hier(7)

NAME
hier - description of the filesystem hierarchy

DESCRIPTION
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 header 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).

STANDARDS
The Filesystem Hierarchy Standard (FHS), Version 3.0 (https://refspecs.linuxfoundation.org/fhs.shtml), published March 19, 2015

BUGS
This list is not exhaustive; different distributions and systems may be configured differently.

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

The Filesystem Hierarchy Standard