title: Bash replace Nth word in a string with a variable
body: <p>I need to find Nth word in a string (space delimited) and replace with a variable.
  In the below example 4th word needs to be replaced with another string.</p>
  
  <pre><code>1 Test 123456 REPLACE_ME 99
  </code></pre>
  
  <p>to </p>
  
  <pre><code>1 Test 123456 $STRING_TO_REPLACE 99
  </code></pre>
  
  <p>I was able to find 4th word using <code>awk '{ print $4}'</code>, but don't know how to replace with another string variable.</p>
  
  <p>Any help will be much appreciated.</p>