<chapter id='theUsrHierarchy'>
<title>The /usr Hierarchy</title>

<section id='purpose18'><title>Purpose</title>

<para><filename>/usr</filename> is the second major section of the
filesystem.  <filename>/usr</filename> is shareable, read-only data.
That means that <filename>/usr</filename> 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.</para>

<para>Large software packages must not use a direct subdirectory under
the <filename>/usr</filename> hierarchy.</para>

</section>

<section id='requirements9'><title>Requirements</title>

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

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

  <tbody>

     <row>
       <entry><filename>bin</filename></entry>
       <entry>Most user commands</entry>
     </row>

     <row>
       <entry><filename>lib</filename></entry>
       <entry>Libraries</entry>
     </row>

     <row>
       <entry><filename>local</filename></entry>
       <entry>Local hierarchy (empty after main installation)</entry>
     </row>

     <row>
       <entry><filename>sbin</filename></entry>
       <entry>Non-vital system binaries</entry>
     </row>

     <row>
       <entry><filename>share</filename></entry>
       <entry>Architecture-independent data</entry>
     </row>

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


</section>

<section id='specificOptions9'><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>games</filename></entry>
       <entry>Games and educational binaries (optional)</entry>
     </row>

     <row>
       <entry><filename>include</filename></entry>
       <entry>Header files included by C programs</entry>
     </row>

     <row>
       <entry><filename>libexec</filename></entry>
       <entry>Binaries run by other programs (optional)</entry>
     </row>

     <row>
       <entry><filename>lib<replaceable>&lt;qual&gt;</replaceable></filename></entry>
       <entry>Alternate Format Libraries (optional)</entry>
     </row>

     <row>
       <entry><filename>src</filename></entry>
       <entry>Source code (optional)</entry>
     </row>

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

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

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

<screen>
    /usr/spool -&gt; /var/spool
    /usr/tmp -&gt; /var/tmp
    /usr/spool/locks -&gt; /var/lock
</screen>

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

</section>

<section id='usrbinMostUserCommands'>
<title>/usr/bin : Most user commands</title>

<section id='purpose20'><title>Purpose</title>

<para>This is the primary directory of executable commands on the
system.</para>

</section>

<section id='requirements9a'><title>Requirements</title>

	<para>There must be no subdirectories in <filename>/usr/bin</filename>.</para>

</section>

<section id='specificOptions11'><title>Specific Options</title>

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

<informaltable frame='none'>
  <tgroup cols='2' align='left'>
    <thead>
       <row><entry>Command</entry><entry>Description</entry></row>
    </thead>
    <tbody>
      <row>
        <entry><command>perl</command></entry>
        <entry>The Practical Extraction and Report Language (optional)</entry>
      </row>
      <row>
        <entry><command>python</command></entry>
        <entry>The Python interpreted language (optional)</entry>
      </row>
      <row>
        <entry><command>tclsh</command></entry>
        <entry>Simple shell containing Tcl interpreter (optional)</entry>
      </row>
      <row>
        <entry><command>wish</command></entry>
        <entry>Simple Tcl/Tk windowing shell (optional)</entry>
      </row>
      <row>
        <entry><command>expect</command></entry>
        <entry>Program for interactive dialog (optional)</entry>
      </row>
    </tbody>
  </tgroup>
</informaltable>


<tip><title>Rationale</title>

<para>In many executable scripts, the interpreter to be invoked to
execute the script is specified using 
<filename>#!<replaceable>path_to_interpreter</replaceable></filename> 
on the first line of a script. 
To make such scripts portable among different systems,
it is advantageous to standardize the interpreter locations.
The shell interpreter is already
fixed in <filename>/bin</filename> by this specification, 
but interpreters for Perl, Python, Tcl and expect may be installed
in various places.  The locations specified here may be implemented
as symbolic links to the physical location of the interpreters.
</para>

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

<section id='usrincludeDirectoryForStandardInclu'>
<title>/usr/include : Directory for standard include files.</title>

<section id='purpose21'><title>Purpose</title>

<para>This is where all of the system's general-use include files for the C
programming language should be placed.</para>

</section>

<section id='specificOptions12'><title>Specific Options</title>

<para>The following directories, or symbolic links to directories,
must be in <filename>/usr/include</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>bsd</entry>
       <entry>BSD compatibility include files (optional)</entry>
     </row>

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

</section>
</section>

<section id='usrlibLibrariesForProgrammingAndPa'>
<title>/usr/lib : Libraries for programming and packages</title>

<section id='purpose22'><title>Purpose</title>

<para><filename>/usr/lib</filename> includes object files and libraries.
<footnote><para> Miscellaneous
architecture-independent application-specific static files and
subdirectories must be placed in <filename>/usr/share</filename>.
</para></footnote>
On some systems, it may also include internal binaries that are not
intended to be executed directly by users or shell scripts.
<footnote><para>See below, in the <filename>/usr/libexec</filename>
section, for a discussion of <filename>/usr/lib</filename>
vs. <filename>/usr/libexec</filename> for executable binaries.
</para></footnote>
</para>

<para>Applications may use a single subdirectory under
<filename>/usr/lib</filename>.  If an application uses a subdirectory,
all architecture-dependent data exclusively used by the application
must be placed within that subdirectory.  

<footnote>
<para> For example, the <filename>perl5</filename> subdirectory for
Perl 5 modules and libraries.</para>  </footnote></para>

</section>

<section id='specificOptions13'><title>Specific Options</title>

<para>For historical reasons, <command>/usr/lib/sendmail</command>
must be a symbolic link which resolves to the
<emphasis>sendmail</emphasis>-compatible command provided by the
system's mail transfer agent, if the latter exists.

<footnote>
<para>
Some executable commands such as <command>makewhatis</command> and
<command>sendmail</command> have also been traditionally placed in
<filename>/usr/lib</filename>.  <command>makewhatis</command> is an
internal binary and must be placed in a binary directory; users access
only <command>catman</command>.  Newer <command>sendmail</command>
binaries are now placed by default in <filename>/usr/sbin</filename>.
Additionally, systems using a <emphasis>sendmail</emphasis>-compatible
mail transfer agent must provide <command>/usr/sbin/sendmail</command>
as the <command>sendmail</command> command, either as the executable
itself or as a symlink to the appropriate executable. </para>
</footnote>

<footnote>
<para>
Host-specific data for the X Window System must not be stored in
<filename>/usr/lib/X11</filename>.  Host-specific configuration files
such as <filename>xorg.conf</filename> must be stored in
<filename>/etc/X11</filename>.  This includes configuration data such
as <filename>system.twmrc</filename> even if it is only made a
symbolic link to a more global configuration file (probably in
<filename>/usr/lib/X11</filename>).
</para>
</footnote></para>

</section>
</section>

<section id='usrlibexec'>
<title>/usr/libexec : Binaries run by other programs (optional)</title>

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

<para><filename>/usr/libexec</filename> includes internal binaries
that are not intended to be executed directly by users or shell
scripts.  Applications may use a single subdirectory under
<filename>/usr/libexec</filename>.</para>

<para>Applications which use <filename>/usr/libexec</filename> in this
way must not also use <filename>/usr/lib</filename> to store internal
binaries, though they may use <filename>/usr/lib</filename> for the
other purposes documented here.</para>

<tip><title>Rationale</title>

<para>Some previous versions of this document did not support
<filename>/usr/libexec</filename>, despite it being standard practice
in a number of environments.
<footnote>
<para>See, for example, the "GNU Coding Standards" from
the Free Software Foundation.</para>
</footnote>
To accomodate this restriction, it became common practice to use
<filename>/usr/lib</filename> instead.  Either practice is now
acceptable, but each application must choose one way or the other to
organize itself.
</para>

</tip>

</section>
</section>

<section id='usrlibltqualgtAlternateFormatLibrari'>
<title>/usr/lib<replaceable>&lt;qual&gt;</replaceable> : Alternate format libraries (optional)</title>

<section id='purpose23'><title>Purpose</title>

<para><filename>/usr/lib<replaceable>&lt;qual&gt;</replaceable></filename> performs the same role as <filename>/usr/lib</filename> for an
alternate binary format, except that the symbolic links
<filename>/usr/lib<replaceable>&lt;qual&gt;</replaceable>/sendmail</filename> and <filename>/usr/lib<replaceable>&lt;qual&gt;</replaceable>/X11</filename> are not required.

<footnote>
<para>
The case where <filename>/usr/lib</filename> and <filename>/usr/lib<replaceable>&lt;qual&gt;</replaceable></filename> are the
same (one is a symbolic link to the other) these files and the
per-application subdirectories will exist.
</para>
</footnote></para>

</section>
</section>

<section id='usrlocalLocalHierarchy'>
<title>/usr/local : Local hierarchy</title>

<section id='purpose24'><title>Purpose</title>

<para>The <filename>/usr/local</filename> 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 <filename>/usr</filename>.</para>

<para>Locally installed software must be placed within
<filename>/usr/local</filename> rather than <filename>/usr</filename>
unless it is being installed to replace or upgrade software in
<filename>/usr</filename>.

<footnote>
<para>
Software placed in <filename>/</filename> or
<filename>/usr</filename> may be overwritten by system upgrades
(though we recommend that distributions do not overwrite data in
<filename>/etc</filename> under these circumstances).  For this
reason, local software must not be placed outside of
<filename>/usr/local</filename> without good reason.
</para>
</footnote>
</para>

</section>

<section id='requirements10'><title>Requirements</title>

<para>The following directories, or symbolic links to directories,
must be in <filename>/usr/local</filename></para>

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

  <tbody>

     <row>
       <entry><filename>bin</filename></entry>
       <entry>Local binaries</entry>
     </row>


     <row>
       <entry><filename>etc</filename></entry>
       <entry>Host-specific system configuration for local binaries</entry>
     </row>

     <row>
       <entry><filename>games</filename></entry>
       <entry>Local game binaries</entry>
     </row>


     <row>
       <entry><filename>include</filename></entry>
       <entry>Local C header files</entry>
     </row>


     <row>
       <entry><filename>lib</filename></entry>
       <entry>Local libraries</entry>
     </row>


     <row>
       <entry><filename>man</filename></entry>
       <entry>Local online manuals</entry>
     </row>


     <row>
       <entry><filename>sbin</filename></entry>
       <entry>Local system binaries</entry>
     </row>


     <row>
       <entry><filename>share</filename></entry>
       <entry>Local architecture-independent hierarchy</entry>
     </row>


     <row>
       <entry><filename>src</filename></entry>
       <entry>Local source code</entry>
     </row>

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

<para>No other directories, except those listed below, may be in
<filename>/usr/local</filename> after first installing a FHS-compliant
system.</para>

</section>

<section id='specificOptions14'><title>Specific Options</title>

<para>If directories <filename>/lib<replaceable>&lt;qual&gt;</replaceable></filename> or
<filename>/usr/lib<replaceable>&lt;qual&gt;</replaceable></filename> exist, the equivalent
directories must also exist in <filename>/usr/local</filename>.</para>

<para><filename>/usr/local/etc</filename> may be a symbolic link to
<filename>/etc/local</filename>.</para>

<tip><title>Rationale</title>

<para>The consistency of <filename>/usr/local/etc</filename> is
beneficial to installers, and is already used in other systems.  As
all of <filename>/usr/local</filename> needs to be backed up to
reproduce a system, it introduces no additional maintenance overhead,
but a symlink to <filename>/etc/local</filename> is suitable if
systems want all their configuration under one hierarchy.
</para>
<para>
Note that <filename>/usr/etc</filename> is still not allowed: programs
in <filename>/usr</filename> should place configuration files in
<filename>/etc</filename>.
</para>

</tip>

<para>If the directory <filename>/usr/share/color</filename> exists as
specified in this document, then the directory
<filename>/usr/local/share/color</filename> must also exist, governed
by the same rules as <filename>/usr/share/color</filename>.</para>

<tip><title>Rationale</title>

<para>This usage allows the sysadmin a place to install color profiles
manually when necessary.</para>

</tip>
</section>

<section id='usrlocalshare1'><title>/usr/local/share : Local architecture-independent hierarchy</title>

<para>The requirements for the contents of this directory are the same
as for <filename>/usr/share</filename>.  
<!-- dropped per bug 798
The only additional constraint is
that <filename>/usr/local/share/man</filename> and
<filename>/usr/local/man</filename> directories must be synonomous
(usually this means that one of them must be a symbolic link).
-->

<!-- bug 798: this note removed; deprecation note added for /usr/local/man
<footnote>
<para>
<filename>/usr/local/man</filename> may be deprecated in future FHS
releases, so if all else is equal, making that one a symlink seems
sensible.
</para>
</footnote>
-->
</para>
</section>

</section>

<section id='usrsbinNonessentialStandardSystemBi'>
<title>/usr/sbin : Non-essential standard system binaries</title>

<section id='purpose25'><title>Purpose</title>

<para>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 <filename>/usr</filename>, or other essential functions must
be placed in <filename>/sbin</filename> instead.

<footnote>
<para>
Locally installed system administration programs should be placed in
<filename>/usr/local/sbin</filename>.
</para>
</footnote></para>
</section>

<section id='requirements10a'><title>Requirements</title>

	<para>There must be no subdirectories in <filename>/usr/sbin</filename>.</para>

</section>

</section>

<section id='usrshareArchitectureindependentData'>
<title>/usr/share : Architecture-independent data</title>

<section id='purpose26'><title>Purpose</title>

<para>The <filename>/usr/share</filename> hierarchy is for all
read-only architecture independent data files.

<footnote>
<para>
Much of this data originally lived in <filename>/usr</filename>
(<filename>man</filename>, <filename>doc</filename>) or
<filename>/usr/lib</filename> (<filename>dict</filename>,
<filename>terminfo</filename>, <filename>zoneinfo</filename>).
</para>
</footnote>

</para>

<para>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
<filename>/usr/share</filename> directory that is centrally-mounted.
Note, however, that <filename>/usr/share</filename> is generally not
intended to be shared by different OSes or by different releases of
the same OS.</para>

<para>Any program or package which contains or requires data that
doesn't need to be modified should store that data in
<filename>/usr/share</filename> (or
<filename>/usr/local/share</filename>, if installed locally).  It is
recommended that a subdirectory be used in
<filename>/usr/share</filename> for this purpose. Applications using
a single file may use <filename>/usr/share/misc</filename>.</para>

<para>Game data stored in <filename>/usr/share/games</filename> must
be purely static data.  Any modifiable files, such as score files,
game play logs, and so forth, should be placed in
<filename>/var/games</filename>.</para>

</section>

<section id='requirements11'><title>Requirements</title>

<para>The following directories, or symbolic links to directories,
must be in <filename>/usr/share</filename></para>

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

  <tbody>

     <row>
       <entry><filename>man</filename></entry>
       <entry>Online manuals</entry>
     </row>

     <row>
       <entry><filename>misc</filename></entry>
       <entry>Miscellaneous architecture-independent data</entry>
     </row>

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


</section>

<section id='specificOptions15'><title>Specific Options</title>
<para>The following directories, or symbolic links to directories, must be in <filename>/usr/share</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>color</filename></entry>
       <entry>Color management information (optional)</entry>
     </row>

     <row>
       <entry><filename>dict</filename></entry>
       <entry>Word lists (optional)</entry>
     </row>

     <row>
       <entry><filename>doc</filename></entry>
       <entry>Miscellaneous documentation (optional)</entry>
     </row>

     <row>
       <entry><filename>games</filename></entry>
       <entry>Static data files for /usr/games (optional)</entry>
     </row>

     <row>
       <entry><filename>info</filename></entry>
       <entry>Primary directory for GNU Info system (optional)</entry>
     </row>

     <row>
       <entry><filename>locale</filename></entry>
       <entry>Locale information (optional)</entry>
     </row>

     <row>
       <entry><filename>nls</filename></entry>
       <entry>Message catalogs for Native language support (optional)</entry>
     </row>

     <row>
       <entry><filename>ppd</filename></entry>
       <entry>Printer definitions (optional)</entry>
     </row>

     <row>
       <entry><filename>sgml</filename></entry>
       <entry>SGML data (optional)</entry>
     </row>

     <row>
       <entry><filename>terminfo</filename></entry>
       <entry>Directories for terminfo database (optional)</entry>
     </row>

     <row>
       <entry><filename>tmac</filename></entry>
       <entry>troff macros not distributed with groff (optional)</entry>
     </row>
     <row>
       <entry><filename>xml</filename></entry>
       <entry>XML data (optional)</entry>
     </row>
     <row>
       <entry><filename>zoneinfo</filename></entry>
       <entry>Timezone information and configuration (optional)</entry>
     </row>

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


<para>It is recommended that application-specific,
architecture-independent directories be placed here.  Such directories
include <command>groff</command>, <command>perl</command>,
<command>ghostscript</command>, <command>texmf</command>, and
<command>kbd</command> (Linux) or <command>syscons</command>
(BSD).  They may, however, be placed in <filename>/usr/lib</filename>
for backwards compatibility, at the distributor's discretion.
Similarly, a <filename>/usr/lib/games</filename> hierarchy may be used
in addition to the <filename>/usr/share/games</filename> hierarchy if
the distributor wishes to place some game data there.</para>

</section>

<section id='usrsharecolorColorManagement'>
<title>/usr/share/color : Color management information (optional)</title>

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

<para>This directory is the home for ICC color management files
installed by the system.</para>

</section>

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

<para>The following directories must be in
<filename>/usr/share/color</filename>, if the corresponding subsystem
is installed:</para>

<informaltable pgwide='0' frame='none'>
  <tgroup cols='2' align='left'>
    <thead>
      <row>
        <entry><filename>Directory</filename></entry>
        <entry>Description</entry>
      </row>
    </thead>
    <tbody>
      <row>
        <entry><filename>icc</filename></entry>
        <entry>ICC color profiles (optional)</entry>
      </row>
    </tbody>
  </tgroup>
</informaltable>

<para>The top-level directory <filename>/usr/share/color</filename>
must not contain any files; all files should be in subdirectories of
<filename>/usr/share/color</filename>.</para>

</section>
</section>

<section id='usrsharedictWordLists'>
<title>/usr/share/dict : Word lists (optional)</title>

<section id='purpose27'><title>Purpose</title>

<para>This directory is the home for word lists on the system;
Traditionally this directory contains only the English
<filename>words</filename> file, which is used by
<command>look(1)</command> and various spelling programs.
<filename>words</filename> may use either American or British
spelling.</para>


<tip><title>Rationale</title>

<para>The reason that only word lists are located here is that they
are the only files common to all spell checkers.</para>

</tip>
</section>

<section id='specificOptions16'><title>Specific Options</title>

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


<informaltable pgwide='0' frame='none'>
  <tgroup cols='2' align='left'>
    <thead>
      <row>
        <entry><filename>File</filename></entry>
        <entry>Description</entry>
      </row>
    </thead>
    <tbody>
      <row>
        <entry><filename>words</filename></entry>
        <entry>List of English words (optional)</entry>
      </row>
    </tbody>
  </tgroup>
</informaltable>


<para>Sites that require both American and British spelling may link
<filename>words</filename> to
<filename>&shy;/usr/share/dict/american-english</filename> or
<filename>&shy;/usr/share/dict/british-english</filename>.</para>

<para>Word lists for other languages may be added using the English
name for that language, e.g.,
<filename>/usr/share/dict/french</filename>,
<filename>/usr/share/dict/danish</filename>, etc.  These should, if
possible, use a character set based on Unicode, with the UTF-8
character set being the preferred option.</para>

<para>Other word lists must be included here, if present.</para>

</section>
</section>

<section id='usrsharemanManualPages'>
<title>/usr/share/man : Manual pages</title>


<section id='purpose28'><title>Purpose</title>

<para>This section details the organization for manual pages
throughout the system, including <filename>/usr/share/man</filename>.
Also refer to the section on
<filename>/var/cache/man</filename>.</para>

<para>The primary <filename>&lt;mandir&gt;</filename> of the system is
<filename>/usr/share/man</filename>.
<filename>/usr/share/man</filename> contains manual information for
commands and data under the <filename>/</filename> and
<filename>/usr</filename> filesystems.

<footnote>
<para>Obviously, there are no manual pages in <filename>/</filename>
because they are not required at boot time nor are they required in
emergencies. Really.</para></footnote></para> 

<para>Manual pages are stored in
<filename>&lt;mandir&gt;/&lt;locale&gt;/man&lt;section&gt;/&lt;arch&gt;</filename>.
An explanation of <filename>&lt;mandir&gt;</filename>,
<filename>&lt;locale&gt;</filename>,
<filename>&lt;section&gt;</filename>, and
<filename>&lt;arch&gt;</filename> is given below.</para>

<para>A description of each section follows:</para>
<itemizedlist spacing="normal" mark="bullet">
<listitem>
<para><filename>man1</filename>: User programs
<!-- .br -->
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.</para>
</listitem>
<listitem>
<para><filename>man2</filename>: System calls
<!-- .br -->
This section describes all of the system calls (requests for the
kernel to perform operations).</para>
<!--  delete parenthesized remark?  assume technical background? -->
</listitem>
<listitem>
<para><filename>man3</filename>: Library functions and subroutines
<!-- .br -->
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.</para>
</listitem>
<listitem>
<para><filename>man4</filename>: Special files
<!-- .br -->
Section 4 describes the special files, related driver functions, and
networking support available in the system.  Typically, this includes
the device files found in <filename>/dev</filename> and the kernel interface to
networking protocol support.</para>
</listitem>
<listitem>
<para><filename>man5</filename>: File formats
<!-- .br -->
The formats for many data files are documented in the
section 5.  This includes various include files, program output files,
and system files.</para>
</listitem>
<listitem>
<para><filename>man6</filename>: Games
<!-- .br -->
This chapter documents games, demos, and generally trivial programs.
Different people have various notions about how essential this is.</para>
</listitem>
<listitem>
<para><filename>man7</filename>: Miscellaneous
<!-- .br -->
Manual pages that are difficult to classify are designated as being
section 7.  The troff and other text processing macro packages are found
here.</para>
</listitem>
<listitem>
<para><filename>man8</filename>: System administration
<!-- .br -->
Programs used by system administrators for system operation and
maintenance are documented here.  Some of these programs are also
occasionally useful for normal users.</para>
</listitem>
</itemizedlist>
</section>

<section id='specificOptions17'><title>Specific Options</title>

<para>The following directories, or symbolic links to directories,
must be in
<filename>/usr/share/&lt;mandir&gt;/&lt;locale&gt;</filename>, unless
they are empty:

<footnote><para>For example, if <filename>/usr/share/man</filename>
has no manual pages in section 4 (Devices), then
<filename>/usr/share/man/man4</filename> may be omitted.</para>
</footnote></para>

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

  <tbody>

     <row>
       <entry><filename>man1</filename></entry>
       <entry>User programs (optional)</entry>
     </row>

     <row>
       <entry><filename>man2</filename></entry>
       <entry>System calls (optional)</entry>
     </row>

     <row>
       <entry><filename>man3</filename></entry>
       <entry>Library calls (optional)</entry>
     </row>

     <row>
       <entry><filename>man4</filename></entry>
       <entry>Special files (optional)</entry>
     </row>

     <row>
       <entry><filename>man5</filename></entry>
       <entry>File formats (optional)</entry>
     </row>

     <row>
       <entry><filename>man6</filename></entry>
       <entry>Games (optional)</entry>
     </row>

     <row>
       <entry><filename>man7</filename></entry>
       <entry>Miscellaneous (optional)</entry>
     </row>

     <row>
       <entry><filename>man8</filename></entry>
       <entry>System administration (optional)</entry>
     </row>

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



<para>The component <filename>&lt;section&gt;</filename> describes the
manual section.</para>

<para>Provisions must be made in the structure of
<filename>/usr/share/man</filename> 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.</para>

<para>This naming of language subdirectories of
<filename>/usr/share/man</filename> 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 <filename>&lt;locale&gt;</filename> string
is:</para>

<para><filename>&lt;language&gt;[_&lt;territory&gt;][.&lt;character-set&gt;][,&lt;version&gt;]</filename></para>

<para>The <filename>&lt;language&gt;</filename> 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.</para>

<para>The <filename>&lt;territory&gt;</filename> 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.
<footnote><para> A major exception to this rule is the
United Kingdom, which is `GB' in the ISO 3166, but `UK' for most email
addresses.</para>  </footnote></para>

<para>The <filename>&lt;character-set&gt;</filename> field must
represent the standard describing the character set.  If the
<filename>&shy;&lt;character-set&gt;</filename> 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.</para>

<para>A parameter specifying a <filename>&lt;version&gt;</filename> of
the profile may be placed after the
<filename>&shy;&lt;character-set&gt;</filename> 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
<filename>&lt;version&gt;</filename> field, unless it is
necessary.</para>

<para>Systems which use a unique language and code set for all manual
pages may omit the <filename>&lt;locale&gt;</filename> substring and
store all manual pages in <filename>&lt;mandir&gt;</filename>.  For
example, systems which only have English manual pages coded with
ASCII, may store manual pages (the
<filename>man&lt;section&gt;</filename> directories) directly in
<filename>/usr/share/man</filename>.  (That is the traditional
circumstance and arrangement, in fact.)</para>

<para>Countries for which there is a well-accepted standard character
code set may omit the <filename>&shy;&lt;character-set&gt;</filename>
field, but it is strongly recommended that it be included, especially
for countries with several competing standards.</para>

<para>Various examples:</para>


<informaltable pgwide='0' frame='none'>
  <tgroup cols='4' align='center'>
    <colspec colname='c1'/>
    <colspec colname='c2'/>
    <colspec colname='c3'/>
    <colspec colname='c4'/>
    <thead>
      <row rowsep='1'>
        <entry align='left'>Language</entry>
        <entry align='left'>Territory</entry>
        <entry align='left'>Character Set</entry>
        <entry align='left'>Directory</entry>
      </row>
    </thead>
    <tbody>
      <row>
        <entry align='left'>English</entry>
        <entry align='left'>&mdash;</entry>
        <entry align='left'>ASCII</entry>
        <entry align='left'>/usr/share/man/en</entry>
      </row>
      <row>
        <entry align='left'>English</entry>
        <entry align='left'>United Kingdom</entry>
        <entry align='left'>Unicode UTF-8</entry>
        <entry align='left'>/usr/share/man/en_GB.10646</entry>
      </row>
      <row>
        <entry align='left'>English</entry>
        <entry align='left'>United States</entry>
        <entry align='left'>ASCII</entry>
        <entry align='left'>/usr/share/man/en_US</entry>
      </row>
      <row>
        <entry align='left'>French</entry>
        <entry align='left'>Canada</entry>
        <entry align='left'>ISO 8859-1</entry>
        <entry align='left'>/usr/share/man/fr_CA.88591</entry>
      </row>
      <row>
        <entry align='left'>French</entry>
        <entry align='left'>France</entry>
        <entry align='left'>ISO 8859-1</entry>
        <entry align='left'>/usr/share/man/fr_FR.88591</entry>
      </row>
      <row>
        <entry align='left'>German</entry>
        <entry align='left'>Germany</entry>
        <entry align='left'>ISO 646</entry>
        <entry align='left'>/usr/share/man/de_DE.646</entry>
      </row>
      <row>
        <entry align='left'>German</entry>
        <entry align='left'>Germany</entry>
        <entry align='left'>ISO 6937</entry>
        <entry align='left'>/usr/share/man/de_DE.6937</entry>
      </row>
      <row>
        <entry align='left'>German</entry>
        <entry align='left'>Germany</entry>
        <entry align='left'>ISO 8859-1</entry>
        <entry align='left'>/usr/share/man/de_DE.88591</entry>
      </row>
      <row>
        <entry align='left'>German</entry>
        <entry align='left'>Switzerland</entry>
        <entry align='left'>ISO 646</entry>
        <entry align='left'>/usr/share/man/de_CH.646</entry>
      </row>
      <row>
        <entry align='left'>Japanese</entry>
        <entry align='left'>Japan</entry>
        <entry align='left'>JIS</entry>
        <entry align='left'>/usr/share/man/ja_JP.jis</entry>
      </row>
      <row>
        <entry align='left'>Japanese</entry>
        <entry align='left'>Japan</entry>
        <entry align='left'>SJIS</entry>
        <entry align='left'>/usr/share/man/ja_JP.sjis</entry>
      </row>
      <row>
        <entry align='left'>Japanese</entry>
        <entry align='left'>Japan</entry>
        <entry align='left'>UJIS (or EUC-J)</entry>
        <entry align='left'>/usr/share/man/ja_JP.ujis</entry>
      </row>
      <row>
        <entry align='left'>Japanese</entry>
        <entry align='left'>Japan</entry>
        <entry align='left'>Unicode UTF-16</entry>
        <entry align='left'>/usr/share/man/ja_JP.10646</entry>
      </row>
    </tbody>
  </tgroup>
</informaltable>


<para>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 <filename>&lt;arch&gt;</filename> directory in the appropriate
<filename>man&lt;section&gt;</filename> directory; for example, a man
page for the i386 ctrlaltdel(8) command might be placed in
<filename>/usr/share/man/&lt;locale&gt;/man8/i386/ctrlaltdel.8</filename>.
</para>

<para>Manual pages for commands and data under
<filename>/usr/local</filename> are stored in
<filename>/usr/local/man</filename> or
<filename>/usr/local/share/man</filename>.
All manual page hierarchies in the system must have the same structure as
<filename>/usr/share/man</filename>, as this structure is expected
by commands which consume manual page content.
<footnote>
<para>
<filename>/usr/local/man</filename> is deprecated and may be
dropped in a future version of this specification.
</para>
</footnote>
</para>

<para>The cat page sections (<filename>cat&lt;section&gt;</filename>)
containing formatted manual page entries are also found within
subdirectories of <filename>&lt;mandir&gt;/&lt;locale&gt;</filename>,
but are not required nor may they be distributed in lieu of nroff
source manual pages.</para>

<para>The numbered sections "1" through "8" are traditionally defined.
In general, the file name for manual pages located within a particular
section end with <filename>.&lt;section&gt;</filename>.</para>

<para>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
<filename>mh</filename> appended to all MH manuals.  All X Window
System manual pages must have an <filename>x</filename> appended to
the filename.</para>

<para>The practice of placing various language manual pages in
appropriate subdirectories of <filename>/usr/share/man</filename> also
applies to the other manual page hierarchies, such as
<filename>/usr/local/man</filename>.  (This portion of the standard
also applies later in the section on the optional
<filename>/var/cache/man</filename> structure.)</para>

</section>
</section>

<section id='usrsharemiscMiscellaneousArchitecture'>
<title>/usr/share/misc : Miscellaneous architecture-independent data</title>

<para>This directory contains miscellaneous architecture-independent
files which don't require a separate subdirectory under
<filename>/usr/share</filename>.</para>

<section id='specificOptions18'><title>Specific Options</title>

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

<informaltable pgwide='0' frame='none'>
  <tgroup cols='2' align='left'>
    <colspec colname='c1'/>
    <colspec colname='c2'/>
    <thead>
     <row>
       <entry>File</entry>
       <entry>Description</entry>
     </row>
    </thead>
    <tbody>
      <row>
        <entry><filename>ascii</filename></entry>
        <entry>ASCII character set table (optional)</entry>
      </row>
      <row>
        <entry><filename>termcap</filename></entry>
        <entry>Terminal capability database (optional)</entry>
      </row>
      <row>
        <entry><filename>termcap.db</filename></entry>
        <entry>Terminal capability database (optional)</entry>
      </row>
    </tbody>
  </tgroup>
</informaltable>

<para>Other (application-specific) files may appear here, but a distributor
may place them in <filename>/usr/lib</filename> at their discretion.
<footnote><para>
Some such files include:

<filename>airport</filename>, <filename>birthtoken</filename>,
<filename>eqnchar</filename>, <filename>getopt</filename>,
<filename>gprof.callg</filename>, <filename>gprof.flat</filename>,
<filename>inter.phone</filename>, <filename>ipfw.samp.filters</filename>,
<filename>ipfw.samp.scripts</filename>, <filename>keycap.pcvt</filename>,
<filename>mail.help</filename>, <filename>mail.tildehelp</filename>,
<filename>man.template</filename>, <filename>map3270</filename>,
<filename>mdoc.template</filename>, <filename>more.help</filename>,
<filename>na.phone</filename>, <filename>nslookup.help</filename>,
<filename>operator</filename>, <filename>scsi_modes</filename>,
<filename>sendmail.hf</filename>, <filename>style</filename>,
<filename>units.lib</filename>, <filename>vgrindefs</filename>,
<filename>vgrindefs.db</filename>, <filename>zipcodes</filename>.

</para>
</footnote>
<footnote><para>
Historically, the <filename>magic</filename> file was placed in
<filename>/usr/share/misc</filename>, but modern variants of the file
command use several files and place them in
<filename>/usr/share/file</filename>. For compatibility,
distribution may create a symlink at
<filename>/usr/share/misc/magic</filename>, pointing to
<filename>/usr/share/file/magic</filename>.
</para>
</footnote>
</para>

</section>
</section>

<section id='usrshareppd'>
<title>/usr/share/ppd : Printer definitions (optional)</title>

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

<para><filename>/usr/share/ppd</filename> contains PostScript Printer
Definition (PPD) files, which are used as descriptions of printer
drivers by many print systems.  PPD files may be placed in this
directory, or in a subdirectory.</para>

</section>
</section>

<section id='usrsharesgmlSgmlAndXmlData'>
<title>/usr/share/sgml : SGML data (optional)</title>

<section id='purpose29'><title>Purpose</title>

<para><filename>/usr/share/sgml</filename> contains
architecture-independent files used by SGML applications, such
as ordinary catalogs (not the centralized ones, see
<filename>/etc/sgml</filename>), DTDs, entities, or style
sheets.</para>

</section>

<section id='specificOptions19'><title>Specific Options</title>

<para>The following directories, or symbolic links to directories,
must be in <filename>/usr/share/sgml</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>docbook</filename></entry>
       <entry>docbook DTD (optional)</entry>
     </row>

     <row>
       <entry><filename>tei</filename></entry>
       <entry>tei DTD (optional)</entry>
     </row>

     <row>
       <entry><filename>html</filename></entry>
       <entry>html DTD (optional)</entry>
     </row>

     <row>
       <entry><filename>mathml</filename></entry>
       <entry>mathml DTD (optional)</entry>
     </row>

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


<para>Other files that are not specific to a given DTD may reside in
their own subdirectory.</para>

</section>
</section>

<section>
<title>/usr/share/xml : XML data (optional)</title>

<section><title>Purpose</title>

<para><filename>/usr/share/xml</filename> contains
architecture-independent files used by XML applications, such
as ordinary catalogs (not the centralized ones, see
<filename>/etc/sgml</filename>), DTDs, entities, or style
sheets.</para>

</section>

<section><title>Specific Options</title>

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

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

  <tbody>

     <row>
       <entry><filename>docbook</filename></entry>
       <entry>docbook XML DTD (optional)</entry>
     </row>

     <row>
       <entry><filename>xhtml</filename></entry>
       <entry>XHTML DTD (optional)</entry>
     </row>

<row>
       <entry><filename>mathml</filename></entry>
       <entry>MathML DTD (optional)</entry>
     </row>

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


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

<section id='usrsrcSourceCode'>
<title>/usr/src : Source code (optional)</title>

<section id='purpose30'><title>Purpose</title>

<para>Source code may be placed in this
subdirectory, only for reference purposes.

<footnote><para>
Generally, source should not be built within this hierarchy.
</para></footnote>
</para>
</section>
</section>
</chapter>
