title: How to detect the physical connected state of a network cable/connector?
body: <p>In a Linux environment, I need to detect the physical connected or disconnected state of an RJ45 connector to its socket.  Preferably using BASH scripting only.</p>
  
  <p>The following solutions which have been proposed on other sites do NOT work for this purpose:</p>
  
  <ol>
  <li>Using 'ifconfig' - since a network cable may be connected but the network not properly configured or not currently up.</li>
  <li>Ping a host - since the product will be within a LAN using an unknown network configuration and unknown hosts.</li>
  </ol>
  
  <p>Isn't there some state which can be used in the /proc file system (everything else is in there)?</p>
  
  <p>How is the Linux world suppose to have their own version of the Windows bubble that pop up from the icon tray indicating that you've just unplugged the network cable?</p>
  
  <hr>
  
  <p><b>Kent Fredric</b> and <b>lothar</b>, both of your answers satisfy my need... thanks a lot!  Which one I'll use... I still don't know.</p>
  
  <p>I guess I can't put you both down as the correct answer?  And its probably fair for you that I do choose one.  Flip a coin I guess?  Again, thanks!</p>