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Filesystem hierarchy

Ever wondered what /etc, /usr, /opt, and so on mean?
Ever wondered what the differences between /lib, /usr/lib, /usr/local/lib are?
Ever wondered what libexec and standalone mean?


Commonly used Darwin specialties at the bottom of this page.

BSD man hier

HIER(7) 	   FreeBSD Miscellaneous Information Manual	       HIER(7)

NAME hier -- layout of file systems

DESCRIPTION A sketch of the file system hierarchy. / root directory of the file system

/bin/ user utilities fundamental to both single-user and multi-user
environments

/boot/ programs and configuration files used during operating system
bootstrap

defaults/ default bootstrapping configuration files; see
loader.conf(5) kernel/ pure kernel executable (the operating system loaded
into memory at boot time).
modules/ third-party loadable kernel modules; see kldstat(8) /cdrom/ default mount point for CD-ROM drives (created by
sysinstall(8))

/compat/ normally a link to /usr/compat. If not, then the /usr/compat comments apply (created by sysinstall(8))

/dev/ device special files managed by devfs(5) fd/ file descriptor files; see fd(4) net/ network devices

/dist/ mount point used by sysinstall(8) /etc/ system configuration files and scripts

defaults/ default system configuration files; see rc(8) bluetooth/ bluetooth configuration files
gnats/ gnats configuration files; see send-pr(1) isdn/ isdn4bsd configuration files; see isdnd(8) localtime local timezone information; see ctime(3) mail/ Sendmail control files
mtree/ mtree configuration files; see mtree(8) namedb/ named configuration files; see named(8) pam.d/ configuration files for the Pluggable Authentica-
tion Modules (PAM) library
periodic/ scripts that are run daily, weekly, and monthly,
via
cron(8); see periodic(8) rc.d/ System and daemon startup/control scripts; see
rc(8) security/ OpenBSM audit configuration files; see audit(8) ppp/ ppp configuration files; see ppp(8) ssh/ OpenSSH configuration files; see ssh(1) ssl/ OpenSSL configuration files

/lib/ critical system libraries needed for binaries in /bin and
/sbin geom/ class-specific libraries for the geom(8) utility

/libexec/ critical system utilities needed for binaries in /bin and
/sbin /media/ contains subdirectories to be used as mount points for remov-
able media such as CDs, USB drives, and floppy disks

/mnt/ empty directory commonly used by system administrators as a
temporary mount point

/proc/ process file system; see procfs(5) /rescue/ statically linked programs for emergency recovery; see
rescue(8) /root/ root's HOME directory

/sbin/ system programs and administration utilities fundamental to
both single-user and multi-user environments

/tmp/ temporary files that are not guaranteed to persist across sys-
tem reboots

/usr/ contains the majority of user utilities and applications

bin/ common utilities, programming tools, and applica-
tions
compat/ files needed to support binary compatibility with
other operating systems, such as Linux (created by
sysinstall(8))
games/ useful and semi-frivolous programs
include/ standard C include files

altq/ C include files for alternate queueing
arpa/ C include files for Internet service
protocols
bsnmp/ C include files for the SNMP daemon
c++/ C++ include files
cam/ C include files for the Common Access
Methods Layer
scsi/ The SCSI device on top of
CAM
dev/ C include files for programming various
FreeBSD devices
ic/ Various header files
describing driver- and bus-
independent hardware cir-
cuits
ofw/ Open Firmware support
pbio/ 8255 PPI cards; see pbio(4) ppbus/ The parallel port bus; see
ppbus(4) usb/ The USB subsystem
utopia/ Physical chip driver for ATM
interfaces; see
utopia(4) wi/ The wi(4) WaveLAN driver
fs/ fdescfs/ per-process file descriptors
file system
fifofs/ IEEE Std 1003.1
(``POSIX.1'') FIFOs file
system
msdosfs/ MS-DOS file system
ntfs/ NTFS file system
nullfs/ loopback file system
nwfs/ NetWare file system
portalfs/ portal file system
procfs/ process file system
smbfs/ SMB/CIFS file system
udf/ UDF file system
unionfs union file system
geom/ GEOM framework
concat/ CONCAT GEOM class
gate/ GATE GEOM class
mirror/ MIRROR GEOM class
nop/ NOP GEOM class
raid3/ RAID3 GEOM class
stripe/ STRIPE GEOM class

isc/ ISC utility library libisc include files
isofs/ cd9660/ iso9660 file system
libmilter/ C include files for libmilter, the
sendmail(8) mail filter API
machine/ machine-specific C include files
net/ miscellaneous network C include files
netatalk/ Appletalk protocol
netatm/ ATM include files; see atm(8) netinet/ C include files for Internet standard
protocols; see
inet(4) netinet6/ C include files for Internet protocol
version 6; see
inet6(4) netipsec/ kernel key-management service; see
ipsec(4) netipx/ IPX/SPX protocol stacks
netnatm/ NATM include files; see natm(4) api/ include files for the sig-
nalling API
msg/ include files that describe
signalling messages and
declare associated functions
saal/ include files for the sig-
nalling AAL layer
sig/ include files for the UNI
signalling protocol
netsmb/ SMB/CIFS requester
nfs/ C include files for NFS (Network File
System)
objc/ Objective C include files
openssl/ OpenSSL (Cryptography/SSL toolkit) head-
ers
pccard/ PC-CARD controllers
protocols/ C include files for Berkeley service
protocols
readline/ get a line from a user, with editing;
see
readline(3) rpc/ remote procedure calls; see rpc(3) rpcsvc/ definition of RPC service structures;
see
rpc(3) security/ PAM; see pam(8) sys/ system C include files (kernel data
structures)
ufs/ C include files for UFS (The U-word File
System)
ffs/ Fast file system
ufs/ UFS file system
vm/ virtual memory; see vmstat(8) lib/ shared and archive ar(1)-type libraries
aout/ a.out archive libraries
compat/ shared libraries for compatibility
aout/ a.out backward compatibility
libraries
dtrace/ DTrace library scripts
engines/ OpenSSL (Cryptography/SSL toolkit)
dynamically loadable engines

libdata/ miscellaneous utility data files
gcc/ gcc(1) configuration data
ldscripts/ linker scripts; see ld(1) lint/ various prebuilt lint libraries; see
lint(1) libexec/ system daemons & system utilities (executed by other
programs)
aout/ utilities to manipulate a.out executa-
bles
elf/ utilities to manipulate ELF executables
lpr/ utilities and filters for LP print sys-
tem; see
lpr(1) sendmail/ the sendmail(8) binary; see
mailwrapper(8) sm.bin/ restricted shell for sendmail(8); see
smrsh(8) local/ local executables, libraries, etc. Also used as the
default destination for the FreeBSD ports framework.
Within local/, the general layout sketched out by
hier for /usr should be used. Exceptions are the
man directory (directly under local/ rather than
under local/share/), ports documentation (in
share/doc/<port>/), and /usr/local/etc (mimics
/etc).
obj/ architecture-specific target tree produced by build-
ing the /usr/src tree
ports/ The FreeBSD ports collection (optional).
sbin/ system daemons & system utilities (executed by
users)
share/ architecture-independent files

calendar/ a variety of pre-fab calendar files; see
calendar(1) dict/ word lists; see look(1) freebsd FreeBSD-specific terms,
proper names, and jargon
words common words
web2 words from Webster's 2nd
International
papers/ reference databases; see
refer(1) doc/ miscellaneous documentation; source for
most of the printed BSD manuals (avail-
able from the USENIX association)
FAQ/ Frequently Asked Questions
IPv6/ implementation notes for IPv6
bind/ documents pertaining to BIND
(the Berkeley Internet Name
Domain)
es/ Spanish translations of docu-
ments in /usr/share/doc
handbook/ FreeBSD Handbook
ja/ Japanese translations of doc-
uments in /usr/share/doc
legal/ License files for vendor sup-
plied firmwares
ncurses/ HTML documents pertaining to
ncurses; see
ncurses(3) ntp/ HTML documents pertaining to
the Network Time Protocol
papers/ UNIX Papers
psd/ UNIX Programmer's Supplemen-
tary Documents
ru/ Russian translations of docu-
ments in /usr/share/doc
smm/ UNIX System Manager's Manual
tutorials/ FreeBSD tutorials
usd/ UNIX User's Supplementary
Documents
zh/ Chinese translations of docu-
ments in /usr/share/doc

examples/ various examples for users and program-
mers
games/ ASCII text files used by various games
groff_font/ device description file for device name info/ GNU Info hypertext system
isdn/ ISDN
locale/ localization files; see setlocale(3) man/ manual pages
me/ macros for use with the me macro package;
see
me(7) misc/ miscellaneous system-wide ASCII text
files
fonts/ ???
termcap terminal characteristics
database; see
termcap(5) mk/ templates for make; see make(1) nls/ national language support files; see
mklocale(1) security/ data files for security policies such as
mac_lomac(4) sendmail/ sendmail(8) configuration files
skel/ example . (dot) files for new accounts
snmp/ MIBs, example files and tree definitions
for the SNMP daemon.
defs/ Tree definition files for use
with
gensnmptree(1) mibs/ MIB files
syscons/ files used by syscons; see syscons(4) fonts/ console fonts; see
vidcontrol(1) and vidfont(1) keymaps/ console keyboard maps; see
kbdcontrol(1) and kbdmap(1) scrnmaps/ console screen maps
tabset/ tab description files for a variety of
terminals; used in the termcap file; see
termcap(5) tmac/ text processing macros; see nroff(1) and
troff(1) vi/ localization support and utilities for
vi(1) zoneinfo/ timezone configuration information; see
tzfile(5) src/ BSD, third-party, and/or local source files

bin/ source code for files in /bin
contrib/ source code for contributed software
crypto/ source code for contributed cryptography
software
etc/ source code for files in /etc
games/ source code for files in /usr/games
gnu/ Utilities covered by the GNU General
Public License
include/ source code for files in /usr/include
kerberos5/ build infrastructure for kerberos ver-
sion 5
lib/ source code for files in /usr/lib
libexec/ source code for files in /usr/libexec
release/ files required to produce a FreeBSD
release
sbin/ source code for files in /sbin
secure/ build directory for files in
/usr/src/crypto
share/ source for files in /usr/share
sys/ kernel source code
tools/ tools used for maintenance and testing
of FreeBSD
usr.bin/ source code for files in /usr/bin
usr.sbin/ source code for files in /usr/sbin

/var/ multi-purpose log, temporary, transient, and spool files

account/ system accounting files

acct execution accounting file; see acct(5) at/ timed command scheduling files; see at(1) jobs/ directory containing job files
spool/ directory containing output spool files

backups/ miscellaneous backup files
crash/ default directory to store kernel crash dumps; see
crash(8) and savecore(8) cron/ files used by cron; see cron(8) tabs/ crontab files; see crontab(5) db/ miscellaneous automatically generated system-spe-
cific database files
empty/ empty directory for use by programs that need a
specifically empty directory. Used for instance by
sshd(8) for privilege separation.
games/ miscellaneous game status and score files
heimdal/ kerberos server databases; see kdc(8) log/ miscellaneous system log files

wtmp login/logout log; see wtmp(5) mail/ user mailbox files
msgs/ system messages database; see msgs(1) preserve/ temporary home of files preserved after an acciden-
tal death of an editor; see
ex(1) quotas/ file system quota information files
run/ system information files describing various info
about system since it was booted

named/ writable by the ``bind'' user; see
named(8) ppp/ writable by the ``network'' group for
command connection sockets; see
ppp(8) utmp database of current users; see utmp(5) rwho/ rwho data files; see rwhod(8), rwho(1), and
ruptime(1) spool/ miscellaneous printer and mail system spooling
directories

clientmqueue/ undelivered submission mail queue; see sendmail(8) ftp/ commonly ~ftp; the anonymous ftp root
directory
mqueue/ undelivered mail queue; see sendmail(8) output/ line printer spooling directories

tmp/ temporary files that are kept between system
reboots
vi.recover/ the directory where recovery files are stored yp/ the NIS maps

NOTES This manual page documents the default FreeBSD file system layout, but the actual hierarchy on a given system is defined at the system adminis- trator's discretion. A well-maintained installation will include a cus- tomized version of this document. SEE ALSO apropos(1), find(1), finger(1), grep(1), ls(1), whatis(1), whereis(1),
which(1), fd(4), devfs(5), fsck(8) HISTORY A hier manual page appeared in Version 7 AT&T UNIX.

FreeBSD 7.0			 June 28, 2007			   FreeBSD 7.0

Commonly used Darwin specialties

  • /opt/local/ MacPorts-installed software
  • /sw/ fink-installed software
  • /usr/local/ Some DarwinBuild-installed software
  • /usr/standalone/i386/ Darwin bootloader

$PATH

Note that in the BSD paths, /usr/local/bin comes after /usr/bin (unlike in GNU world, where /usr/local/bin might come before /usr/bin)

Darwin 9

PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin

Mac OS X 10.5

PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/libexec:/System/Library/CoreServices

FreeBSD (example for "BSD world")

to be posted

Ubuntu (example for "GNU world")

PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games

Library path

Darwin world: $DYLD_LIBRARY_PATH
GNU world: $LD_LIBRARY_PATH
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