• http://simonstamm.de/kodierung-utf-8-ohne-bom
• http://www.linuxask.com/questions/how-to-remove-bom-from-utf-8
• http://stackoverflow.com/questions/1068650/using-awk-to-remove-the-byte-order-mark

awk 'NR==1{sub(/^\xef\xbb\xbf/,"")}{print}' text.txt > ohne_BOM.txt

awk '{if(NR==1)sub(/^\xef\xbb\xbf/,"");print}' text.txt > ohne_BOM.txt

sed -i '1 s/^\xEF\xBB\xBF//' text.txt

$str = file_get_contents('utf8_with_bom.php');
$bom = pack("CCC", 0xef, 0xbb, 0xbf);
if (0 == strncmp($str, $bom, 3)) {
    echo "BOM detected - file is UTF-8\n";
    $str = substr($str, 3);
}