title: Linux commandline find and add up numbers
body: <p>In the log file which may contain information of different form, I need to grep only those lines that contain substring "ABC", then among chosen lines extract (it always exists) the number of Kb at the end (pattern is ": %n Kb", where %n is the number from 0 and above). Finally I need to add up all the values to get the amount of memory used by an app.</p>
  
  <pre><code>2016-01-14T16:15:01.695Z [INFO] application - ABC 5f18dda7-a30a-44f5-82dd-69d4b5469245: 118 Kb
  2016-01-14T16:15:04.535Z [INFO] application - 5f18dda7-a30a-44f5-82dd-69d4b5469245
  </code></pre>