary for booting the operating system. This includes kernel files, boot-loader files (like GRUB), and EFI files for modern systems. It is vital to the functioning of your Linux system; any errors here could prevent your system from starting correctly.

Short for "device," the /dev directory contains references to most devices connected to the system, both physical and virtual. Here, you can find references for hard drives, USB devices, and even a null device for discarding unwanted output.

You have likely explored the /etc directory, where Linux keeps critical configuration files for both its native applications and any third-party software you may have installed. Modifications to program behavior, network settings, and crontabs are typically made here.

This intuitively named directory is where users' home directories reside, acting as personal spaces within the operating system. Each user owns their respective files and subdirectories, identifiable by usernames. While logged in, you can quickly reference your home directory using the ~ character, which translates to /home/<user>. This is the ideal location for personal files like images, music, and documents.

The /lib directory contains shared C libraries and kernel modules essential for the binaries found in the /bin directory. These libraries are crucial for starting the OS and utilizing default binaries.

Note: If various architectures are present, additional `lib<qual>` directories will also appear.

This directory is straightforward, containing files that have been corrupted but have had recovery attempts made. Such situations often arise from unexpected power failures or hardware malfunctions.

The /media directory acts as a mount point for removable media, traditionally used for devices like CDs, floppy disks, or Zip drives. Nowadays, it also accommodates mounted virtual ISOs and USB drives.

This is a more general mount point for attaching either removable media or entire file systems. Currently, it often holds external disks, NFS, and remote storage solutions. The contents here are determined by user actions.

An abbreviation for "optional," this directory was originally intended for add-on packages not included with the system initially. Nowadays, it serves as one of several locations for installing third-party packages and their static configuration files.

The /proc directory is unique in that it does not store traditional files. Instead, it serves as an information hub for the Linux kernel, containing metrics related to processes, memory, and subsystems. The files here provide insights into kernel operations.

This directory is the home of the root user. When logged in as root, the home directory is at /root, not /home/root, ensuring safety if /home is located on a distant or corrupted partition.

The /run directory is used for temporary boot and runtime data, often holding process ID files that indicate where a process is running. It is also utilized for ephemeral data like lock files and socket information.

Similar to /bin, the /sbin directory contains system executable binaries, but these are specifically designed for administrative functions. Commands with the potential to significantly alter the operating system, such as fdisk and usermod, reside here.

This directory is reserved for files that the system serves. For instance, if the system functions as a web server, your HTML and image assets would be stored in this location.

Depending on the Linux distribution and its version, you may find a /sys directory. It provides structured information about devices and the kernel, similar to /proc.

The /tmp directory is designated for temporary files. You can store anything here, but don't expect it to persist across reboots. It's useful for unimportant data or testing file outputs.

The /usr directory is significant enough to warrant its own discussion. According to the Linux Foundation FHS specification, it is meant for:

“…shareable, read-only data.”

Essentially, it should contain unmodified structures that can be transferred between systems. While it may house arbitrary data in practice, keeping configuration or special data not covered by previous directories is advisable here.

Short for "variable," this directory is intended for variable data. Examples include:

• Printer spools
• Lock files
• Caches for running programs
• Email data
• Logs

The /var directory is designed to hold dynamic data that the system modifies during operation. If you need to write logs or manage dynamic configuration files, this is the place.

Additionally, the /var/local directory often becomes a catch-all for miscellaneous configurations and data snippets that don't fit elsewhere.

The Linux filesystem hierarchy is intricate, with a rich history of development. Once you grasp the meanings behind these directory names, navigating them becomes more intuitive. Exploring each directory and understanding the standards will enhance your comfort with file placement and the underlying workings of Linux.

For more in-depth information about each directory, refer to the official FHS 3.0 documentation here:

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<h2>Filesystem Hierarchy Standard</h2>

<div><h3>This standard consists of a set of requirements and guidelines for file and directory placement under UNIX-like systems...</h3></div>

<div><p>refspecs.linuxfoundation.org</p></div>

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