#!/usr/bin/perl

use strict;
use warnings;

my $cdata = join('', <DATA>);

while ($cdata =~ s/<!\[CDATA\[(.*?)\]\]>/$1/ms)
{
    print "cdata = $1\n";
}

__DATA__
<?xml version="1.0" encoding="UTF-8" ?> 
<![CDATA[This is the first cdata]]>
<![CDATA[This is the second cdata]]>
<some/>

##</code><code>##

cdata = This is the first cdata
cdata = This is the second cdata