generate_4_billion_numbers.php

<?php
declare(strict_types=1);
$fp=fopen("4_billion_numbers.txt","xb");
if(!$fp){die("ERROR CREATING FILE");}
$str="";
$chunk_size = 1*1024*1024*1024;
for($i=0;$i<4_000_000_000;++$i){
        // random_int() is a 64bit cryptograpically secure RNG, using https://man7.org/linux/man-pages/man2/getrandom.2.html
        // (aka /dev/urandom )
        $str.=(string)random_int(0,PHP_INT_MAX);
        $str.="\n";
        if(strlen($str)>$chunk_size){
                echo ".";
                $written = fwrite($fp,$str);
                if($written!==strlen($str)){
                        echo "\n";
                        throw new \RuntimeException("tried to write ".strlen($str)." bytes but could only write {$written} bytes");
                }
                $str = "";
        }
}
if(strlen($str)>0){
                        $written = fwrite($fp,$str);
                if($written!==strlen($str)){
                        echo "\n";
                        throw new \RuntimeException("AT THE VERY LAST WRITE, tried to write ".strlen($str)." bytes but could only write {$written} bytes");
                }

}