title: Pass pattern from variable to grep command
body: <p>Hi I need help to know how can we pass the vairble 2015-12-16 08:16: to grep command   </p>
  
  <pre><code>bash-3.2$ Heartbeat=$(date +%Y-%m-%d$'\t'%H:%M:)                            
  bash-3.2$ echo $Heartbeat
  2015-12-16 08:16:
  </code></pre>
  
  <p><code>bash-3.2$ grep $Heartbeat file.txt</code> is not working correct, but 
  <code>grep '2015-12-16 08:16:' file.txt</code> works correctly.</p>
  
  <p>Please help me how can we do this for variable.</p>