svn commit: r39880 - head/en_US.ISO8859-1/articles/rc-scripting

[Eitan Adler]

Author: eadler
Date: Wed Oct 31 21:24:26 2012
New Revision: 39880
URL: http://svn.freebsd.org/changeset/doc/39880

Log:
  Bring the RC article up to date.
  
  PR:		docs/172692
  Submitted by:	crees
  Reviewed by:	Michael Telahun Makonnen <mmakonnen at gmail.com>
  Approved by:	bcr (mentor)

Modified:
  head/en_US.ISO8859-1/articles/rc-scripting/article.xml

Modified: head/en_US.ISO8859-1/articles/rc-scripting/article.xml
==============================================================================
--- head/en_US.ISO8859-1/articles/rc-scripting/article.xml	Wed Oct 31 12:55:35 2012	(r39879)
+++ head/en_US.ISO8859-1/articles/rc-scripting/article.xml	Wed Oct 31 21:24:26 2012	(r39880)
@@ -400,8 +400,8 @@ start_cmd="${name}_start"
 stop_cmd=":"
 
 load_rc_config $name<co id="rcng-confdummy-loadconfig"/>
-eval "${rcvar}=\${${rcvar}:-'NO'}"<co id="rcng-confdummy-enable"/>
-dummy_msg=${dummy_msg:-"Nothing started."}<co id="rcng-confdummy-opt"/>
+: ${dummy_enable:=no} <co id="rcng-confdummy-enable"/>
+: ${dummy_msg="Nothing started."}<co id="rcng-confdummy-opt"/>
 
 dummy_start()
 {
@@ -448,7 +448,7 @@ run_rc_command "$1"</programlisting>
 	  system, you should add a default setting for the knob to
 	  <filename>/etc/defaults/rc.conf</filename> and document
 	  it in &man.rc.conf.5;.  Otherwise it is your script that
-	  should provide a default setting for the knob.  A portable
+	  should provide a default setting for the knob.  The canonical
 	  approach to the latter case is shown in the example.</para>
 
 	<note>
@@ -479,7 +479,7 @@ run_rc_command "$1"</programlisting>
 	<important>
 	  <para>The names of all &man.rc.conf.5; variables used
 	    exclusively by our script <emphasis>must</emphasis>
-	    have the same prefix: <envar>${name}</envar>.  For
+	    have the same prefix: <envar>${name}_</envar>.  For
 	    example: <envar>dummy_mode</envar>,
 	    <envar>dummy_state_file</envar>, and so on.</para>
 	</important>
@@ -487,19 +487,10 @@ run_rc_command "$1"</programlisting>
 	<note>
 	  <para>While it is possible to use a shorter name internally,
 	    e.g., just <envar>msg</envar>, adding the unique prefix
-	    <envar>${name}</envar> to all global names introduced by
+	    <envar>${name}_</envar> to all global names introduced by
 	    our script will save us from possible
 	    collisions with the &man.rc.subr.8; namespace.</para>
 
-	  <para>As long as an &man.rc.conf.5; variable and its
-	    internal equivalent are the same, we can use a more
-	    compact expression to set the default value:</para>
-
-	  <programlisting>: ${dummy_msg:="Nothing started."}</programlisting>
-
-	  <para>The current style is to use the more verbose form
-	    though.</para>
-
 	  <para>As a rule, <filename>rc.d</filename> scripts of the
 	    base system need not provide defaults for their
 	    &man.rc.conf.5; variables because the defaults should
@@ -512,7 +503,11 @@ run_rc_command "$1"</programlisting>
 
       <callout arearefs="rcng-confdummy-msg">
 	<para>Here we use <envar>dummy_msg</envar> to actually
-	  control our script, i.e., to emit a variable message.</para>
+	  control our script, i.e., to emit a variable message.
+	  Use of a shell function is overkill here, since it only
+	  runs a single command; an equally valid alternative is:</para>
+
+	<programlisting>start_cmd="echo \"$dummy_msg\""</programlisting>
       </callout>
     </calloutlist>
   </sect1>