$re = '/(?s)^(?:\s*{{.*?}}|\s*\[\[.*?]])*\n?/';
$str = '{{Ver desambig}}
{{Mais notas||ci|data=janeiro de 2013}}
{{Info/Taxonomia}}
[[Ficheiro:Pêra amarela.JPG|thumbnail|upright]]
A {{AO-pAO|pera|pêra}} é o fruto comestÃvel da pereira, uma [[árvore]] do.';
$subst = "";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php