title: Access denied when trying to access serial port for the second time in Cygwin
body: <p>I am trying to get data from a USB serial port that is connected to an Arduino. I am using Cygwin and I write</p>
  
  <pre><code>cat /dev/ttyS4
  </code></pre>
  
  <p>to output the data in the shell.</p>
  
  <p>When I stop the process, I am given</p>
  
  <blockquote>
    <p>Access Denied </p>
  </blockquote>
  
  <p>when I try to access it again. I have to close Cygwin, open it again and type in the same 
  command to get the output to the shell.</p>
  
  <p>I have noticed that I am able to read the serial port from only one program. For example, if I read the data from the serial port in the Arduino Software, I can't access it in Cygwin.</p>
  
  <p>Is there a way I can access the serial port data as many times as I want in Cygwin without having to have to close the program, open it again and write in the same command?</p>