HIER(R) Linux Programmer's Manual HIER(R) NAME hier - Description of the file system 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 only holds the files which are needed during the boot process. The map installer and configuration files should go to /sbin and /etc. /dev Special or device files, which refer to physical devices. See mknod(d). /dos If both MS-DOS and Linux are run on one computer, this is a typical place to mount a DOS file system. /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 appli- cations installed in /opt. /etc/sgml This directory contains the configuration files for SGML and XML (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). /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. /lib This directory should hold those shared libraries that are necessary to boot the system and to run the commands in the root filesystem. /mnt This directory contains mount points for temporar- ily mounted 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-file system is described in more detail in proc(c). /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. /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 sharable, 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-Windows system; often, there is a symbolic link from the more tra- ditional /usr/bin/X11 to here. /usr/X11R6/lib Data files associated with the X-Windows 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 pro- grams using the X11 window system. Often, there is a symbolic link from /usr/inlcude/X11 to this directory. /usr/bin This is the primary directory for executable pro- grams. 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/X11 is the traditional place to look for X11 executa- bles; 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/games Binaries for games and educational programs (optional). /usr/include Include files for the C compiler. /usr/include/X11 Include files for the C compiler and the X-Windows system. This is usually a symbolic link to /usr/X11R6/include/X11. /usr/include/asm Include files which declare some assembler func- tions. 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/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(c). /usr/lib/groff Files for the GNU groff document formatting system. /usr/lib/uucp Files for uucp(p). /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/include Header files for the local C compiler. /usr/local/info Info pages associated with locally installed pro- grams. /usr/local/man Man pages associated with locally installed pro- grams. /usr/local/sbin Locally installed programs for system administra- tion. /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 spe- cific 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. /usr/share/doc Documentation about installed programs. /usr/share/games Static data files for games in /usr/games. /usr/share/info Info pages go here. /usr/share/locale Locale information goes here. /usr/share/man Manpages go here in subdirectories according to the man page sections. /usr/share/man/<locale>/man[1-9] These directories contain manual pages for the spe- cific 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 differ- ent architectures of the same OS. /usr/share/nls The message catalogs for native language support go here. /usr/share/sgml Files for SGML and XML. /usr/share/terminfo The datebase for terminfo. /usr/share/tmac Troff macros that are not distributed with groff. /usr/share/zoneinfo Files for timezone information. /usr/share/doc /usr/share/man Manpages go in there, into their subdirectories. /usr/share/man/<locale>/man[1-9] These directories contain manual pages which are in source code form. Systems which use a unique lan- guage and code set for all manual pages may omit the <locale> substring. /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. /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 ker- nel. /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/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/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/cron Reserved for historical reasons. /var/lib Variable state information for programs. /var/local Variable data for /usr/local. /var/lock Lock files are placed in this directory. The nam- ing 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, i.e. 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(t). /var/spool/cron Spooled jobs for cron(n). /var/spool/lpd Spooled files for printing. /var/spool/mail Replaced by /var/mail. /var/spool/mqueue Queued outgoing mail. /var/spool/news Spool directory for news. /var/spool/rwho Spooled files for rwhod(d). /var/spool/smail Spooled files for the smail(l) mail delivery pro- gram. /var/spool/news Spool directory for the news subsystem. /var/spool/uucp Spooled files for uucp(p). /var/tmp Like /tmp, this directory holds temporary files stored for an unspecified duration. /var/yp Database files for NIS. CONFORMS TO The Filesystem Hierarchy Standard, Version 2.2 <http://www.pathname.com/fhs/> BUGS This list is not exhaustive; different systems may be con- figured differently. SEE ALSO find(d), ln(n), mount(t), proc(c), The Filesystem Hierar- chy Standard Linux 2001-09-07 HIER(R)