title: bash script for analyzin file on runtime
body: <p>I want to do a bash script for analyzing a log file for errors. 
  I was looking an efficient way for getting the information as soon as they are written.</p>
  
  <p>Can you suggest me some solutions?</p>
  
  <p>Let's say my script will always running and getting each new line that is written in the log file, particulars events will generate alert or e-mail (that's not a problem).</p>
  
  <p>Thanks!</p>