Laravel PHP Command Not Found

tl;dr

Run composer install in your project's root folder.

Explanation

This happens when you create a project by downloading and extracting the laravel/laravel repo from GitHub, not by using the Composer command:

composer create-project laravel/laravel your-project-name

In this case the dependencies are not installed, so the vendor folder that contains Artisan doesn't exist. Running composer install in your project's root folder will install the dependencies vendor folder.

For more, see my other answer on how to install Artisan.

Side note

This is independent from your problem but your Artisan command is a bit deficient. You forgot =users (the table name) from the end. Also if you create a table you dont have to specify the table name again with the --table option so this command would be enough:

php artisan migrate:make create_users_table --create=users

You have to gain access over STDERR and, probably, STDOUT. Use proc_open, e.g.:

$desc = [
  1 => ['pipe', 'w'], // STDOUT
  2 => ['pipe', 'w'], // STDERR
];

$proc = proc_open('ls -l . something', $desc, $pipes);
if (is_resource($proc)) {

  if ($out = stream_get_contents($pipes[1])) {
    echo $out;
  }
  fclose($pipes[1]);


  if ($err = stream_get_contents($pipes[2])) {
    fprintf(STDERR, "Error: %sn", $err);
  }
  fclose($pipes[2]);

  // You can also check the process exit status
  // 0 means success, otherwise error.
  $exit_status = proc_close($proc);
}

Of course, there is no need in STDOUT pipe, if the command redirects it to a file.

And yes, system() won't throw exceptions. Obviously, you can implement your own class which will throw an exception in case if the process exit status is non-zero, or there is something caught in the STDERR pipe:

class MyShellException extends Exception {}

class MyShell {
  public static function execute($command, &$out = null) {
    if (func_num_args() > 1) {
      $desc[1] = ['pipe', 'w'];
    } else {
      $desc[1] = ['file', '/dev/null'];
    }

    $desc[2] = ['pipe', 'w'];

    $proc = proc_open($command, $desc, $pipes);
    if (is_resource($proc)) {
      if (isset($pipes[1])) {
        $out = stream_get_contents($pipes[1]);
        fclose($pipes[1]);
      }

      if ($err = stream_get_contents($pipes[2])) {
        fclose($pipes[2]);
        throw new MyShellException("Command $command failed: $err");
      }

      if ($exit_status = proc_close($proc)) {
        throw new MyShellException("Command $command exited with non-zero status");
      }
    }
  }
}


try {
  MyShell::execute('ls -l . something', $out);
  echo "Output: $outn";
} catch (MyShellException $e) {
  if (!empty($out)) {
    echo "Output: $outn";
  }
  fprintf(STDERR, "MyShell error: " . $e->getMessage());
  exit(1);
}