На пхп 3 строчки

$fp = file("file.txt");
$n = 0
$fw = fopen("res.txt", "a+");
while($n<count($fp)
{
list($uin, $fst, $snd) = split(';',$fp[$n]);
fwrite($fw, $uin.";".$fst."\r\n");
$n++;
}
fclose($fw);
}