title: sed replace in-line a specific column number value at a specific line number
body: <p>I have a 5 columns csv file (space separated) like this :</p>
  
  <pre><code>username1 20130310 enabled 20130310 enabled
  username2 20130310 enabled 20130321 disabled
  username3 20130320 disabled 20130321 enabled
  username4 20130310 disabled 20130310 disabled
  </code></pre>
  
  <p>I'am trying to change the value of the 4th column for <code>username4</code>.</p>
  
  <p>My script already gets the line number and the new value to store for <code>username4</code> : so I would like to replace column 4 value with <code>$newValue</code> at line number <code>$lineNumber</code>.</p>
  
  <p>In my sample: </p>
  
  <pre><code>newValue=anything
  lineNumber=4
  </code></pre>
  
  <p>So that it will render:</p>
  
  <pre><code>username1 20130310 enabled 20130310 enabled
  username2 20130310 enabled 20130321 disabled
  username3 20130320 disabled 20130321 enabled
  username4 20130310 disabled anything disabled
  </code></pre>
  
  <p>I plan to use <code>sed</code> instead of <code>awk</code> because with <code>sed</code> we can do in-line changes with <code>-i</code></p>