>/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"