Insert line in a specfic line in a file : <p>I have a very simple question but I don't find the answer ...</p>

<p>I have a file (data.txt) it contains </p>

<pre><code>A
B
C
D
E
F
</code></pre>

<p>I just want to make function to insert line where I want in this file.</p>

<p>Like : Insert('Bouh', 3)</p>

<p>Render :</p>

<pre><code>A
B
C
D
Bouh
E
F
</code></pre>

<p>Any idea please ?</p>
