在多个文本文件中递增计数器

I'm trying to increment a counter in a multiple text file when a user visit my page, but the code I'm working is not working below is the code

$files = glob("counters/visit/*.txt");


foreach($files as $file) {
    $content = file_get_contents($file);


    if(!isset($_SESSION['hasVisited'])){
      $_SESSION['hasVisited']="yes";
      $content++;
      $f = fopen($files, "w");
      fwrite($f, $content);
      fclose($f);
    }
}

First make sure that $contentis an integer by doing the following :

$content = intval(file_get_contents($file));

Then you're using :

$f = fopen($files, "w");

Instead of :

$f = fopen($file, "w");

fopen can't accept an array as parameter

Also as mentioned by @alanlittle, if you want all your files to be incremented, you should think about the moment where you set $_SESSION['hasVisited']="yes"; and put it at the end of the loop.