Avoid "useless use of cat" award by using a real world example.

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@275094 13f79535-47bb-0310-9956-ffa450edef68

docs/faq.html

@@ -673,26 +673,27 @@
       How do I redirect standard input or standard output
         in the <code>&lt;exec&gt;</code> task?
     </p>
-                  <p>Say you want to redirect the standard input stream of the
-        <code>cat</code> command to read from a file, something
+                  <p>Say you want to redirect the standard output stream of the
+        <code>m4</code> command to write to a file, something
         like:</p>
                         <pre class="code">
-shell-prompt&gt; cat &lt; foo
+shell-prompt&gt; m4 foo.m4 &gt; foo
 </pre>
                         <p>and try to translate it into</p>
                         <pre class="code">
-&lt;exec executable=&quot;cat&quot;&gt;
-  &lt;arg value=&quot;&amp;lt;&quot; /&gt;
-  &lt;arg value=&quot;foo&quot; /&gt;
+&lt;exec executable=&quot;m4&quot;&gt;
+  &lt;arg value=&quot;foo.m4&quot;/&gt;
+  &lt;arg value=&quot;&amp;gt;&quot;/&gt;
+  &lt;arg value=&quot;foo&quot;/&gt;
 &lt;/exec&gt;
 </pre>
-                        <p>This will not do what you expect.  The input redirection is
+                        <p>This will not do what you expect.  The output redirection is
         performed by your shell, not the command itself, so this
         should read:</p>
                         <pre class="code">
 &lt;exec executable=&quot;/bin/sh&quot;&gt;
   &lt;arg value=&quot;-c&quot; /&gt;
-  &lt;arg value=&quot;cat &amp;lt; foo&quot; /&gt;
+  &lt;arg value=&quot;m4 foo.m4 &amp;gt; foo&quot; /&gt;
 &lt;/exec&gt;
 </pre>
                         <p>Note that you must use the <code>value</code> attribute of
@@ -701,7 +702,7 @@ shell-prompt&gt; cat &lt; foo
         you can use:</p>
                         <pre class="code">
 &lt;exec executable=&quot;/bin/sh&quot;&gt;
-  &lt;arg line='-c &quot;cat &amp;lt; foo&quot;'/&gt;
+  &lt;arg line='-c &quot;m4 foo.m4 &amp;gt; foo&quot;'/&gt;
 &lt;/exec&gt;
 </pre>
                         <p>Note the double-quotes nested inside the single-quotes.</p>

xdocs/faq.xml

@@ -313,31 +313,32 @@
       <question>How do I redirect standard input or standard output
         in the <code>&lt;exec&gt;</code> task?</question>
       <answer>
-        <p>Say you want to redirect the standard input stream of the
-        <code>cat</code> command to read from a file, something
+        <p>Say you want to redirect the standard output stream of the
+        <code>m4</code> command to write to a file, something
         like:</p>
 
         <source><![CDATA[
-shell-prompt> cat < foo
+shell-prompt> m4 foo.m4 > foo
 ]]></source>
         
         <p>and try to translate it into</p>
 
         <source><![CDATA[
-<exec executable="cat">
-  <arg value="&lt;" />
-  <arg value="foo" />
+<exec executable="m4">
+  <arg value="foo.m4"/>
+  <arg value="&gt;"/>
+  <arg value="foo"/>
 </exec>
 ]]></source>
 
-        <p>This will not do what you expect.  The input redirection is
+        <p>This will not do what you expect.  The output redirection is
         performed by your shell, not the command itself, so this
         should read:</p>
         
         <source><![CDATA[
 <exec executable="/bin/sh">
   <arg value="-c" />
-  <arg value="cat &lt; foo" />
+  <arg value="m4 foo.m4 &gt; foo" />
 </exec>
 ]]></source>
 
@@ -347,7 +348,7 @@ shell-prompt> cat < foo
         you can use:</p>
         <source><![CDATA[
 <exec executable="/bin/sh">
-  <arg line='-c "cat &lt; foo"'/>
+  <arg line='-c "m4 foo.m4 &gt; foo"'/>
 </exec>
 ]]></source>