hier - description of the filesystem hierarchy

A typical Linux system has, among others, the following directories:

/

This is the root directory. This is where the whole tree starts.

/bin

This directory contains executable programs which are needed in single user mode and to bring the system up or repair it.

/boot

Contains static files for the boot loader. This directory holds only the files which are needed during the boot process. The map installer and configuration files should go to /sbin and /etc. The operating system kernel (initrd for example) must be located in either / or /boot.

/dev

Special or device files, which refer to physical devices. See mknod(1).

/etc

Contains configuration files which are local to the machine. Some larger software packages, like X11, can have their own subdirectories below /etc. Site-wide configuration files may be placed here or in /usr/etc. Nevertheless, programs should always look for these files in /etc and you may have links for these files to /usr/etc.

/etc/opt

Host-specific configuration files for add-on applications installed in /opt.

/etc/sgml

This directory contains the configuration files for SGML (optional).

/etc/skel

When a new user account is created, files from this directory are usually copied into the user's home directory.

/etc/X11

Configuration files for the X11 window system (optional).

/etc/xml

This directory contains the configuration files for XML (optional).

/home

On machines with home directories for users, these are usually beneath this directory, directly or not. The structure of this directory depends on local administration decisions (optional).

/lib

This directory should hold those shared libraries that are necessary to boot the system and to run the commands in the root filesystem.

/lib<qual>

These directories are variants of /lib on system which support more than one binary format requiring separate libraries (optional).

/lib/modules

Loadable kernel modules (optional).

/lost+found

This directory contains items lost in the filesystem. These items are usually chunks of files mangled as a consequence of a faulty disk or a system crash.

/media

This directory contains mount points for removable media such as CD and DVD disks or USB sticks. On systems where more than one device exists for mounting a certain type of media, mount directories can be created by appending a digit to the name of those available above starting with '0', but the unqualified name must also exist.

/media/floppy[1-9]

Floppy drive (optional).

/media/cdrom[1-9]

CD-ROM drive (optional).

/media/cdrecorder[1-9]

CD writer (optional).

/media/zip[1-9]

Zip drive (optional).

/media/usb[1-9]

USB drive (optional).

/mnt

This directory is a mount point for a temporarily mounted filesystem. In some distributions, /mnt contains subdirectories intended to be used as mount points for several temporary filesystems.

/opt

This directory should contain add-on packages that contain static files.

/proc

This is a mount point for the proc filesystem, which provides information about running processes and the kernel. This pseudo-filesystem is described in more detail in proc(5).

/root

This directory is usually the home directory for the root user (optional).

/run

This directory contains information which describes the system since it was booted. Once this purpose was served by /var/run and programs may continue to use it.

/sbin

Like /bin, this directory holds commands needed to boot the system, but which are usually not executed by normal users.

/srv

This directory contains site-specific data that is served by this system.

/sys

This is a mount point for the sysfs filesystem, which provides information about the kernel like /proc, but better structured, following the formalism of kobject infrastructure.

/tmp

This directory contains temporary files which may be deleted with no notice, such as by a regular job or at system boot up.

/usr

This directory is usually mounted from a separate partition. It should hold only shareable, read-only data, so that it can be mounted by various machines running Linux.

/usr/X11R6

The X-Window system, version 11 release 6 (present in FHS 2.3, removed in FHS 3.0).

/usr/X11R6/bin

Binaries which belong to the X-Window system; often, there is a symbolic link from the more traditional /usr/bin/X11 to here.

/usr/X11R6/lib

Data files associated with the X-Window system.

/usr/X11R6/lib/X11

These contain miscellaneous files needed to run X; Often, there is a symbolic link from /usr/lib/X11 to this directory.

/usr/X11R6/include/X11

Contains include files needed for compiling programs using the X11 window system. Often, there is a symbolic link from /usr/include/X11 to this directory.

/usr/bin

This is the primary directory for executable programs. Most programs executed by normal users which are not needed for booting or for repairing the system and which are not installed locally should be placed in this directory.

/usr/bin/mh

Commands for the MH mail handling system (optional).

/usr/bin/X11

This is the traditional place to look for X11 executables; on Linux, it usually is a symbolic link to /usr/X11R6/bin.

/usr/dict

Replaced by /usr/share/dict.

/usr/doc

Replaced by /usr/share/doc.

/usr/etc

Site-wide configuration files to be shared between several machines may be stored in this directory. However, commands should always reference those files using the /etc directory. Links from files in /etc should point to the appropriate files in /usr/etc.

/usr/games

Binaries for games and educational programs (optional).

/usr/include

Include files for the C compiler.

/usr/include/bsd

BSD compatibility include files (optional).

/usr/include/X11

Include files for the C compiler and the X-Window system. This is usually a symbolic link to /usr/X11R6/include/X11.

/usr/include/asm

Include files which declare some assembler functions. This used to be a symbolic link to /usr/src/linux/include/asm.

/usr/include/linux

This contains information which may change from system release to system release and used to be a symbolic link to /usr/src/linux/include/linux to get at operating-system-specific information.

(Note that one should have include files there that work correctly with the current libc and in user space. However, Linux kernel source is not designed to be used with user programs and does not know anything about the libc you are using. It is very likely that things will break if you let /usr/include/asm and /usr/include/linux point at a random kernel tree. Debian systems don't do this and use headers from a known good kernel version, provided in the libc*-dev package.)

/usr/include/g++

Include files to use with the GNU C++ compiler.

/usr/lib

Object libraries, including dynamic libraries, plus some executables which usually are not invoked directly. More complicated programs may have whole subdirectories there.

/usr/libexec

Directory contains binaries for internal use only and they are not meant to be executed directly by users shell or scripts.

/usr/lib<qual>

These directories are variants of /usr/lib on system which support more than one binary format requiring separate libraries, except that the symbolic link /usr/libqual/X11 is not required (optional).

/usr/lib/X11

The usual place for data files associated with X programs, and configuration files for the X system itself. On Linux, it usually is a symbolic link to /usr/X11R6/lib/X11.

/usr/lib/gcc-lib

contains executables and include files for the GNU C compiler, gcc(1).

/usr/lib/groff

Files for the GNU groff document formatting system.

/usr/lib/uucp

Files for uucp(1).

/usr/local

This is where programs which are local to the site typically go.

/usr/local/bin

Binaries for programs local to the site.

/usr/local/doc

Local documentation.

/usr/local/etc

Configuration files associated with locally installed programs.

/usr/local/games

Binaries for locally installed games.

/usr/local/lib

Files associated with locally installed programs.

/usr/local/lib<qual>

These directories are variants of /usr/local/lib on system which support more than one binary format requiring separate libraries (optional).

/usr/local/include

Header files for the local C compiler.

/usr/local/info

Info pages associated with locally installed programs.

/usr/local/man

Man pages associated with locally installed programs.

/usr/local/sbin

Locally installed programs for system administration.

/usr/local/share

Local application data that can be shared among different architectures of the same OS.

/usr/local/src

Source code for locally installed software.

/usr/man

Replaced by /usr/share/man.

/usr/sbin

This directory contains program binaries for system administration which are not essential for the boot process, for mounting /usr, or for system repair.

/usr/share

This directory contains subdirectories with specific application data, that can be shared among different architectures of the same OS. Often one finds stuff here that used to live in /usr/doc or /usr/lib or /usr/man.

/usr/share/color

Contains color management information, like International Color Consortium (ICC) Color profiles (optional).

/usr/share/dict

Contains the word lists used by spell checkers (optional).

/usr/share/dict/words

List of English words (optional).

/usr/share/doc

Documentation about installed programs (optional).

/usr/share/games

Static data files for games in /usr/games (optional).

/usr/share/info

Info pages go here (optional).

/usr/share/locale

Locale information goes here (optional).

/usr/share/man

Manual pages go here in subdirectories according to the man page sections.

/usr/share/man/locale/man[1-9]

These directories contain manual pages for the specific locale in source code form. Systems which use a unique language and code set for all manual pages may omit the <locale> substring.

/usr/share/misc

Miscellaneous data that can be shared among different architectures of the same OS.

/usr/share/nls

The message catalogs for native language support go here (optional).

/usr/share/ppd

Postscript Printer Definition (PPD) files (optional).

/usr/share/sgml

Files for SGML (optional).

/usr/share/sgml/docbook

DocBook DTD (optional).

/usr/share/sgml/tei

TEI DTD (optional).

/usr/share/sgml/html

HTML DTD (optional).

/usr/share/sgml/mathml

MathML DTD (optional).

/usr/share/terminfo

The database for terminfo (optional).

/usr/share/tmac

Troff macros that are not distributed with groff (optional).

/usr/share/xml

Files for XML (optional).

/usr/share/xml/docbook

DocBook DTD (optional).

/usr/share/xml/xhtml

XHTML DTD (optional).

/usr/share/xml/mathml

MathML DTD (optional).

/usr/share/zoneinfo

Files for timezone information (optional).

/usr/src

Source files for different parts of the system, included with some packages for reference purposes. Don't work here with your own projects, as files below /usr should be read-only except when installing software (optional).

/usr/src/linux

This was the traditional place for the kernel source. Some distributions put here the source for the default kernel they ship. You should probably use another directory when building your own kernel.

/usr/tmp

Obsolete. This should be a link to /var/tmp. This link is present only for compatibility reasons and shouldn't be used.

/var

This directory contains files which may change in size, such as spool and log files.

/var/account

Process accounting logs (optional).

/var/adm

This directory is superseded by /var/log and should be a symbolic link to /var/log.

/var/backups

Reserved for historical reasons.

/var/cache

Data cached for programs.

/var/cache/fonts

Locally generated fonts (optional).

/var/cache/man

Locally formatted man pages (optional).

/var/cache/www

WWW proxy or cache data (optional).

/var/cache/<package>

Package specific cache data (optional).

/var/catman/cat[1-9] or /var/cache/man/cat[1-9]

These directories contain preformatted manual pages according to their man page section. (The use of preformatted manual pages is deprecated.)

/var/crash

System crash dumps (optional).

/var/cron

Reserved for historical reasons.

/var/games

Variable game data (optional).

/var/lib

Variable state information for programs.

/var/lib/color

Variable files containing color management information (optional).

/var/lib/hwclock

State directory for hwclock (optional).

/var/lib/misc

Miscellaneous state data.

/var/lib/xdm

X display manager variable data (optional).

/var/lib/<editor>

Editor backup files and state (optional).

/var/lib/<name>

These directories must be used for all distribution packaging support.

/var/lib/<package>

State data for packages and subsystems (optional).

/var/lib/<pkgtool>

Packaging support files (optional).

/var/local

Variable data for /usr/local.

/var/lock

Lock files are placed in this directory. The naming convention for device lock files is LCK..<device> where <device> is the device's name in the filesystem. The format used is that of HDU UUCP lock files, that is, lock files contain a PID as a 10-byte ASCII decimal number, followed by a newline character.

/var/log

Miscellaneous log files.

/var/opt

Variable data for /opt.

/var/mail

Users' mailboxes. Replaces /var/spool/mail.

/var/msgs

Reserved for historical reasons.

/var/preserve

Reserved for historical reasons.

/var/run

Run-time variable files, like files holding process identifiers (PIDs) and logged user information (utmp). Files in this directory are usually cleared when the system boots.

/var/spool

Spooled (or queued) files for various programs.

/var/spool/at

Spooled jobs for at(1).

/var/spool/cron

Spooled jobs for cron(8).

/var/spool/lpd

Spooled files for printing (optional).

/var/spool/lpd/printer

Spools for a specific printer (optional).

/var/spool/mail

Replaced by /var/mail.

/var/spool/mqueue

Queued outgoing mail (optional).

/var/spool/news

Spool directory for news (optional).

/var/spool/rwho

Spooled files for rwhod(8) (optional).

/var/spool/smail

Spooled files for the smail(1) mail delivery program.

/var/spool/uucp

Spooled files for uucp(1) (optional).

/var/tmp

Like /tmp, this directory holds temporary files stored for an unspecified duration.

/var/yp

Database files for NIS, formerly known as the Sun Yellow Pages (YP).

find(1), ln(1), proc(5), file-hierarchy(7), mount(8)

The Filesystem Hierarchy Standard