Dump Drupal nodes as YML

dump.php

<?php

// Download to Drupal root (where index.php is) and run "drush scr dump.php"

$storage = \Drupal::entityTypeManager()->getStorage('node');

$nodes = $storage->loadMultiple();

echo 'Processing ' . count($nodes) . ' nodes...' . "\n";

/** @var Drupal\node\Entity\Node $node */
foreach ($nodes as $node) {
  $path = 'node_dump/' . ltrim(urldecode($node->url()), '/') . '.yml';
  file_prepare_directory(dirname($path), FILE_CREATE_DIRECTORY);
  echo "Saving node " . $node->id() . " to $path\n";
  file_put_contents($path, \Drupal\Core\Serialization\Yaml::encode($node->toArray()));
}

echo "Done!\n";