How Replace string with php : <p>I need to replace this kind of a string:</p>

<pre><code>https://r2---sn-vgqs7nez.c.docs.google.com/
https://r2---sn-testne4.c.docs.google.com/
https://r5---sn-vfghtgh.c.docs.google.com/
</code></pre>

<p>to this</p>

<pre><code>https://redirector.googlevideo.com/
</code></pre>

<p>using php, help me please</p>
