Filesystem Hierarchy Standard Articles

This standard consists of a set of requirements and guidelines for file and directory placement under UNIX-like operating systems. The guidelines are intended to support interoperability of applications, system administration tools, development tools, and scripts as well as greater uniformity of documentation for these systems.

• 1. Introduction

• Purpose
• Conventions
• 2. The Filesystem

• 3. The Root Filesystem

• Purpose
• Requirements
• Specific Options

• /bin : Essential user command binaries (for use by all users)

• Purpose
• Requirements
• Specific Options

• /boot : Static files of the boot loader

• Purpose
• Specific Options

• /dev : Device files

• Purpose
• Specific Options

• /etc : Host-specific system configuration

• Purpose
• Requirements
• Specific Options
• /etc/opt : Configuration files for /opt
• /etc/X11 : Configuration for the X Window System (optional)
• /etc/sgml : Configuration files for SGML (optional)
• /etc/xml : Configuration files for XML (optional)

• /home : User home directories (optional)

• Purpose
• Requirements

• /lib : Essential shared libraries and kernel modules

• Purpose
• Requirements
• Specific Options

• /lib<qual> : Alternate format essential shared libraries (optional)

• Purpose
• Requirements

• /media : Mount point for removeable media

• Purpose
• Specific Options

• /mnt : Mount point for a temporarily mounted filesystem

• Purpose

• /opt : Add-on application software packages

• Purpose
• Requirements

• /root : Home directory for the root user (optional)

• Purpose

• /sbin : System binaries

• Purpose
• Requirements
• Specific Options

• /srv : Data for services provided by this system

• Purpose

• /tmp : Temporary files

• Purpose

• 4. The /usr Hierarchy

• Purpose
• Requirements
• Specific Options

• /usr/X11R6 : X Window System, Version 11 Release 6 (optional)

• Purpose
• Specific Options

• /usr/bin : Most user commands

• Purpose
• Specific Options

• /usr/include : Directory for standard include files.

• Purpose
• Specific Options

• /usr/lib : Libraries for programming and packages

• Purpose
• Specific Options

• /usr/lib<qual> : Alternate format libraries (optional)

• Purpose
• /usr/local : Local hierarchy
• /usr/local/share

• /usr/sbin : Non-essential standard system binaries

• Purpose

• /usr/share : Architecture-independent data

• Purpose
• Requirements
• Specific Options
• /usr/share/dict : Word lists (optional)
• /usr/share/man : Manual pages
• /usr/share/misc : Miscellaneous architecture-independent data
• /usr/share/sgml : SGML data (optional)
• /usr/share/xml : XML data (optional)

• /usr/src : Source code (optional)

• Purpose

• 5. The /var Hierarchy

• Purpose
• Requirements
• Specific Options

• /var/account : Process accounting logs (optional)

• Purpose

• /var/cache : Application cache data

• Purpose
• Specific Options
• /var/cache/fonts : Locally-generated fonts (optional)
• /var/cache/man : Locally-formatted manual pages (optional)

• /var/crash : System crash dumps (optional)

• Purpose

• /var/games : Variable game data (optional)

• Purpose

• /var/lib : Variable state information

• Purpose
• Requirements
• Specific Options
• /var/lib/<editor> : Editor backup files and state (optional)
• /var/lib/hwclock : State directory for hwclock (optional)
• /var/lib/misc : Miscellaneous variable data

• /var/lock : Lock files

• Purpose

• /var/log : Log files and directories

• Purpose
• Specific Options

• /var/mail : User mailbox files (optional)

• Purpose

• /var/opt : Variable data for /opt

• Purpose

• /var/run : Run-time variable data

• Purpose
• Requirements

• /var/spool : Application spool data

• Purpose
• Specific Options
• /var/spool/lpd : Line-printer daemon print queues (optional)
• /var/spool/rwho : Rwhod files (optional)

• /var/tmp : Temporary files preserved between system reboots

• Purpose

• /var/yp : Network Information Service (NIS) database files (optional)

• Purpose

• 6. Operating System Specific Annex

• Linux

• / : Root directory
• /bin : Essential user command binaries (for use by all users)
• /dev : Devices and special files
• /etc : Host-specific system configuration
• /lib64 and /lib32 : 64/32-bit libraries (architecture dependent)
• /proc : Kernel and process information virtual filesystem
• /sbin : Essential system binaries
• /usr/include : Header files included by C programs
• /usr/src : Source code
• /var/spool/cron : cron and at jobs

• 7. Appendix

• The FHS mailing list
• Background of the FHS
• General Guidelines
• Scope
• Acknowledgments
• Contributors