Filesystem Hierarchy Standard

The Filesystem Hierarchy Standard (FHS) defines the main directories and their contents in Linux and other Unix computer operating systems.

All files and directories appear under the root directory /, even if stored on different physical devices. Examples of directories defined by the FHS include:

/bin/ Essential command binaries for all users (cat, ls, cp...)
/dev/ Essential devices
/home/ Users' home directories
/etc/ System-wide configuration files
/lib/ Libraries essential for the binaries in /bin and /sbin
/var/ Variable files, such as logs and temporary files
/opt/ Static application software packages
/sbin/ Essential superuser binaries (init, route, ifup..)
/proc/ Virtual filesystem documenting kernel status, mostly text files (uptime, network...)
/mnt/ Temporarily mounted filesystems

External sites

Home of the FHS standard