如何跟踪推荐人？

Currently, I am using this:

<A href="/?id=page_name2&referrer=<?php echo $_GET['id']; ?>">Page Name 2</A>

Which displays the URL like this:

www.domain.com/?id=page_name2&referrer=page_name

I want to store the referring data to a TXT file, which will be in a folder on a server. I do not want to use Google Analytics nor any SQL.

Hmm, you can build a referrers.json file like this:

{
  "page_name": 1,
  "page_name_2": 4,
  "page_name_etc": 9
}

Where 1, 4 and 9 are the times those pages were used as referrers.

Look at this code:

$file = 'referrers.json';

$arr = (is_file($file))
    ? json_decode(file_get_contents($file), true)
    : [];

$referrerId = 'some_page';

if (array_key_exists($referrerId, $arr)) {
    $arr[$referrerId]++;
} else {
    $arr[$referrerId] = 1;
}

file_put_contents($file, json_encode($arr));