batch-cli.php

<?php

function batch_cli( $command, $totalPages,$loop ) {
  $state = new \stdClass();
  $state->page = 1;
  $state->totalPages = $totalPages;
  $state->command = $command;
  $createProcess = function($state){
    return new Process(sprintf( "%s --page=%n", $state->command, $state->page );
  };
 $first = $createProcess($state);
 $first->start($loop);

$first->on('exit', function () use ($loop,$state) {
    $state->page = $state->page + 1;
    if( $state->page !== $state->pageTotal ){
      $next = new Process('cat second');
    $next->start($loop);
    }
    
}); 
  
  
$loop = React\EventLoop\Factory::create();
batch_cli('wp something', 17, $loop );

$loop->run();
  
}

https://github.com/reactphp/child-process