如何使用php停止将重复值写入文本文件

i have a script that keeps reloading every 2 seconds, i made a code to create a txt file for each user IP and write the user name $name inside it. my problem is that everytime my script reloads it will write the $name of the specific IP again with every reload. the code is

 $ip_file = "ips/".$ip.".txt";

    $logip = fopen($ip_file,"a", 1);

    $name = $name."
";

    fwrite($logip, $name);  

    fclose($logip);

    return;

i need some way to verify if the name is already in the $ip_file and if it's there then not to write it again.

the idea behind this is to check if the same IP is used by more than one $name and then create a function to check all the $ip_file files for more than 1 $name and if so ban the violating $ip

thanks in advance

$ip_file = "ips/".$ip.".txt";
$names = file_get_contents($ip_file); //read names into string
if(false === strpos($names,$name)) { //write name if it's not there already
    file_put_contents($ip_file,"$name
",FILE_APPEND);
}

Is this what you need?

<?php
$ip_file = "ips/".$ip.".txt";
$name = $name."
";

if (file_exists($ip_file)) {

    $valueInFile = file_get_contents($ip_file, true);

    if ($valueInFile == $name) {
       //Do something
    }
} else {
    $logip = fopen($ip_file,"a", 1);
    fwrite($logip, $name);  
    fclose($logip);
}
return;
?>

From: http://php.net/manual/en/function.file-exists.php