title: Inserting particular string into text (bash sed)
body: <p>Hi I am looking for a way to insert , into a text by using sed command.
  I've found a way to do it just once or in like every 5 characters.</p>
  <p>However I have a text (ex containing 10 characters here) I would like to put , after first 2 characters, then 3characters after that. And it continues till the text end.</p>
  <p>So text I have would be like</p>
  <pre><code>abcdefghij
  </code></pre>
  <p>and output I am looking for would be like</p>
  <pre><code>ab,cde,fg,hij,
  </code></pre>
  <p>Is there any way to do this kind of inserting by sed?</p>