Update the man page.

Author: Simon MacMullen

docs/rabbitmqctl.1.xml

@@ -163,20 +163,28 @@
         </varlistentry>
 
         <varlistentry>
-          <term><cmdsynopsis><command>wait</command></cmdsynopsis></term>
+          <term><cmdsynopsis><command>wait</command> <arg choice="req"><replaceable>pid_file</replaceable></arg></cmdsynopsis></term>
           <listitem>
             <para>
               Wait for the RabbitMQ application to start.
             </para>
             <para>
               This command will wait for the RabbitMQ application to
-              start at the node. As long as the Erlang node is up but
-              the RabbitMQ application is down it will wait
-              indefinitely. If the node itself goes down, or takes
-              more than five seconds to come up, it will fail.
+              start at the node. It will wait for the pid file to
+              be created, then for a process with a pid specified in the
+              pid file to start, and then for the RabbitMQ application
+              to start in that process. It will fail if the process
+              terminates without starting the RabbitMQ application.
+            </para>
+            <para>
+              A suitable pid file is created by
+              the <command>rabbitmq-server</command> script. By
+              default this is located in the Mnesia directory. Modify
+              the <command>RABBITMQ_PID_FILE</command> environment
+              variable to change the location.
             </para>
             <para role="example-prefix">For example:</para>
-            <screen role="example">rabbitmqctl wait</screen>
+            <screen role="example">rabbitmqctl wait /var/run/rabbitmq/pid</screen>
             <para role="example">
               This command will return when the RabbitMQ node has
               started up.