HIER(7) 						     Linux Programmer's Manual							   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 subdirec-
	      tories 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 filesys-
	      tem.

       /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).

       /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,  fol-
	      lowing 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 (optional).

       /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
	      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 pro-
	      grams may have whole subdirectories there.

       /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/lib<qual>/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/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/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/mathtml
	      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/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).

CONFORMING TO

       The Filesystem Hierarchy Standard, Version 2.3 <http://www.pathname.com/fhs/>.

BUGS

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

SEE ALSO

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

       The Filesystem Hierarchy Standard

COLOPHON

       This page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and  the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

Linux								    2017-11-26								   HIER(7)