Add to losetup example

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@1254 42af7a65-404d-4744-a932-0658087f49c3

Documentation/NuttShell.html

@@ -954,7 +954,10 @@ losetup [-o <offset>] [-r] &lt;dev-path&gt; &lt;file-path&gt;
 <p>
   <b>Synopsis</b>.
    Setup the loop device at &lt;dev-path&gt; to access the file at &lt;file-path&gt; as a block device.
-   Example:
+   In the following example a 256Kb file is created (<code>dd</code>) and <code>losetup</code> is
+   used to make the file accessible as a block device. 
+   A FAT file system is created (<code>mkfatfs</code>) and mounted (<code>mount</code>).
+   Files can then be managed on the loop-mounted file.
 <ul><pre>
 nsh&gt; dd if=/dev/zero of=/tmp/image bs=512 count=512
 nsh&gt; ls -l /tmp
@@ -970,6 +973,13 @@ nsh&gt; ls -l /mnt
 ls -l /mnt
 /mnt:
  drw-rw-rw-       0 example/
+nsh&gt; echo &quot;This is a test&quot; &gt;/mnt/example/atest.txt
+nsh&gt; ls -l /mnt/example
+/mnt/example:
+ -rw-rw-rw-      16 ATEST.TXT
+nsh&gt; cat /mnt/example/atest.txt
+This is a test
+nsh&gt;
 </pre></ul>
 </p>