Index: en_US.ISO8859-1/books/porters-handbook/plist/chapter.xml
===================================================================
--- en_US.ISO8859-1/books/porters-handbook/plist/chapter.xml
+++ en_US.ISO8859-1/books/porters-handbook/plist/chapter.xml
@@ -288,6 +288,74 @@
       must be listed as specified in the <link
 	linkend="porting-shlibs">shared libraries</link>
       section.</para>
+
+    <sect2 xml:id="plist-autoplist-regex">
+      <title>Expanding <varname>PLIST_SUB</varname> With Regular
+	Expressions</title>
+
+      <para>Sometime, the replaced strings are too generic and get
+	replaced in paths where they do not make sense.  It often
+	happens with shorter values.</para>
+
+      <para>To address this problem, for each
+	<literal><replaceable>PLACEHOLDER</replaceable>=<replaceable>value</replaceable></literal>,
+	a
+	<literal><replaceable>PLACEHOLDER</replaceable>_regex=<replaceable>regex</replaceable></literal>
+	can be set, with the
+	<literal><replaceable>regex</replaceable></literal> part
+	matching <replaceable>value</replaceable> more
+	precisely.</para>
+
+      <example xml:id="plist-autoplist-regex-ex1">
+	<title>Using PLIST_SUB With Regular Expressions</title>
+
+	<para>For example, <application>Perl</application> ports can
+	  install files in a architecture dependent architecture,
+	  which is currently called <literal>mach</literal>.  It is
+	  generally not a problem but if the port installs a file
+	  whose path contains a word that contains
+	  <literal>mach</literal>, it gets replaced in wrong places.
+	  Given this <filename>Makefile</filename>:</para>
+
+	<programlisting>PORTNAME=	Machine-Build
+PORTVERSION=	1
+CATEGORIES=	devel perl5
+MASTER_SITES=	CPAN
+PKGNAMEPREFIX=	p5-
+
+MAINTAINER=	perl@FreeBSD.org
+COMMENT=	Building machine
+
+USES=		perl5
+USE_PERL5=	configure
+
+PLIST_SUB=	PERL_ARCH=mach</programlisting>
+
+	<para>Runnnig <command>make makeplist</command> will wrongly
+	  generate:</para>
+
+	<programlisting>bin/%%PERL_ARCH%%ine-build
+%%PERL5_MAN1%%/%%PERL_ARCH%%ine-build.1.gz
+%%PERL5_MAN3%%/Machine::Build.3.gz
+%%SITE_PERL%%/Machine/Build.pm
+%%SITE_PERL%%/%%PERL_ARCH%%/Machine/Build/Build.so</programlisting>
+
+	<para>Changing the <varname>PLIST_SUB</varname> line from the
+	  <filename>Makefile</filename> to:</para>
+
+	<programlisting>PLIST_SUB=	PERL_ARCH=mach \
+		PERL_ARCH_regex=\bmach\b</programlisting>
+
+	<para>Now <command>make makeplist</command> will correctly
+	  generate:</para>
+
+	<programlisting>bin/machine-build
+%%PERL5_MAN1%%/machine-build.1.gz
+%%PERL5_MAN3%%/Machine::Build.3.gz
+%%SITE_PERL%%/Machine/Build.pm
+%%SITE_PERL%%/%%PERL_ARCH%%/Machine/Build/Build.so</programlisting>
+      </example>
+    </sect2>
   </sect1>
 
   <sect1 xml:id="plist-keywords">