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Filesystem Hierarchy Standard
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>Filesystem Hierarchy Standard</TITLE
 
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CLASS="TITLEPAGE"
 
><H1
 
CLASS="TITLE"
 
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NAME="AEN2"
 
>Filesystem Hierarchy Standard</A
 
></H1
 
><H3
 
CLASS="CORPAUTHOR"
 
>Filesystem Hierarchy Standard Group</H3
 
><H4
 
CLASS="EDITEDBY"
 
>Edited by</H4
 
><H3
 
CLASS="EDITOR"
 
>Rusty Russell</H3
 
><H3
 
CLASS="EDITOR"
 
>Daniel Quinlan</H3
 
><H3
 
CLASS="EDITOR"
 
>Christopher Yeoh</H3
 
><P
 
CLASS="COPYRIGHT"
 
>Copyright &copy; 1994-2004 Daniel Quinlan</P
 
><P
 
CLASS="COPYRIGHT"
 
>Copyright &copy; 2001-2004 Paul 'Rusty' Russell</P
 
><P
 
CLASS="COPYRIGHT"
 
>Copyright &copy; 2003-2004 Christopher Yeoh</P
 
><DIV
 
><DIV
 
CLASS="ABSTRACT"
 
><P
 
></P
 
><A
 
NAME="AEN30"
 
></A
 
><P
 
>This standard consists of a set of requirements and guidelines for file
 
and directory placement under UNIX-like operating systems.  The
 
guidelines are intended to support interoperability of applications,
 
system administration tools, development tools, and scripts as well as
 
greater uniformity of documentation for these systems.</P
 
><P
 
></P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="LEGALNOTICE"
 
><P
 
></P
 
><A
 
NAME="AEN25"
 
></A
 
><P
 
>All trademarks and copyrights are owned by their owners, unless
 
specifically noted otherwise.  Use of a term in this document should not
 
be regarded as affecting the validity of any trademark or service
 
mark.</P
 
><P
 
>Permission is granted to make and distribute verbatim copies of
 
this standard provided the copyright and this permission notice are
 
preserved on all copies.</P
 
><P
 
>Permission is granted to copy and distribute modified versions of this
 
standard under the conditions for verbatim copying, provided also that
 
the title page is labeled as modified including a reference to the
 
original standard, provided that information on retrieving the original
 
standard is included, and provided that the entire resulting derived
 
work is distributed under the terms of a permission notice identical to
 
this one.</P
 
><P
 
>Permission is granted to copy and distribute translations of this
 
standard into another language, under the above conditions for modified
 
versions, except that this permission notice may be stated in a
 
translation approved by the copyright holder.</P
 
></DIV
 
><HR></DIV
 
><P <A HREF=http://www.pathname.com/fhs/ >Here</A> is the home of the Filesystem Hierarchy Standard (FHS). The copy you are reading is version 2.3. It was announced on January 29, 2004. </P
 
></P
 
></DIV
 
><HR></DIV
 
><DIV
 
CLASS="TOC"
 
><DL
 
><DT
 
><B
 
>Table of Contents</B
 
></DT
 
><DT
 
>1. <A
 
HREF="#INTRODUCTION"
 
>Introduction</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#CONVENTIONS"
 
>Conventions</A
 
></DT
 
></DL
 
></DD
 
><DT
 
>2. <A
 
HREF="#THEFILESYSTEM"
 
>The Filesystem</A
 
></DT
 
><DT
 
>3. <A
 
HREF="#THEROOTFILESYSTEM"
 
>The Root Filesystem</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE2"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#REQUIREMENTS"
 
>Requirements</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONS"
 
>Specific Options</A
 
></DT
 
><DT
 
><A
 
HREF="#BINESSENTIALUSERCOMMANDBINARIES"
 
>/bin : Essential user command binaries (for use by all users)</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE3"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#REQUIREMENTS2"
 
>Requirements</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONS2"
 
>Specific Options</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#BOOTSTATICFILESOFTHEBOOTLOADER"
 
>/boot : Static files of the boot loader</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE4"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONS3"
 
>Specific Options</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#DEVDEVICEFILES"
 
>/dev : Device files</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE5"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONS4"
 
>Specific Options</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#ETCHOSTSPECIFICSYSTEMCONFIGURATION"
 
>/etc : Host-specific system configuration</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE6"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#REQUIREMENTS3"
 
>Requirements</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONS5"
 
>Specific Options</A
 
></DT
 
><DT
 
><A
 
HREF="#ETCOPTCONFIGURATIONFILESFOROPT"
 
>/etc/opt : Configuration files for /opt</A
 
></DT
 
><DT
 
><A
 
HREF="#ETCX11CONFIGURATIONFORTHEXWINDOWS"
 
>/etc/X11 : Configuration for the X Window System (optional)</A
 
></DT
 
><DT
 
><A
 
HREF="#ETCSGMLCONFIGURATIONFILESFORSGMLAN"
 
>/etc/sgml : Configuration files for SGML (optional)</A
 
></DT
 
><DT
 
><A
 
HREF="#AEN795"
 
>/etc/xml : Configuration files for XML (optional)</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#HOMEUSERHOMEDIRECTORIES"
 
>/home : User home directories (optional)</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE10"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#REQUIREMENTS4A"
 
>Requirements</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#LIBESSENTIALSHAREDLIBRARIESANDKERN"
 
>/lib : Essential shared libraries and kernel modules</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE11"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#REQUIREMENTS5"
 
>Requirements</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONS7"
 
>Specific Options</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#LIBLTQUALGTALTERNATEFORMATESSENTIAL"
 
>/lib&lt;qual&gt; : Alternate format essential shared libraries (optional)</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE12"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#REQUIREMENTS6"
 
>Requirements</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#MEDIAMOUNTPOINT"
 
>/media : Mount point for removeable media</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSEMEDIAMOUNTPOINT"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONSMEDIAMOUNT"
 
>Specific Options</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#MNTMOUNTPOINTFORATEMPORARILYMOUNT"
 
>/mnt : Mount point for a temporarily mounted filesystem</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE13"
 
>Purpose</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#OPTADDONAPPLICATIONSOFTWAREPACKAGES"
 
>/opt : Add-on application software packages</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE14"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#REQUIREMENTS7"
 
>Requirements</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#ROOTHOMEDIRECTORYFORTHEROOTUSER"
 
>/root : Home directory for the root user (optional)</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE15"
 
>Purpose</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#SBINSYSTEMBINARIES"
 
>/sbin : System binaries</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE16"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#REQUIREMENTS8"
 
>Requirements</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONS8"
 
>Specific Options</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#SRVDATAFORSERVICESPROVIDEDBYSYSTEM"
 
>/srv : Data for services provided by this system</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE16A"
 
>Purpose</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#TMPTEMPORARYFILES"
 
>/tmp : Temporary files</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE17"
 
>Purpose</A
 
></DT
 
></DL
 
></DD
 
></DL
 
></DD
 
><DT
 
>4. <A
 
HREF="#THEUSRHIERARCHY"
 
>The /usr Hierarchy</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE18"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#REQUIREMENTS9"
 
>Requirements</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONS9"
 
>Specific Options</A
 
></DT
 
><DT
 
><A
 
HREF="#USRX11R6XWINDOWSYSTEMVERSION11REL"
 
>/usr/X11R6 : X Window System, Version 11 Release 6 (optional)</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE19"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONS10"
 
>Specific Options</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#USRBINMOSTUSERCOMMANDS"
 
>/usr/bin : Most user commands</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE20"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONS11"
 
>Specific Options</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#USRINCLUDEDIRECTORYFORSTANDARDINCLU"
 
>/usr/include : Directory for standard include files.</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE21"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONS12"
 
>Specific Options</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#USRLIBLIBRARIESFORPROGRAMMINGANDPA"
 
>/usr/lib : Libraries for programming and packages</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE22"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONS13"
 
>Specific Options</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#USRLIBLTQUALGTALTERNATEFORMATLIBRARI"
 
>/usr/lib&lt;qual&gt; : Alternate format libraries (optional)</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE23"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#USRLOCALLOCALHIERARCHY"
 
>/usr/local : Local hierarchy</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#USRLOCALSHARE1"
 
>/usr/local/share</A
 
></DT
 
><DT
 
><A
 
HREF="#USRSBINNONESSENTIALSTANDARDSYSTEMBI"
 
>/usr/sbin : Non-essential standard system binaries</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE25"
 
>Purpose</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#USRSHAREARCHITECTUREINDEPENDENTDATA"
 
>/usr/share : Architecture-independent data</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE26"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#REQUIREMENTS11"
 
>Requirements</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONS15"
 
>Specific Options</A
 
></DT
 
><DT
 
><A
 
HREF="#USRSHAREDICTWORDLISTS"
 
>/usr/share/dict : Word lists (optional)</A
 
></DT
 
><DT
 
><A
 
HREF="#USRSHAREMANMANUALPAGES"
 
>/usr/share/man : Manual pages</A
 
></DT
 
><DT
 
><A
 
HREF="#USRSHAREMISCMISCELLANEOUSARCHITECTURE"
 
>/usr/share/misc : Miscellaneous architecture-independent data</A
 
></DT
 
><DT
 
><A
 
HREF="#USRSHARESGMLSGMLANDXMLDATA"
 
>/usr/share/sgml : SGML data (optional)</A
 
></DT
 
><DT
 
><A
 
HREF="#AEN2007"
 
>/usr/share/xml : XML data (optional)</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#USRSRCSOURCECODE"
 
>/usr/src : Source code (optional)</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE30"
 
>Purpose</A
 
></DT
 
></DL
 
></DD
 
></DL
 
></DD
 
><DT
 
>5. <A
 
HREF="#THEVARHIERARCHY"
 
>The /var Hierarchy</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE31"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#REQUIREMENTS12"
 
>Requirements</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONS20"
 
>Specific Options</A
 
></DT
 
><DT
 
><A
 
HREF="#VARACCOUNTPROCESSACCOUNTINGLOGS"
 
>/var/account : Process accounting logs (optional)</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE32"
 
>Purpose</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#VARCACHEAPPLICATIONCACHEDATA"
 
>/var/cache : Application cache data</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE33"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONS21"
 
>Specific Options</A
 
></DT
 
><DT
 
><A
 
HREF="#VARCACHEFONTSLOCALLYGENERATEDFONTS"
 
>/var/cache/fonts : Locally-generated fonts (optional)</A
 
></DT
 
><DT
 
><A
 
HREF="#VARCACHEMANLOCALLYFORMATTEDMANUALPAG"
 
>/var/cache/man : Locally-formatted manual pages (optional)</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#VARCRASHSYSTEMCRASHDUMPS"
 
>/var/crash : System crash dumps (optional)</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE36"
 
>Purpose</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#VARGAMESVARIABLEGAMEDATA"
 
>/var/games : Variable game data (optional)</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE37"
 
>Purpose</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#VARLIBVARIABLESTATEINFORMATION"
 
>/var/lib : Variable state information</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE38"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#REQUIREMENTS13"
 
>Requirements</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONS23"
 
>Specific Options</A
 
></DT
 
><DT
 
><A
 
HREF="#VARLIBLTEDITORGTEDITORBACKUPFILESAN"
 
>/var/lib/&lt;editor&gt; : Editor backup files and state (optional)</A
 
></DT
 
><DT
 
><A
 
HREF="#VARLIBHWCLOCKSTATEDIRECTORYFORHWCLO"
 
>/var/lib/hwclock : State directory for hwclock (optional)</A
 
></DT
 
><DT
 
><A
 
HREF="#VARLIBMISCMISCELLANEOUSVARIABLEDATA"
 
>/var/lib/misc : Miscellaneous variable data</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#VARLOCKLOCKFILES"
 
>/var/lock : Lock files</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE42"
 
>Purpose</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#VARLOGLOGFILESANDDIRECTORIES"
 
>/var/log : Log files and directories</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE43"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONS24"
 
>Specific Options</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#VARMAILUSERMAILBOXFILES"
 
>/var/mail : User mailbox files (optional)</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE44"
 
>Purpose</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#VAROPTVARIABLEDATAFOROPT"
 
>/var/opt : Variable data for /opt</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE45"
 
>Purpose</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#VARRUNRUNTIMEVARIABLEDATA"
 
>/var/run : Run-time variable data</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE46"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#REQUIREMENTS14"
 
>Requirements</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#VARSPOOLAPPLICATIONSPOOLDATA"
 
>/var/spool : Application spool data</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE47"
 
>Purpose</A
 
></DT
 
><DT
 
><A
 
HREF="#SPECIFICOPTIONS25"
 
>Specific Options</A
 
></DT
 
><DT
 
><A
 
HREF="#VARSPOOLLPDLINEPRINTERDAEMONPRINTQU"
 
>/var/spool/lpd : Line-printer daemon print queues (optional)</A
 
></DT
 
><DT
 
><A
 
HREF="#VARSPOOLRWHORWHODFILES"
 
>/var/spool/rwho : Rwhod files (optional)</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#VARTMPTEMPORARYFILESPRESERVEDBETWEE"
 
>/var/tmp : Temporary files preserved between system reboots</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE50"
 
>Purpose</A
 
></DT
 
></DL
 
></DD
 
><DT
 
><A
 
HREF="#VARYPNETWORKINFORMATIONSERVICE"
 
>/var/yp : Network Information Service (NIS) database files (optional)</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#PURPOSE51"
 
>Purpose</A
 
></DT
 
></DL
 
></DD
 
></DL
 
></DD
 
><DT
 
>6. <A
 
HREF="#OPERATINGSYSTEMSPECIFICANNEX"
 
>Operating System Specific Annex</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#LINUX"
 
>Linux</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#ROOTDIRECTORY"
 
>/ : Root directory</A
 
></DT
 
><DT
 
><A
 
HREF="#BINESSENTIALUSERCOMMANDBINARIES2"
 
>/bin : Essential user command binaries (for use by all users)</A
 
></DT
 
><DT
 
><A
 
HREF="#DEVDEVICESANDSPECIALFILES"
 
>/dev : Devices and special files</A
 
></DT
 
><DT
 
><A
 
HREF="#ETCHOSTSPECIFICSYSTEMCONFIGURATION2"
 
>/etc : Host-specific system configuration</A
 
></DT
 
><DT
 
><A
 
HREF="#LIB64"
 
>/lib64 and /lib32 : 64/32-bit libraries (architecture dependent)</A
 
></DT
 
><DT
 
><A
 
HREF="#PROCKERNELANDPROCESSINFORMATIONVIR"
 
>/proc : Kernel and process information virtual filesystem</A
 
></DT
 
><DT
 
><A
 
HREF="#SBINESSENTIALSYSTEMBINARIES"
 
>/sbin : Essential system binaries</A
 
></DT
 
><DT
 
><A
 
HREF="#USRINCLUDEHEADERFILESINCLUDEDBYCP"
 
>/usr/include : Header files included by C programs</A
 
></DT
 
><DT
 
><A
 
HREF="#USRSRCSOURCECODE2"
 
>/usr/src : Source code</A
 
></DT
 
><DT
 
><A
 
HREF="#VARSPOOLCRONCRONANDATJOBS"
 
>/var/spool/cron : cron and at jobs</A
 
></DT
 
></DL
 
></DD
 
></DL
 
></DD
 
><DT
 
>7. <A
 
HREF="#APPENDIX"
 
>Appendix</A
 
></DT
 
><DD
 
><DL
 
><DT
 
><A
 
HREF="#THEFHSMAILINGLIST"
 
>The FHS mailing list</A
 
></DT
 
><DT
 
><A
 
HREF="#BACKGROUNDOFTHEFHS"
 
>Background of the FHS</A
 
></DT
 
><DT
 
><A
 
HREF="#GENERALGUIDELINES"
 
>General Guidelines</A
 
></DT
 
><DT
 
><A
 
HREF="#SCOPE"
 
>Scope</A
 
></DT
 
><DT
 
><A
 
HREF="#ACKNOWLEDGMENTS"
 
>Acknowledgments</A
 
></DT
 
><DT
 
><A
 
HREF="#CONTRIBUTORS"
 
>Contributors</A
 
></DT
 
></DL
 
></DD
 
></DL
 
></DIV
 
><DIV
 
CLASS="CHAPTER"
 
><HR><H1
 
><A
 
NAME="INTRODUCTION"
 
></A
 
>Chapter 1. Introduction</H1
 
><DIV
 
CLASS="SECTION"
 
><H2
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE"
 
>Purpose</A
 
></H2
 
><P
 
>This standard enables:</P
 
><P
 
></P
 
><UL
 
><LI
 
><P
 
>Software to predict the location of installed files and
 
directories, and</P
 
></LI
 
><LI
 
><P
 
>Users to predict the location of installed files and
 
directories.</P
 
></LI
 
></UL
 
><P
 
>We do this by:</P
 
><P
 
></P
 
><UL
 
><LI
 
><P
 
>Specifying guiding principles for each area of the filesystem,</P
 
></LI
 
><LI
 
><P
 
>Specifying the minimum files and directories required,</P
 
></LI
 
><LI
 
><P
 
>Enumerating exceptions to the principles, and</P
 
></LI
 
><LI
 
><P
 
>Enumerating specific cases where there has been historical conflict.</P
 
></LI
 
></UL
 
><P
 
>The FHS document is used by:</P
 
><P
 
></P
 
><UL
 
><LI
 
><P
 
>Independent software suppliers to create applications which are FHS
 
compliant, and work with distributions which are FHS complaint,</P
 
></LI
 
><LI
 
><P
 
>OS creators to provide systems which are FHS compliant, and</P
 
></LI
 
><LI
 
><P
 
>Users to understand and maintain the FHS compliance of a system.</P
 
></LI
 
></UL
 
><P
 
>The FHS document has a limited scope:</P
 
><P
 
></P
 
><UL
 
><LI
 
><P
 
>Local placement of local files is a local issue, so FHS does not
 
attempt to usurp system administrators.</P
 
></LI
 
><LI
 
><P
 
>FHS addresses issues where file placements need to be coordinated
 
between multiple parties such as local sites, distributions,
 
applications, documentation, etc.</P
 
></LI
 
></UL
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="CONVENTIONS"
 
>Conventions</A
 
></H2
 
><P
 
>We recommend that you read a typeset version of this document rather
 
than the plain text version.  In the typeset version, the names of files
 
and directories are displayed in a constant-width font.</P
 
><P
 
>Components of filenames that vary are represented by a description
 
of the contents enclosed in "<SPAN
 
CLASS="emphasis"
 
><I
 
CLASS="EMPHASIS"
 
>&lt;</I
 
></SPAN
 
>" and
 
"<SPAN
 
CLASS="emphasis"
 
><I
 
CLASS="EMPHASIS"
 
>&gt;</I
 
></SPAN
 
>" characters, <SPAN
 
CLASS="emphasis"
 
><I
 
CLASS="EMPHASIS"
 
>&lt;thus&gt;</I
 
></SPAN
 
>.  Electronic mail addresses are also
 
enclosed in "&lt;" and "&gt;" but are shown in the usual
 
typeface.</P
 
><P
 
>Optional components of filenames are enclosed in
 
"<SPAN
 
CLASS="emphasis"
 
><I
 
CLASS="EMPHASIS"
 
>[</I
 
></SPAN
 
>" and "<SPAN
 
CLASS="emphasis"
 
><I
 
CLASS="EMPHASIS"
 
>]</I
 
></SPAN
 
>" characters and may
 
be combined with the "<SPAN
 
CLASS="emphasis"
 
><I
 
CLASS="EMPHASIS"
 
>&lt;</I
 
></SPAN
 
>" and
 
"<SPAN
 
CLASS="emphasis"
 
><I
 
CLASS="EMPHASIS"
 
>&gt;</I
 
></SPAN
 
>" convention.  For example, if a filename is
 
allowed to occur either with or without an extension, it might be
 
represented by
 
<SPAN
 
CLASS="emphasis"
 
><I
 
CLASS="EMPHASIS"
 
>&lt;filename&gt;[.&lt;extension&gt;]</I
 
></SPAN
 
>.</P
 
><P
 
>Variable substrings of directory names and filenames are indicated
 
by "<SPAN
 
CLASS="emphasis"
 
><I
 
CLASS="EMPHASIS"
 
>*</I
 
></SPAN
 
>".</P
 
><P
 
>The sections of the text marked as
 
<SPAN
 
CLASS="emphasis"
 
><I
 
CLASS="EMPHASIS"
 
>Rationale</I
 
></SPAN
 
> are explanatory and are
 
non-normative.</P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="CHAPTER"
 
><HR><H1
 
><A
 
NAME="THEFILESYSTEM"
 
></A
 
>Chapter 2. The Filesystem</H1
 
><P
 
>This standard assumes that the operating system underlying an
 
FHS-compliant file system supports the same basic security features
 
found in most UNIX filesystems.</P
 
><P
 
>It is possible to define two independent distinctions among
 
files: shareable vs. unshareable and variable vs. static.  In general,
 
files that differ in either of these respects should be located in
 
different directories.  This makes it easy to store files with
 
different usage characteristics on different filesystems.</P
 
><P
 
>"Shareable" files are those that can be stored on one host
 
and used on others.  "Unshareable" files are those that are not
 
shareable.  For example, the files in user home directories are
 
shareable whereas device lock files are not.</P
 
><P
 
>"Static" files include binaries, libraries, documentation
 
files and other files that do not change without system administrator
 
intervention.  "Variable" files are files that are not static.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>Shareable files can be stored on one host and used on several
 
others.  Typically, however, not all files in the filesystem
 
hierarchy are shareable and so each system has local storage
 
containing at least its unshareable files.  It is convenient if all
 
the files a system requires that are stored on a foreign host can be
 
made available by mounting one or a few directories from the foreign
 
host.</P
 
><P
 
>Static and variable files should be segregated because static
 
files, unlike variable files, can be stored on read-only media and
 
do not need to be backed up on the same schedule as variable
 
files.</P
 
><P
 
>Historical UNIX-like filesystem hierarchies contained both
 
static and variable files under both <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> and
 
<TT
 
CLASS="FILENAME"
 
>/etc</TT
 
>.  In order to realize the advantages
 
mentioned above, the <TT
 
CLASS="FILENAME"
 
>/var</TT
 
> hierarchy was
 
created and all variable files were transferred from
 
<TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> to <TT
 
CLASS="FILENAME"
 
>/var</TT
 
>.
 
Consequently <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> can now be mounted read-only
 
(if it is a separate filesystem).  Variable files have been
 
transferred from <TT
 
CLASS="FILENAME"
 
>/etc</TT
 
> to
 
<TT
 
CLASS="FILENAME"
 
>/var</TT
 
> over a longer period as technology has
 
permitted.</P
 
><P
 
>Here is an example of a FHS-compliant system.
 
(Other FHS-compliant layouts are possible.)</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN103"
 
></A
 
><TABLE
 
BORDER="1"
 
FRAME="hsides"
 
CLASS="CALSTABLE"
 
><COL><COL><COL><THEAD
 
><TR
 
><TH
 
><SPAN
 
CLASS="emphasis"
 
><I
 
CLASS="EMPHASIS"
 
></I
 
></SPAN
 
></TH
 
><TH
 
>shareable</TH
 
><TH
 
>unshareable</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
>static</TD
 
><TD
 
>/usr</TD
 
><TD
 
>/etc</TD
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
>/opt</TD
 
><TD
 
>/boot</TD
 
></TR
 
><TR
 
><TD
 
>variable</TD
 
><TD
 
>/var/mail</TD
 
><TD
 
>/var/run</TD
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
>/var/spool/news</TD
 
><TD
 
>/var/lock</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
><DIV
 
CLASS="CHAPTER"
 
><HR><H1
 
><A
 
NAME="THEROOTFILESYSTEM"
 
></A
 
>Chapter 3. The Root Filesystem</H1
 
><DIV
 
CLASS="SECTION"
 
><H2
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE2"
 
>Purpose</A
 
></H2
 
><P
 
>The contents of the root filesystem must be adequate to boot,
 
restore, recover, and/or repair the system.</P
 
><P
 
></P
 
><UL
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>To boot a system, enough must be present on the root partition
 
to mount other filesystems.  This includes utilities, configuration,
 
boot loader information, and other essential start-up data.
 
<TT
 
CLASS="FILENAME"
 
>/usr</TT
 
>, <TT
 
CLASS="FILENAME"
 
>/opt</TT
 
>, and
 
<TT
 
CLASS="FILENAME"
 
>/var</TT
 
> are designed such that they may be located
 
on other partitions or filesystems.</P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>To enable recovery and/or repair of a system, those utilities
 
needed by an experienced maintainer to diagnose and reconstruct a
 
damaged system must be present on the root filesystem.</P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>To restore a system, those utilities needed to restore from
 
system backups (on floppy, tape, etc.) must be present on the root
 
filesystem.</P
 
></LI
 
></UL
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>The primary concern used to balance these considerations, which
 
favor placing many things on the root filesystem, is the goal of
 
keeping root as small as reasonably possible.  For several reasons, it
 
is desirable to keep the root filesystem small:</P
 
><P
 
></P
 
><UL
 
><LI
 
><P
 
>It is occasionally mounted from very small media.</P
 
></LI
 
><LI
 
><P
 
>The root filesystem contains many system-specific configuration
 
files.  Possible examples include a kernel that is specific to the
 
system, a specific hostname, etc.  This means that the root filesystem
 
isn't always shareable between networked systems.  Keeping it small on
 
servers in networked systems minimizes the amount of lost space for
 
areas of unshareable files.  It also allows workstations with smaller
 
local hard drives.</P
 
></LI
 
><LI
 
><P
 
>While you may have the root filesystem on a large partition, and
 
may be able to fill it to your heart's content, there will be people
 
with smaller partitions.  If you have more files installed, you may
 
find incompatibilities with other systems using root filesystems on
 
smaller partitions.  If you are a developer then you may be turning
 
your assumption into a problem for a large number of users.</P
 
></LI
 
><LI
 
><P
 
>Disk errors that corrupt data on the root filesystem are a
 
greater problem than errors on any other partition.  A small root
 
filesystem is less prone to corruption as the result of a system
 
crash.</P
 
></LI
 
></UL
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
><P
 
>Applications must never create or require special files or
 
subdirectories in the root directory.  Other locations in the FHS
 
hierarchy provide more than enough flexibility for any package.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>There are several reasons why creating a new subdirectory of
 
the root filesystem is prohibited:</P
 
><P
 
></P
 
><UL
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>It demands space on a root partition which the system
 
administrator may want kept small and simple for either performance or
 
security reasons.</P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>It evades whatever discipline the system administrator may have
 
set up for distributing standard file hierarchies across mountable
 
volumes.</P
 
></LI
 
></UL
 
><P
 
>Distributions should not create new directories in the root
 
hierarchy without extremely careful consideration of the consequences
 
including for application portability.</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="REQUIREMENTS"
 
>Requirements</A
 
></H2
 
><P
 
>The following directories, or symbolic links to directories, are
 
required in <TT
 
CLASS="FILENAME"
 
>/</TT
 
>.</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN169"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>bin</TT
 
></TD
 
><TD
 
>Essential command binaries</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>boot</TT
 
></TD
 
><TD
 
>Static files of the boot loader</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>dev</TT
 
></TD
 
><TD
 
>Device files</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>etc</TT
 
></TD
 
><TD
 
>Host-specific system configuration</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>lib</TT
 
></TD
 
><TD
 
>Essential shared libraries and kernel modules</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>media</TT
 
></TD
 
><TD
 
>Mount point for removeable media</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>mnt</TT
 
></TD
 
><TD
 
>Mount point for mounting a filesystem temporarily</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>opt</TT
 
></TD
 
><TD
 
>Add-on application software packages</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>sbin</TT
 
></TD
 
><TD
 
>Essential system binaries</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>srv</TT
 
></TD
 
><TD
 
>Data for services provided by this system</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>tmp</TT
 
></TD
 
><TD
 
>Temporary files</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>usr</TT
 
></TD
 
><TD
 
>Secondary hierarchy</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>var</TT
 
></TD
 
><TD
 
>Variable data</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>Each directory listed above is specified in detail in separate
 
subsections below.  <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> and
 
<TT
 
CLASS="FILENAME"
 
>/var</TT
 
> each have a complete section in this
 
document due to the complexity of those directories.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS"
 
>Specific Options</A
 
></H2
 
><P
 
>The following directories, or symbolic links to directories,
 
must be in <TT
 
CLASS="FILENAME"
 
>/</TT
 
>, if the corresponding subsystem is
 
installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN235"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>home</TT
 
></TD
 
><TD
 
>User home directories (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>lib&lt;qual&gt;</TT
 
></TD
 
><TD
 
>Alternate format essential shared libraries (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>root</TT
 
></TD
 
><TD
 
>Home directory for the root user (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>Each directory listed above is specified in detail in separate
 
subsections below.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="BINESSENTIALUSERCOMMANDBINARIES"
 
>/bin : Essential user command binaries (for use by all users)</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE3"
 
>Purpose</A
 
></H3
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/bin</TT
 
> contains commands that may be used by
 
both the system administrator and by users, but which are required
 
when no other filesystems are mounted (e.g. in single user mode).  It
 
may also contain commands which are used indirectly by scripts.
 
  
<A
+
Here are some excerpts to help explain why GT.M needs to go in /opt and not /usr/local. You may want to glance at some of this to understand why the FHS was written, why it's important, and why software distributions (like GT.M) need to be placed in a certain directory.
NAME="AEN261"
 
HREF="#FTN.AEN261"
 
><SPAN
 
CLASS="footnote"
 
>[1]</SPAN
 
></A
 
></P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="REQUIREMENTS2"
 
>Requirements</A
 
></H3
 
><P
 
>There must be no subdirectories in
 
<TT
 
CLASS="FILENAME"
 
>/bin</TT
 
>.</P
 
><P
 
>The following commands, or symbolic links to commands, are
 
required in <TT
 
CLASS="FILENAME"
 
>/bin</TT
 
>.</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN272"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Command</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>cat</B
 
></TD
 
><TD
 
>Utility to concatenate files to standard output</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>chgrp</B
 
></TD
 
><TD
 
>Utility to change file group ownership</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>chmod</B
 
></TD
 
><TD
 
>Utility to change file access permissions</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>chown</B
 
></TD
 
><TD
 
>Utility to change file owner and group</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>cp</B
 
></TD
 
><TD
 
>Utility to copy files and directories</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>date</B
 
></TD
 
><TD
 
>Utility to print or set the system data and time</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>dd</B
 
></TD
 
><TD
 
>Utility to convert and copy a file</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>df</B
 
></TD
 
><TD
 
>Utility to report filesystem disk space usage</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>dmesg</B
 
></TD
 
><TD
 
>Utility to print or control the kernel message buffer</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>echo</B
 
></TD
 
><TD
 
>Utility to display a line of text</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>false</B
 
></TD
 
><TD
 
>Utility to do nothing, unsuccessfully</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>hostname</B
 
></TD
 
><TD
 
>Utility to show or set the system's host name</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>kill</B
 
></TD
 
><TD
 
>Utility to send signals to processes</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>ln</B
 
></TD
 
><TD
 
>Utility to make links between files</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>login</B
 
></TD
 
><TD
 
>Utility to begin a session on the system</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>ls</B
 
></TD
 
><TD
 
>Utility to list directory contents</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>mkdir</B
 
></TD
 
><TD
 
>Utility to make directories</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>mknod</B
 
></TD
 
><TD
 
>Utility to make block or character special files</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>more</B
 
></TD
 
><TD
 
>Utility to page through text</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>mount</B
 
></TD
 
><TD
 
>Utility to mount a filesystem</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>mv</B
 
></TD
 
><TD
 
>Utility to move/rename files</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>ps</B
 
></TD
 
><TD
 
>Utility to report process status</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>pwd</B
 
></TD
 
><TD
 
>Utility to print name of current working directory</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>rm</B
 
></TD
 
><TD
 
>Utility to remove files or directories</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>rmdir</B
 
></TD
 
><TD
 
>Utility to remove empty directories</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>sed</B
 
></TD
 
><TD
 
>The `sed' stream editor</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>sh</B
 
></TD
 
><TD
 
>The Bourne command shell</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>stty</B
 
></TD
 
><TD
 
>Utility to change and print terminal line settings</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>su</B
 
></TD
 
><TD
 
>Utility to change user ID</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>sync</B
 
></TD
 
><TD
 
>Utility to flush filesystem buffers</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>true</B
 
></TD
 
><TD
 
>Utility to do nothing, successfully</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>umount</B
 
></TD
 
><TD
 
>Utility to unmount file systems</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>uname</B
 
></TD
 
><TD
 
>Utility to print system information</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>If <B
 
CLASS="COMMAND"
 
>/bin/sh</B
 
> is not a true Bourne shell, it
 
must be a hard or symbolic link to the real shell command.</P
 
><P
 
>The <B
 
CLASS="COMMAND"
 
>[</B
 
> and <B
 
CLASS="COMMAND"
 
>test</B
 
>
 
commands must be placed together in either <TT
 
CLASS="FILENAME"
 
>/bin</TT
 
>
 
or <TT
 
CLASS="FILENAME"
 
>/usr/bin</TT
 
>.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>For example bash behaves differently when called as
 
<B
 
CLASS="COMMAND"
 
>sh</B
 
> or <B
 
CLASS="COMMAND"
 
>bash</B
 
>.  The use of a
 
symbolic link also allows users to easily see that
 
<B
 
CLASS="COMMAND"
 
>/bin/sh</B
 
> is not a true Bourne shell.</P
 
><P
 
>The requirement for the <B
 
CLASS="COMMAND"
 
>[</B
 
> and
 
<B
 
CLASS="COMMAND"
 
>test</B
 
> commands to be included as binaries (even if
 
implemented internally by the shell) is shared with the POSIX.2
 
standard.&#13;</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS2"
 
>Specific Options</A
 
></H3
 
><P
 
>The following programs, or symbolic links to programs, must be
 
in <TT
 
CLASS="FILENAME"
 
>/bin</TT
 
> if the corresponding subsystem is
 
installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN431"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Command</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>csh</B
 
></TD
 
><TD
 
>The C shell (optional)</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>ed</B
 
></TD
 
><TD
 
>The `ed' editor (optional)</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>tar</B
 
></TD
 
><TD
 
>The tar archiving utility (optional)</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>cpio</B
 
></TD
 
><TD
 
>The cpio archiving utility (optional)</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>gzip</B
 
></TD
 
><TD
 
>The GNU compression utility (optional)</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>gunzip</B
 
></TD
 
><TD
 
>The GNU uncompression utility (optional)</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>zcat</B
 
></TD
 
><TD
 
>The GNU uncompression utility (optional)</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>netstat</B
 
></TD
 
><TD
 
>The network statistics utility (optional)</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>ping</B
 
></TD
 
><TD
 
>The ICMP network test utility (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>If the <B
 
CLASS="COMMAND"
 
>gunzip</B
 
> and <B
 
CLASS="COMMAND"
 
>zcat</B
 
>
 
programs exist, they must be symbolic or hard links to
 
gzip. <B
 
CLASS="COMMAND"
 
>/bin/csh</B
 
> may be a symbolic link to
 
<B
 
CLASS="COMMAND"
 
>/bin/tcsh</B
 
> or
 
<B
 
CLASS="COMMAND"
 
>/usr/bin/tcsh</B
 
>.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>The tar, gzip and cpio commands have been added to make restoration of a
 
system possible (provided that <TT
 
CLASS="FILENAME"
 
>/</TT
 
> is intact).</P
 
><P
 
>Conversely, if no restoration from the root partition is ever
 
expected, then these binaries might be omitted (e.g., a ROM chip root,
 
mounting <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> through NFS).  If restoration of a
 
system is planned through the network, then <B
 
CLASS="COMMAND"
 
>ftp</B
 
>
 
or <B
 
CLASS="COMMAND"
 
>tftp</B
 
> (along with everything necessary to get
 
an ftp connection) must be available on the root partition.&#13;</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="BOOTSTATICFILESOFTHEBOOTLOADER"
 
>/boot : Static files of the boot loader</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE4"
 
>Purpose</A
 
></H3
 
><P
 
>This directory contains everything required for the boot process
 
except configuration files not needed at boot time and the map
 
installer. Thus /boot stores data that is used before the kernel
 
begins executing user-mode programs.  This may include saved master
 
boot sectors and sector map files.
 
  
<A
+
[http://www.pathname.com/fhs/ Here] is the home of the Filesystem Hierarchy Standard (FHS). Refer to the original for the complete text.
NAME="AEN493"
+
The copy you are reading is version 2.3, announced January 29, 2004.  
HREF="#FTN.AEN493"
 
><SPAN
 
CLASS="footnote"
 
>[2]</SPAN
 
></A
 
>&#13;</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS3"
 
>Specific Options</A
 
></H3
 
><P
 
>The operating system kernel must be located in either
 
<TT
 
CLASS="FILENAME"
 
>/</TT
 
> or <TT
 
CLASS="FILENAME"
 
>/boot</TT
 
>.
 
  
<A
 
NAME="AEN507"
 
HREF="#FTN.AEN507"
 
><SPAN
 
CLASS="footnote"
 
>[3]</SPAN
 
></A
 
></P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="DEVDEVICEFILES"
 
>/dev : Device files</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE5"
 
>Purpose</A
 
></H3
 
><P
 
>The <TT
 
CLASS="FILENAME"
 
>/dev</TT
 
> directory is the location of
 
special or device files.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS4"
 
>Specific Options</A
 
></H3
 
><P
 
>If it is possible that devices in <TT
 
CLASS="FILENAME"
 
>/dev</TT
 
> will
 
need to be manually created, <TT
 
CLASS="FILENAME"
 
>/dev</TT
 
> must contain a
 
command named <TT
 
CLASS="FILENAME"
 
>MAKEDEV</TT
 
>, which can create devices
 
as needed.  It may also contain a <TT
 
CLASS="FILENAME"
 
>MAKEDEV.local</TT
 
>
 
for any local devices.</P
 
><P
 
>If required, <TT
 
CLASS="FILENAME"
 
>MAKEDEV</TT
 
> must have provisions
 
for creating any device that may be found on the system, not just
 
those that a particular implementation installs.</P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="ETCHOSTSPECIFICSYSTEMCONFIGURATION"
 
>/etc : Host-specific system configuration</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE6"
 
>Purpose</A
 
></H3
 
><P
 
>The <TT
 
CLASS="FILENAME"
 
>/etc</TT
 
> hierarchy contains configuration
 
files.  A "configuration file" is a local file used to control the
 
operation of a program; it must be static and cannot be an executable
 
binary.
 
  
<A
+
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
NAME="AEN534"
+
HREF="#FTN.AEN534"
+
== Introduction ==
><SPAN
 
CLASS="footnote"
 
>[4]</SPAN
 
></A
 
></P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="REQUIREMENTS3"
 
>Requirements</A
 
></H3
 
><P
 
>No binaries may be located under <TT
 
CLASS="FILENAME"
 
>/etc</TT
 
>.
 
  
<A
+
This standard consists of a set of requirements and guidelines for file and
NAME="AEN540"
+
directory placement under UNIX-like operating systems. The guidelines are
HREF="#FTN.AEN540"
+
intended to support interoperability of applications, system administration
><SPAN
+
tools, development tools, and scripts as well as greater uniformity of
CLASS="footnote"
+
documentation for these systems.
>[5]</SPAN
 
></A
 
></P
 
><P
 
>The following directories, or symbolic links to directories are
 
required in <TT
 
CLASS="FILENAME"
 
>/etc</TT
 
>:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN546"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
>opt</TD
 
><TD
 
>Configuration for /opt</TD
 
></TR
 
><TR
 
><TD
 
>X11</TD
 
><TD
 
>Configuration for the X Window system (optional)</TD
 
></TR
 
><TR
 
><TD
 
>sgml</TD
 
><TD
 
>Configuration for SGML (optional)</TD
 
></TR
 
><TR
 
><TD
 
>xml</TD
 
><TD
 
>Configuration for XML (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS5"
 
>Specific Options</A
 
></H3
 
><P
 
>The following directories, or symbolic links to directories must
 
be in <TT
 
CLASS="FILENAME"
 
>/etc</TT
 
>, if the corresponding subsystem is
 
installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN569"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
>opt</TD
 
><TD
 
>Configuration for /opt</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>The following files, or symbolic links to files, must be in
 
<TT
 
CLASS="FILENAME"
 
>/etc</TT
 
> if the corresponding subsystem is
 
installed:
 
  
<A
 
NAME="AEN581"
 
HREF="#FTN.AEN581"
 
><SPAN
 
CLASS="footnote"
 
>[6]</SPAN
 
></A
 
></P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN588"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>File</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>csh.login</TT
 
></TD
 
><TD
 
>Systemwide initialization file for C shell logins (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>exports</TT
 
></TD
 
><TD
 
>NFS filesystem access control list (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>fstab</TT
 
></TD
 
><TD
 
>Static information about filesystems (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>ftpusers</TT
 
></TD
 
><TD
 
>FTP daemon user access control list (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>gateways</TT
 
></TD
 
><TD
 
>File which lists gateways for routed (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>gettydefs</TT
 
></TD
 
><TD
 
>Speed and terminal settings used by getty (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>group</TT
 
></TD
 
><TD
 
>User group file (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>host.conf</TT
 
></TD
 
><TD
 
>Resolver configuration file (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>hosts</TT
 
></TD
 
><TD
 
>Static information about host names (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>hosts.allow</TT
 
></TD
 
><TD
 
>Host access file for TCP wrappers (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>hosts.deny</TT
 
></TD
 
><TD
 
>Host access file for TCP wrappers (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>hosts.equiv</TT
 
></TD
 
><TD
 
>List of trusted hosts for rlogin, rsh, rcp (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>hosts.lpd</TT
 
></TD
 
><TD
 
>List of trusted hosts for lpd (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>inetd.conf</TT
 
></TD
 
><TD
 
>Configuration file for inetd (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>inittab</TT
 
></TD
 
><TD
 
>Configuration file for init (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>issue</TT
 
></TD
 
><TD
 
>Pre-login message and identification file (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>ld.so.conf</TT
 
></TD
 
><TD
 
>List of extra directories to search for shared libraries (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>motd</TT
 
></TD
 
><TD
 
>Post-login message of the day file (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>mtab</TT
 
></TD
 
><TD
 
>Dynamic information about filesystems (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>mtools.conf</TT
 
></TD
 
><TD
 
>Configuration file for mtools (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>networks</TT
 
></TD
 
><TD
 
>Static information about network names (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>passwd</TT
 
></TD
 
><TD
 
>The password file (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>printcap</TT
 
></TD
 
><TD
 
>The lpd printer capability database (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>profile</TT
 
></TD
 
><TD
 
>Systemwide initialization file for sh shell logins (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>protocols</TT
 
></TD
 
><TD
 
>IP protocol listing (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>resolv.conf</TT
 
></TD
 
><TD
 
>Resolver configuration file (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>rpc</TT
 
></TD
 
><TD
 
>RPC protocol listing (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>securetty</TT
 
></TD
 
><TD
 
>TTY access control for root login (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>services</TT
 
></TD
 
><TD
 
>Port names for network services (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>shells</TT
 
></TD
 
><TD
 
>Pathnames of valid login shells (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>syslog.conf</TT
 
></TD
 
><TD
 
>Configuration file for syslogd (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
><TT
 
CLASS="FILENAME"
 
>mtab</TT
 
> does not fit the static nature of
 
<TT
 
CLASS="FILENAME"
 
>/etc</TT
 
>: it is excepted for historical reasons.
 
  
<A
+
=== Purpose ===
NAME="AEN722"
 
HREF="#FTN.AEN722"
 
><SPAN
 
CLASS="footnote"
 
>[7]</SPAN
 
></A
 
>&#13;</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="ETCOPTCONFIGURATIONFILESFOROPT"
 
>/etc/opt : Configuration files for /opt</A
 
></H3
 
><DIV
 
CLASS="SECTION"
 
><H4
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE7"
 
>Purpose</A
 
></H4
 
><P
 
>Host-specific configuration files for add-on application
 
software packages must be installed within the directory
 
<TT
 
CLASS="FILENAME"
 
>/etc/opt/&lt;subdir&gt;</TT
 
>, where
 
<TT
 
CLASS="FILENAME"
 
>&lt;subdir&gt;</TT
 
> is the name of the subtree in
 
<TT
 
CLASS="FILENAME"
 
>/opt</TT
 
> where the static data from that package is
 
stored.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H4
 
CLASS="SECTION"
 
><A
 
NAME="REQUIREMENTS4"
 
>Requirements</A
 
></H4
 
><P
 
>No structure is imposed on the internal arrangement of
 
<TT
 
CLASS="FILENAME"
 
>/etc/opt/&lt;subdir&gt;</TT
 
>.</P
 
><P
 
>If a configuration file must reside in a different location in
 
order for the package or system to function properly, it may be placed
 
in a location other than
 
<TT
 
CLASS="FILENAME"
 
>/etc/opt/&lt;subdir&gt;</TT
 
>.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>Refer to the rationale for <TT
 
CLASS="FILENAME"
 
>/opt</TT
 
>.</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="ETCX11CONFIGURATIONFORTHEXWINDOWS"
 
>/etc/X11 : Configuration for the X Window System (optional)</A
 
></H3
 
><DIV
 
CLASS="SECTION"
 
><H4
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE8"
 
>Purpose</A
 
></H4
 
><P
 
><SPAN
 
CLASS="emphasis"
 
><I
 
CLASS="EMPHASIS"
 
>/etc/X11</I
 
></SPAN
 
> is the location for all X11
 
host-specific configuration.  This directory is necessary to allow
 
local control if <SPAN
 
CLASS="emphasis"
 
><I
 
CLASS="EMPHASIS"
 
>/usr</I
 
></SPAN
 
> is mounted read
 
only.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H4
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS6"
 
>Specific Options</A
 
></H4
 
><P
 
>The following files, or symbolic links to files, must be in
 
<TT
 
CLASS="FILENAME"
 
>/etc/X11</TT
 
> if the corresponding subsystem is
 
installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN754"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL
 
WIDTH="1*"
 
TITLE="C1"><COL
 
WIDTH="1*"
 
TITLE="C2"><THEAD
 
><TR
 
><TH
 
>File</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>Xconfig</TT
 
></TD
 
><TD
 
>The configuration file for early versions of XFree86 (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>XF86Config</TT
 
></TD
 
><TD
 
>The configuration file for XFree86 versions 3 and 4 (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>Xmodmap</TT
 
></TD
 
><TD
 
>Global X11 keyboard modification file (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>Subdirectories of <TT
 
CLASS="FILENAME"
 
>/etc/X11</TT
 
> may include
 
those for <TT
 
CLASS="FILENAME"
 
>xdm</TT
 
> and for any other programs (some
 
window managers, for example) that need them.
 
  
<A
+
This standard enables:
NAME="AEN778"
 
HREF="#FTN.AEN778"
 
><SPAN
 
CLASS="footnote"
 
>[8]</SPAN
 
></A
 
>
 
  
We recommend that window managers with only one configuration file
+
  • Software to predict the location of installed files and directories, and
which is a default <TT
 
CLASS="FILENAME"
 
>.*wmrc</TT
 
> file must name it
 
<TT
 
CLASS="FILENAME"
 
>system.*wmrc</TT
 
> (unless there is a widely-accepted
 
alternative name) and not use a subdirectory.  Any window manager
 
subdirectories must be identically named to the actual window manager
 
binary.</P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="ETCSGMLCONFIGURATIONFILESFORSGMLAN"
 
>/etc/sgml : Configuration files for SGML (optional)</A
 
></H3
 
><DIV
 
CLASS="SECTION"
 
><H4
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE9"
 
>Purpose</A
 
></H4
 
><P
 
>Generic configuration files defining high-level parameters of
 
the SGML systems are installed here.  Files with names
 
<TT
 
CLASS="FILENAME"
 
>*.conf</TT
 
> indicate generic configuration files.
 
File with names <TT
 
CLASS="FILENAME"
 
>*.cat</TT
 
> are the DTD-specific
 
centralized catalogs, containing references to all other catalogs
 
needed to use the given DTD.  The super catalog file
 
<TT
 
CLASS="FILENAME"
 
>catalog</TT
 
> references all the centralized
 
catalogs.</P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="AEN795"
 
>/etc/xml : Configuration files for XML (optional)</A
 
></H3
 
><DIV
 
CLASS="SECTION"
 
><H4
 
CLASS="SECTION"
 
><A
 
NAME="AEN797"
 
>Purpose</A
 
></H4
 
><P
 
>Generic configuration files defining high-level parameters of
 
the XML systems are installed here.  Files with names
 
<TT
 
CLASS="FILENAME"
 
>*.conf</TT
 
> indicate generic configuration files.
 
The super catalog file
 
<TT
 
CLASS="FILENAME"
 
>catalog</TT
 
> references all the centralized
 
catalogs.</P
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="HOMEUSERHOMEDIRECTORIES"
 
>/home : User home directories (optional)</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE10"
 
>Purpose</A
 
></H3
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/home</TT
 
> is a fairly standard concept, but it
 
is clearly a site-specific filesystem.
 
  
<A
+
  • Users to predict the location of installed files and directories.
NAME="AEN808"
 
HREF="#FTN.AEN808"
 
><SPAN
 
CLASS="footnote"
 
>[9]</SPAN
 
></A
 
>
 
  
The setup will differ from host to host.  Therefore, no program should
+
We do this by:
rely on this location.
 
  
<A
+
  • Specifying guiding principles for each area of the filesystem,
NAME="AEN819"
 
HREF="#FTN.AEN819"
 
><SPAN
 
CLASS="footnote"
 
>[10]</SPAN
 
></A
 
>&#13;</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="REQUIREMENTS4A"
 
>Requirements</A
 
></H3
 
><P
 
>User specific configuration files for applications are stored in the
 
user's home directory in a file that starts with the '.' character (a
 
"dot file").  If an application needs to create more than one dot file
 
then they should be placed in a subdirectory with a name starting with
 
a '.' character, (a "dot directory").  In this case the configuration
 
files should not start with the '.' character.
 
<A
 
NAME="AEN826"
 
HREF="#FTN.AEN826"
 
><SPAN
 
CLASS="footnote"
 
>[11]</SPAN
 
></A
 
></P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="LIBESSENTIALSHAREDLIBRARIESANDKERN"
 
>/lib : Essential shared libraries and kernel modules</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE11"
 
>Purpose</A
 
></H3
 
><P
 
>The <TT
 
CLASS="FILENAME"
 
>/lib</TT
 
> directory contains those shared
 
library images needed to boot the system and run the commands in the
 
root filesystem, ie. by binaries in <TT
 
CLASS="FILENAME"
 
>/bin</TT
 
> and
 
<TT
 
CLASS="FILENAME"
 
>/sbin</TT
 
>.
 
  
<A
+
  • Specifying the minimum files and directories required,
NAME="AEN836"
 
HREF="#FTN.AEN836"
 
><SPAN
 
CLASS="footnote"
 
>[12]</SPAN
 
></A
 
></P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="REQUIREMENTS5"
 
>Requirements</A
 
></H3
 
><P
 
>At least one of each of the following filename patterns are
 
required (they may be files, or symbolic links):</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN849"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>File</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>libc.so.*</TT
 
></TD
 
><TD
 
>The dynamically-linked C library (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>ld*</TT
 
></TD
 
><TD
 
>The execution time linker/loader (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>If a C preprocessor is installed, <SPAN
 
CLASS="emphasis"
 
><I
 
CLASS="EMPHASIS"
 
>/lib/cpp</I
 
></SPAN
 
>
 
must be a reference to it, for historical reasons.
 
  
<A
+
  • Enumerating exceptions to the principles, and
NAME="AEN866"
 
HREF="#FTN.AEN866"
 
><SPAN
 
CLASS="footnote"
 
>[13]</SPAN
 
></A
 
></P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS7"
 
>Specific Options</A
 
></H3
 
><P
 
>The following directories, or symbolic links to directories,
 
must be in <TT
 
CLASS="FILENAME"
 
>/lib</TT
 
>, if the corresponding subsystem
 
is installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN873"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>modules</TT
 
></TD
 
><TD
 
>Loadable kernel modules (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="LIBLTQUALGTALTERNATEFORMATESSENTIAL"
 
>/lib&lt;qual&gt; : Alternate format essential shared libraries (optional)</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE12"
 
>Purpose</A
 
></H3
 
><P
 
>There may be one or more variants of the
 
<TT
 
CLASS="FILENAME"
 
>/lib</TT
 
> directory on systems which support more than
 
one binary format requiring separate libraries.
 
  
<A
+
  • Enumerating specific cases where there has been [[historical~|Historical]] conflict.
NAME="AEN890"
 
HREF="#FTN.AEN890"
 
><SPAN
 
CLASS="footnote"
 
>[14]</SPAN
 
></A
 
></P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="REQUIREMENTS6"
 
>Requirements</A
 
></H3
 
><P
 
>If one or more of these directories exist, the requirements for
 
their contents are the same as the normal <TT
 
CLASS="FILENAME"
 
>/lib</TT
 
>
 
directory, except that <TT
 
CLASS="FILENAME"
 
>/lib&lt;qual&gt;/cpp</TT
 
> is
 
not required.
 
  
<A
+
The FHS document is used by:
NAME="AEN900"
 
HREF="#FTN.AEN900"
 
><SPAN
 
CLASS="footnote"
 
>[15]</SPAN
 
></A
 
></P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="MEDIAMOUNTPOINT"
 
>/media : Mount point for removeable media</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSEMEDIAMOUNTPOINT"
 
>Purpose</A
 
></H3
 
><P
 
>This directory contains subdirectories which are used as mount
 
points for removeable media such as floppy disks, cdroms and zip
 
disks.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>Historically there have been a number of other different places
 
used to mount removeable media such as <TT
 
CLASS="FILENAME"
 
>/cdrom</TT
 
>,
 
<TT
 
CLASS="FILENAME"
 
>/mnt</TT
 
> or <TT
 
CLASS="FILENAME"
 
>/mnt/cdrom</TT
 
>. Placing
 
the mount points for all removeable media directly in the root
 
directory would potentially result in a large number of extra
 
directories in <TT
 
CLASS="FILENAME"
 
>/</TT
 
>. Although the use of
 
subdirectories in <TT
 
CLASS="FILENAME"
 
>/mnt</TT
 
> as a mount point has
 
recently been common, it conflicts with a much older tradition of
 
using <TT
 
CLASS="FILENAME"
 
>/mnt</TT
 
> directly as a temporary mount point.</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONSMEDIAMOUNT"
 
>Specific Options</A
 
></H3
 
><P
 
>The following directories, or symbolic links to directories,
 
must be in <TT
 
CLASS="FILENAME"
 
>/media</TT
 
>, if the corresponding subsystem
 
is installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN923"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>floppy</TT
 
></TD
 
><TD
 
>Floppy drive (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>cdrom</TT
 
></TD
 
><TD
 
>CD-ROM drive (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>cdrecorder</TT
 
></TD
 
><TD
 
>CD writer (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>zip</TT
 
></TD
 
><TD
 
>Zip drive (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>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.
 
  
<A
+
  • Independent software suppliers to create [[application~|Application]]s which are FHS
NAME="AEN947"
+
    compliant, and work with distributions which are FHS complaint,
HREF="#FTN.AEN947"
 
><SPAN
 
CLASS="footnote"
 
>[16]</SPAN
 
></A
 
>&#13;</P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="MNTMOUNTPOINTFORATEMPORARILYMOUNT"
 
>/mnt : Mount point for a temporarily mounted filesystem</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE13"
 
>Purpose</A
 
></H3
 
><P
 
>This directory is provided so that the system administrator may
 
temporarily mount a filesystem as needed.  The content of this
 
directory is a local issue and should not affect the manner in which
 
any program is run.</P
 
><P
 
>This directory must not be used by installation programs: a
 
suitable temporary directory not in use by the system must be used
 
instead.</P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="OPTADDONAPPLICATIONSOFTWAREPACKAGES"
 
>/opt : Add-on application software packages</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE14"
 
>Purpose</A
 
></H3
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/opt</TT
 
> is reserved for the installation of
 
add-on application software packages.</P
 
><P
 
>A package to be installed in <TT
 
CLASS="FILENAME"
 
>/opt</TT
 
> must
 
locate its static files in a separate
 
<TT
 
CLASS="FILENAME"
 
>/opt/&lt;package&gt;</TT
 
> or
 
<TT
 
CLASS="FILENAME"
 
>/opt/&lt;provider&gt;</TT
 
> directory
 
tree, where <TT
 
CLASS="FILENAME"
 
>&lt;package&gt;</TT
 
> is a name that
 
describes the software package and
 
<TT
 
CLASS="FILENAME"
 
>&lt;provider&gt;</TT
 
> is the provider's LANANA
 
registered name.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="REQUIREMENTS7"
 
>Requirements</A
 
></H3
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN972"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
>&lt;package&gt;</TD
 
><TD
 
>Static package objects</TD
 
></TR
 
><TR
 
><TD
 
>&lt;provider&gt;</TD
 
><TD
 
>LANANA registered provider name</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>The directories <TT
 
CLASS="FILENAME"
 
>/opt/bin</TT
 
>,
 
<TT
 
CLASS="FILENAME"
 
>/opt/doc</TT
 
>, <TT
 
CLASS="FILENAME"
 
>/opt/include</TT
 
>,
 
<TT
 
CLASS="FILENAME"
 
>/opt/info</TT
 
>, <TT
 
CLASS="FILENAME"
 
>/opt/lib</TT
 
>, and
 
<TT
 
CLASS="FILENAME"
 
>/opt/man</TT
 
> are reserved for local system
 
administrator use.  Packages may provide "front-end" files intended to
 
be placed in (by linking or copying) these reserved directories by the
 
local system administrator, but must function normally in the absence
 
of these reserved directories.</P
 
><P
 
>Programs to be invoked by users must be located in the directory
 
<TT
 
CLASS="FILENAME"
 
>/opt/&lt;package&gt;/bin</TT
 
> or under the
 
<TT
 
CLASS="FILENAME"
 
>/opt/&lt;provider&gt;</TT
 
> hierarchy. If the package
 
includes UNIX manual pages, they must be located in
 
<TT
 
CLASS="FILENAME"
 
>/opt/&lt;package&gt;/share/man</TT
 
> or under the
 
<TT
 
CLASS="FILENAME"
 
>/opt/&lt;provider&gt;</TT
 
> hierarchy, and the same
 
substructure as <TT
 
CLASS="FILENAME"
 
>/usr/share/man</TT
 
> must be
 
used.</P
 
><P
 
>Package files that are variable (change in normal operation)
 
must be installed in <TT
 
CLASS="FILENAME"
 
>/var/opt</TT
 
>.  See the section
 
on <TT
 
CLASS="FILENAME"
 
>/var/opt</TT
 
> for more information.</P
 
><P
 
>Host-specific configuration files must be installed in
 
<TT
 
CLASS="FILENAME"
 
>/etc/opt</TT
 
>.  See the section on
 
<TT
 
CLASS="FILENAME"
 
>/etc</TT
 
> for more information.</P
 
><P
 
>No other package files may exist outside the
 
<TT
 
CLASS="FILENAME"
 
>/opt</TT
 
>, <TT
 
CLASS="FILENAME"
 
>/var/opt</TT
 
>, and
 
<TT
 
CLASS="FILENAME"
 
>/etc/opt</TT
 
> hierarchies except for those package
 
files that must reside in specific locations within the filesystem
 
tree in order to function properly.  For example, device lock files
 
must be placed in <TT
 
CLASS="FILENAME"
 
>/var/lock</TT
 
> and devices must be
 
located in <TT
 
CLASS="FILENAME"
 
>/dev</TT
 
>.</P
 
><P
 
>Distributions may install software in <TT
 
CLASS="FILENAME"
 
>/opt</TT
 
>,
 
but must not modify or delete software installed by the local system
 
administrator without the assent of the local system
 
administrator.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>The use of <TT
 
CLASS="FILENAME"
 
>/opt</TT
 
> for add-on software is a
 
well-established practice in the UNIX community.  The System V
 
Application Binary Interface [AT&amp;T 1990], based on the System V
 
Interface Definition (Third Edition), provides for an
 
<TT
 
CLASS="FILENAME"
 
>/opt</TT
 
> structure very similar to the one defined
 
here.</P
 
><P
 
>The Intel Binary Compatibility Standard v. 2 (iBCS2) also
 
provides a similar structure for <TT
 
CLASS="FILENAME"
 
>/opt</TT
 
>.</P
 
><P
 
>Generally, all data required to support a package on a system
 
must be present within <TT
 
CLASS="FILENAME"
 
>/opt/&lt;package&gt;</TT
 
>,
 
including files intended to be copied into
 
<TT
 
CLASS="FILENAME"
 
>/etc/opt/&lt;package&gt;</TT
 
> and
 
<TT
 
CLASS="FILENAME"
 
>/var/opt/&lt;package&gt;</TT
 
> as well as reserved
 
directories in <TT
 
CLASS="FILENAME"
 
>/opt</TT
 
>.</P
 
><P
 
>The minor restrictions on distributions using
 
<TT
 
CLASS="FILENAME"
 
>/opt</TT
 
> are necessary because conflicts are possible
 
between distribution-installed and locally-installed software,
 
especially in the case of fixed pathnames found in some binary
 
software.</P
 
><P
 
>The structure of the directories below
 
<TT
 
CLASS="FILENAME"
 
>/opt/&lt;provider&gt;</TT
 
> is left up to the packager
 
of the software, though it is recommended that packages are installed
 
in <TT
 
CLASS="FILENAME"
 
>/opt/&lt;provider&gt;/&lt;package&gt;</TT
 
> and
 
follow a similar structure to the guidelines for
 
<TT
 
CLASS="FILENAME"
 
>/opt/package</TT
 
>. A valid reason for diverging from
 
this structure is for support packages which may have files installed
 
in <TT
 
CLASS="FILENAME"
 
>/opt/&lt;provider&gt;/lib</TT
 
> or
 
<TT
 
CLASS="FILENAME"
 
>/opt/&lt;provider&gt;/bin</TT
 
>.</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="ROOTHOMEDIRECTORYFORTHEROOTUSER"
 
>/root : Home directory for the root user (optional)</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE15"
 
>Purpose</A
 
></H3
 
><P
 
>The root account's home directory may be determined by developer
 
or local preference, but this is the recommended default
 
location.
 
  
<A
+
  • OS creators to provide systems which are FHS compliant, and
NAME="AEN1037"
 
HREF="#FTN.AEN1037"
 
><SPAN
 
CLASS="footnote"
 
>[17]</SPAN
 
></A
 
></P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="SBINSYSTEMBINARIES"
 
>/sbin : System binaries</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE16"
 
>Purpose</A
 
></H3
 
><P
 
>Utilities used for system administration (and other root-only
 
commands) are stored in <TT
 
CLASS="FILENAME"
 
>/sbin</TT
 
>,
 
<TT
 
CLASS="FILENAME"
 
>/usr/sbin</TT
 
>, and
 
<TT
 
CLASS="FILENAME"
 
>/usr/local/sbin</TT
 
>.  <TT
 
CLASS="FILENAME"
 
>/sbin</TT
 
>
 
contains binaries essential for booting, restoring, recovering, and/or
 
repairing the system in addition to the binaries in
 
<TT
 
CLASS="FILENAME"
 
>/bin</TT
 
>.
 
  
<A
+
  • Users to understand and maintain the FHS compliance of a system.
NAME="AEN1051"
 
HREF="#FTN.AEN1051"
 
><SPAN
 
CLASS="footnote"
 
>[18]</SPAN
 
></A
 
> Programs executed after
 
<TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> is known to be mounted (when there are no
 
problems) are generally placed into <TT
 
CLASS="FILENAME"
 
>/usr/sbin</TT
 
>.
 
Locally-installed system administration programs should be placed into
 
<TT
 
CLASS="FILENAME"
 
>/usr/local/sbin</TT
 
>.
 
  
<A
+
The FHS document has a limited scope:
NAME="AEN1058"
 
HREF="#FTN.AEN1058"
 
><SPAN
 
CLASS="footnote"
 
>[19]</SPAN
 
></A
 
></P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="REQUIREMENTS8"
 
>Requirements</A
 
></H3
 
><P
 
>The following commands, or symbolic links to commands, are
 
required in <TT
 
CLASS="FILENAME"
 
>/sbin</TT
 
>.</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN1077"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Command</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>shutdown</B
 
></TD
 
><TD
 
>Command to bring the system down.</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS8"
 
>Specific Options</A
 
></H3
 
><P
 
>The following files, or symbolic links to files, must be in
 
<TT
 
CLASS="FILENAME"
 
>/sbin</TT
 
> if the corresponding subsystem is
 
installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN1092"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL
 
WIDTH="1*"
 
TITLE="C1"><COL
 
WIDTH="1*"
 
TITLE="C2"><THEAD
 
><TR
 
><TH
 
>Command</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>fastboot</TT
 
></TD
 
><TD
 
>Reboot the system without checking the disks (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>fasthalt</TT
 
></TD
 
><TD
 
>Stop the system without checking the disks (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>fdisk</TT
 
></TD
 
><TD
 
>Partition table manipulator (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>fsck</TT
 
></TD
 
><TD
 
>File system check and repair utility (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>fsck.*</TT
 
></TD
 
><TD
 
>File system check and repair utility for a specific filesystem (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>getty</TT
 
></TD
 
><TD
 
>The getty program (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>halt</TT
 
></TD
 
><TD
 
>Command to stop the system (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>ifconfig</TT
 
></TD
 
><TD
 
>Configure a network interface (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>init</TT
 
></TD
 
><TD
 
>Initial process (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>mkfs</TT
 
></TD
 
><TD
 
>Command to build a filesystem (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>mkfs.*</TT
 
></TD
 
><TD
 
>Command to build a specific filesystem (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>mkswap</TT
 
></TD
 
><TD
 
>Command to set up a swap area (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>reboot</TT
 
></TD
 
><TD
 
>Command to reboot the system (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>route</TT
 
></TD
 
><TD
 
>IP routing table utility (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>swapon</TT
 
></TD
 
><TD
 
>Enable paging and swapping (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>swapoff</TT
 
></TD
 
><TD
 
>Disable paging and swapping (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>update</TT
 
></TD
 
><TD
 
>Daemon to periodically flush filesystem buffers (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="SRVDATAFORSERVICESPROVIDEDBYSYSTEM"
 
>/srv : Data for services provided by this system</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE16A"
 
>Purpose</A
 
></H3
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/srv</TT
 
> contains site-specific data which is
 
served by this system.
 
  
<DIV
+
  • Local placement of local files is a local issue, so FHS does not attempt to
CLASS="TIP"
+
     usurp system administrators.
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>This main purpose of specifying this is so that users may find the
 
location of the data files for particular service, and so that
 
services which require a single tree for readonly data, writable data
 
and scripts (such as cgi scripts) can be reasonably placed. Data that
 
is only of interest to a specific user should go in that users' home
 
directory.</P
 
><P
 
>The methodology used to name subdirectories of
 
<TT
 
CLASS="FILENAME"
 
>/srv</TT
 
> is unspecified as there is currently no
 
consensus on how this should be done.  One method for structuring data
 
under <TT
 
CLASS="FILENAME"
 
>/srv</TT
 
> is by protocol,
 
eg. <TT
 
CLASS="FILENAME"
 
>ftp</TT
 
>, <TT
 
CLASS="FILENAME"
 
>rsync</TT
 
>,
 
<TT
 
CLASS="FILENAME"
 
>www</TT
 
>, and <TT
 
CLASS="FILENAME"
 
>cvs</TT
 
>. On large
 
systems it can be useful to structure <TT
 
CLASS="FILENAME"
 
>/srv</TT
 
> by
 
administrative context, such as <TT
 
CLASS="FILENAME"
 
>/srv/physics/www</TT
 
>,
 
<TT
 
CLASS="FILENAME"
 
>/srv/compsci/cvs</TT
 
>, etc. This setup will differ
 
from host to host. Therefore, no program should rely on a specific
 
subdirectory structure of <TT
 
CLASS="FILENAME"
 
>/srv</TT
 
> existing or data
 
necessarily being stored in <TT
 
CLASS="FILENAME"
 
>/srv</TT
 
>.  However
 
<TT
 
CLASS="FILENAME"
 
>/srv</TT
 
> should always exist on FHS compliant systems
 
and should be used as the default location for such data.</P
 
><P
 
>Distributions must take care not to remove locally placed files in
 
these directories without administrator permission.
 
<A
 
NAME="AEN1192"
 
HREF="#FTN.AEN1192"
 
><SPAN
 
CLASS="footnote"
 
>[20]</SPAN
 
></A
 
></P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
>&#13;</P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="TMPTEMPORARYFILES"
 
>/tmp : Temporary files</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE17"
 
>Purpose</A
 
></H3
 
><P
 
>The <TT
 
CLASS="FILENAME"
 
>/tmp</TT
 
> directory must be made available
 
for programs that require temporary files.</P
 
><P
 
>Programs must not assume that any files or directories in
 
<TT
 
CLASS="FILENAME"
 
>/tmp</TT
 
> are preserved between invocations of the
 
program.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>IEEE standard P1003.2 (POSIX, part 2) makes requirements that
 
are similar to the above section.</P
 
><P
 
>Although data stored in <TT
 
CLASS="FILENAME"
 
>/tmp</TT
 
> may be deleted
 
in a site-specific manner, it is recommended that files and
 
directories located in <TT
 
CLASS="FILENAME"
 
>/tmp</TT
 
> be deleted whenever
 
the system is booted.</P
 
><P
 
>FHS added this recommendation on the basis of historical
 
precedent and common practice, but did not make it a requirement
 
because system administration is not within the scope of this
 
standard.&#13;</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="CHAPTER"
 
><HR><H1
 
><A
 
NAME="THEUSRHIERARCHY"
 
></A
 
>Chapter 4. The /usr Hierarchy</H1
 
><DIV
 
CLASS="SECTION"
 
><H2
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE18"
 
>Purpose</A
 
></H2
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> is the second major section of the
 
filesystem.  <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> is shareable, read-only data.
 
That means that <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> should be shareable between
 
various FHS-compliant hosts and must not be written to.  Any
 
information that is host-specific or varies with time is stored
 
elsewhere.</P
 
><P
 
>Large software packages must not use a direct subdirectory under
 
the <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> hierarchy.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="REQUIREMENTS9"
 
>Requirements</A
 
></H2
 
><P
 
>The following directories, or symbolic links to directories, are
 
required in <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
>.</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN1223"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>bin</TT
 
></TD
 
><TD
 
>Most user commands</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>include</TT
 
></TD
 
><TD
 
>Header files included by C programs</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>lib</TT
 
></TD
 
><TD
 
>Libraries</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>local</TT
 
></TD
 
><TD
 
>Local hierarchy (empty after main installation)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>sbin</TT
 
></TD
 
><TD
 
>Non-vital system binaries</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>share</TT
 
></TD
 
><TD
 
>Architecture-independent data</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS9"
 
>Specific Options</A
 
></H2
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN1256"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>X11R6</TT
 
></TD
 
><TD
 
>XWindow System, version 11 release 6 (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>games</TT
 
></TD
 
><TD
 
>Games and educational binaries (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>lib&lt;qual&gt;</TT
 
></TD
 
><TD
 
>Alternate Format Libraries (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>src</TT
 
></TD
 
><TD
 
>Source code (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>An exception is made for the X Window System because of
 
considerable precedent and widely-accepted practice.</P
 
><P
 
>The following symbolic links to directories may be present. This
 
possibility is based on the need to preserve compatibility with older
 
systems until all implementations can be assumed to use the
 
<TT
 
CLASS="FILENAME"
 
>/var</TT
 
> hierarchy.</P
 
><TABLE
 
BORDER="0"
 
BGCOLOR="#E0E0E0"
 
WIDTH="100%"
 
><TR
 
><TD
 
><PRE
 
CLASS="SCREEN"
 
>    /usr/spool -&gt; /var/spool
 
     /usr/tmp -&gt; /var/tmp
 
    /usr/spool/locks -&gt; /var/lock</PRE
 
></TD
 
></TR
 
></TABLE
 
><P
 
>Once a system no longer requires any one of the above symbolic links,
 
the link may be removed, if desired.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="USRX11R6XWINDOWSYSTEMVERSION11REL"
 
>/usr/X11R6 : X Window System, Version 11 Release 6 (optional)</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE19"
 
>Purpose</A
 
></H3
 
><P
 
>This hierarchy is reserved for the X Window System, version 11
 
release 6, and related files.</P
 
><P
 
>To simplify matters and make XFree86 more compatible with the X
 
Window System on other systems, the following symbolic links must be
 
present if <TT
 
CLASS="FILENAME"
 
>/usr/X11R6</TT
 
> exists:</P
 
><TABLE
 
BORDER="0"
 
BGCOLOR="#E0E0E0"
 
WIDTH="100%"
 
><TR
 
><TD
 
><PRE
 
CLASS="SCREEN"
 
>    /usr/bin/X11 -&gt; /usr/X11R6/bin
 
    /usr/lib/X11 -&gt; /usr/X11R6/lib/X11
 
    /usr/include/X11 -&gt; /usr/X11R6/include/X11</PRE
 
></TD
 
></TR
 
></TABLE
 
><P
 
>In general, software must not be installed or managed via the above
 
symbolic links.  They are intended for utilization by users only.  The
 
difficulty is related to the release version of the X Window System &mdash;
 
in transitional periods, it is impossible to know what release of X11 is
 
in use.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS10"
 
>Specific Options</A
 
></H3
 
><P
 
>Host-specific data in <TT
 
CLASS="FILENAME"
 
>/usr/X11R6/lib/X11</TT
 
> should be interpreted
 
as a demonstration file.  Applications requiring information about the
 
current host must reference a configuration file in <TT
 
CLASS="FILENAME"
 
>/etc/X11</TT
 
>,
 
which may be linked to a file in <TT
 
CLASS="FILENAME"
 
>/usr/X11R6/lib</TT
 
>.
 
  
<A
+
  • FHS addresses issues where file placements need to be coordinated between
NAME="AEN1299"
+
    multiple parties such as local sites, distributions, [[application~|Application]]s,
HREF="#FTN.AEN1299"
+
    documentation, etc.
><SPAN
 
CLASS="footnote"
 
>[21]</SPAN
 
></A
 
></P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="USRBINMOSTUSERCOMMANDS"
 
>/usr/bin : Most user commands</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE20"
 
>Purpose</A
 
></H3
 
><P
 
>This is the primary directory of executable commands on the
 
system.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS11"
 
>Specific Options</A
 
></H3
 
><P
 
>The following directories, or symbolic links to directories,
 
must be in <TT
 
CLASS="FILENAME"
 
>/usr/bin</TT
 
>, if the corresponding
 
subsystem is installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN1313"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>mh</TT
 
></TD
 
><TD
 
>Commands for the MH mail handling system (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/usr/bin/X11</TT
 
> must be a symlink to
 
<TT
 
CLASS="FILENAME"
 
>/usr/X11R6/bin</TT
 
> if the latter exists.</P
 
><P
 
>The following files, or symbolic links to files, must be in
 
<TT
 
CLASS="FILENAME"
 
>/usr/bin</TT
 
>, if the corresponding subsystem is
 
installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN1329"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Command</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>perl</B
 
></TD
 
><TD
 
>The Practical Extraction and Report Language (optional)</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>python</B
 
></TD
 
><TD
 
>The Python interpreted language (optional)</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>tclsh</B
 
></TD
 
><TD
 
>Simple shell containing Tcl interpreter (optional)</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>wish</B
 
></TD
 
><TD
 
>Simple Tcl/Tk windowing shell (optional)</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>expect</B
 
></TD
 
><TD
 
>Program for interactive dialog (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>Because shell script interpreters (invoked with
 
<TT
 
CLASS="FILENAME"
 
>#!&lt;path&gt;</TT
 
> on the first line of a shell
 
script) cannot rely on a path, it is advantageous to standardize their
 
locations.  The Bourne shell and C-shell interpreters are already
 
fixed in <TT
 
CLASS="FILENAME"
 
>/bin</TT
 
>, but Perl, Python, and Tcl are
 
often found in many different places.  They may be symlinks to the
 
physical location of the shell interpreters.&#13;</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="USRINCLUDEDIRECTORYFORSTANDARDINCLU"
 
>/usr/include : Directory for standard include files.</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE21"
 
>Purpose</A
 
></H3
 
><P
 
>This is where all of the system's general-use include files for the C
 
programming language should be placed.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS12"
 
>Specific Options</A
 
></H3
 
><P
 
>The following directories, or symbolic links to directories,
 
must be in <TT
 
CLASS="FILENAME"
 
>/usr/include</TT
 
>, if the corresponding
 
subsystem is installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN1370"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
>bsd</TD
 
><TD
 
>BSD compatibility include files (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>The symbolic link <TT
 
CLASS="FILENAME"
 
>/usr/include/X11</TT
 
> must
 
link to <TT
 
CLASS="FILENAME"
 
>/usr/X11R6/include/X11</TT
 
> if the latter
 
exists.</P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="USRLIBLIBRARIESFORPROGRAMMINGANDPA"
 
>/usr/lib : Libraries for programming and packages</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE22"
 
>Purpose</A
 
></H3
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/usr/lib</TT
 
> includes object files, libraries,
 
and internal binaries that are not intended to be executed directly by
 
users or shell scripts.
 
<A
 
NAME="AEN1389"
 
HREF="#FTN.AEN1389"
 
><SPAN
 
CLASS="footnote"
 
>[22]</SPAN
 
></A
 
></P
 
><P
 
>Applications may use a single subdirectory under
 
<TT
 
CLASS="FILENAME"
 
>/usr/lib</TT
 
>.  If an application uses a subdirectory,
 
all architecture-dependent data exclusively used by the application
 
must be placed within that subdirectory.
 
  
<A
+
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
NAME="AEN1394"
+
== The Filesystem ==
HREF="#FTN.AEN1394"
 
><SPAN
 
CLASS="footnote"
 
>[23]</SPAN
 
></A
 
></P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS13"
 
>Specific Options</A
 
></H3
 
><P
 
>For historical reasons, <B
 
CLASS="COMMAND"
 
>/usr/lib/sendmail</B
 
>
 
must be a symbolic link to <B
 
CLASS="COMMAND"
 
>/usr/sbin/sendmail</B
 
> if
 
the latter exists.
 
  
<A
+
This standard assumes that the operating system underlying an FHS-compliant
NAME="AEN1402"
+
file system supports the same basic security features found in most UNIX
HREF="#FTN.AEN1402"
+
filesystems.
><SPAN
 
CLASS="footnote"
 
>[24]</SPAN
 
></A
 
></P
 
><P
 
>If <TT
 
CLASS="FILENAME"
 
>/lib/X11</TT
 
> exists,
 
<TT
 
CLASS="FILENAME"
 
>/usr/lib/X11</TT
 
> must be a symbolic link to
 
<TT
 
CLASS="FILENAME"
 
>/lib/X11</TT
 
>, or to whatever
 
<TT
 
CLASS="FILENAME"
 
>/lib/X11</TT
 
> is a symbolic link to.
 
  
<A
+
It is possible to define two independent distinctions among files: shareable
NAME="AEN1418"
+
vs. unshareable and variable vs. static. In general, files that differ in
HREF="#FTN.AEN1418"
+
either of these respects should be located in different directories. This makes
><SPAN
+
it easy to store files with different usage characteristics on different
CLASS="footnote"
+
filesystems.
>[25]</SPAN
 
></A
 
></P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="USRLIBLTQUALGTALTERNATEFORMATLIBRARI"
 
>/usr/lib&lt;qual&gt; : Alternate format libraries (optional)</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE23"
 
>Purpose</A
 
></H3
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/usr/lib&lt;qual&gt;</TT
 
> performs the same role as <TT
 
CLASS="FILENAME"
 
>/usr/lib</TT
 
> for an
 
alternate binary format, except that the symbolic links
 
<TT
 
CLASS="FILENAME"
 
>/usr/lib&lt;qual&gt;/sendmail</TT
 
> and <TT
 
CLASS="FILENAME"
 
>/usr/lib&lt;qual&gt;/X11</TT
 
> are not required.
 
  
<A
+
"Shareable" files are those that can be stored on one host and used on others.
NAME="AEN1435"
+
"Unshareable" files are those that are not shareable. For example, the files in
HREF="#FTN.AEN1435"
+
user home directories are shareable whereas device lock files are not.
><SPAN
 
CLASS="footnote"
 
>[26]</SPAN
 
></A
 
></P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="USRLOCALLOCALHIERARCHY"
 
>/usr/local : Local hierarchy</A
 
></H3
 
><DIV
 
CLASS="SECTION"
 
><H4
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE24"
 
>Purpose</A
 
></H4
 
><P
 
>The <TT
 
CLASS="FILENAME"
 
>/usr/local</TT
 
> hierarchy is for use by the
 
system administrator when installing software locally. It needs to be
 
safe from being overwritten when the system software is updated.  It
 
may be used for programs and data that are shareable amongst a group
 
of hosts, but not found in <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
>.</P
 
><P
 
>Locally installed software must be placed within
 
<TT
 
CLASS="FILENAME"
 
>/usr/local</TT
 
> rather than <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
>
 
unless it is being installed to replace or upgrade software in
 
<TT
 
CLASS="FILENAME"
 
>/usr</TT
 
>.
 
  
<A
+
"Static" files include binaries, libraries, documentation files and other files
NAME="AEN1450"
+
that do not change without system administrator intervention. "Variable" files
HREF="#FTN.AEN1450"
+
are files that are not static.
><SPAN
 
CLASS="footnote"
 
>[27]</SPAN
 
></A
 
></P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H4
 
CLASS="SECTION"
 
><A
 
NAME="REQUIREMENTS10"
 
>Requirements</A
 
></H4
 
><P
 
>The following directories, or symbolic links to directories,
 
must be in <TT
 
CLASS="FILENAME"
 
>/usr/local</TT
 
></P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN1460"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>bin</TT
 
></TD
 
><TD
 
>Local binaries</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>etc</TT
 
></TD
 
><TD
 
>Host-specific system configuration for local binaries</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>games</TT
 
></TD
 
><TD
 
>Local game binaries</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>include</TT
 
></TD
 
><TD
 
>Local C header files</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>lib</TT
 
></TD
 
><TD
 
>Local libraries</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>man</TT
 
></TD
 
><TD
 
>Local online manuals</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>sbin</TT
 
></TD
 
><TD
 
>Local system binaries</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>share</TT
 
></TD
 
><TD
 
>Local architecture-independent hierarchy</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>src</TT
 
></TD
 
><TD
 
>Local source code</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>No other directories, except those listed below, may be in
 
<TT
 
CLASS="FILENAME"
 
>/usr/local</TT
 
> after first installing a FHS-compliant
 
system.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H4
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS14"
 
>Specific Options</A
 
></H4
 
><P
 
>If directories <TT
 
CLASS="FILENAME"
 
>/lib&lt;qual&gt;</TT
 
> or
 
<TT
 
CLASS="FILENAME"
 
>/usr/lib&lt;qual&gt;</TT
 
> exist, the equivalent
 
directories must also exist in <TT
 
CLASS="FILENAME"
 
>/usr/local</TT
 
>.</P
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/usr/local/etc</TT
 
> may be a symbolic link to
 
<TT
 
CLASS="FILENAME"
 
>/etc/local</TT
 
>.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>The consistency of <TT
 
CLASS="FILENAME"
 
>/usr/local/etc</TT
 
> is
 
beneficial to installers, and is already used in other systems.  As
 
all of <TT
 
CLASS="FILENAME"
 
>/usr/local</TT
 
> needs to be backed up to
 
reproduce a system, it introduces no additional maintenance overhead,
 
but a symlink to <TT
 
CLASS="FILENAME"
 
>/etc/local</TT
 
> is suitable if
 
systems want alltheir configuration under one hierarchy.</P
 
><P
 
>Note that <TT
 
CLASS="FILENAME"
 
>/usr/etc</TT
 
> is still not allowed: programs
 
in <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> should place configuration files in
 
<TT
 
CLASS="FILENAME"
 
>/etc</TT
 
>.</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="USRLOCALSHARE1"
 
>/usr/local/share</A
 
></H2
 
><P
 
>The requirements for the contents of this directory are the same
 
as <TT
 
CLASS="FILENAME"
 
>/usr/share</TT
 
>.  The only additional constraint is
 
that <TT
 
CLASS="FILENAME"
 
>/usr/local/share/man</TT
 
> and
 
<TT
 
CLASS="FILENAME"
 
>/usr/local/man</TT
 
> directories must be synonomous
 
(usually this means that one of them must be a symbolic link).
 
  
<A
+
=== Rationale: ===  
NAME="AEN1530"
+
Shareable files can be stored on one host and used on several others. Typically, however, not all files in the filesystem hierarchy are shareable and so each system has local storage containing at least its unshareable files. It is convenient if all the files a system requires that are stored on a foreign host can be made available by mounting one or a few directories from the foreign host.
HREF="#FTN.AEN1530"
 
><SPAN
 
CLASS="footnote"
 
>[28]</SPAN
 
></A
 
></P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="USRSBINNONESSENTIALSTANDARDSYSTEMBI"
 
>/usr/sbin : Non-essential standard system binaries</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE25"
 
>Purpose</A
 
></H3
 
><P
 
>This directory contains any non-essential binaries used
 
exclusively by the system administrator. System administration
 
programs that are required for system repair, system recovery,
 
mounting <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
>, or other essential functions must
 
be placed in <TT
 
CLASS="FILENAME"
 
>/sbin</TT
 
> instead.
 
  
<A
+
Static and variable files should be segregated because static files, unlike variable files, can be stored on read-only media and do not need to be backed up on the same schedule as variable files. [[Historical~|Historical]] UNIX-like filesystem hierarchies contained both static and variable files under both /usr and /etc. In order to realize the advantages mentioned above, the /var hierarchy was created and all variable files were transferred from /usr to /var. Consequently /usr can now be mounted read-only (if it is a separate filesystem). Variable files have been transferred from /etc to /var over a longer period as technology has permitted.
NAME="AEN1540"
 
HREF="#FTN.AEN1540"
 
><SPAN
 
CLASS="footnote"
 
>[29]</SPAN
 
></A
 
></P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="USRSHAREARCHITECTUREINDEPENDENTDATA"
 
>/usr/share : Architecture-independent data</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE26"
 
>Purpose</A
 
></H3
 
><P
 
>The <TT
 
CLASS="FILENAME"
 
>/usr/share</TT
 
> hierarchy is for all
 
read-only architecture independent data files.
 
  
<A
+
Here is an example of a FHS-compliant system. (Other FHS-compliant layouts are possible.)
NAME="AEN1550"
 
HREF="#FTN.AEN1550"
 
><SPAN
 
CLASS="footnote"
 
>[30]</SPAN
 
></A
 
>&#13;</P
 
><P
 
>This hierarchy is intended to be shareable among all
 
architecture platforms of a given OS; thus, for example, a site with
 
i386, Alpha, and PPC platforms might maintain a single
 
<TT
 
CLASS="FILENAME"
 
>/usr/share</TT
 
> directory that is centrally-mounted.
 
Note, however, that <TT
 
CLASS="FILENAME"
 
>/usr/share</TT
 
> is generally not
 
intended to be shared by different OSes or by different releases of
 
the same OS.</P
 
><P
 
>Any program or package which contains or requires data that
 
doesn't need to be modified should store that data in
 
<TT
 
CLASS="FILENAME"
 
>/usr/share</TT
 
> (or
 
<TT
 
CLASS="FILENAME"
 
>/usr/local/share</TT
 
>, if installed locally).  It is
 
recommended that a subdirectory be used in
 
<TT
 
CLASS="FILENAME"
 
>/usr/share</TT
 
> for this purpose.</P
 
><P
 
>Game data stored in <TT
 
CLASS="FILENAME"
 
>/usr/share/games</TT
 
> must
 
be purely static data.  Any modifiable files, such as score files,
 
game play logs, and so forth, should be placed in
 
<TT
 
CLASS="FILENAME"
 
>/var/games</TT
 
>.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="REQUIREMENTS11"
 
>Requirements</A
 
></H3
 
><P
 
>The following directories, or symbolic links to directories,
 
must be in <TT
 
CLASS="FILENAME"
 
>/usr/share</TT
 
></P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN1573"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>man</TT
 
></TD
 
><TD
 
>Online manuals</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>misc</TT
 
></TD
 
><TD
 
>Miscellaneous architecture-independent data</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS15"
 
>Specific Options</A
 
></H3
 
><P
 
>The following directories, or symbolic links to directories, must be in <TT
 
CLASS="FILENAME"
 
>/usr/share</TT
 
>, if the corresponding
 
subsystem is installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN1592"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>dict</TT
 
></TD
 
><TD
 
>Word lists (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>doc</TT
 
></TD
 
><TD
 
>Miscellaneous documentation (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>games</TT
 
></TD
 
><TD
 
>Static data files for /usr/games (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>info</TT
 
></TD
 
><TD
 
>GNU Info system s primary directory (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>locale</TT
 
></TD
 
><TD
 
>Locale information (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>nls</TT
 
></TD
 
><TD
 
>Message catalogs for Native language support (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>sgml</TT
 
></TD
 
><TD
 
>SGML data (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>terminfo</TT
 
></TD
 
><TD
 
>Directories for terminfo database (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>tmac</TT
 
></TD
 
><TD
 
>troff macros not distributed with groff (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>xml</TT
 
></TD
 
><TD
 
>XML data (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>zoneinfo</TT
 
></TD
 
><TD
 
>Timezone information and configuration (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>It is recommended that application-specific,
 
architecture-independent directories be placed here.  Such directories
 
include <B
 
CLASS="COMMAND"
 
>groff</B
 
>, <B
 
CLASS="COMMAND"
 
>perl</B
 
>,
 
<B
 
CLASS="COMMAND"
 
>ghostscript</B
 
>, <B
 
CLASS="COMMAND"
 
>texmf</B
 
>, and
 
<B
 
CLASS="COMMAND"
 
>kbd</B
 
> (Linux) or <B
 
CLASS="COMMAND"
 
>syscons</B
 
>
 
(BSD).  They may, however, be placed in <TT
 
CLASS="FILENAME"
 
>/usr/lib</TT
 
>
 
for backwards compatibility, at the distributor's discretion.
 
Similarly, a <TT
 
CLASS="FILENAME"
 
>/usr/lib/games</TT
 
> hierarchy may be used
 
in addition to the <TT
 
CLASS="FILENAME"
 
>/usr/share/games</TT
 
> hierarchy if
 
the distributor wishes to place some game data there.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="USRSHAREDICTWORDLISTS"
 
>/usr/share/dict : Word lists (optional)</A
 
></H3
 
><DIV
 
CLASS="SECTION"
 
><H4
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE27"
 
>Purpose</A
 
></H4
 
><P
 
>This directory is the home for word lists on the system;
 
Traditionally this directory contains only the English
 
<TT
 
CLASS="FILENAME"
 
>words</TT
 
> file, which is used by
 
<B
 
CLASS="COMMAND"
 
>look(1)</B
 
> and various spelling programs.
 
<TT
 
CLASS="FILENAME"
 
>words</TT
 
> may use either American or British
 
spelling.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>The reason that only word lists are located here is that they
 
are the only files common to all spell checkers.</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H4
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS16"
 
>Specific Options</A
 
></H4
 
><P
 
>The following files, or symbolic links to files, must be in
 
<TT
 
CLASS="FILENAME"
 
>/usr/share/dict</TT
 
>, if the corresponding subsystem
 
is installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN1668"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
><TT
 
CLASS="FILENAME"
 
>File</TT
 
></TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>words</TT
 
></TD
 
><TD
 
>List of English words (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>Sites that require both American and British spelling may link
 
<TT
 
CLASS="FILENAME"
 
>words</TT
 
> to
 
<TT
 
CLASS="FILENAME"
 
>&shy;/usr/share/dict/american-english</TT
 
> or
 
<TT
 
CLASS="FILENAME"
 
>&shy;/usr/share/dict/british-english</TT
 
>.</P
 
><P
 
>Word lists for other languages may be added using the English
 
name for that language, e.g.,
 
<TT
 
CLASS="FILENAME"
 
>/usr/share/dict/french</TT
 
>,
 
<TT
 
CLASS="FILENAME"
 
>/usr/share/dict/danish</TT
 
>, etc. These should, if
 
possible, use an ISO 8859 character set which is appropriate for the
 
language in question; if possible the Latin1 (ISO 8859-1) character
 
set should be used (this is often not possible).</P
 
><P
 
>Other word lists must be included here, if present.</P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="USRSHAREMANMANUALPAGES"
 
>/usr/share/man : Manual pages</A
 
></H3
 
><DIV
 
CLASS="SECTION"
 
><H4
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE28"
 
>Purpose</A
 
></H4
 
><P
 
>This section details the organization for manual pages
 
throughout the system, including <TT
 
CLASS="FILENAME"
 
>/usr/share/man</TT
 
>.
 
Also refer to the section on
 
<TT
 
CLASS="FILENAME"
 
>/var/cache/man</TT
 
>.</P
 
><P
 
>The primary <TT
 
CLASS="FILENAME"
 
>&lt;mandir&gt;</TT
 
> of the system is
 
<TT
 
CLASS="FILENAME"
 
>/usr/share/man</TT
 
>.
 
<TT
 
CLASS="FILENAME"
 
>/usr/share/man</TT
 
> contains manual information for
 
commands and data under the <TT
 
CLASS="FILENAME"
 
>/</TT
 
> and
 
<TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> filesystems.
 
  
<A
+
    ┌────────┬───────────────┬───────────┐
NAME="AEN1701"
+
    │        │  shareable  │unshareable│
HREF="#FTN.AEN1701"
+
    ├────────┼───────────────┼───────────┤
><SPAN
+
    │static /usr          │/etc      │
CLASS="footnote"
+
    ├────────┼───────────────┼───────────┤
>[31]</SPAN
+
    │        │/opt          │/boot      │
></A
+
    ├────────┼───────────────┼───────────┤
></P
+
    │variable│/var/mail      │/var/run  │
><P
+
    ├────────┼───────────────┼───────────┤
>Manual pages are stored in
+
    │        │/var/spool/news│/var/lock
<TT
+
    └────────┴───────────────┴───────────┘
CLASS="FILENAME"
 
>&lt;mandir&gt;/&lt;locale&gt;/man&lt;section&gt;/&lt;arch&gt;</TT
 
>.
 
An explanation of <TT
 
CLASS="FILENAME"
 
>&lt;mandir&gt;</TT
 
>,
 
<TT
 
CLASS="FILENAME"
 
>&lt;locale&gt;</TT
 
>,
 
<TT
 
CLASS="FILENAME"
 
>&lt;section&gt;</TT
 
>, and
 
<TT
 
CLASS="FILENAME"
 
>&lt;arch&gt;</TT
 
> is given below.</P
 
><P
 
>A description of each section follows:</P
 
><P
 
></P
 
><UL
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><TT
 
CLASS="FILENAME"
 
>man1</TT
 
>: User programs
 
Manual pages that describe publicly accessible commands are contained in
 
this chapter. Most program documentation that a user will need to use
 
is located here.</P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><TT
 
CLASS="FILENAME"
 
>man2</TT
 
>: System calls
 
This section describes all of the system calls (requests for the
 
kernel to perform operations).</P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><TT
 
CLASS="FILENAME"
 
>man3</TT
 
>: Library functions and subroutines
 
Section 3 describes program library routines that are not direct calls
 
to kernel services.  This and chapter 2 are only really of interest to
 
programmers.</P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><TT
 
CLASS="FILENAME"
 
>man4</TT
 
>: Special files
 
Section 4 describes the special files, related driver functions, and
 
networking support available in the system.  Typically, this includes
 
the device files found in <TT
 
CLASS="FILENAME"
 
>/dev</TT
 
> and the kernel interface to
 
networking protocol support.</P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><TT
 
CLASS="FILENAME"
 
>man5</TT
 
>: File formats
 
The formats for many data files are documented in the
 
section 5.  This includes various include files, program output files,
 
and system files.</P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><TT
 
CLASS="FILENAME"
 
>man6</TT
 
>: Games
 
This chapter documents games, demos, and generally trivial programs.
 
Different people have various notions about how essential this is.</P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><TT
 
CLASS="FILENAME"
 
>man7</TT
 
>: Miscellaneous
 
Manual pages that are difficult to classify are designated as being
 
section 7.  The troff and other text processing macro packages are found
 
here.</P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><TT
 
CLASS="FILENAME"
 
>man8</TT
 
>: System administration
 
Programs used by system administrators for system operation and
 
maintenance are documented here. Some of these programs are also
 
occasionally useful for normal users.</P
 
></LI
 
></UL
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H4
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS17"
 
>Specific Options</A
 
></H4
 
><P
 
>The following directories, or symbolic links to directories,
 
must be in
 
<TT
 
CLASS="FILENAME"
 
>/usr/share/&lt;mandir&gt;/&lt;locale&gt;</TT
 
>, unless
 
they are empty:
 
  
<A
+
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
NAME="AEN1741"
+
== The Root Filesystem ==
HREF="#FTN.AEN1741"
+
=== /opt : Add-on [[application~|Application]] software packages ===
><SPAN
 
CLASS="footnote"
 
>[32]</SPAN
 
></A
 
></P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN1745"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>man1</TT
 
></TD
 
><TD
 
>User programs (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>man2</TT
 
></TD
 
><TD
 
>System calls (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>man3</TT
 
></TD
 
><TD
 
>Library calls (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>man4</TT
 
></TD
 
><TD
 
>Special files (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>man5</TT
 
></TD
 
><TD
 
>File formats (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>man6</TT
 
></TD
 
><TD
 
>Games (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>man7</TT
 
></TD
 
><TD
 
>Miscellaneous (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>man8</TT
 
></TD
 
><TD
 
>System administration (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>The component <TT
 
CLASS="FILENAME"
 
>&lt;section&gt;</TT
 
> describes the
 
manual section.</P
 
><P
 
>Provisions must be made in the structure of
 
<TT
 
CLASS="FILENAME"
 
>/usr/share/man</TT
 
> to support manual pages which are
 
written in different (or multiple) languages.  These provisions must
 
take into account the storage and reference of these manual pages.
 
Relevant factors include language (including geographical-based
 
differences), and character code set.</P
 
><P
 
>This naming of language subdirectories of
 
<TT
 
CLASS="FILENAME"
 
>/usr/share/man</TT
 
> is based on Appendix E of the
 
POSIX 1003.1 standard which describes the locale identification string
 
&mdash; the most well-accepted method to describe a cultural
 
environment.  The <TT
 
CLASS="FILENAME"
 
>&lt;locale&gt;</TT
 
> string
 
is:</P
 
><P
 
><TT
 
CLASS="FILENAME"
 
>&lt;language&gt;[_&lt;territory&gt;][.&lt;character-set&gt;][,&lt;version&gt;]</TT
 
></P
 
><P
 
>The <TT
 
CLASS="FILENAME"
 
>&lt;language&gt;</TT
 
> field must be taken
 
from ISO 639 (a code for the representation of names of languages).
 
It must be two characters wide and specified with lowercase letters
 
only.</P
 
><P
 
>The <TT
 
CLASS="FILENAME"
 
>&lt;territory&gt;</TT
 
> field must be the
 
two-letter code of ISO 3166 (a specification of representations of
 
countries), if possible.  (Most people are familiar with the
 
two-letter codes used for the country codes in email addresses.) It
 
must be two characters wide and specified with uppercase letters
 
only.
 
<A
 
NAME="AEN1797"
 
HREF="#FTN.AEN1797"
 
><SPAN
 
CLASS="footnote"
 
>[33]</SPAN
 
></A
 
></P
 
><P
 
>The <TT
 
CLASS="FILENAME"
 
>&lt;character-set&gt;</TT
 
> field must
 
represent the standard describing the character set.  If the
 
<TT
 
CLASS="FILENAME"
 
>&shy;&lt;character-set&gt;</TT
 
> field is just a
 
numeric specification, the number represents the number of the
 
international standard describing the character set.  It is
 
recommended that this be a numeric representation if possible (ISO
 
standards, especially), not include additional punctuation symbols,
 
and that any letters be in lowercase.</P
 
><P
 
>A parameter specifying a <TT
 
CLASS="FILENAME"
 
>&lt;version&gt;</TT
 
> of
 
the profile may be placed after the
 
<TT
 
CLASS="FILENAME"
 
>&shy;&lt;character-set&gt;</TT
 
> field, delimited by a
 
comma.  This may be used to discriminate between different cultural
 
needs; for instance, dictionary order versus a more systems-oriented
 
collating order.  This standard recommends not using the
 
<TT
 
CLASS="FILENAME"
 
>&lt;version&gt;</TT
 
> field, unless it is
 
necessary.</P
 
><P
 
>Systems which use a unique language and code set for all manual
 
pages may omit the <TT
 
CLASS="FILENAME"
 
>&lt;locale&gt;</TT
 
> substring and
 
store all manual pages in <TT
 
CLASS="FILENAME"
 
>&lt;mandir&gt;</TT
 
>.  For
 
example, systems which only have English manual pages coded with
 
ASCII, may store manual pages (the
 
<TT
 
CLASS="FILENAME"
 
>man&lt;section&gt;</TT
 
> directories) directly in
 
<TT
 
CLASS="FILENAME"
 
>/usr/share/man</TT
 
>.  (That is the traditional
 
circumstance and arrangement, in fact.)</P
 
><P
 
>Countries for which there is a well-accepted standard character
 
code set may omit the <TT
 
CLASS="FILENAME"
 
>&shy;&lt;character-set&gt;</TT
 
>
 
field, but it is strongly recommended that it be included, especially
 
for countries with several competing standards.</P
 
><P
 
>Various examples:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN1814"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL
 
WIDTH="1*"
 
TITLE="C1"><COL
 
WIDTH="1*"
 
TITLE="C2"><COL
 
WIDTH="1*"
 
TITLE="C3"><COL
 
WIDTH="1*"
 
TITLE="C4"><THEAD
 
><TR
 
><TH
 
ALIGN="LEFT"
 
>Language</TH
 
><TH
 
ALIGN="LEFT"
 
>Territory</TH
 
><TH
 
ALIGN="LEFT"
 
>Character Set</TH
 
><TH
 
ALIGN="LEFT"
 
>Directory</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>English</TD
 
><TD
 
ALIGN="LEFT"
 
>&mdash;</TD
 
><TD
 
ALIGN="LEFT"
 
>ASCII</TD
 
><TD
 
ALIGN="LEFT"
 
>/usr/share/man/en</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>English</TD
 
><TD
 
ALIGN="LEFT"
 
>United Kingdom</TD
 
><TD
 
ALIGN="LEFT"
 
>ISO 8859-15</TD
 
><TD
 
ALIGN="LEFT"
 
>/usr/share/man/en_GB</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>English</TD
 
><TD
 
ALIGN="LEFT"
 
>United States</TD
 
><TD
 
ALIGN="LEFT"
 
>ASCII</TD
 
><TD
 
ALIGN="LEFT"
 
>/usr/share/man/en_US</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>French</TD
 
><TD
 
ALIGN="LEFT"
 
>Canada</TD
 
><TD
 
ALIGN="LEFT"
 
>ISO 8859-1</TD
 
><TD
 
ALIGN="LEFT"
 
>/usr/share/man/fr_CA</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>French</TD
 
><TD
 
ALIGN="LEFT"
 
>France</TD
 
><TD
 
ALIGN="LEFT"
 
>ISO 8859-1</TD
 
><TD
 
ALIGN="LEFT"
 
>/usr/share/man/fr_FR</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>German</TD
 
><TD
 
ALIGN="LEFT"
 
>Germany</TD
 
><TD
 
ALIGN="LEFT"
 
>ISO 646</TD
 
><TD
 
ALIGN="LEFT"
 
>/usr/share/man/de_DE.646</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>German</TD
 
><TD
 
ALIGN="LEFT"
 
>Germany</TD
 
><TD
 
ALIGN="LEFT"
 
>ISO 6937</TD
 
><TD
 
ALIGN="LEFT"
 
>/usr/share/man/de_DE.6937</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>German</TD
 
><TD
 
ALIGN="LEFT"
 
>Germany</TD
 
><TD
 
ALIGN="LEFT"
 
>ISO 8859-1</TD
 
><TD
 
ALIGN="LEFT"
 
>/usr/share/man/de_DE.88591</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>German</TD
 
><TD
 
ALIGN="LEFT"
 
>Switzerland</TD
 
><TD
 
ALIGN="LEFT"
 
>ISO 646</TD
 
><TD
 
ALIGN="LEFT"
 
>/usr/share/man/de_CH.646</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Japanese</TD
 
><TD
 
ALIGN="LEFT"
 
>Japan</TD
 
><TD
 
ALIGN="LEFT"
 
>JIS</TD
 
><TD
 
ALIGN="LEFT"
 
>/usr/share/man/ja_JP.jis</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Japanese</TD
 
><TD
 
ALIGN="LEFT"
 
>Japan</TD
 
><TD
 
ALIGN="LEFT"
 
>SJIS</TD
 
><TD
 
ALIGN="LEFT"
 
>/usr/share/man/ja_JP.sjis</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Japanese</TD
 
><TD
 
ALIGN="LEFT"
 
>Japan</TD
 
><TD
 
ALIGN="LEFT"
 
>UJIS (or EUC-J)</TD
 
><TD
 
ALIGN="LEFT"
 
>/usr/share/man/ja_JP.ujis</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>Similarly, provision must be made for manual pages which are
 
architecture-dependent, such as documentation on device-drivers or
 
low-level system administration commands.  These must be placed under
 
an <TT
 
CLASS="FILENAME"
 
>&lt;arch&gt;</TT
 
> directory in the appropriate
 
<TT
 
CLASS="FILENAME"
 
>man&lt;section&gt;</TT
 
> directory; for example, a man
 
page for the i386 ctrlaltdel(8) command might be placed in
 
<TT
 
CLASS="FILENAME"
 
>/usr/share/man/&lt;locale&gt;/man8/i386/ctrlaltdel.8</TT
 
>.</P
 
><P
 
>Manual pages for commands and data under
 
<TT
 
CLASS="FILENAME"
 
>/usr/local</TT
 
> are stored in
 
<TT
 
CLASS="FILENAME"
 
>/usr/local/man</TT
 
>.  Manual pages for X11R6 are
 
stored in <TT
 
CLASS="FILENAME"
 
>/usr/X11R6/man</TT
 
>.  It follows that all
 
manual page hierarchies in the system must have the same structure as
 
<TT
 
CLASS="FILENAME"
 
>/usr/share/man</TT
 
>.</P
 
><P
 
>The cat page sections (<TT
 
CLASS="FILENAME"
 
>cat&lt;section&gt;</TT
 
>)
 
containing formatted manual page entries are also found within
 
subdirectories of <TT
 
CLASS="FILENAME"
 
>&lt;mandir&gt;/&lt;locale&gt;</TT
 
>,
 
but are not required nor may they be distributed in lieu of nroff
 
source manual pages.</P
 
><P
 
>The numbered sections "1" through "8" are traditionally defined.
 
In general, the file name for manual pages located within a particular
 
section end with <TT
 
CLASS="FILENAME"
 
>.&lt;section&gt;</TT
 
>.</P
 
><P
 
>In addition, some large sets of application-specific manual
 
pages have an additional suffix appended to the manual page filename.
 
For example, the MH mail handling system manual pages must have
 
<TT
 
CLASS="FILENAME"
 
>mh</TT
 
> appended to all MH manuals.  All X Window
 
System manual pages must have an <TT
 
CLASS="FILENAME"
 
>x</TT
 
> appended to
 
the filename.</P
 
><P
 
>The practice of placing various language manual pages in
 
appropriate subdirectories of <TT
 
CLASS="FILENAME"
 
>/usr/share/man</TT
 
> also
 
applies to the other manual page hierarchies, such as
 
<TT
 
CLASS="FILENAME"
 
>/usr/local/man</TT
 
> and
 
<TT
 
CLASS="FILENAME"
 
>/usr/X11R6/man</TT
 
>.  (This portion of the standard
 
also applies later in the section on the optional
 
<TT
 
CLASS="FILENAME"
 
>/var/cache/man</TT
 
> structure.)</P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="USRSHAREMISCMISCELLANEOUSARCHITECTURE"
 
>/usr/share/misc : Miscellaneous architecture-independent data</A
 
></H3
 
><P
 
>This directory contains miscellaneous architecture-independent
 
files which don't require a separate subdirectory under
 
<TT
 
CLASS="FILENAME"
 
>/usr/share</TT
 
>.</P
 
><DIV
 
CLASS="SECTION"
 
><HR><H4
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS18"
 
>Specific Options</A
 
></H4
 
><P
 
>The following files, or symbolic links to files, must be in
 
<TT
 
CLASS="FILENAME"
 
>/usr/share/misc</TT
 
>, if the corresponding subsystem
 
is installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN1917"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL
 
WIDTH="1*"
 
TITLE="C1"><COL
 
WIDTH="1*"
 
TITLE="C2"><THEAD
 
><TR
 
><TH
 
>File</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>ascii</TT
 
></TD
 
><TD
 
>ASCII character set table (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>magic</TT
 
></TD
 
><TD
 
>Default list of magic numbers for the file command (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>termcap</TT
 
></TD
 
><TD
 
>Terminal capability database (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>termcap.db</TT
 
></TD
 
><TD
 
>Terminal capability database (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>Other (application-specific) files may appear here, but a distributor
 
may place them in <TT
 
CLASS="FILENAME"
 
>/usr/lib</TT
 
> at their discretion.
 
<A
 
NAME="AEN1944"
 
HREF="#FTN.AEN1944"
 
><SPAN
 
CLASS="footnote"
 
>[34]</SPAN
 
></A
 
></P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="USRSHARESGMLSGMLANDXMLDATA"
 
>/usr/share/sgml : SGML data (optional)</A
 
></H3
 
><DIV
 
CLASS="SECTION"
 
><H4
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE29"
 
>Purpose</A
 
></H4
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/usr/share/sgml</TT
 
> contains
 
architecture-independent files used by SGML applications, such
 
as ordinary catalogs (not the centralized ones, see
 
<TT
 
CLASS="FILENAME"
 
>/etc/sgml</TT
 
>), DTDs, entities, or style
 
sheets.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H4
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS19"
 
>Specific Options</A
 
></H4
 
><P
 
>The following directories, or symbolic links to directories,
 
must be in <TT
 
CLASS="FILENAME"
 
>/usr/share/sgml</TT
 
>, if the corresponding
 
subsystem is installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN1983"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>docbook</TT
 
></TD
 
><TD
 
>docbook DTD (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>tei</TT
 
></TD
 
><TD
 
>tei DTD (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>html</TT
 
></TD
 
><TD
 
>html DTD (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>mathml</TT
 
></TD
 
><TD
 
>mathml DTD (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>Other files that are not specific to a given DTD may reside in
 
their own subdirectory.</P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="AEN2007"
 
>/usr/share/xml : XML data (optional)</A
 
></H3
 
><DIV
 
CLASS="SECTION"
 
><H4
 
CLASS="SECTION"
 
><A
 
NAME="AEN2009"
 
>Purpose</A
 
></H4
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/usr/share/xml</TT
 
> contains
 
architecture-independent files used by XML applications, such
 
as ordinary catalogs (not the centralized ones, see
 
<TT
 
CLASS="FILENAME"
 
>/etc/sgml</TT
 
>), DTDs, entities, or style
 
sheets.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H4
 
CLASS="SECTION"
 
><A
 
NAME="AEN2014"
 
>Specific Options</A
 
></H4
 
><P
 
>The following directories, or symbolic links to directories,
 
must be in <TT
 
CLASS="FILENAME"
 
>/usr/share/xml</TT
 
>, if the corresponding
 
subsystem is installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN2018"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>docbook</TT
 
></TD
 
><TD
 
>docbook XML DTD (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>xhtml</TT
 
></TD
 
><TD
 
>XHTML DTD (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>mathml</TT
 
></TD
 
><TD
 
>MathML DTD (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="USRSRCSOURCECODE"
 
>/usr/src : Source code (optional)</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE30"
 
>Purpose</A
 
></H3
 
><P
 
>Source code may be place placed in this
 
subdirectory, only for reference purposes.
 
  
<A
+
====   Purpose ====
NAME="AEN2042"
 
HREF="#FTN.AEN2042"
 
><SPAN
 
CLASS="footnote"
 
>[35]</SPAN
 
></A
 
></P
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="CHAPTER"
 
><HR><H1
 
><A
 
NAME="THEVARHIERARCHY"
 
></A
 
>Chapter 5. The /var Hierarchy</H1
 
><DIV
 
CLASS="SECTION"
 
><H2
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE31"
 
>Purpose</A
 
></H2
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/var</TT
 
> contains variable data files.  This
 
includes spool directories and files, administrative and logging data,
 
and transient and temporary files.</P
 
><P
 
>Some portions of <TT
 
CLASS="FILENAME"
 
>/var</TT
 
> are not shareable
 
between different systems.  For instance,
 
<TT
 
CLASS="FILENAME"
 
>/var/log</TT
 
>, <TT
 
CLASS="FILENAME"
 
>/var/lock</TT
 
>, and
 
<TT
 
CLASS="FILENAME"
 
>/var/run</TT
 
>.  Other portions may be shared, notably
 
<TT
 
CLASS="FILENAME"
 
>/var/mail</TT
 
>, <TT
 
CLASS="FILENAME"
 
>/var/cache/man</TT
 
>,
 
<TT
 
CLASS="FILENAME"
 
>/var/cache/fonts</TT
 
>, and
 
<TT
 
CLASS="FILENAME"
 
>/var/spool/news</TT
 
>.</P
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/var</TT
 
> is specified here in order to make it
 
possible to mount <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> read-only.  Everything
 
that once went into <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> that is written to
 
during system operation (as opposed to installation and software
 
maintenance) must be in <TT
 
CLASS="FILENAME"
 
>/var</TT
 
>.</P
 
><P
 
>If <TT
 
CLASS="FILENAME"
 
>/var</TT
 
> cannot be made a separate
 
partition, it is often preferable to move <TT
 
CLASS="FILENAME"
 
>/var</TT
 
>
 
out of the root partition and into the <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
>
 
partition.  (This is sometimes done to reduce the size of the root
 
partition or when space runs low in the root partition.)  However,
 
<TT
 
CLASS="FILENAME"
 
>/var</TT
 
> must not be linked to
 
<TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> because this makes separation of
 
<TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> and <TT
 
CLASS="FILENAME"
 
>/var</TT
 
> more difficult
 
and is likely to create a naming conflict.  Instead, link
 
<TT
 
CLASS="FILENAME"
 
>/var</TT
 
> to <TT
 
CLASS="FILENAME"
 
>/usr/var</TT
 
>.</P
 
><P
 
>Applications must generally not add directories to the top level
 
of <TT
 
CLASS="FILENAME"
 
>/var</TT
 
>.  Such directories should only be added
 
if they have some system-wide implication, and in consultation with
 
the FHS mailing list.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="REQUIREMENTS12"
 
>Requirements</A
 
></H2
 
><P
 
>The following directories, or symbolic links to directories, are
 
required in <TT
 
CLASS="FILENAME"
 
>/var</TT
 
>.</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN2080"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>cache</TT
 
></TD
 
><TD
 
>Application cache data</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>lib</TT
 
></TD
 
><TD
 
>Variable state information</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>local</TT
 
></TD
 
><TD
 
>Variable data for /usr/local</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>lock</TT
 
></TD
 
><TD
 
>Lock files</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>log</TT
 
></TD
 
><TD
 
>Log files and directories</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>opt</TT
 
></TD
 
><TD
 
>Variable data for /opt</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>run</TT
 
></TD
 
><TD
 
>Data relevant to running processes</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>spool</TT
 
></TD
 
><TD
 
>Application spool data</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>tmp</TT
 
></TD
 
><TD
 
>Temporary files preserved between system reboots</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
><P
 
>Several directories are `reserved' in the sense that they must
 
not be used arbitrarily by some new application, since they would
 
conflict with historical and/or local practice.  They are:</P
 
><TABLE
 
BORDER="0"
 
BGCOLOR="#E0E0E0"
 
WIDTH="100%"
 
><TR
 
><TD
 
><PRE
 
CLASS="SCREEN"
 
>    /var/backups
 
    /var/cron
 
    /var/msgs
 
    /var/preserve</PRE
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS20"
 
>Specific Options</A
 
></H2
 
><P
 
>The following directories, or symbolic links to directories,
 
must be in <TT
 
CLASS="FILENAME"
 
>/var</TT
 
>, if the corresponding subsystem
 
is installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN2129"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>account</TT
 
></TD
 
><TD
 
>Process accounting logs (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>crash</TT
 
></TD
 
><TD
 
>System crash dumps (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>games</TT
 
></TD
 
><TD
 
>Variable game data (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>mail</TT
 
></TD
 
><TD
 
>User mailbox files (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>yp</TT
 
></TD
 
><TD
 
>Network Information Service (NIS) database files (optional)
 
      </TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="VARACCOUNTPROCESSACCOUNTINGLOGS"
 
>/var/account : Process accounting logs (optional)</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE32"
 
>Purpose</A
 
></H3
 
><P
 
>This directory holds the current active process accounting log
 
and the composite process usage data (as used in some UNIX-like
 
systems by <B
 
CLASS="COMMAND"
 
>lastcomm</B
 
> and
 
<B
 
CLASS="COMMAND"
 
>sa</B
 
>).</P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="VARCACHEAPPLICATIONCACHEDATA"
 
>/var/cache : Application cache data</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE33"
 
>Purpose</A
 
></H3
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/var/cache</TT
 
> is intended for cached data from
 
applications.  Such data is locally generated as a result of
 
time-consuming I/O or calculation.  The application must be able to
 
regenerate or restore the data.  Unlike
 
<TT
 
CLASS="FILENAME"
 
>/var/spool</TT
 
>, the cached files can be deleted
 
without data loss.  The data must remain valid between invocations of
 
the application and rebooting the system.</P
 
><P
 
>Files located under <TT
 
CLASS="FILENAME"
 
>/var/cache</TT
 
> may be
 
expired in an application specific manner, by the system
 
administrator, or both.  The application must always be able to
 
recover from manual deletion of these files (generally because of a
 
disk space shortage).  No other requirements are made on the data
 
format of the cache directories.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>The existence of a separate directory for cached data allows
 
system administrators to set different disk and backup policies from
 
other directories in <TT
 
CLASS="FILENAME"
 
>/var</TT
 
>.&#13;</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS21"
 
>Specific Options</A
 
></H3
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN2178"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>fonts</TT
 
></TD
 
><TD
 
>Locally-generated fonts (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>man</TT
 
></TD
 
><TD
 
>Locally-formatted manual pages (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>www</TT
 
></TD
 
><TD
 
>WWW proxy or cache data (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>&lt;package&gt;</TT
 
></TD
 
><TD
 
>Package specific cache data (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="VARCACHEFONTSLOCALLYGENERATEDFONTS"
 
>/var/cache/fonts : Locally-generated fonts (optional)</A
 
></H3
 
><DIV
 
CLASS="SECTION"
 
><H4
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE34"
 
>Purpose</A
 
></H4
 
><P
 
>The directory <TT
 
CLASS="FILENAME"
 
>/var/cache/fonts</TT
 
> should be used to store any
 
dynamically-created fonts.  In particular, all of the fonts which are
 
automatically generated by <B
 
CLASS="COMMAND"
 
>mktexpk</B
 
> must be located in
 
appropriately-named subdirectories of <TT
 
CLASS="FILENAME"
 
>/var/cache/fonts</TT
 
>.
 
  
<A
+
/opt is reserved for the installation of add-on [[application~|Application]] software packages.
NAME="AEN2209"
 
HREF="#FTN.AEN2209"
 
><SPAN
 
CLASS="footnote"
 
>[36]</SPAN
 
></A
 
></P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H4
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS22"
 
>Specific Options</A
 
></H4
 
><P
 
>Other dynamically created fonts may also be placed in this tree,
 
under appropriately-named subdirectories of
 
<TT
 
CLASS="FILENAME"
 
>/var/cache/fonts</TT
 
>.</P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="VARCACHEMANLOCALLYFORMATTEDMANUALPAG"
 
>/var/cache/man : Locally-formatted manual pages (optional)</A
 
></H3
 
><DIV
 
CLASS="SECTION"
 
><H4
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE35"
 
>Purpose</A
 
></H4
 
><P
 
>This directory provides a standard location for sites that provide a
 
read-only <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> partition, but wish to allow caching of
 
locally-formatted man pages.  Sites that mount <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> as writable
 
(e.g., single-user installations) may choose not to use
 
<TT
 
CLASS="FILENAME"
 
>/var/cache/man</TT
 
> and may write formatted man pages into the
 
<TT
 
CLASS="FILENAME"
 
>cat&lt;section&gt;</TT
 
> directories in <TT
 
CLASS="FILENAME"
 
>/usr/share/man</TT
 
> directly.  We
 
recommend that most sites use one of the following options instead:</P
 
><P
 
></P
 
><UL
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>Preformat all manual pages alongside the unformatted versions.</P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>Allow no caching of formatted man pages, and require formatting to be
 
done each time a man page is brought up.</P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>Allow local caching of formatted man pages in <TT
 
CLASS="FILENAME"
 
>/var/cache/man</TT
 
>.</P
 
></LI
 
></UL
 
><P
 
>The structure of <TT
 
CLASS="FILENAME"
 
>/var/cache/man</TT
 
> needs to
 
reflect both the fact of multiple man page hierarchies and the
 
possibility of multiple language support.</P
 
><P
 
>Given an unformatted manual page that normally appears in
 
<TT
 
CLASS="FILENAME"
 
>&lt;path&gt;/man/&lt;locale&gt;/man&lt;section&gt;</TT
 
>,
 
the directory to place formatted man pages in is
 
<TT
 
CLASS="FILENAME"
 
>/var/cache/man/&lt;catpath&gt;/&lt;locale&gt;/cat&lt;section&gt;</TT
 
>,
 
where <TT
 
CLASS="FILENAME"
 
>&lt;catpath&gt;</TT
 
> is derived from
 
<TT
 
CLASS="FILENAME"
 
>&lt;path&gt;</TT
 
> by removing any leading
 
<TT
 
CLASS="FILENAME"
 
>usr</TT
 
> and/or trailing <TT
 
CLASS="FILENAME"
 
>share</TT
 
>
 
pathname components.  (Note that the
 
<TT
 
CLASS="FILENAME"
 
>&lt;locale&gt;</TT
 
> component may be missing.)
 
  
<A
+
A package to be installed in /opt must locate its static files in a separate /
NAME="AEN2244"
+
opt/<package> or /opt/<provider> directory tree, where <package> is a name that
HREF="#FTN.AEN2244"
+
describes the software package and <provider> is the provider's LANANA
><SPAN
+
registered name.
CLASS="footnote"
 
>[37]</SPAN
 
></A
 
></P
 
><P
 
>Man pages written to <TT
 
CLASS="FILENAME"
 
>/var/cache/man</TT
 
> may
 
eventually be transferred to the appropriate preformatted directories
 
in the source <TT
 
CLASS="FILENAME"
 
>man</TT
 
> hierarchy or expired; likewise
 
formatted man pages in the source <TT
 
CLASS="FILENAME"
 
>man</TT
 
> hierarchy
 
may be expired if they are not accessed for a period of time.</P
 
><P
 
>If preformatted manual pages come with a system on read-only
 
media (a CD-ROM, for instance), they must be installed in the source
 
<TT
 
CLASS="FILENAME"
 
>man</TT
 
> hierarchy
 
(e.g. <TT
 
CLASS="FILENAME"
 
>/usr/share/man/cat&lt;section&gt;</TT
 
>).
 
<TT
 
CLASS="FILENAME"
 
>/var/cache/man</TT
 
> is reserved as a writable cache
 
for formatted manual pages.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>Release 1.2 of the standard specified
 
<TT
 
CLASS="FILENAME"
 
>/var/catman</TT
 
> for this hierarchy.  The path has
 
been moved under <TT
 
CLASS="FILENAME"
 
>/var/cache</TT
 
> to better reflect the
 
dynamic nature of the formatted man pages.  The directory name has
 
been changed to <TT
 
CLASS="FILENAME"
 
>man</TT
 
> to allow for enhancing the
 
hierarchy to include post-processed formats other than "cat", such as
 
PostScript, HTML, or DVI.&#13;</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="VARCRASHSYSTEMCRASHDUMPS"
 
>/var/crash : System crash dumps (optional)</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE36"
 
>Purpose</A
 
></H3
 
><P
 
>This directory holds system crash dumps.  As of the date of this
 
release of the standard, system crash dumps were not supported under
 
Linux but may be supported by other systems which may comply with the
 
FHS.</P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="VARGAMESVARIABLEGAMEDATA"
 
>/var/games : Variable game data (optional)</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE37"
 
>Purpose</A
 
></H3
 
><P
 
>Any variable data relating to games in <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
>
 
should be placed here.  <TT
 
CLASS="FILENAME"
 
>/var/games</TT
 
> should hold
 
the variable data previously found in <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
>;
 
static data, such as help text, level descriptions, and so on, must
 
remain elsewhere, such as
 
<TT
 
CLASS="FILENAME"
 
>/usr/share/games</TT
 
>.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/var/games</TT
 
> has been given a hierarchy of
 
its own, rather than leaving it merged in with the old
 
<TT
 
CLASS="FILENAME"
 
>/var/lib</TT
 
> as in release 1.2.  The separation
 
allows local control of backup strategies, permissions, and disk
 
usage, as well as allowing inter-host sharing and reducing clutter in
 
<TT
 
CLASS="FILENAME"
 
>/var/lib</TT
 
>.  Additionally,
 
<TT
 
CLASS="FILENAME"
 
>/var/games</TT
 
> is the path traditionally used by BSD.&#13;</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="VARLIBVARIABLESTATEINFORMATION"
 
>/var/lib : Variable state information</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE38"
 
>Purpose</A
 
></H3
 
><P
 
>This hierarchy holds state information pertaining to an
 
application or the system.  State information is data that programs
 
modify while they run, and that pertains to one specific host.  Users
 
must never need to modify files in <TT
 
CLASS="FILENAME"
 
>/var/lib</TT
 
> to
 
configure a package's operation.</P
 
><P
 
>State information is generally used to preserve the condition of
 
an application (or a group of inter-related applications) between
 
invocations and between different instances of the same application.
 
State information should generally remain valid after a reboot, should
 
not be logging output, and should not be spooled data.</P
 
><P
 
>An application (or a group of inter-related applications) must
 
use a subdirectory of <TT
 
CLASS="FILENAME"
 
>/var/lib</TT
 
> for its data.
 
There is one required subdirectory,
 
<TT
 
CLASS="FILENAME"
 
>/var/lib/misc</TT
 
>, which is intended for state files
 
that don't need a subdirectory; the other subdirectories should only
 
be present if the application in question is included in the
 
distribution.
 
  
<A
+
====   Requirements ====
NAME="AEN2295"
 
HREF="#FTN.AEN2295"
 
><SPAN
 
CLASS="footnote"
 
>[38]</SPAN
 
></A
 
></P
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/var/lib/&lt;name&gt;</TT
 
> is the location that
 
must be used for all distribution packaging support.  Different
 
distributions may use different names, of course.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="REQUIREMENTS13"
 
>Requirements</A
 
></H3
 
><P
 
>The following directories, or symbolic links to directories, are
 
required in <TT
 
CLASS="FILENAME"
 
>/var/lib</TT
 
>:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN2305"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>misc</TT
 
></TD
 
><TD
 
>Miscellaneous state data</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS23"
 
>Specific Options</A
 
></H3
 
><P
 
>The following directories, or symbolic links to directories, must be in <TT
 
CLASS="FILENAME"
 
>/var/lib</TT
 
>, if the
 
corresponding subsystem is installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN2320"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
>&lt;editor&gt;</TD
 
><TD
 
>Editor backup files and state (optional)</TD
 
></TR
 
><TR
 
><TD
 
>&lt;pkgtool&gt;</TD
 
><TD
 
>Packaging support files (optional)</TD
 
></TR
 
><TR
 
><TD
 
>&lt;package&gt;</TD
 
><TD
 
>State data for packages and subsystems (optional)</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>hwclock</B
 
></TD
 
><TD
 
>State directory for hwclock (optional)</TD
 
></TR
 
><TR
 
><TD
 
><B
 
CLASS="COMMAND"
 
>xdm</B
 
></TD
 
><TD
 
>X display manager variable data (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="VARLIBLTEDITORGTEDITORBACKUPFILESAN"
 
>/var/lib/&lt;editor&gt; : Editor backup files and state (optional)</A
 
></H3
 
><DIV
 
CLASS="SECTION"
 
><H4
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE39"
 
>Purpose</A
 
></H4
 
><P
 
>These directories contain saved files generated by any
 
unexpected termination of an editor (e.g., <B
 
CLASS="COMMAND"
 
>elvis</B
 
>,
 
<B
 
CLASS="COMMAND"
 
>jove</B
 
>, <B
 
CLASS="COMMAND"
 
>nvi</B
 
>).</P
 
><P
 
>Other editors may not require a directory for crash-recovery
 
files, but may require a well-defined place to store other information
 
while the editor is running.  This information should be stored in a
 
subdirectory under <TT
 
CLASS="FILENAME"
 
>/var/lib</TT
 
> (for example, GNU
 
Emacs would place lock files in
 
<TT
 
CLASS="FILENAME"
 
>/var/lib/emacs/lock</TT
 
>).</P
 
><P
 
>Future editors may require additional state information beyond
 
crash-recovery files and lock files &mdash; this information should
 
also be placed under
 
<TT
 
CLASS="FILENAME"
 
>/var/lib/&lt;editor&gt;</TT
 
>.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>Previous Linux releases, as well as all commercial vendors, use
 
<TT
 
CLASS="FILENAME"
 
>/var/preserve</TT
 
> for vi or its clones.  However,
 
each editor uses its own format for these crash-recovery files, so a
 
separate directory is needed for each editor.</P
 
><P
 
>Editor-specific lock files are usually quite different from the
 
device or resource lock files that are stored in
 
<TT
 
CLASS="FILENAME"
 
>/var/lock</TT
 
> and, hence, are stored under
 
<TT
 
CLASS="FILENAME"
 
>/var/lib</TT
 
>.&#13;</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="VARLIBHWCLOCKSTATEDIRECTORYFORHWCLO"
 
>/var/lib/hwclock : State directory for hwclock (optional)</A
 
></H3
 
><DIV
 
CLASS="SECTION"
 
><H4
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE40"
 
>Purpose</A
 
></H4
 
><P
 
>This directory contains the file
 
<TT
 
CLASS="FILENAME"
 
>/var/lib/hwclock/adjtime</TT
 
>.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>In FHS 2.1, this file was <TT
 
CLASS="FILENAME"
 
>/etc/adjtime</TT
 
>, but
 
as <B
 
CLASS="COMMAND"
 
>hwclock</B
 
> updates it, that was obviously
 
incorrect.&#13;</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="VARLIBMISCMISCELLANEOUSVARIABLEDATA"
 
>/var/lib/misc : Miscellaneous variable data</A
 
></H3
 
><DIV
 
CLASS="SECTION"
 
><H4
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE41"
 
>Purpose</A
 
></H4
 
><P
 
>This directory contains variable data not placed in a
 
subdirectory in <TT
 
CLASS="FILENAME"
 
>/var/lib</TT
 
>.  An attempt should be
 
made to use relatively unique names in this directory to avoid
 
namespace conflicts.
 
  
<A
+
Directory            Description
NAME="AEN2381"
+
<package> Static package objects
HREF="#FTN.AEN2381"
+
<provider> LANANA registered provider name
><SPAN
 
CLASS="footnote"
 
>[39]</SPAN
 
></A
 
></P
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="VARLOCKLOCKFILES"
 
>/var/lock : Lock files</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE42"
 
>Purpose</A
 
></H3
 
><P
 
>Lock files should be stored within the
 
<TT
 
CLASS="FILENAME"
 
>/var/lock</TT
 
> directory structure.</P
 
><P
 
>Lock files for devices and other resources shared by multiple
 
applications, such as the serial device lock files that were
 
originally found in either <TT
 
CLASS="FILENAME"
 
>/usr/spool/locks</TT
 
> or
 
<TT
 
CLASS="FILENAME"
 
>/usr/spool/uucp</TT
 
>, must now be stored in
 
<TT
 
CLASS="FILENAME"
 
>/var/lock</TT
 
>.  The naming convention which must be
 
used is "LCK.." followed by the base name of the device.  For example,
 
to lock /dev/ttyS0 the file "LCK..ttyS0" would be created.
 
  
<A
+
The directories /opt/bin, /opt/doc, /opt/include, /opt/info, /opt/lib, and /opt
NAME="AEN2396"
+
/man are reserved for local system administrator use. Packages may provide
HREF="#FTN.AEN2396"
+
"front-end" files intended to be placed in (by linking or copying) these
><SPAN
+
reserved directories by the local system administrator, but must function
CLASS="footnote"
+
normally in the absence of these reserved directories.
>[40]</SPAN
 
></A
 
></P
 
><P
 
>The format used for the contents of such lock files must be the
 
HDB UUCP lock file format.  The HDB format is to store the process
 
identifier (PID) as a ten byte ASCII decimal number, with a trailing
 
newline.  For example, if process 1230 holds a lock file, it would
 
contain the eleven characters: space, space, space, space, space,
 
space, one, two, three, zero, and newline.</P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="VARLOGLOGFILESANDDIRECTORIES"
 
>/var/log : Log files and directories</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE43"
 
>Purpose</A
 
></H3
 
><P
 
>This directory contains miscellaneous log files.  Most logs must
 
be written to this directory or an appropriate subdirectory.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS24"
 
>Specific Options</A
 
></H3
 
><P
 
>The following files, or symbolic links to files, must be in
 
<TT
 
CLASS="FILENAME"
 
>/var/log</TT
 
>, if the corresponding subsystem is
 
installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN2410"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>File</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>lastlog</TT
 
></TD
 
><TD
 
>record of last login of each user</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>messages</TT
 
></TD
 
><TD
 
>system messages from <B
 
CLASS="COMMAND"
 
>syslogd</B
 
></TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>wtmp</TT
 
></TD
 
><TD
 
>record of all logins and logouts</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="VARMAILUSERMAILBOXFILES"
 
>/var/mail : User mailbox files (optional)</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE44"
 
>Purpose</A
 
></H3
 
><P
 
>The mail spool must be accessible through
 
<TT
 
CLASS="FILENAME"
 
>/var/mail</TT
 
> and the mail spool files must take the
 
form <TT
 
CLASS="FILENAME"
 
>&lt;username&gt;</TT
 
>.
 
<A
 
NAME="AEN2437"
 
HREF="#FTN.AEN2437"
 
><SPAN
 
CLASS="footnote"
 
>[41]</SPAN
 
></A
 
></P
 
><P
 
>User mailbox files in this location must be stored in the standard
 
UNIX mailbox format.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>The logical location for this directory was changed from
 
<TT
 
CLASS="FILENAME"
 
>/var/spool/mail</TT
 
> in order to bring FHS in-line
 
with nearly every UNIX implementation.  This change is important for
 
inter-operability since a single <TT
 
CLASS="FILENAME"
 
>/var/mail</TT
 
> is
 
often shared between multiple hosts and multiple UNIX implementations
 
(despite NFS locking issues).</P
 
><P
 
>It is important to note that there is no requirement to
 
physically move the mail spool to this location.  However, programs
 
and header files must be changed to use
 
<TT
 
CLASS="FILENAME"
 
>/var/mail</TT
 
>.&#13;</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="VAROPTVARIABLEDATAFOROPT"
 
>/var/opt : Variable data for /opt</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE45"
 
>Purpose</A
 
></H3
 
><P
 
>Variable data of the packages in <TT
 
CLASS="FILENAME"
 
>/opt</TT
 
> must
 
be installed in <TT
 
CLASS="FILENAME"
 
>/var/opt/&lt;subdir&gt;</TT
 
>, where
 
<TT
 
CLASS="FILENAME"
 
>&lt;subdir&gt;</TT
 
> is the name of the subtree in
 
<TT
 
CLASS="FILENAME"
 
>/opt</TT
 
> where the static data from an add-on
 
software package is stored, except where superseded by another file in
 
<TT
 
CLASS="FILENAME"
 
>/etc</TT
 
>.  No structure is imposed on the internal
 
arrangement of <TT
 
CLASS="FILENAME"
 
>/var/opt/&lt;subdir&gt;</TT
 
>.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>Refer to the rationale for <TT
 
CLASS="FILENAME"
 
>/opt</TT
 
>.&#13;</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="VARRUNRUNTIMEVARIABLEDATA"
 
>/var/run : Run-time variable data</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE46"
 
>Purpose</A
 
></H3
 
><P
 
>This directory contains system information data describing the
 
system since it was booted.  Files under this directory must be
 
cleared (removed or truncated as appropriate) at the beginning of the
 
boot process.  Programs may have a subdirectory of
 
<TT
 
CLASS="FILENAME"
 
>/var/run</TT
 
>; this is encouraged for programs that
 
use more than one run-time file.
 
  
<A
+
Programs to be invoked by users must be located in the directory /opt/<package>
NAME="AEN2469"
+
/bin or under the /opt/<provider> hierarchy. If the package includes UNIX
HREF="#FTN.AEN2469"
+
manual pages, they must be located in /opt/<package>/share/man or under the /
><SPAN
+
opt/<provider> hierarchy, and the same substructure as /usr/share/man must be
CLASS="footnote"
+
used.
>[42]</SPAN
 
></A
 
>
 
  
Process identifier (PID) files, which were originally placed in
+
Package files that are variable (change in normal operation) must be installed
<TT
+
in /var/opt. See the section on /var/opt for more information.
CLASS="FILENAME"
 
>/etc</TT
 
>, must be placed in
 
<TT
 
CLASS="FILENAME"
 
>/var/run</TT
 
>. The naming convention for PID files is
 
<TT
 
CLASS="FILENAME"
 
>&lt;program-name&gt;.pid</TT
 
>.  For example, the
 
<B
 
CLASS="COMMAND"
 
>crond</B
 
> PID file is named
 
<TT
 
CLASS="FILENAME"
 
>/var/run/crond.pid</TT
 
>.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="REQUIREMENTS14"
 
>Requirements</A
 
></H3
 
><P
 
>The internal format of PID files remains unchanged.  The file
 
must consist of the process identifier in ASCII-encoded decimal,
 
followed by a newline character.  For example, if
 
<B
 
CLASS="COMMAND"
 
>crond</B
 
> was process number 25,
 
<TT
 
CLASS="FILENAME"
 
>/var/run/crond.pid</TT
 
> would contain three
 
characters: two, five, and newline.</P
 
><P
 
>Programs that read PID files should be somewhat flexible in what
 
they accept; i.e., they should ignore extra whitespace, leading
 
zeroes, absence of the trailing newline, or additional lines in the
 
PID file.  Programs that create PID files should use the simple
 
specification located in the above paragraph.</P
 
><P
 
>The <TT
 
CLASS="FILENAME"
 
>utmp</TT
 
> file, which stores information
 
about who is currently using the system, is located in this
 
directory.</P
 
><P
 
>System programs that maintain transient UNIX-domain sockets must place
 
them in this directory.</P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="VARSPOOLAPPLICATIONSPOOLDATA"
 
>/var/spool : Application spool data</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE47"
 
>Purpose</A
 
></H3
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/var/spool</TT
 
> contains data which is awaiting
 
some kind of later processing.  Data in
 
<TT
 
CLASS="FILENAME"
 
>/var/spool</TT
 
> represents work to be done in the
 
future (by a program, user, or administrator); often data is deleted
 
after it has been processed.
 
  
<A
+
Host-specific [[configuration~|Configuration]] files must be installed in /etc/opt. See the
NAME="AEN2493"
+
section on /etc for more information.
HREF="#FTN.AEN2493"
 
><SPAN
 
CLASS="footnote"
 
>[43]</SPAN
 
></A
 
></P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS25"
 
>Specific Options</A
 
></H3
 
><P
 
>The following directories, or symbolic links to directories,
 
must be in <TT
 
CLASS="FILENAME"
 
>/var/spool</TT
 
>, if the corresponding
 
subsystem is installed:</P
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN2501"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>lpd</TT
 
></TD
 
><TD
 
>Printer spool directory (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>mqueue</TT
 
></TD
 
><TD
 
>Outgoing mail queue (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>news</TT
 
></TD
 
><TD
 
>News spool directory (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>rwho</TT
 
></TD
 
><TD
 
>Rwhod files (optional)</TD
 
></TR
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>uucp</TT
 
></TD
 
><TD
 
>Spool directory for UUCP (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="VARSPOOLLPDLINEPRINTERDAEMONPRINTQU"
 
>/var/spool/lpd : Line-printer daemon print queues (optional)</A
 
></H3
 
><DIV
 
CLASS="SECTION"
 
><H4
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE48"
 
>Purpose</A
 
></H4
 
><P
 
>The lock file for <B
 
CLASS="COMMAND"
 
>lpd</B
 
>,
 
<TT
 
CLASS="FILENAME"
 
>lpd.lock</TT
 
>, must be placed in
 
<TT
 
CLASS="FILENAME"
 
>/var/spool/lpd</TT
 
>. It is suggested that the lock
 
file for each printer be placed in the spool directory for that
 
specific printer and named <TT
 
CLASS="FILENAME"
 
>lock</TT
 
>.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H4
 
CLASS="SECTION"
 
><A
 
NAME="SPECIFICOPTIONS26"
 
>Specific Options</A
 
></H4
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN2539"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL><COL><THEAD
 
><TR
 
><TH
 
>Directory</TH
 
><TH
 
>Description</TH
 
></TR
 
></THEAD
 
><TBODY
 
><TR
 
><TD
 
><TT
 
CLASS="FILENAME"
 
>printer</TT
 
></TD
 
><TD
 
>Spools for a specific printer (optional)</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="VARSPOOLRWHORWHODFILES"
 
>/var/spool/rwho : Rwhod files (optional)</A
 
></H3
 
><DIV
 
CLASS="SECTION"
 
><H4
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE49"
 
>Purpose</A
 
></H4
 
><P
 
>This directory holds the <B
 
CLASS="COMMAND"
 
>rwhod</B
 
> information
 
for other systems on the local net.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>Some BSD releases use <TT
 
CLASS="FILENAME"
 
>/var/rwho</TT
 
> for this
 
data; given its historical location in <TT
 
CLASS="FILENAME"
 
>/var/spool</TT
 
>
 
on other systems and its approximate fit to the definition of
 
`spooled' data, this location was deemed more appropriate.</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="VARTMPTEMPORARYFILESPRESERVEDBETWEE"
 
>/var/tmp : Temporary files preserved between system reboots</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE50"
 
>Purpose</A
 
></H3
 
><P
 
>The <TT
 
CLASS="FILENAME"
 
>/var/tmp</TT
 
> directory is made available
 
for programs that require temporary files or directories that are
 
preserved between system reboots.  Therefore, data stored in
 
<TT
 
CLASS="FILENAME"
 
>/var/tmp</TT
 
> is more persistent than data in
 
<TT
 
CLASS="FILENAME"
 
>/tmp</TT
 
>.</P
 
><P
 
>Files and directories located in <TT
 
CLASS="FILENAME"
 
>/var/tmp</TT
 
>
 
must not be deleted when the system is booted.  Although data stored
 
in <TT
 
CLASS="FILENAME"
 
>/var/tmp</TT
 
> is typically deleted in a
 
site-specific manner, it is recommended that deletions occur at a less
 
frequent interval than <TT
 
CLASS="FILENAME"
 
>/tmp</TT
 
>.</P
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="VARYPNETWORKINFORMATIONSERVICE"
 
>/var/yp : Network Information Service (NIS) database files (optional)</A
 
></H2
 
><DIV
 
CLASS="SECTION"
 
><H3
 
CLASS="SECTION"
 
><A
 
NAME="PURPOSE51"
 
>Purpose</A
 
></H3
 
><P
 
>Variable data for the Network Information Service (NIS),
 
formerly known as the Sun Yellow Pages (YP), must be placed in this
 
directory.</P
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/var/yp</TT
 
> is the standard directory for NIS
 
(YP) data and is almost exclusively used in NIS documentation and
 
systems.
 
  
<A
+
No other package files may exist outside the /opt, /var/opt, and /etc/opt
NAME="AEN2582"
+
hierarchies except for those package files that must reside in specific
HREF="#FTN.AEN2582"
+
locations within the filesystem tree in order to function properly. For
><SPAN
+
example, device lock files must be placed in /var/lock and devices must be
CLASS="footnote"
+
located in /dev.
>[44]</SPAN
 
></A
 
></P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="CHAPTER"
 
><HR><H1
 
><A
 
NAME="OPERATINGSYSTEMSPECIFICANNEX"
 
></A
 
>Chapter 6. Operating System Specific Annex</H1
 
><P
 
>This section is for additional requirements and recommendations
 
that only apply to a specific operating system.  The material in this
 
section should never conflict with the base standard.</P
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="LINUX"
 
>Linux</A
 
></H2
 
><P
 
>This is the annex for the Linux operating system.</P
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="ROOTDIRECTORY"
 
>/ : Root directory</A
 
></H3
 
><P
 
>On Linux systems, if the kernel is located in
 
<TT
 
CLASS="FILENAME"
 
>/</TT
 
>, we recommend using the names
 
<TT
 
CLASS="FILENAME"
 
>vmlinux</TT
 
> or <TT
 
CLASS="FILENAME"
 
>vmlinuz</TT
 
>, which
 
have been used in recent Linux kernel source packages.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="BINESSENTIALUSERCOMMANDBINARIES2"
 
>/bin : Essential user command binaries (for use by all users)</A
 
></H3
 
><P
 
>Linux systems which require them place these additional files into
 
<TT
 
CLASS="FILENAME"
 
>/bin</TT
 
>:</P
 
><P
 
></P
 
><UL
 
><LI
 
><P
 
><B
 
CLASS="COMMAND"
 
>setserial</B
 
></P
 
></LI
 
></UL
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="DEVDEVICESANDSPECIALFILES"
 
>/dev : Devices and special files</A
 
></H3
 
><P
 
>The following devices must exist under /dev.  
 
  
<P
+
Distributions may install software in /opt, but must not modify or delete
></P
+
software installed by the local system administrator without the assent of the
><DIV
+
local system administrator.
CLASS="VARIABLELIST"
 
><DL
 
><DT
 
><TT
 
CLASS="FILENAME"
 
>/dev/null</TT
 
></DT
 
><DD
 
><P
 
>All data written to this device is discarded. A read from this device
 
will return an EOF condition.</P
 
></DD
 
><DT
 
><TT
 
CLASS="FILENAME"
 
>/dev/zero</TT
 
></DT
 
><DD
 
><P
 
>This device is a source of zeroed out data. All data written to this
 
device is discarded. A read from this device will return as many bytes
 
containing the value zero as was requested.</P
 
></DD
 
><DT
 
><TT
 
CLASS="FILENAME"
 
>/dev/tty</TT
 
></DT
 
><DD
 
><P
 
>This device is a synonym for the controlling terminal of a
 
process. Once this device is opened, all reads and writes will behave
 
as if the actual controlling terminal device had been opened.</P
 
></DD
 
></DL
 
></DIV
 
>
 
  
<DIV
+
==== Rationale: ====
CLASS="TIP"
+
The use of /opt for add-on software is a well-established practice in the UNIX community. The System V [[Application~|Application]] Binary Interface  [AT&T 1990], based on the System V Interface Definition (Third Edition), provides for an /opt structure very similar to the one defined here.
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>Previous versions of the FHS had stricter requirements for
 
<TT
 
CLASS="FILENAME"
 
>/dev</TT
 
>. Other devices may also exist in
 
/dev. Device names may exist as symbolic links to other device nodes
 
located in /dev or subdirectories of /dev. There is no requirement
 
concerning major/minor number values.</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
>&#13;</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="ETCHOSTSPECIFICSYSTEMCONFIGURATION2"
 
>/etc : Host-specific system configuration</A
 
></H3
 
><P
 
>Linux systems which require them place these additional files into
 
<TT
 
CLASS="FILENAME"
 
>/etc</TT
 
>.</P
 
><P
 
></P
 
><UL
 
><LI
 
><P
 
><TT
 
CLASS="FILENAME"
 
>lilo.conf</TT
 
></P
 
></LI
 
></UL
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="LIB64"
 
>/lib64 and /lib32 : 64/32-bit libraries (architecture dependent)</A
 
></H3
 
><P
 
>&#13;The 64-bit architectures PPC64, s390x, sparc64 and AMD64 must place
 
64-bit libraries in <TT
 
CLASS="FILENAME"
 
>/lib64</TT
 
>, and 32-bit
 
(or 31-bit on s390) libraries in <TT
 
CLASS="FILENAME"
 
>/lib</TT
 
>.</P
 
><P
 
>The 64-bit architecture IA64 must place 64-bit libraries in
 
<TT
 
CLASS="FILENAME"
 
>/lib</TT
 
>.  
 
  
<DIV
+
The Intel Binary Compatibility Standard v. 2 (iBCS2) also provides a similar structure for /opt.
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>This is a refinement of the general rules for
 
<TT
 
CLASS="FILENAME"
 
>/lib&lt;qual&gt;</TT
 
> and
 
<TT
 
CLASS="FILENAME"
 
>/usr/lib&lt;qual&gt;</TT
 
>.  The architectures PPC64,
 
s390x, sparc64 and AMD64 support support both 32-bit (for s390 more
 
precise 31-bit) and 64-bit programs.  Using <TT
 
CLASS="FILENAME"
 
>lib</TT
 
>
 
for 32-bit binaries allows existing binaries from the 32-bit systems
 
to work without any changes: such binaries are expected to be numerous.
 
IA-64 uses a different scheme, reflecting the deprecation of 32-bit
 
binaries (and hence libraries) on that architecture.</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="PROCKERNELANDPROCESSINFORMATIONVIR"
 
>/proc : Kernel and process information virtual filesystem</A
 
></H3
 
><P
 
>The <TT
 
CLASS="FILENAME"
 
>proc</TT
 
> filesystem is the de-facto
 
standard Linux method for handling process and system information,
 
rather than <TT
 
CLASS="FILENAME"
 
>/dev/kmem</TT
 
> and other similar methods.
 
We strongly encourage this for the storage and retrieval of process
 
information as well as other kernel and memory information.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="SBINESSENTIALSYSTEMBINARIES"
 
>/sbin : Essential system binaries</A
 
></H3
 
><P
 
>Linux systems place these additional files into <TT
 
CLASS="FILENAME"
 
>/sbin</TT
 
>.</P
 
><P
 
></P
 
><UL
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>Second extended filesystem commands (optional):</P
 
><P
 
></P
 
><UL
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><B
 
CLASS="COMMAND"
 
>badblocks</B
 
></P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><B
 
CLASS="COMMAND"
 
>dumpe2fs</B
 
></P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><B
 
CLASS="COMMAND"
 
>e2fsck</B
 
></P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><B
 
CLASS="COMMAND"
 
>mke2fs</B
 
></P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><B
 
CLASS="COMMAND"
 
>mklost+found</B
 
></P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><B
 
CLASS="COMMAND"
 
>tune2fs</B
 
></P
 
></LI
 
></UL
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>Boot-loader map installer (optional):</P
 
><P
 
></P
 
><UL
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><B
 
CLASS="COMMAND"
 
>lilo</B
 
></P
 
></LI
 
></UL
 
></LI
 
></UL
 
><P
 
>Optional files for /sbin:</P
 
><P
 
></P
 
><UL
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>Static binaries:</P
 
><P
 
></P
 
><UL
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><B
 
CLASS="COMMAND"
 
>ldconfig</B
 
></P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><B
 
CLASS="COMMAND"
 
>sln</B
 
></P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><B
 
CLASS="COMMAND"
 
>ssync</B
 
></P
 
></LI
 
></UL
 
><P
 
>Static <B
 
CLASS="COMMAND"
 
>ln</B
 
> (<B
 
CLASS="COMMAND"
 
>sln</B
 
>) and
 
static <B
 
CLASS="COMMAND"
 
>sync</B
 
> (<B
 
CLASS="COMMAND"
 
>ssync</B
 
>) are
 
useful when things go wrong.  The primary use of
 
<B
 
CLASS="COMMAND"
 
>sln</B
 
> (to repair incorrect symlinks in
 
<TT
 
CLASS="FILENAME"
 
>/lib</TT
 
> after a poorly orchestrated upgrade) is no
 
longer a major concern now that the <B
 
CLASS="COMMAND"
 
>ldconfig</B
 
>
 
program (usually located in <TT
 
CLASS="FILENAME"
 
>/usr/sbin</TT
 
>) exists and
 
can act as a guiding hand in upgrading the dynamic libraries.  Static
 
<B
 
CLASS="COMMAND"
 
>sync</B
 
> is useful in some emergency situations.
 
Note that these need not be statically linked versions of the standard
 
<B
 
CLASS="COMMAND"
 
>ln</B
 
> and <B
 
CLASS="COMMAND"
 
>sync</B
 
>, but may
 
be.</P
 
><P
 
>The <B
 
CLASS="COMMAND"
 
>ldconfig</B
 
> binary is optional for
 
<TT
 
CLASS="FILENAME"
 
>/sbin</TT
 
> since a site may choose to run
 
<B
 
CLASS="COMMAND"
 
>ldconfig</B
 
> at boot time, rather than only when
 
upgrading the shared libraries.  (It's not clear whether or not it is
 
advantageous to run <B
 
CLASS="COMMAND"
 
>ldconfig</B
 
> on each boot.)  Even
 
so, some people like <B
 
CLASS="COMMAND"
 
>ldconfig</B
 
> around for the
 
following (all too common) situation:</P
 
><P
 
></P
 
><OL
 
TYPE="1"
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>I've just removed <TT
 
CLASS="FILENAME"
 
>/lib/&lt;file&gt;</TT
 
>.</P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>I can't find out the name of the library because <B
 
CLASS="COMMAND"
 
>ls</B
 
> is
 
dynamically linked, I'm using a shell that doesn't have <B
 
CLASS="COMMAND"
 
>ls</B
 
>
 
built-in, and I don't know about using "<B
 
CLASS="COMMAND"
 
>echo *</B
 
>" as a
 
replacement.</P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>I have a static <B
 
CLASS="COMMAND"
 
>sln</B
 
>, but I don't know what to call the link.</P
 
></LI
 
></OL
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>Miscellaneous:</P
 
><P
 
></P
 
><UL
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><B
 
CLASS="COMMAND"
 
>ctrlaltdel</B
 
></P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
><B
 
CLASS="COMMAND"
 
>kbdrate</B
 
></P
 
></LI
 
></UL
 
><P
 
>So as to cope with the fact that some keyboards come up with
 
such a high repeat rate as to be unusable,
 
<B
 
CLASS="COMMAND"
 
>kbdrate</B
 
> may be installed in
 
<TT
 
CLASS="FILENAME"
 
>/sbin</TT
 
> on some systems.</P
 
><P
 
>Since the default action in the kernel for the Ctrl-Alt-Del key
 
combination is an instant hard reboot, it is generally advisable to
 
disable the behavior before mounting the root filesystem in read-write
 
mode.  Some <B
 
CLASS="COMMAND"
 
>init</B
 
> suites are able to disable
 
Ctrl-Alt-Del, but others may require the
 
<B
 
CLASS="COMMAND"
 
>ctrlaltdel</B
 
> program, which may be installed in
 
<TT
 
CLASS="FILENAME"
 
>/sbin</TT
 
> on those systems.</P
 
></LI
 
></UL
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="USRINCLUDEHEADERFILESINCLUDEDBYCP"
 
>/usr/include : Header files included by C programs</A
 
></H3
 
><P
 
>These symbolic links are required if a C or C++ compiler is
 
installed and only for systems not based on glibc.</P
 
><TABLE
 
BORDER="0"
 
BGCOLOR="#E0E0E0"
 
WIDTH="100%"
 
><TR
 
><TD
 
><PRE
 
CLASS="SCREEN"
 
>    /usr/include/asm -&gt; /usr/src/linux/include/asm-&lt;arch&gt;
 
    /usr/include/linux -&gt; /usr/src/linux/include/linux</PRE
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="USRSRCSOURCECODE2"
 
>/usr/src : Source code</A
 
></H3
 
><P
 
>For systems based on glibc, there are no specific guidelines for
 
this directory.  For systems based on Linux libc revisions prior to
 
glibc, the following guidelines and rationale apply:</P
 
><P
 
>The only source code that should be placed in a specific
 
location is the Linux kernel source code.  It is located in
 
<TT
 
CLASS="FILENAME"
 
>/usr/src/linux</TT
 
>.</P
 
><P
 
>If a C or C++ compiler is installed, but the complete Linux
 
kernel source code is not installed, then the include files from the
 
kernel source code must be located in these directories:</P
 
><TABLE
 
BORDER="0"
 
BGCOLOR="#E0E0E0"
 
WIDTH="100%"
 
><TR
 
><TD
 
><PRE
 
CLASS="SCREEN"
 
>    /usr/src/linux/include/asm-&lt;arch&gt;
 
    /usr/src/linux/include/linux</PRE
 
></TD
 
></TR
 
></TABLE
 
><P
 
><TT
 
CLASS="FILENAME"
 
>&lt;arch&gt;</TT
 
> is the name of the system
 
architecture.</P
 
><DIV
 
CLASS="NOTE"
 
><P
 
></P
 
><TABLE
 
CLASS="NOTE"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="/usr/share/sgml/docbook/stylesheet/dsssl/modular/images/note.gif"
 
HSPACE="5"
 
ALT="Note"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Note</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
> <TT
 
CLASS="FILENAME"
 
>/usr/src/linux</TT
 
>
 
may be a symbolic link to a kernel source code tree.</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
><DIV
 
CLASS="TIP"
 
><P
 
></P
 
><TABLE
 
CLASS="TIP"
 
WIDTH="100%"
 
BORDER="0"
 
><TR
 
><TD
 
WIDTH="25"
 
ALIGN="CENTER"
 
VALIGN="TOP"
 
><IMG
 
SRC="tip.gif"
 
HSPACE="5"
 
ALT="Tip"></TD
 
><TH
 
ALIGN="LEFT"
 
VALIGN="CENTER"
 
><B
 
>Rationale</B
 
></TH
 
></TR
 
><TR
 
><TD
 
>&nbsp;</TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
><P
 
>It is important that the kernel include files be located in
 
<TT
 
CLASS="FILENAME"
 
>/usr/src/linux</TT
 
> and not in
 
<TT
 
CLASS="FILENAME"
 
>/usr/include</TT
 
> so there are no problems when system
 
administrators upgrade their kernel version for the first time.&#13;</P
 
></TD
 
></TR
 
></TABLE
 
></DIV
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H3
 
CLASS="SECTION"
 
><A
 
NAME="VARSPOOLCRONCRONANDATJOBS"
 
>/var/spool/cron : cron and at jobs</A
 
></H3
 
><P
 
>This directory contains the variable data for the
 
<B
 
CLASS="COMMAND"
 
>cron</B
 
> and <B
 
CLASS="COMMAND"
 
>at</B
 
> programs.</P
 
></DIV
 
></DIV
 
></DIV
 
><DIV
 
CLASS="CHAPTER"
 
><HR><H1
 
><A
 
NAME="APPENDIX"
 
></A
 
>Chapter 7. Appendix</H1
 
><DIV
 
CLASS="SECTION"
 
><H2
 
CLASS="SECTION"
 
><A
 
NAME="THEFHSMAILINGLIST"
 
>The FHS mailing list</A
 
></H2
 
><P
 
>The FHS mailing list is located at
 
&lt;freestandards-fhs-discuss@lists.sourceforge.net&gt;. You can
 
subscribe to the mailing list at this page <A
 
HREF="http://sourceforge.net/projects/freestandards/"
 
TARGET="_top"
 
>http://sourceforge.net/projects/freestandards/</A
 
>.</P
 
><P
 
>Thanks to Network Operations at the University of California at
 
San Diego who allowed us to use their excellent mailing list
 
server.</P
 
><P
 
>As noted in the introduction, please do not send mail to the mailing
 
list without first contacting the FHS editor or a listed contributor.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="BACKGROUNDOFTHEFHS"
 
>Background of the FHS</A
 
></H2
 
><P
 
>The process of developing a standard filesystem hierarchy began
 
in August 1993 with an effort to restructure the file and directory
 
structure of Linux.  The FSSTND, a filesystem hierarchy standard
 
specific to the Linux operating system, was released on February 14,
 
1994.  Subsequent revisions were released on October 9, 1994 and March
 
28, 1995.</P
 
><P
 
>In early 1995, the goal of developing a more comprehensive
 
version of FSSTND to address not only Linux, but other UNIX-like
 
systems was adopted with the help of members of the BSD development
 
community.  As a result, a concerted effort was made to focus on
 
issues that were general to UNIX-like systems.  In recognition of this
 
widening of scope, the name of the standard was changed to Filesystem
 
Hierarchy Standard or FHS for short.</P
 
><P
 
>Volunteers who have contributed extensively to this standard are
 
listed at the end of this document.  This standard represents a
 
consensus view of those and other contributors.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="GENERALGUIDELINES"
 
>General Guidelines</A
 
></H2
 
><P
 
>Here are some of the guidelines that have been used in the development
 
of this standard:</P
 
><P
 
></P
 
><UL
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>Solve technical problems while limiting transitional difficulties.</P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>Make the specification reasonably stable.</P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>Gain the approval of distributors, developers, and other decision-makers
 
in relevant development groups and encourage their participation.</P
 
></LI
 
><LI
 
STYLE="list-style-type: disc"
 
><P
 
>Provide a standard that is attractive to the implementors of different
 
UNIX-like systems.</P
 
></LI
 
></UL
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="SCOPE"
 
>Scope</A
 
></H2
 
><P
 
>This document specifies a standard filesystem hierarchy for FHS
 
filesystems by specifying the location of files and directories, and
 
the contents of some system files.</P
 
><P
 
>This standard has been designed to be used by system
 
integrators, package developers, and system administrators in the
 
construction and maintenance of FHS compliant filesystems.  It is
 
primarily intended to be a reference and is not a tutorial on how to
 
manage a conforming filesystem hierarchy.</P
 
><P
 
>The FHS grew out of earlier work on FSSTND, a filesystem
 
organization standard for the Linux operating system.  It builds on
 
FSSTND to address interoperability issues not just in the Linux
 
community but in a wider arena including 4.4BSD-based operating
 
systems.  It incorporates lessons learned in the BSD world and
 
elsewhere about multi-architecture support and the demands of
 
heterogeneous networking.</P
 
><P
 
>Although this standard is more comprehensive than previous
 
attempts at filesystem hierarchy standardization, periodic updates may
 
become necessary as requirements change in relation to emerging
 
technology.  It is also possible that better solutions to the problems
 
addressed here will be discovered so that our solutions will no longer
 
be the best possible solutions.  Supplementary drafts may be released
 
in addition to periodic updates to this document.  However, a specific
 
goal is backwards compatibility from one release of this document to
 
the next.</P
 
><P
 
>Comments related to this standard are welcome.  Any comments or
 
suggestions for changes may be directed to the FHS editor (Daniel
 
Quinlan &lt;quinlan@pathname.com&gt;) or the FHS mailing list.
 
Typographical or grammatical comments should be directed to the FHS
 
editor.</P
 
><P
 
>Before sending mail to the mailing list it is requested that you
 
first contact the FHS editor in order to avoid excessive re-discussion
 
of old topics.</P
 
><P
 
>Questions about how to interpret items in this document may
 
occasionally arise.  If you have need for a clarification, please
 
contact the FHS editor.  Since this standard represents a consensus of
 
many participants, it is important to make certain that any
 
interpretation also represents their collective opinion.  For this
 
reason it may not be possible to provide an immediate response unless
 
the inquiry has been the subject of previous discussion.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="ACKNOWLEDGMENTS"
 
>Acknowledgments</A
 
></H2
 
><P
 
>The developers of the FHS wish to thank the developers, system
 
administrators, and users whose input was essential to this standard.
 
We wish to thank each of the contributors who helped to write,
 
compile, and compose this standard.</P
 
><P
 
>The FHS Group also wishes to thank those Linux developers who
 
supported the FSSTND, the predecessor to this standard.  If they
 
hadn't demonstrated that the FSSTND was beneficial, the FHS could
 
never have evolved.</P
 
></DIV
 
><DIV
 
CLASS="SECTION"
 
><HR><H2
 
CLASS="SECTION"
 
><A
 
NAME="CONTRIBUTORS"
 
>Contributors</A
 
></H2
 
><DIV
 
CLASS="INFORMALTABLE"
 
><P
 
></P
 
><A
 
NAME="AEN2813"
 
></A
 
><TABLE
 
BORDER="0"
 
FRAME="void"
 
CLASS="CALSTABLE"
 
><COL
 
WIDTH="1*"
 
TITLE="C1"><COL
 
WIDTH="1*"
 
TITLE="C2"><TBODY
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Brandon S. Allbery</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;bsa@kf8nh.wariat.org&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Keith Bostic</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;bostic@cs.berkeley.edu&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Drew Eckhardt</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;drew@colorado.edu&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Rik Faith</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;faith@cs.unc.edu&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Stephen Harris</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;sweh@spuddy.mew.co.uk&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Ian Jackson</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;ijackson@cus.cam.ac.uk&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Andreas Jaeger</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;aj@suse.de&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>John A. Martin</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;jmartin@acm.org&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Ian McCloghrie</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;ian@ucsd.edu&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Chris Metcalf</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;metcalf@lcs.mit.edu&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Ian Murdock</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;imurdock@debian.org&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>David C. Niemi</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;niemidc@clark.net&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Daniel Quinlan</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;quinlan@pathname.com&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Eric S. Raymond</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;esr@thyrsus.com&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Rusty Russell</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;rusty@rustcorp.com.au&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Mike Sangrey</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;mike@sojurn.lns.pa.us&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>David H. Silber</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;dhs@glowworm.firefly.com&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Thomas Sippel-Dau</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;t.sippel-dau@ic.ac.uk&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Theodore Ts'o</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;tytso@athena.mit.edu&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Stephen Tweedie</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;sct@dcs.ed.ac.uk&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Fred N. van Kempen</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;waltje@infomagic.com&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Bernd Warken</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;bwarken@mayn.de&gt;</TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
>Christopher Yeoh</TD
 
><TD
 
ALIGN="LEFT"
 
>&lt;cyeoh@samba.org&gt;</TD
 
></TR
 
></TBODY
 
></TABLE
 
><P
 
></P
 
></DIV
 
></DIV
 
></DIV
 
></DIV
 
><H3
 
CLASS="FOOTNOTES"
 
>Notes</H3
 
><TABLE
 
BORDER="0"
 
CLASS="FOOTNOTES"
 
WIDTH="100%"
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN261"
 
HREF="#AEN261"
 
><SPAN
 
CLASS="footnote"
 
>[1]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>Command binaries that are not essential enough to place into
 
<TT
 
CLASS="FILENAME"
 
>/bin</TT
 
> must be placed in
 
<TT
 
CLASS="FILENAME"
 
>/usr/bin</TT
 
>, instead.  Items that are required only
 
by non-root users (the X Window System, <TT
 
CLASS="FILENAME"
 
>chsh</TT
 
>,
 
etc.) are generally not essential enough to be placed into the root
 
partition.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN493"
 
HREF="#AEN493"
 
><SPAN
 
CLASS="footnote"
 
>[2]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
> Programs necessary to arrange for the boot loader to be
 
able to boot a file must be placed in <TT
 
CLASS="FILENAME"
 
>/sbin</TT
 
>.
 
Configuration files for boot loaders must be placed in
 
<TT
 
CLASS="FILENAME"
 
>/etc</TT
 
>.</P
 
><P
 
>The GRUB bootloader reads its configurations file before
 
booting, so that must be placed in <TT
 
CLASS="FILENAME"
 
>/boot</TT
 
>.  However, it is a
 
configuration file, so should be in <TT
 
CLASS="FILENAME"
 
>/etc</TT
 
>.  The answer here is a
 
symbolic link such as <TT
 
CLASS="FILENAME"
 
>/etc/grub/menu.lst</TT
 
> -&#62; <TT
 
CLASS="FILENAME"
 
>/boot/menu.lst</TT
 
>.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN507"
 
HREF="#AEN507"
 
><SPAN
 
CLASS="footnote"
 
>[3]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>On some i386 machines, it may be necessary for
 
<TT
 
CLASS="FILENAME"
 
>/boot</TT
 
> to be located on a separate partition
 
located completely below cylinder 1024 of the boot device due to
 
hardware constraints.</P
 
><P
 
>Certain MIPS systems require a <TT
 
CLASS="FILENAME"
 
>/boot</TT
 
>
 
partition that is a mounted MS-DOS filesystem or whatever other
 
filesystem type is accessible for the firmware.  This may result in
 
restrictions with respect to usable filenames within
 
<TT
 
CLASS="FILENAME"
 
>/boot</TT
 
> (only for affected systems).</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN534"
 
HREF="#AEN534"
 
><SPAN
 
CLASS="footnote"
 
>[4]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>The setup of command scripts invoked at boot time may resemble System
 
V, BSD or other models.  Further specification in this area may be
 
added to a future version of this standard.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN540"
 
HREF="#AEN540"
 
><SPAN
 
CLASS="footnote"
 
>[5]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>It is recommended that files be stored in subdirectories of
 
<TT
 
CLASS="FILENAME"
 
>/etc</TT
 
> rather than directly in
 
<TT
 
CLASS="FILENAME"
 
>/etc</TT
 
>.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN581"
 
HREF="#AEN581"
 
><SPAN
 
CLASS="footnote"
 
>[6]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>Systems that use the shadow password suite will have additional
 
configuration files in <TT
 
CLASS="FILENAME"
 
>/etc</TT
 
>
 
(<TT
 
CLASS="FILENAME"
 
>/etc/shadow</TT
 
> and others) and programs in
 
<TT
 
CLASS="FILENAME"
 
>/usr/sbin</TT
 
> (<B
 
CLASS="COMMAND"
 
>useradd</B
 
>,
 
<B
 
CLASS="COMMAND"
 
>usermod</B
 
>, and others).</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN722"
 
HREF="#AEN722"
 
><SPAN
 
CLASS="footnote"
 
>[7]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>On some Linux systems, this may be a symbolic link to
 
<TT
 
CLASS="FILENAME"
 
>/proc/mounts</TT
 
>, in which case this exception is not
 
required.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN778"
 
HREF="#AEN778"
 
><SPAN
 
CLASS="footnote"
 
>[8]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/etc/X11/xdm</TT
 
> holds the configuration files for
 
<TT
 
CLASS="FILENAME"
 
>xdm</TT
 
>.  These are most of the files previously
 
found in <TT
 
CLASS="FILENAME"
 
>/usr/lib/X11/xdm</TT
 
>.  Some local variable
 
data for <TT
 
CLASS="FILENAME"
 
>xdm</TT
 
> is stored in
 
<TT
 
CLASS="FILENAME"
 
>/var/lib/xdm</TT
 
>.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN808"
 
HREF="#AEN808"
 
><SPAN
 
CLASS="footnote"
 
>[9]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>Different people prefer to place user accounts in a variety of places.
 
This section describes only a suggested placement for user home
 
directories; nevertheless we recommend that all FHS-compliant
 
distributions use this as the default location for home
 
directories.</P
 
><P
 
>On small systems, each user's directory is typically one of the
 
many subdirectories of <TT
 
CLASS="FILENAME"
 
>/home</TT
 
> such as
 
<TT
 
CLASS="FILENAME"
 
>/home/smith</TT
 
>, <TT
 
CLASS="FILENAME"
 
>/home/torvalds</TT
 
>,
 
<TT
 
CLASS="FILENAME"
 
>/home/operator</TT
 
>, etc.  On large systems
 
(especially when the <TT
 
CLASS="FILENAME"
 
>/home</TT
 
> directories are shared
 
amongst many hosts using NFS) it is useful to subdivide user home
 
directories.  Subdivision may be accomplished by using subdirectories
 
such as <TT
 
CLASS="FILENAME"
 
>/home/staff</TT
 
>,
 
<TT
 
CLASS="FILENAME"
 
>/home/guests</TT
 
>,
 
<TT
 
CLASS="FILENAME"
 
>/home/students</TT
 
>, etc.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN819"
 
HREF="#AEN819"
 
><SPAN
 
CLASS="footnote"
 
>[10]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>If you want to find out a user's home directory, you should use the
 
<TT
 
CLASS="FILENAME"
 
>getpwent(3)</TT
 
> library function rather than relying
 
on <TT
 
CLASS="FILENAME"
 
>/etc/passwd</TT
 
> because user information may be
 
stored remotely using systems such as NIS.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN826"
 
HREF="#AEN826"
 
><SPAN
 
CLASS="footnote"
 
>[11]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>It is recommended that apart from autosave and lock files programs
 
should refrain from creating non dot files or directories in a home
 
directory without user intervention.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN836"
 
HREF="#AEN836"
 
><SPAN
 
CLASS="footnote"
 
>[12]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>Shared libraries that are only necessary for binaries in
 
<TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> (such as any X Window binaries) must not be
 
in <TT
 
CLASS="FILENAME"
 
>/lib</TT
 
>. Only the shared libraries required to
 
run binaries in <TT
 
CLASS="FILENAME"
 
>/bin</TT
 
> and
 
<TT
 
CLASS="FILENAME"
 
>/sbin</TT
 
> may be here.  In particular, the library
 
<TT
 
CLASS="FILENAME"
 
>libm.so.*</TT
 
> may also be placed in
 
<TT
 
CLASS="FILENAME"
 
>/usr/lib</TT
 
> if it is not required by anything in
 
<TT
 
CLASS="FILENAME"
 
>/bin</TT
 
> or <TT
 
CLASS="FILENAME"
 
>/sbin</TT
 
>.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN866"
 
HREF="#AEN866"
 
><SPAN
 
CLASS="footnote"
 
>[13]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>The usual placement of this binary is <TT
 
CLASS="FILENAME"
 
>/usr/bin/cpp</TT
 
>.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN890"
 
HREF="#AEN890"
 
><SPAN
 
CLASS="footnote"
 
>[14]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>This is commonly used for 64-bit or 32-bit support on
 
systems which support multiple binary formats, but require libraries
 
of the same name.  In this case, <TT
 
CLASS="FILENAME"
 
>/lib32</TT
 
> and
 
<TT
 
CLASS="FILENAME"
 
>/lib64</TT
 
> might be the library directories, and
 
<TT
 
CLASS="FILENAME"
 
>/lib</TT
 
> a symlink to one of them.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN900"
 
HREF="#AEN900"
 
><SPAN
 
CLASS="footnote"
 
>[15]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/lib&lt;qual&gt;/cpp</TT
 
> is still permitted: this
 
allows the case where <TT
 
CLASS="FILENAME"
 
>/lib</TT
 
> and
 
<TT
 
CLASS="FILENAME"
 
>/lib&lt;qual&gt;</TT
 
> are the same (one is a symbolic
 
link to the other). </P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN947"
 
HREF="#AEN947"
 
><SPAN
 
CLASS="footnote"
 
>[16]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>A compliant implementation with two CDROM drives might have
 
<TT
 
CLASS="FILENAME"
 
>/media/cdrom0</TT
 
> and
 
<TT
 
CLASS="FILENAME"
 
>/media/cdrom1</TT
 
> with
 
<TT
 
CLASS="FILENAME"
 
>/media/cdrom</TT
 
> a symlink to either of these.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN1037"
 
HREF="#AEN1037"
 
><SPAN
 
CLASS="footnote"
 
>[17]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>If the home directory of the root account is not
 
stored on the root partition it will be necessary to make certain it
 
will default to <TT
 
CLASS="FILENAME"
 
>/</TT
 
> if it can not be
 
located.</P
 
><P
 
>We recommend against using the root account for tasks that can be
 
performed as an unprivileged user, and that it be used solely for system
 
administration.  For this reason, we recommend that subdirectories for
 
mail and other applications not appear in the root account's home
 
directory, and that mail for administration roles such as root,
 
postmaster, and webmaster be forwarded to an appropriate user.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN1051"
 
HREF="#AEN1051"
 
><SPAN
 
CLASS="footnote"
 
>[18]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>Originally, <TT
 
CLASS="FILENAME"
 
>/sbin</TT
 
> binaries were kept in
 
<TT
 
CLASS="FILENAME"
 
>/etc</TT
 
>. </P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN1058"
 
HREF="#AEN1058"
 
><SPAN
 
CLASS="footnote"
 
>[19]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>Deciding what things go into
 
<SPAN
 
CLASS="emphasis"
 
><I
 
CLASS="EMPHASIS"
 
>"sbin"</I
 
></SPAN
 
> directories is simple: if a normal (not a
 
system administrator) user will ever run it directly, then it must be
 
placed in one of the <SPAN
 
CLASS="emphasis"
 
><I
 
CLASS="EMPHASIS"
 
>"bin"</I
 
></SPAN
 
> directories.  Ordinary
 
users should not have to place any of the <TT
 
CLASS="FILENAME"
 
>sbin</TT
 
>
 
directories in their path.</P
 
><P
 
>For example, files such as <B
 
CLASS="COMMAND"
 
>chfn</B
 
> which users
 
only occasionally use must still be placed in
 
<TT
 
CLASS="FILENAME"
 
>/usr/bin</TT
 
>.  <B
 
CLASS="COMMAND"
 
>ping</B
 
>, although it
 
is absolutely necessary for root (network recovery and diagnosis) is
 
often used by users and must live in <TT
 
CLASS="FILENAME"
 
>/bin</TT
 
> for
 
that reason.</P
 
><P
 
>We recommend that users have read and execute permission for
 
everything in <TT
 
CLASS="FILENAME"
 
>/sbin</TT
 
> except, perhaps, certain
 
setuid and setgid programs.  The division between
 
<TT
 
CLASS="FILENAME"
 
>/bin</TT
 
> and <TT
 
CLASS="FILENAME"
 
>/sbin</TT
 
> was not
 
created for security reasons or to prevent users from seeing the
 
operating system, but to provide a good partition between binaries
 
that everyone uses and ones that are primarily used for administration
 
tasks.  There is no inherent security advantage in making
 
<TT
 
CLASS="FILENAME"
 
>/sbin</TT
 
> off-limits for users.&#13;</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN1192"
 
HREF="#AEN1192"
 
><SPAN
 
CLASS="footnote"
 
>[20]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>This is particularly important as these areas will often contain both
 
files initially installed by the distributor, and those added by the
 
administrator.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN1299"
 
HREF="#AEN1299"
 
><SPAN
 
CLASS="footnote"
 
>[21]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>Examples of such configuration files include
 
<TT
 
CLASS="FILENAME"
 
>Xconfig</TT
 
>, <TT
 
CLASS="FILENAME"
 
>XF86Config</TT
 
>, or
 
<TT
 
CLASS="FILENAME"
 
>system.twmrc</TT
 
>)</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN1389"
 
HREF="#AEN1389"
 
><SPAN
 
CLASS="footnote"
 
>[22]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
> Miscellaneous
 
architecture-independent application-specific static files and
 
subdirectories must be placed in <TT
 
CLASS="FILENAME"
 
>/usr/share</TT
 
>.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN1394"
 
HREF="#AEN1394"
 
><SPAN
 
CLASS="footnote"
 
>[23]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
> For example, the <TT
 
CLASS="FILENAME"
 
>perl5</TT
 
> subdirectory for
 
Perl 5 modules and libraries.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN1402"
 
HREF="#AEN1402"
 
><SPAN
 
CLASS="footnote"
 
>[24]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>Some executable commands such as <B
 
CLASS="COMMAND"
 
>makewhatis</B
 
> and
 
<B
 
CLASS="COMMAND"
 
>sendmail</B
 
> have also been traditionally placed in
 
<TT
 
CLASS="FILENAME"
 
>/usr/lib</TT
 
>.  <B
 
CLASS="COMMAND"
 
>makewhatis</B
 
> is an
 
internal binary and must be placed in a binary directory; users access
 
only <B
 
CLASS="COMMAND"
 
>catman</B
 
>.  Newer <B
 
CLASS="COMMAND"
 
>sendmail</B
 
>
 
binaries are now placed by default in <TT
 
CLASS="FILENAME"
 
>/usr/sbin</TT
 
>.
 
Additionally, systems using a <SPAN
 
CLASS="emphasis"
 
><I
 
CLASS="EMPHASIS"
 
>sendmail</I
 
></SPAN
 
>-compatible
 
mail transfer agent must provide
 
<B
 
CLASS="COMMAND"
 
>/usr/sbin/sendmail</B
 
> as a symbolic link to the
 
appropriate executable. </P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN1418"
 
HREF="#AEN1418"
 
><SPAN
 
CLASS="footnote"
 
>[25]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>Host-specific data for the X Window System must not be stored in
 
<TT
 
CLASS="FILENAME"
 
>/usr/lib/X11</TT
 
>.  Host-specific configuration files
 
such as <TT
 
CLASS="FILENAME"
 
>Xconfig</TT
 
> or
 
<TT
 
CLASS="FILENAME"
 
>XF86Config</TT
 
> must be stored in
 
<TT
 
CLASS="FILENAME"
 
>/etc/X11</TT
 
>.  This includes configuration data such
 
as <TT
 
CLASS="FILENAME"
 
>system.twmrc</TT
 
> even if it is only made a
 
symbolic link to a more global configuration file (probably in
 
<TT
 
CLASS="FILENAME"
 
>/usr/X11R6/lib/X11</TT
 
>).</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN1435"
 
HREF="#AEN1435"
 
><SPAN
 
CLASS="footnote"
 
>[26]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>The case where <TT
 
CLASS="FILENAME"
 
>/usr/lib</TT
 
> and <TT
 
CLASS="FILENAME"
 
>/usr/lib&lt;qual&gt;</TT
 
> are the
 
same (one is a symbolic link to the other) these files and the
 
per-application subdirectories will exist.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN1450"
 
HREF="#AEN1450"
 
><SPAN
 
CLASS="footnote"
 
>[27]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>Software placed in <TT
 
CLASS="FILENAME"
 
>/</TT
 
> or
 
<TT
 
CLASS="FILENAME"
 
>/usr</TT
 
> may be overwritten by system upgrades
 
(though we recommend that distributions do not overwrite data in
 
<TT
 
CLASS="FILENAME"
 
>/etc</TT
 
> under these circumstances).  For this
 
reason, local software must not be placed outside of
 
<TT
 
CLASS="FILENAME"
 
>/usr/local</TT
 
> without good reason.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN1530"
 
HREF="#AEN1530"
 
><SPAN
 
CLASS="footnote"
 
>[28]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/usr/local/man</TT
 
> may be deprecated in future FHS
 
releases, so if all else is equal, making that one a symlink seems
 
sensible.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN1540"
 
HREF="#AEN1540"
 
><SPAN
 
CLASS="footnote"
 
>[29]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>Locally installed system administration programs should be placed in
 
<TT
 
CLASS="FILENAME"
 
>/usr/local/sbin</TT
 
>.</P
 
><P
 
></P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN1550"
 
HREF="#AEN1550"
 
><SPAN
 
CLASS="footnote"
 
>[30]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>Much of this data originally lived in <TT
 
CLASS="FILENAME"
 
>/usr</TT
 
>
 
(<TT
 
CLASS="FILENAME"
 
>man</TT
 
>, <TT
 
CLASS="FILENAME"
 
>doc</TT
 
>) or
 
<TT
 
CLASS="FILENAME"
 
>/usr/lib</TT
 
> (<TT
 
CLASS="FILENAME"
 
>dict</TT
 
>,
 
<TT
 
CLASS="FILENAME"
 
>terminfo</TT
 
>, <TT
 
CLASS="FILENAME"
 
>zoneinfo</TT
 
>).</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN1701"
 
HREF="#AEN1701"
 
><SPAN
 
CLASS="footnote"
 
>[31]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>Obviously, there are no manual pages in <TT
 
CLASS="FILENAME"
 
>/</TT
 
>
 
because they are not required at boot time nor are they required in
 
emergencies. Really.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN1741"
 
HREF="#AEN1741"
 
><SPAN
 
CLASS="footnote"
 
>[32]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>For example, if <TT
 
CLASS="FILENAME"
 
>/usr/local/man</TT
 
>
 
has no manual pages in section 4 (Devices), then
 
<TT
 
CLASS="FILENAME"
 
>/usr/local/man/man4</TT
 
> may be omitted.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN1797"
 
HREF="#AEN1797"
 
><SPAN
 
CLASS="footnote"
 
>[33]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
> A major exception to this rule is the
 
United Kingdom, which is `GB' in the ISO 3166, but `UK' for most email
 
addresses.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN1944"
 
HREF="#AEN1944"
 
><SPAN
 
CLASS="footnote"
 
>[34]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>Some such files include:
 
  
<TT
+
Generally, all data required to support a package on a system must be present within /opt/<package>, including files intended to be copied into /etc/opt/<package> and /var/opt/<package> as well as reserved directories in/opt.
CLASS="FILENAME"
+
 
>airport</TT
+
The minor restrictions on distributions using /opt are necessary because conflicts are possible between distribution-installed and locally-installed software, especially in the case of fixed pathnames found in some binary software.
>, <TT
+
 
CLASS="FILENAME"
+
The structure of the directories below /opt/<provider> is left up to the packager of the software, though it is recommended that packages are installed in /opt/<provider>/<package> and follow a similar structure to the guidelines for /opt/package. A valid reason for diverging from this structure is for support packages which may have files installed in /opt/ <provider>/lib or /opt/<provider>/bin.
> birthtoken</TT
+
 
>, <TT
+
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
CLASS="FILENAME"
+
 
>eqnchar</TT
+
== The /usr Hierarchy ==
>, <TT
+
 
CLASS="FILENAME"
+
==== Purpose ====
> getopt</TT
+
 
>, <TT
+
/usr is the second major section of the filesystem. /usr is shareable,
CLASS="FILENAME"
+
read-only data. That means that /usr should be shareable between various
>gprof.callg</TT
+
FHS-compliant hosts and must not be written to. Any information that is
>, <TT
+
host-specific or varies with time is stored elsewhere.
CLASS="FILENAME"
+
 
> gprof.flat</TT
+
Large software packages must not use a direct subdirectory under the /usr
>, <TT
+
hierarchy.
CLASS="FILENAME"
+
 
>inter.phone</TT
+
==== Requirements ====
>, <TT
+
 
CLASS="FILENAME"
+
The following directories, or symbolic links to directories, are required in /
> ipfw.samp.filters</TT
+
usr.
>,
+
 
<TT
+
Directory                  Description
CLASS="FILENAME"
+
bin      Most user commands
> ipfw.samp.scripts</TT
+
include  Header files included by C programs
>, <TT
+
lib      Libraries
CLASS="FILENAME"
+
local    Local hierarchy (empty after main installation)
>keycap.pcvt</TT
+
sbin      Non-vital system binaries
>, <TT
+
share    Architecture-independent data
CLASS="FILENAME"
+
 
> mail.help</TT
+
==== Specific Options ====
>, <TT
+
 
CLASS="FILENAME"
+
Directory                  Description
>mail.tildehelp</TT
+
X11R6    XWindow System, version 11 release 6 (optional)
>, <TT
+
games    Games and educational binaries (optional)
CLASS="FILENAME"
+
lib<qual> Alternate Format Libraries (optional)
> man.template</TT
+
src      Source code (optional)
>,
+
 
<TT
+
An exception is made for the X Window System because of considerable precedent
CLASS="FILENAME"
+
and widely-accepted practice.
>map3270</TT
+
 
>, <TT
+
The following symbolic links to directories may be present. This possibility is
CLASS="FILENAME"
+
based on the need to preserve compatibility with older systems until all
> mdoc.template</TT
+
implementations can be assumed to use the /var hierarchy.
>,
+
 
<TT
+
    /usr/spool -> /var/spool
CLASS="FILENAME"
+
    /usr/tmp -> /var/tmp
>more.help</TT
+
    /usr/spool/locks -> /var/lock
>, <TT
+
 
CLASS="FILENAME"
+
Once a system no longer requires any one of the above symbolic links, the link
> na.phone</TT
+
may be removed, if desired.
>,
+
 
<TT
+
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
CLASS="FILENAME"
+
 
>nslookup.help</TT
+
=== /usr/local : Local hierarchy ===
>, <TT
+
 
CLASS="FILENAME"
+
==== Purpose ====
> operator</TT
+
 
>,
+
The /usr/local hierarchy is for use by the system administrator when installing
<TT
+
software locally. It needs to be safe from being overwritten when the system
CLASS="FILENAME"
+
software is updated. It may be used for programs and data that are shareable
>scsi_modes</TT
+
amongst a group of hosts, but not found in /usr.
>, <TT
+
 
CLASS="FILENAME"
+
Locally installed software must be placed within /usr/local rather than /usr
> sendmail.hf</TT
+
unless it is being installed to replace or upgrade software in /usr. [27]
>,
+
 
<TT
+
==== Requirements ====
CLASS="FILENAME"
+
 
>style</TT
+
The following directories, or symbolic links to directories, must be in /usr/
>, <TT
+
local
CLASS="FILENAME"
+
 
> units.lib</TT
+
<pre>Directory                      Description
>,
+
bin      Local binaries
<TT
+
etc      Host-specific system [[configuration~|Configuration]] for local binaries
CLASS="FILENAME"
+
games    Local game binaries
>vgrindefs</TT
+
include  Local C header files
>, <TT
+
lib      Local libraries
CLASS="FILENAME"
+
man      Local online manuals
> vgrindefs.db</TT
+
sbin      Local system binaries
>,
+
share    Local architecture-independent hierarchy
<TT
+
src      Local source code</pre>
CLASS="FILENAME"
+
 
>zipcodes</TT
+
No other directories, except those listed below {omitted}, may be in /usr/local after
>&#13;</P
+
first installing a FHS-compliant system.
></TD
+
 
></TR
+
 
><TR
+
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
><TD
+
 
ALIGN="LEFT"
+
== Background of the FHS ==
VALIGN="TOP"
+
 
WIDTH="5%"
+
The process of developing a standard filesystem hierarchy began in August 1993
><A
+
with an effort to restructure the file and directory structure of Linux. The
NAME="FTN.AEN2042"
+
FSSTND, a filesystem hierarchy standard specific to the Linux operating system,
HREF="#AEN2042"
+
was released on February 14, 1994. Subsequent revisions were released on
><SPAN
+
October 9, 1994 and March 28, 1995.
CLASS="footnote"
+
 
>[35]</SPAN
+
In early 1995, the goal of developing a more comprehensive version of FSSTND to
></A
+
address not only Linux, but other UNIX-like systems was adopted with the help
></TD
+
of members of the BSD development community. As a result, a concerted effort
><TD
+
was made to focus on issues that were general to UNIX-like systems. In
ALIGN="LEFT"
+
recognition of this widening of scope, the name of the standard was changed to
VALIGN="TOP"
+
Filesystem Hierarchy Standard or FHS for short.
WIDTH="95%"
+
 
><P
+
Volunteers who have contributed extensively to this standard are listed at the
>Generally, source should not be built within this hierarchy.</P
+
end of this document. This standard represents a consensus view of those and
></TD
+
other contributors.
></TR
+
 
><TR
+
== General Guidelines ==
><TD
+
 
ALIGN="LEFT"
+
Here are some of the guidelines that have been used in the development of this
VALIGN="TOP"
+
standard:
WIDTH="5%"
+
 
><A
+
  • Solve technical problems while limiting transitional difficulties.
NAME="FTN.AEN2209"
+
 
HREF="#AEN2209"
+
  • Make the specification reasonably stable.
><SPAN
+
 
CLASS="footnote"
+
  • Gain the approval of distributors, developers, and other decision-makers in
>[36]</SPAN
+
    relevant development groups and encourage their participation.
></A
+
 
></TD
+
  • Provide a standard that is attractive to the implementors of different
><TD
+
    UNIX-like systems.
ALIGN="LEFT"
+
 
VALIGN="TOP"
+
=== Scope ===
WIDTH="95%"
+
 
><P
+
This document specifies a standard filesystem hierarchy for FHS filesystems by
>This standard does not currently incorporate the TeX Directory
+
specifying the location of files and directories, and the contents of some
Structure (a document that describes the layout TeX files and
+
system files.
directories), but it may be useful reading. It is located at
+
 
<A
+
This standard has been designed to be used by system integrators, package
HREF="ftp://ctan.tug.org/tex/"
+
developers, and system administrators in the construction and maintenance of
TARGET="_top"
+
FHS compliant filesystems. It is primarily intended to be a reference and is
>ftp://ctan.tug.org/tex/</A
+
not a tutorial on how to manage a conforming filesystem hierarchy.
></P
+
 
></TD
+
The FHS grew out of earlier work on FSSTND, a filesystem organization standard
></TR
+
for the Linux operating system. It builds on FSSTND to address interoperability
><TR
+
issues not just in the Linux community but in a wider arena including
><TD
+
4.4BSD-based operating systems. It incorporates lessons learned in the BSD
ALIGN="LEFT"
+
world and elsewhere about multi-architecture support and the demands of
VALIGN="TOP"
+
heterogeneous networking.
WIDTH="5%"
 
><A
 
NAME="FTN.AEN2244"
 
HREF="#AEN2244"
 
><SPAN
 
CLASS="footnote"
 
>[37]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>For example, <TT
 
CLASS="FILENAME"
 
>/usr/share/man/man1/ls.1</TT
 
> is
 
formatted into <TT
 
CLASS="FILENAME"
 
>/var/cache/man/cat1/ls.1</TT
 
>, and
 
<TT
 
CLASS="FILENAME"
 
>/usr/X11R6/man/&lt;locale&gt;/man3/XtClass.3x</TT
 
> into
 
<TT
 
CLASS="FILENAME"
 
>/var/cache/man/X11R6/&lt;locale&gt;/cat3/XtClass.3x</TT
 
>.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN2295"
 
HREF="#AEN2295"
 
><SPAN
 
CLASS="footnote"
 
>[38]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>An important difference between this version of this standard and
 
previous ones is that applications are now required to use a
 
subdirectory of <TT
 
CLASS="FILENAME"
 
>/var/lib</TT
 
>.  </P
 
><P
 
></P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN2381"
 
HREF="#AEN2381"
 
><SPAN
 
CLASS="footnote"
 
>[39]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>This hierarchy should contain files stored in
 
<TT
 
CLASS="FILENAME"
 
>/var/db</TT
 
> in current BSD releases. These include
 
<TT
 
CLASS="FILENAME"
 
>locate.database</TT
 
> and
 
<TT
 
CLASS="FILENAME"
 
>mountdtab</TT
 
>, and the kernel symbol database(s).</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN2396"
 
HREF="#AEN2396"
 
><SPAN
 
CLASS="footnote"
 
>[40]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>Then, anything wishing to use <TT
 
CLASS="FILENAME"
 
>/dev/ttyS0</TT
 
>
 
can read the lock file and act accordingly (all locks in
 
<TT
 
CLASS="FILENAME"
 
>/var/lock</TT
 
> should be world-readable).</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN2437"
 
HREF="#AEN2437"
 
><SPAN
 
CLASS="footnote"
 
>[41]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>Note that <TT
 
CLASS="FILENAME"
 
>/var/mail</TT
 
> may be a symbolic link to
 
another directory.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN2469"
 
HREF="#AEN2469"
 
><SPAN
 
CLASS="footnote"
 
>[42]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
><TT
 
CLASS="FILENAME"
 
>/var/run</TT
 
> should be unwritable for unprivileged
 
users (root or users running daemons); it is a major security problem
 
if any user can write in this directory.</P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN2493"
 
HREF="#AEN2493"
 
><SPAN
 
CLASS="footnote"
 
>[43]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>UUCP lock files must be placed in <TT
 
CLASS="FILENAME"
 
>/var/lock</TT
 
>. See
 
the above section on <TT
 
CLASS="FILENAME"
 
>/var/lock</TT
 
>. </P
 
></TD
 
></TR
 
><TR
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="5%"
 
><A
 
NAME="FTN.AEN2582"
 
HREF="#AEN2582"
 
><SPAN
 
CLASS="footnote"
 
>[44]</SPAN
 
></A
 
></TD
 
><TD
 
ALIGN="LEFT"
 
VALIGN="TOP"
 
WIDTH="95%"
 
><P
 
>NIS should not be confused with Sun NIS+, which uses a different
 
directory, <TT
 
CLASS="FILENAME"
 
>/var/nis</TT
 
>.</P
 
></TD
 
></TR
 
></TABLE
 
></BODY
 
></HTML
 
>
 

Latest revision as of 20:02, 1 November 2012

Filesystem Hierarchy Standard

Here are some excerpts to help explain why GT.M needs to go in /opt and not /usr/local. You may want to glance at some of this to understand why the FHS was written, why it's important, and why software distributions (like GT.M) need to be placed in a certain directory.

Here is the home of the Filesystem Hierarchy Standard (FHS). Refer to the original for the complete text. The copy you are reading is version 2.3, announced January 29, 2004.


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Introduction

This standard consists of a set of requirements and guidelines for file and directory placement under UNIX-like operating systems. The guidelines are intended to support interoperability of applications, system administration tools, development tools, and scripts as well as greater uniformity of documentation for these systems.


Purpose

This standard enables:

 • Software to predict the location of installed files and directories, and
 • Users to predict the location of installed files and directories.

We do this by:

 • Specifying guiding principles for each area of the filesystem,
 • Specifying the minimum files and directories required,
 • Enumerating exceptions to the principles, and
 • Enumerating specific cases where there has been Historical conflict.

The FHS document is used by:

 • Independent software suppliers to create Applications which are FHS
   compliant, and work with distributions which are FHS complaint,
 • OS creators to provide systems which are FHS compliant, and
 • Users to understand and maintain the FHS compliance of a system.

The FHS document has a limited scope:

 • Local placement of local files is a local issue, so FHS does not attempt to
   usurp system administrators.
 • FHS addresses issues where file placements need to be coordinated between
   multiple parties such as local sites, distributions, Applications,
   documentation, etc.

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The Filesystem

This standard assumes that the operating system underlying an FHS-compliant file system supports the same basic security features found in most UNIX filesystems.

It is possible to define two independent distinctions among files: shareable vs. unshareable and variable vs. static. In general, files that differ in either of these respects should be located in different directories. This makes it easy to store files with different usage characteristics on different filesystems.

"Shareable" files are those that can be stored on one host and used on others. "Unshareable" files are those that are not shareable. For example, the files in user home directories are shareable whereas device lock files are not.

"Static" files include binaries, libraries, documentation files and other files that do not change without system administrator intervention. "Variable" files are files that are not static.

Rationale:

Shareable files can be stored on one host and used on several others. Typically, however, not all files in the filesystem hierarchy are shareable and so each system has local storage containing at least its unshareable files. It is convenient if all the files a system requires that are stored on a foreign host can be made available by mounting one or a few directories from the foreign host.

Static and variable files should be segregated because static files, unlike variable files, can be stored on read-only media and do not need to be backed up on the same schedule as variable files. Historical UNIX-like filesystem hierarchies contained both static and variable files under both /usr and /etc. In order to realize the advantages mentioned above, the /var hierarchy was created and all variable files were transferred from /usr to /var. Consequently /usr can now be mounted read-only (if it is a separate filesystem). Variable files have been transferred from /etc to /var over a longer period as technology has permitted.

Here is an example of a FHS-compliant system. (Other FHS-compliant layouts are possible.)

   ┌────────┬───────────────┬───────────┐
   │        │   shareable   │unshareable│
   ├────────┼───────────────┼───────────┤
   │static  │/usr           │/etc       │
   ├────────┼───────────────┼───────────┤
   │        │/opt           │/boot      │
   ├────────┼───────────────┼───────────┤
   │variable│/var/mail      │/var/run   │
   ├────────┼───────────────┼───────────┤
   │        │/var/spool/news│/var/lock  │
   └────────┴───────────────┴───────────┘

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The Root Filesystem

/opt : Add-on Application software packages

Purpose

/opt is reserved for the installation of add-on Application software packages.

A package to be installed in /opt must locate its static files in a separate / opt/<package> or /opt/<provider> directory tree, where <package> is a name that describes the software package and <provider> is the provider's LANANA registered name.

Requirements

Directory Description <package> Static package objects <provider> LANANA registered provider name

The directories /opt/bin, /opt/doc, /opt/include, /opt/info, /opt/lib, and /opt /man are reserved for local system administrator use. Packages may provide "front-end" files intended to be placed in (by linking or copying) these reserved directories by the local system administrator, but must function normally in the absence of these reserved directories.

Programs to be invoked by users must be located in the directory /opt/<package> /bin or under the /opt/<provider> hierarchy. If the package includes UNIX manual pages, they must be located in /opt/<package>/share/man or under the / opt/<provider> hierarchy, and the same substructure as /usr/share/man must be used.

Package files that are variable (change in normal operation) must be installed in /var/opt. See the section on /var/opt for more information.

Host-specific Configuration files must be installed in /etc/opt. See the section on /etc for more information.

No other package files may exist outside the /opt, /var/opt, and /etc/opt hierarchies except for those package files that must reside in specific locations within the filesystem tree in order to function properly. For example, device lock files must be placed in /var/lock and devices must be located in /dev.

Distributions may install software in /opt, but must not modify or delete software installed by the local system administrator without the assent of the local system administrator.

Rationale:

The use of /opt for add-on software is a well-established practice in the UNIX community. The System V Application Binary Interface [AT&T 1990], based on the System V Interface Definition (Third Edition), provides for an /opt structure very similar to the one defined here.

The Intel Binary Compatibility Standard v. 2 (iBCS2) also provides a similar structure for /opt.

Generally, all data required to support a package on a system must be present within /opt/<package>, including files intended to be copied into /etc/opt/<package> and /var/opt/<package> as well as reserved directories in/opt.

The minor restrictions on distributions using /opt are necessary because conflicts are possible between distribution-installed and locally-installed software, especially in the case of fixed pathnames found in some binary software.

The structure of the directories below /opt/<provider> is left up to the packager of the software, though it is recommended that packages are installed in /opt/<provider>/<package> and follow a similar structure to the guidelines for /opt/package. A valid reason for diverging from this structure is for support packages which may have files installed in /opt/ <provider>/lib or /opt/<provider>/bin.

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The /usr Hierarchy

Purpose

/usr is the second major section of the filesystem. /usr is shareable, read-only data. That means that /usr should be shareable between various FHS-compliant hosts and must not be written to. Any information that is host-specific or varies with time is stored elsewhere.

Large software packages must not use a direct subdirectory under the /usr hierarchy.

Requirements

The following directories, or symbolic links to directories, are required in / usr.

Directory Description bin Most user commands include Header files included by C programs lib Libraries local Local hierarchy (empty after main installation) sbin Non-vital system binaries share Architecture-independent data

Specific Options

Directory Description X11R6 XWindow System, version 11 release 6 (optional) games Games and educational binaries (optional) lib<qual> Alternate Format Libraries (optional) src Source code (optional)

An exception is made for the X Window System because of considerable precedent and widely-accepted practice.

The following symbolic links to directories may be present. This possibility is based on the need to preserve compatibility with older systems until all implementations can be assumed to use the /var hierarchy.

   /usr/spool -> /var/spool
   /usr/tmp -> /var/tmp
   /usr/spool/locks -> /var/lock

Once a system no longer requires any one of the above symbolic links, the link may be removed, if desired.

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/usr/local : Local hierarchy

Purpose

The /usr/local hierarchy is for use by the system administrator when installing software locally. It needs to be safe from being overwritten when the system software is updated. It may be used for programs and data that are shareable amongst a group of hosts, but not found in /usr.

Locally installed software must be placed within /usr/local rather than /usr unless it is being installed to replace or upgrade software in /usr. [27]

Requirements

The following directories, or symbolic links to directories, must be in /usr/ local

Directory                      Description
bin       Local binaries
etc       Host-specific system [[configuration~|Configuration]] for local binaries
games     Local game binaries
include   Local C header files
lib       Local libraries
man       Local online manuals
sbin      Local system binaries
share     Local architecture-independent hierarchy
src       Local source code

No other directories, except those listed below {omitted}, may be in /usr/local after first installing a FHS-compliant system.


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Background of the FHS

The process of developing a standard filesystem hierarchy began in August 1993 with an effort to restructure the file and directory structure of Linux. The FSSTND, a filesystem hierarchy standard specific to the Linux operating system, was released on February 14, 1994. Subsequent revisions were released on October 9, 1994 and March 28, 1995.

In early 1995, the goal of developing a more comprehensive version of FSSTND to address not only Linux, but other UNIX-like systems was adopted with the help of members of the BSD development community. As a result, a concerted effort was made to focus on issues that were general to UNIX-like systems. In recognition of this widening of scope, the name of the standard was changed to Filesystem Hierarchy Standard or FHS for short.

Volunteers who have contributed extensively to this standard are listed at the end of this document. This standard represents a consensus view of those and other contributors.

General Guidelines

Here are some of the guidelines that have been used in the development of this standard:

 • Solve technical problems while limiting transitional difficulties.
 • Make the specification reasonably stable.
 • Gain the approval of distributors, developers, and other decision-makers in
   relevant development groups and encourage their participation.
 • Provide a standard that is attractive to the implementors of different
   UNIX-like systems.

Scope

This document specifies a standard filesystem hierarchy for FHS filesystems by specifying the location of files and directories, and the contents of some system files.

This standard has been designed to be used by system integrators, package developers, and system administrators in the construction and maintenance of FHS compliant filesystems. It is primarily intended to be a reference and is not a tutorial on how to manage a conforming filesystem hierarchy.

The FHS grew out of earlier work on FSSTND, a filesystem organization standard for the Linux operating system. It builds on FSSTND to address interoperability issues not just in the Linux community but in a wider arena including 4.4BSD-based operating systems. It incorporates lessons learned in the BSD world and elsewhere about multi-architecture support and the demands of heterogeneous networking.