title: Want to display position of match in string using grep command
body: <p>Please help me with this </p>
  
  <p>example string :</p>
  
  <pre><code>error on port 1:2:4
  </code></pre>
  
  <p>help me with grep command which would display the postion of 1:2:4 in that string considering space as delimeter .</p>
  
  <p>expected result :</p>
  
  <pre><code>4:error on port 1:2:4
  </code></pre>
  
  <p>I have tried grep -b "1:2:4" filename ... but it returns </p>
  
  <pre><code>0:error on port 1:2:4
  </code></pre>