title: How to check sd card file system
body: <p>I try to run file system check on my sd card.
  I opened adb shell and run the following command:</p>
  
  <pre><code>/system/bin $ fsck_msdos -f /mnt/extSdCard
  </code></pre>
  
  <p>I get the following error:</p>
  
  <pre><code>** /mnt/extSdCard (NO WRITE)
  Invalid signature in boot block: 00002|shell@android:/system/bin 
  </code></pre>
  
  <p>I use Cyanogen mod 10.1 on Galaxy S2.</p>
  
  <p>Any ideas?</p>