var.xml

<chapter id='theVarHierarchy'><title>The /var Hierarchy</title>

<section id='purpose31'><title>Purpose</title>

<para><filename>/var</filename> contains variable data files.  This
includes spool directories and files, administrative and logging data,
and transient and temporary files.</para>

<para>Some portions of <filename>/var</filename> are not shareable
between different systems.  For instance,
<filename>/var/log</filename>, <filename >/var/lock</filename>, and
<filename>/var/run</filename>.  Other portions may be shared, notably
<filename>/var/mail</filename>, <filename >/var/cache/man</filename>,
<filename>/var/cache/fonts</filename>, and
<filename>/var/spool/news</filename>.</para>

<para><filename>/var</filename> is specified here in order to make it
possible to mount <filename>/usr</filename> read-only.  Everything
that once went into <filename>/usr</filename> that is written to
during system operation (as opposed to installation and software
maintenance) must be in <filename>/var</filename>.</para>

<para>If <filename>/var</filename> cannot be made a separate
partition, it is often preferable to move <filename>/var</filename>
out of the root partition and into the <filename>/usr</filename>
partition.  (This is sometimes done to reduce the size of the root
partition or when space runs low in the root partition.)  However,
<filename>/var</filename> must not be linked to
<filename>/usr</filename> because this makes separation of
<filename>/usr</filename> and <filename>/var</filename> more difficult
and is likely to create a naming conflict.  Instead, link
<filename>/var</filename> to <filename>/usr/var</filename>.</para>

<para>Applications must generally not add directories to the top level
of <filename>/var</filename>.  Such directories should only be added
if they have some system-wide implication, and in consultation with
the FHS mailing list.</para> 
</section>

<section id='requirements12'><title>Requirements</title>

<para>The following directories, or symbolic links to directories, are
required in <filename>/var</filename>:</para>

<informaltable frame='none'>
  <tgroup cols='2' align='left'>
  <thead>
     <row>
       <entry>Directory</entry>
       <entry>Description</entry>
     </row>
  </thead>

  <tbody>

     <row>
       <entry><filename>cache</filename></entry>
       <entry>Application cache data</entry>
     </row>

     <row>
       <entry><filename>lib</filename></entry>
       <entry>Variable state information</entry>
     </row>

     <row>
       <entry><filename>local</filename></entry>
       <entry>Variable data for /usr/local</entry>
     </row>

     <row>
       <entry><filename>lock</filename></entry>
       <entry>Lock files</entry>
     </row>

     <row>
       <entry><filename>log</filename></entry>
       <entry>Log files and directories</entry>
     </row>

     <row>
       <entry><filename>opt</filename></entry>
       <entry>Variable data for /opt</entry>
     </row>

     <row>
       <entry><filename>run</filename></entry>
       <entry>Data relevant to running processes</entry>
     </row>

     <row>
       <entry><filename>spool</filename></entry>
       <entry>Application spool data</entry>
     </row>

     <row>
       <entry><filename>tmp</filename></entry>
       <entry>Temporary files preserved between system reboots</entry>
     </row>

   </tbody>
  </tgroup>
</informaltable>


<para>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:</para>

<screen>
    /var/backups
    /var/cron
    /var/msgs
    /var/preserve
</screen>

</section>

<section id='specificOptions20'><title>Specific Options</title>

<para>The following directories, or symbolic links to directories,
must be in <filename>/var</filename>, if the corresponding subsystem
is installed:</para>

<informaltable frame='none'>
  <tgroup cols='2' align='left'>
  <thead>
     <row>
       <entry>Directory</entry>
       <entry>Description</entry>
     </row>
  </thead>

  <tbody>

     <row>
       <entry><filename>account</filename></entry>
       <entry>Process accounting logs (optional)</entry>
     </row>

     <row>
       <entry><filename>crash</filename></entry>
       <entry>System crash dumps (optional)</entry>
     </row>

     <row>
       <entry><filename>games</filename></entry>
       <entry>Variable game data (optional)</entry>
     </row>

     <row>
       <entry><filename>mail</filename></entry>
       <entry>User mailbox files (optional)</entry>
     </row>

     <row>
       <entry><filename>yp</filename></entry>
       <entry>Network Information Service (NIS) database files (optional)
       </entry>
     </row>

   </tbody>
  </tgroup>
</informaltable>

</section>

<section id='varaccountProcessAccountingLogs'>
<title>/var/account : Process accounting logs (optional)</title>

<section id='purpose32'><title>Purpose</title>

<para>This directory holds the current active process accounting log
and the composite process usage data (as used in some UNIX-like
systems by <command>lastcomm</command> and
<command>sa</command>).</para>

</section>
</section>

<section id='varcacheApplicationCacheData'>
<title>/var/cache : Application cache data</title>

<section id='purpose33'><title>Purpose</title>

<para><filename>/var/cache</filename> 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
<filename>/var/spool</filename>, the cached files can be deleted
without data loss.  The data must remain valid between invocations of
the application and rebooting the system.</para>

<para>Files located under <filename>/var/cache</filename> 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.</para>


<tip><title>Rationale</title>

<para>The existence of a separate directory for cached data allows
system administrators to set different disk and backup policies from
other directories in <filename>/var</filename>.</para>

</tip>

</section>

<section id='specificOptions21'><title>Specific Options</title>

<informaltable frame='none'>
  <tgroup cols='2' align='left'>
  <thead>
     <row>
       <entry>Directory</entry>
       <entry>Description</entry>
     </row>
  </thead>

  <tbody>

     <row>
       <entry><filename>fonts</filename></entry>
       <entry>Locally-generated fonts (optional)</entry>
     </row>

     <row>
       <entry><filename>man</filename></entry>
       <entry>Locally-formatted manual pages (optional)</entry>
     </row>

     <row>
       <entry><filename>www</filename></entry>
       <entry>WWW proxy or cache data (optional)</entry>
     </row>

     <row>
       <entry><filename>&lt;package&gt;</filename></entry>
       <entry>Package specific cache data (optional)</entry>
     </row>

   </tbody>
  </tgroup>
</informaltable>

</section>

<section id='varcachefontsLocallygeneratedFonts'>
<title>/var/cache/fonts : Locally-generated fonts (optional)</title>

<section id='purpose34'><title>Purpose</title>

<para>The directory <filename>/var/cache/fonts</filename> should be used to store any
dynamically-created fonts.  In particular, all of the fonts which are
automatically generated by <command>mktexpk</command> must be located in
appropriately-named subdirectories of <filename>/var/cache/fonts</filename>.

<footnote>
<para>
This standard does not currently incorporate the TeX Directory
Structure (a document that describes the layout TeX files and
directories), but it may be useful reading.  It is located at
<ulink url="ftp://ctan.tug.org/tex/">ftp://ctan.tug.org/tex/</ulink></para>
</footnote></para>

</section>

<section id='specificOptions22'><title>Specific Options</title>

<para>Other dynamically created fonts may also be placed in this tree,
under appropriately-named subdirectories of
<filename>/var/cache/fonts</filename>.</para>

</section>
</section>

<section id='varcachemanLocallyformattedManualPag'>
<title>/var/cache/man : Locally-formatted manual pages (optional)</title>

<section id='purpose35'><title>Purpose</title>

<para>This directory provides a standard location for sites that provide a
read-only <filename>/usr</filename> partition, but wish to allow caching of
locally-formatted man pages.  Sites that mount <filename>/usr</filename> as writable
(e.g., single-user installations) may choose not to use
<filename>/var/cache/man</filename> and may write formatted man pages into the
<filename>cat&lt;section&gt;</filename> directories in <filename>/usr/share/man</filename> directly.  We
recommend that most sites use one of the following options instead:</para>
<itemizedlist spacing="normal" mark="bullet">
<listitem>
<para>Preformat all manual pages alongside the unformatted versions.</para>
</listitem>
<listitem>
<para>Allow no caching of formatted man pages, and require formatting to be
done each time a man page is brought up.</para>
</listitem>
<listitem>
<para>Allow local caching of formatted man pages in <filename>/var/cache/man</filename>.</para>
</listitem>
</itemizedlist>

<para>The structure of <filename>/var/cache/man</filename> needs to
reflect both the fact of multiple man page hierarchies and the
possibility of multiple language support.</para>

<para>Given an unformatted manual page that normally appears in
<filename>&lt;path&gt;/man/&lt;locale&gt;/man&lt;section&gt;</filename>,
the directory to place formatted man pages in is
<filename>/var/cache/man/&lt;catpath&gt;/&lt;locale&gt;/cat&lt;section&gt;</filename>,
where <filename>&lt;catpath&gt;</filename> is derived from
<filename>&lt;path&gt;</filename> by removing any leading
<filename>usr</filename> and/or trailing <filename>share</filename>
pathname components.  (Note that the
<filename>&lt;locale&gt;</filename> component may be missing.)

<footnote><para>
For example, <filename>/usr/share/man/man1/ls.1</filename> is
formatted into <filename>/var/cache/man/cat1/ls.1</filename>, and
<filename>/usr/X11R6/man/&lt;locale&gt;/man3/XtClass.3x</filename> into
<filename>/var/cache/man/X11R6/&lt;locale&gt;/cat3/XtClass.3x</filename>.
</para>
</footnote></para>

<para>Man pages written to <filename>/var/cache/man</filename> may
eventually be transferred to the appropriate preformatted directories
in the source <filename>man</filename> hierarchy or expired; likewise
formatted man pages in the source <filename>man</filename> hierarchy
may be expired if they are not accessed for a period of time.</para>

<para>If preformatted manual pages come with a system on read-only
media (a CD-ROM, for instance), they must be installed in the source
<filename>man</filename> hierarchy
(e.g. <filename>/usr/share/man/cat&lt;section&gt;</filename>).
<filename>/var/cache/man</filename> is reserved as a writable cache
for formatted manual pages.</para>


<tip><title>Rationale</title>

<para>Release 1.2 of this standard specified
<filename>/var/catman</filename> for this hierarchy.  The path has
been moved under <filename>/var/cache</filename> to better reflect the
dynamic nature of the formatted man pages.  The directory name has
been changed to <filename>man</filename> to allow for enhancing the
hierarchy to include post-processed formats other than "cat", such as
PostScript, HTML, or DVI.</para>

</tip>

</section>
</section>
</section>

<section id='varcrashSystemCrashDumps'>
<title>/var/crash : System crash dumps (optional)</title>


<section id='purpose36'><title>Purpose</title>

<para>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.</para>

</section>
</section>

<section id='vargamesVariableGameData'>

<title>/var/games : Variable game data (optional)</title>


<section id='purpose37'><title>Purpose</title>

<para>Any variable data relating to games in <filename>/usr</filename>
should be placed here.  <filename>/var/games</filename> should hold
the variable data previously found in <filename>/usr</filename>;
static data, such as help text, level descriptions, and so on, must
remain elsewhere, such as
<filename>/usr/share/games</filename>.</para>


<tip><title>Rationale</title>

<para><filename>/var/games</filename> has been given a hierarchy of
its own, rather than leaving it underneath
<filename>/var/lib</filename> as in release 1.2 of this standard.
The separation
allows local control of backup strategies, permissions, and disk
usage, as well as allowing inter-host sharing and reducing clutter in
<filename>/var/lib</filename>.  Additionally,
<filename>/var/games</filename> is the path traditionally used by BSD.</para>

</tip>
</section>
</section>

<section id='varlibVariableStateInformation'>
<title>/var/lib : Variable state information</title>

<section id='purpose38'><title>Purpose</title>

<para>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 <filename>/var/lib</filename> to
configure a package's operation, and the specific file hierarchy
used to store the data must not be exposed to regular users.

<footnote><para>
Data with exposed filesystem structure should be stored in
<filename>/srv</filename>.
</para></footnote>
</para>

<para>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.</para>

<para>An application (or a group of inter-related applications) must
use a subdirectory of <filename>/var/lib</filename> for its data.
There is one required subdirectory,
<filename>/var/lib/misc</filename>, 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.

<footnote>
<para>
An important difference between this version of this standard and
previous ones is that applications are now required to use a
subdirectory of <filename>/var/lib</filename>.  
</para>
</footnote></para>

<para><filename>/var/lib/&lt;name&gt;</filename> is the location that
must be used for all distribution packaging support.  Different
distributions may use different names, of course.</para>

</section>

<section id='requirements13'><title>Requirements</title>

<para>The following directories, or symbolic links to directories, are
required in <filename>/var/lib</filename>:</para>

<informaltable frame='none'>
  <tgroup cols='2' align='left'>
  <thead>
     <row>
       <entry>Directory</entry>
       <entry>Description</entry>
     </row>
  </thead>

  <tbody>

     <row>
       <entry><filename>misc</filename></entry>
       <entry>Miscellaneous state data</entry>
     </row>

   </tbody>
  </tgroup>
</informaltable>


</section>

<section id='specificOptions23'><title>Specific Options</title>
<para>The following directories, or symbolic links to directories, must be in <filename>/var/lib</filename>, if the
corresponding subsystem is installed:</para>

<informaltable frame='none'>
  <tgroup cols='2' align='left'>
  <thead>
     <row>
       <entry>Directory</entry>
       <entry>Description</entry>
     </row>
  </thead>
  <tbody>

     <row>
       <entry>&lt;editor&gt;</entry>
       <entry>Editor backup files and state (optional)</entry>
     </row>

     <row>
       <entry>&lt;pkgtool&gt;</entry>
       <entry>Packaging support files (optional)</entry>
     </row>

     <row>
       <entry>&lt;package&gt;</entry>
       <entry>State data for packages and subsystems (optional)</entry>
     </row>

     <row>
       <entry><filename>color</filename></entry>
       <entry>Color management information (optional)</entry>
     </row>

     <row>
       <entry><command>hwclock</command></entry>
       <entry>State directory for hwclock (optional)</entry>
     </row>

     <row>
       <entry><command>xdm</command></entry>
       <entry>X display manager variable data (optional)</entry>
     </row>

   </tbody>
  </tgroup>
</informaltable>

</section>

<section id='varliblteditorgtEditorBackupFilesAn'>
<title>/var/lib/&lt;editor&gt; : Editor backup files and state (optional)</title>

<section id='purpose39'><title>Purpose</title>

<para>These directories contain saved files generated by any
unexpected termination of an editor (e.g., <command>elvis</command>,
<command>jove</command>, <command>nvi</command>).</para>

<para>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 <filename>/var/lib</filename> (for example, GNU
Emacs would place lock files in
<filename>/var/lib/emacs/lock</filename>).</para>

<para>Future editors may require additional state information beyond
crash-recovery files and lock files &mdash; this information should
also be placed under
<filename>/var/lib/&lt;editor&gt;</filename>.</para>

<tip><title>Rationale</title>

<para>Previous Linux releases, as well as all commercial vendors, use
<filename>/var/preserve</filename> 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.</para>

<para>Editor-specific lock files are usually quite different from the
device or resource lock files that are stored in
<filename>/var/lock</filename> and, hence, are stored under
<filename>/var/lib</filename>.</para>

</tip>
</section>
</section>


<section id='varlibcolor'>
<title>/var/lib/color : Color management information (optional)</title>

<section id='varlibcolorPurpose'><title>Purpose</title>

<para>This directory is the home for ICC color management files
installed dynamically.  This directory shall be laid out using the
same rules as the <filename>/usr/share/color</filename>
directory.</para>

</section>

</section>

<section id='varlibhwclockStateDirectoryForHwclo'>
<title>/var/lib/hwclock : State directory for hwclock (optional)</title>

<section id='purpose40'><title>Purpose</title>

<para>This directory contains the file
<filename>/var/lib/hwclock/adjtime</filename>.</para>


<tip>
<title>Rationale</title>

<para>In FHS 2.1, this file was <filename>/etc/adjtime</filename>, but
as <command>hwclock</command> updates it, that was obviously
incorrect.</para>

</tip>
</section>
</section>

<section id='varlibmiscMiscellaneousVariableData'>
<title>/var/lib/misc : Miscellaneous variable data</title>

<section id='purpose41'><title>Purpose</title>

<para>This directory contains variable data not placed in a
subdirectory in <filename>/var/lib</filename>.  An attempt should be
made to use relatively unique names in this directory to avoid
namespace conflicts.

<footnote><para>This hierarchy should contain files stored in
<filename>/var/db</filename> in current BSD releases.  These include
<filename>locate.database</filename> and
<filename>mountdtab</filename>, and the kernel symbol database(s).
</para></footnote></para>

</section>
</section>
</section>

<section id='varlockLockFiles'>
<title>/var/lock : Lock files</title>

<section id='purpose42'><title>Purpose</title>

<para>Lock files should be stored within the
<filename>/var/lock</filename> directory structure.</para>

<para>Lock files for devices and other resources shared by multiple
applications, such as the serial device lock files that were
originally found in either <filename>/usr/spool/locks</filename> or
<filename>/usr/spool/uucp</filename>, must now be stored in
<filename>/var/lock</filename>.  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.

<footnote>
<para>Then, anything wishing to use <filename>/dev/ttyS0</filename>
can read the lock file and act accordingly (all locks in
<filename>/var/lock</filename> should be world-readable).
</para>
</footnote></para>

<para>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.</para>

</section>
</section>

<section id='varlogLogFilesAndDirectories'>
<title>/var/log : Log files and directories</title>

<section id='purpose43'><title>Purpose</title>

<para>This directory contains miscellaneous log files.  Most logs must
be written to this directory or an appropriate subdirectory.</para>

</section>

<section id='specificOptions24'><title>Specific Options</title>

<para>The following files, or symbolic links to files, must be in
<filename>/var/log</filename>, if the corresponding subsystem is
installed:</para>

<informaltable pgwide='0' frame='none'>
  <tgroup cols='2' align='left'>
    <thead>
     <row>
       <entry>File</entry>
       <entry>Description</entry>
     </row>
    </thead>
    <tbody>
      <row>
        <entry><filename>lastlog</filename></entry>
        <entry>record of last login of each user</entry>
      </row>
      <row>
        <entry><filename>messages</filename></entry>
        <entry>system messages from <command>syslogd</command></entry>
      </row>
      <row>
        <entry><filename>wtmp</filename></entry>
        <entry>record of all logins and logouts</entry>
      </row>
    </tbody>
  </tgroup>
</informaltable>

</section>
</section>

<section id='varmailUserMailboxFiles'>
<title>/var/mail : User mailbox files (optional)</title>

<section id='purpose44'><title>Purpose</title>

<para>The mail spool must be accessible through
<filename>/var/mail</filename> and the mail spool files must take the
form <filename>&lt;username&gt;</filename>.
<footnote>
<para>Note that <filename>/var/mail</filename> may be a symbolic link to
another directory.</para>
</footnote></para>

<para>User mailbox files in this location must be stored in the standard
UNIX mailbox format.</para>

<tip><title>Rationale</title>

<para>The logical location for this directory was changed from
<filename>/var/spool/mail</filename> in order to bring FHS in-line
with nearly every UNIX distribution.  This change is important for
inter-operability since a single <filename>/var/mail</filename> is
often shared between multiple hosts and multiple UNIX distribution
(despite NFS locking issues).</para>

<para>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
<filename>/var/mail</filename>.</para>

</tip>
</section>
</section>

<section id='varoptVariableDataForOpt'>
<title>/var/opt : Variable data for /opt</title>

<section id='purpose45'><title>Purpose</title>

<para>Variable data of the packages in <filename>/opt</filename> must
be installed in <filename>/var/opt/&lt;subdir&gt;</filename>, where
<filename>&lt;subdir&gt;</filename> is the name of the subtree in
<filename>/opt</filename> where the static data from an add-on
software package is stored, except where superseded by another file in
<filename>/etc</filename>.  No structure is imposed on the internal
arrangement of <filename>/var/opt/&lt;subdir&gt;</filename>.</para>

<tip><title>Rationale</title>

<para>Refer to the rationale for <filename>/opt</filename>.</para>

</tip>
</section>
</section>

<section id='varrunRuntimeVariableData'>
<title>/var/run : Run-time variable data</title>

<section id='purpose46'><title>Purpose</title>

<para>This directory was once intended for system information data
describing the system since it was booted.  These functions have been
moved to <filename>/run</filename>; this directory exists to ensure
compatibility with systems and software using an older version of this
specification.</para>

</section>

<section id='requirements14'><title>Requirements</title>

<para>In general, the requirements for <filename>/run</filename> shall
also apply to <filename>/var/run</filename>.  It is valid to implement
<filename>/var/run</filename> as a symlink to
<filename>/run</filename>.</para>

<para>The <filename>utmp</filename> file, which stores information
about who is currently using the system, is located in this
directory.</para>

<para>Programs should not access both <filename>/var/run</filename>
and <filename>/run</filename> directly, except to access
<filename>/var/run/utmp</filename>.

<footnote>
<para>This is to prevent confusion about where transient files are
located.  In general, a program should use either
<filename>/var/run</filename> or <filename>/run</filename> to access
these files, not both.</para>
</footnote>

</para>

</section>
</section>

<section id='varspoolApplicationSpoolData'>
<title>/var/spool : Application spool data</title>

<section id='purpose47'><title>Purpose</title>

<para><filename>/var/spool</filename> contains data which is awaiting
some kind of later processing.  Data in
<filename>/var/spool</filename> represents work to be done in the
future (by a program, user, or administrator); often data is deleted
after it has been processed.

<footnote>
<para>
UUCP lock files must be placed in <filename>/var/lock</filename>.  See
the above section on <filename>/var/lock</filename>.  </para>
</footnote></para>

</section>

<section id='specificOptions25'><title>Specific Options</title>

<para>The following directories, or symbolic links to directories,
must be in <filename>/var/spool</filename>, if the corresponding
subsystem is installed:</para>

<informaltable frame='none'>
  <tgroup cols='2' align='left'>
  <thead>
     <row>
       <entry>Directory</entry>
       <entry>Description</entry>
     </row>
  </thead>

  <tbody>

     <row>
       <entry><filename>lpd</filename></entry>
       <entry>Printer spool directory (optional)</entry>
     </row>

     <row>
       <entry><filename>mqueue</filename></entry>
       <entry>Outgoing mail queue (optional)</entry>
     </row>

     <row>
       <entry><filename>news</filename></entry>
       <entry>News spool directory (optional)</entry>
     </row>

     <row>
       <entry><filename>rwho</filename></entry>
       <entry>Rwhod files (optional)</entry>
     </row>

     <row>
       <entry><filename>uucp</filename></entry>
       <entry>Spool directory for UUCP (optional)</entry>
     </row>

   </tbody>
  </tgroup>
</informaltable>


</section>

<section id='varspoollpdLineprinterDaemonPrintQu'>
<title>/var/spool/lpd : Line-printer daemon print queues (optional)</title>

<section id='purpose48'><title>Purpose</title>

<para>The lock file for <command>lpd</command>,
<filename>lpd.lock</filename>, must be placed in
<filename>/var/spool/lpd</filename>.  It is suggested that the lock
file for each printer be placed in the spool directory for that
specific printer and named <filename>lock</filename>.</para>

</section>

<section id='specificOptions26'><title>Specific Options</title>

<informaltable frame='none'>
  <tgroup cols='2' align='left'>
  <thead>
     <row>
       <entry>Directory</entry>
       <entry>Description</entry>
     </row>
  </thead>

  <tbody>

     <row>
       <entry><filename>printer</filename></entry>
       <entry>Spools for a specific printer (optional)</entry>
     </row>

   </tbody>
  </tgroup>
</informaltable>

</section>
</section>

<section id='varspoolrwhoRwhodFiles'>
<title>/var/spool/rwho : Rwhod files (optional)</title>


<section id='purpose49'><title>Purpose</title>

<para>This directory holds the <command>rwhod</command> information
for other systems on the local net.</para>

<tip><title>Rationale</title>

<para>Some BSD releases use <filename>/var/rwho</filename> for this
data; given its historical location in <filename>/var/spool</filename>
on other systems and its approximate fit to the definition of
`spooled' data, this location was deemed more appropriate.</para>


</tip>
</section>
</section>
</section>

<section id='vartmpTemporaryFilesPreservedBetwee'>
<title>/var/tmp : Temporary files preserved between system reboots</title>

<section id='purpose50'><title>Purpose</title>

<para>The <filename>/var/tmp</filename> directory is made available
for programs that require temporary files or directories that are
preserved between system reboots.  Therefore, data stored in
<filename>/var/tmp</filename> is more persistent than data in
<filename>/tmp</filename>.</para>

<para>Files and directories located in <filename>/var/tmp</filename>
must not be deleted when the system is booted.  Although data stored
in <filename>/var/tmp</filename> is typically deleted in a
site-specific manner, it is recommended that deletions occur at a less
frequent interval than <filename>/tmp</filename>.</para>

</section>
</section>

<section id='varypNetworkInformationService'>
<title>/var/yp : Network Information Service (NIS) database files (optional)</title>


<section id='purpose51'><title>Purpose</title>

<para>Variable data for the Network Information Service (NIS),
formerly known as the Sun Yellow Pages (YP), must be placed in this
directory.</para>

<tip><title>Rationale</title>

<para><filename>/var/yp</filename> is the standard directory for NIS
(YP) data and is almost exclusively used in NIS documentation and
systems.

<footnote>
<para>
NIS should not be confused with Sun NIS+, which uses a different
directory, <filename>/var/nis</filename>.
</para>
</footnote></para>
</tip>

</section>
</section>
</chapter>