title: unix command to search count of 5XX status HTTP requests in the log
body: <p>i need to write a unix command to search count of 5XX status HTTP requests in the log. Log format is like below example : </p>
  
  <pre><code>192.168.0.101 - - [12/Dec/2019:23:15:56 +0900] "GET /index.html HTTP/1.1" 200 - "-" "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:29.0) Gecko/20100101 Firefox/29.0" 
  </code></pre>
  
  <p>any suggestions ? </p>