The Linux File System

/bin - Binaries

The /bin folder contains the basic set of binaries available to every user. It contains the binaries for basic commands such as ls, cat, chmod, mv, and more.

/boot - Bootloaders

The /boot folder contains the files necessary to load the operating system when the computer is turned on.

/dev - Devices

The /dev folder contains files that represent devices. In Unix-like systems like Linux, disks and just about everything else are represented as files.

For example: sda is a disk. Originally sd stood for SCSI device but became a catch-all for any block storage device. The letter that follows sd, a in this case, represents the order in which the device was found.

/etc - Etcetera (and so on)

The /etc folder contains system-wide (as opposed to user-specific) configuration files.

/home - Home Folders

The /home directory contains home directories for users other than root.

/media - Media

The /media folder is where removable disks (e.g. CDs, thumb drives) are automatically mounted.

/mnt - Mount

The /media folder is where removable disks (e.g. CDs, thumb drives) are manually mounted, very similar to the /media folder.

/opt - Optional

The /opt folder is intended to hold manually installed 3rd-party software.

/proc - Processes

The /proc folder contains pseudo files that contain information about processes and resources. All running processes have a folder under /proc.

/root - Root (user) Home

The /root folder is the root user's home directory

/run - Run (temporary) Files

The /run directory contains temporary files, all of which actually reside in memory. The contents of this directory are deleted upon reboot (because memory is cleared).

/sbin - System (or Super User) Binaries

The /sbin folder contains binaries used for system administration tasks including disk and network management. It contains the binaries for commands such as chkconfig, ifcondfig, and fsck.

/srv - Service (or Server) Data

The /srv folder stores service/server data to be accessed by external users, for example via a web server.

/sys - System Temporary Files

The /sys folder contains temporary files used by the system, all of which are stored in memory (very similar to the /run folder). The contents of this directory are deleted upon reboot (because memory is cleared).

/tmp - Temporary Files

The /tmp folder contains temporary files. Unlike the /run folder, files stored in /tmp are less restricted and may be accessed by other users. Generally speaking, developers should prever to use /run over /tmp for security.

/usr - Users

The /usr folder contains "non essential" apps and files used by users (as opposed to the system).

/var - Variable

The /var folder contains files that are expected to grow over time (e.g. logs and caches).

Broader Topics Related to Linux File System

Linux

A free and open-source operating system

Linux File System Knowledge Graph