Filesystem Hierarchy Standard
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The Filesystem Hierarchy Standard (FHS) defines the main directories and their contents in Linux and other Unix-like computer operating systems.
The process of developing a standard filesystem hierarchy began in August 1993 with an effort to restructure the file and directory structure of Linux. The FSSTND (Filesystem Standard), a filesystem hierarchy standard specific to the Linux operating system, was released on February 14, 1994. Subsequent revisions were released on October 9, 1994 and March 28, 1995.
In early 1995, the goal of developing a more comprehensive version of FSSTND to address not only Linux, but other UNIX-like systems was adopted with the help of members of the BSD development community. As a result, a concerted effort was made to focus on issues that were general to UNIX-like systems. In recognition of this widening of scope, the name of the standard was changed to Filesystem Hierarchy Standard or FHS for short.
The FHS is maintained by the Free Standards Group, a non-profit organization consisting of major software and hardware vendors, such as HP, Red Hat, IBM and Dell. Still, the vast majority of the Linux distributions, including those developed by members of the Free Standards Group, do not follow this proposed standard. In particular, paths specifically created by the FHS editors, such as /media/ and /srv/, do not see widespread usage.
All files and directories appear under the root directory "/", even if stored on different physical devices. Directories defined by the FHS include:
| Directory | Description |
|---|---|
| /bin/ | Essential command binaries for all users (e.g., cat, ls, cp) |
| /boot/ | Boot loader files (e.g., kernels, initrd) |
| /dev/ | Essential devices (e.g., /dev/null) |
| /etc/ | Host-specific system-wide configuration files (from et cetera) |
| Configuration files for /opt/ |
| Configuration files for the X Window System, version 11 |
| Configuration files for SGML |
| Configuration files for XML |
| /home/ (optional) | Users' home directories |
| /lib/ | Libraries essential for the binaries in /bin/ and /sbin/ |
| /mnt/ | Temporarily mounted filesystems |
| /media/ | Mount points for removable media such as CD-ROMs (appeared in FHS-2.3) |
| /opt/ | Static application software packages |
| /proc/ | Virtual filesystem documenting kernel and process status, mostly text files (e.g., uptime, network) |
| /root/ (optional) | Home directory for the root user |
| /sbin/ | Essential binaries for root (e.g., init, route, ifup) (superuser binaries) |
| /tmp/ | Temporary files |
| /srv/ | Site-specific data which is served by the system |
| /usr/ | Secondary hierarchy for shareable, read-only data (formerly from user now from UNIX system resources) |
| Same as for top-level hierarchy |
| Standard include files |
| Same as for top-level hierarchy |
| Same as for top-level hierarchy |
| Architecture-independent (shared) data |
| Source code |
| X Window System, Version 11 Release 6 |
| Tertiary hierarchy for local data installed by the system administrator |
| /var/ | Variable files, such as logs, databases, websites, and temporary e-mail files |
External links
- Home of the FHS standard (http://www.pathname.com/fhs/)da:Filesystem Hierarchy Standard
de:Filesystem Hierarchy Standard es:FHS fi:Filesystem Hierarchy Standard