$tmpfile = "/var/tmp/teste";
$fw = fopen($tmpfile,"w");


$fp = fopen("/etc/resolv.conf","r");
$fw = fopen($tmpfile,"w");

while(!feof($fp)) {
		$line_x = fgets($fp);
		if (preg_match($search,$line_x)) {
			$line = preg_replace($search,$replace,$line_x);
		}
		else {
			$line = $line_x;
		}
		fwrite($fw,$line);
	}

.....
root@ubwifidog:/tmp# cat /etc/resolv.conf
nameserver 200.xxxxxxx
nameserver 200.xxxxxxx
domain test.com
root@ubwifidog:/tmp# 

but in /var/tmp/teste

root@ubwifidog:/tmp# cat /var/tmp/teste
nameserver 200.xxxxxxx
nameserver 200.xxxxxxx
domain test.com

root@ubwifidog:/tmp# 


I have blank line, how to solve this ?