title: Regular Expression to Replace & with &amp;
body: <p>I have a string which have &amp; like the one below.</p>
  
  <pre><code>"This R&amp;M &amp; Exapmle &amp;nbsp;. It is very big &amp; Complicated &amp;146; example."
  </code></pre>
  
  <p>I wants to replace <code>&amp;</code> with <code>&amp;amp;</code> but when I use <code>$str =~ s/&amp;/&amp;amp;/ig;</code> which give the following output.</p>
  
  <pre><code>"This R&amp;amp;M &amp;amp; Company &amp;amp;nbsp;. It is very big &amp;amp; CMM Level3 &amp;amp;146; Organization."
  </code></pre>
  
  <p>And I am expecting this one.</p>
  
  <pre><code>"This R&amp;amp;M &amp;amp; Company &amp;nbsp;. It is very big &amp;amp; CMM Level3 &amp;146; Organization."
  </code></pre>
  
  <p>Please help me I don't have any idea how to fix it.</p>