<sect1 id="using-sub-files">

	<title>Making use of <makevar>SUB_FILES</makevar> and

	  <makevar>SUB_LIST</makevar></title>

	<para>If your port wants to modify some of your files (that means not

	  included in the original distribution) according to some values, you

	  can use <makevar>SUB_FILES</makevar> and <makevar>SUB_LIST</makevar>

	  variables.</para>

	<para><makevar>SUB_FILES</makevar> specifies a list of files to be

	  automatically modified.  Each <replaceable>file</replaceable> in

	  <makevar>SUB_FILES</makevar> must have a corresponding

	  <filename><replaceable>file</replaceable>.in</filename> in

	  <makevar>FILESDIR</makevar>.  If you add some special files

	  (<filename>pkg-message</filename>, <filename>pkg-install</filename>,

	  <filename>pkg-deinstall</filename> or <filename>pkg-reg</filename>),

	  <makevar>PKG-<replaceable>FILE</replaceable></makevar> associated

	  variables will be set to

	  <filename><makevar>WRKDIR</makevar>/pkg-<replaceable>file</replaceable></filename>.</para>

	<para><makevar>SUB_LIST</makevar> is a list of <literal>VAR=VALUE</literal>

	  pairs.  The modified version of each file will be created in

	  <makevar>WRKDIR</makevar>.  For each <literal>VAR=VALUE</literal> in

	  <makevar>SUB_LIST</makevar>, <literal>%%VAR%%</literal> gets replaced

	  by <literal>VALUE</literal> in each file in <makevar>SUB_FILES</makevar>.

	  Some usual pairs are automatically added to <makevar>SUB_LIST</makevar>,

	  so you don't have to worry about them : <literal>PREFIX=&dollar;{PREFIX}

	  DOCSDIR=&dollar;{DOCSDIR}</literal>, etc. (see

	  <filename>bsd.port.mk</filename> for the entire list).</para>

	<para> The substition process is almost the same as with

	  <makevar>PLIST_SUB</makevar>.  Note that any line beginning with

	  <literal>@comment</literal> after variables substitution are deleted from

	  resulting files.</para>

	<para>The following example can be enough for a port wanting to display a

	  custom <filename>pkg-message</filename> (using <literal>%%PREFIX%%</literal>)

	  and to install a rcNG startup script (using

	  <literal>%%RC_SUBR%%</literal>).</para>

	<programlisting>SUB_FILES= pkg-message myport.sh

SUB_LIST= RC_SUBR=${RC_SUBR}

USE_RC_SUBR=  yes</programlisting>

	<para>Note that you must have (in this case) at least

	  <filename>pkg-message.in</filename> and <filename>myport.sh.in</filename>

	  in <makevar>FILESDIR</makevar>.</para>

      </sect1>