title: fetch the number of record from a JSON file using shell
body: <p>I have a test.txt file in this format </p>
  
  <pre><code>{
   "user": "sthapa",
   "ticket": "LIN-5867_3",
   "start_date": "2018-03-16",
   "end_date": "2018-03-16",
   "demo_nos": [692],
   "service_names": [
      "service1",  
      "service2",
      "service3",
      "service4",
      "service5",
      "service6",
      "service7",
      "service8",
      "service9"
  
   ]
  }
  </code></pre>
  
  <p>I need to look for a tag called demo_nos and provide the count of it.
  For example in the above file "demo_nos": [692] which means only one demo nos...similarly if it had "demo_nos": [692,300] then the count would be 2</p>
  
  <p>so what shell script can i write to fetch and print the count?</p>
  
  <p>The output should say the demo nos = 1 or 2 depending on the values inside the tag [].</p>
  
  <p>i.e I have a variable in my shell script called market_nos which should give me it's count</p>