从.txt文件中读取数字并在PHP中的foreach循环中打印数字的算法

I have a foreach loop in a PHP code which processes 2000 .txt files from a folder, for example:

    $files = glob('files/*.txt');
foreach($files as $file) {
    $rand = rand(5000,10000); 
    $file_name  = basename($file, ".txt");
    echo $file .$rand. $number. '.txt' ."<br>";
// Number should be read from the number.txt file
}

Assume that there is a number.txt file that $number variable is read from in the above example (each number is in one row, see the below picture). Also, assume that we don’t know whether the total number of rows is greater or smaller than 2000. So my question is how to write an algorithm which satisfies the below conditions:

1. If there are more than 2000 listed numbers in the number.txt file, the code prints any number where none of them is duplicated.

2. If there are less than 2000 numbers in the number.txt file, the code prints all listed numbers at least once where it can print duplicated numbers until the foreach loop ends.

Should get you started:

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

foreach ($files as $file) {
    $lines = file($file);

    if(count($lines) >= 2000) {
        $lines = array_unique($lines);
    }
    foreach($lines as $number) {
        echo $number;
    }
}