Drush script to delete a subtree of a taxonomy in Drupal 8+

drupal-delete-taxonomy-subtree.php

<?php

/* Root term not deleted */

$exit = 0;
$vid = $extra[0];
if (empty($vid)) {
  $exit = 1;
}
$parent = $extra[1];
if (empty($parent)) {
  $exit = 1;
}
if ($exit) {
  echo "\n\nUsage:./vendor/bin/drush scr scripts/delete-taxonomy-subtree.php -- <vid> <parent_tid>\n\n";
  exit -2;
}

$terms = \Drupal::entityTypeManager()->getStorage('taxonomy_term')->loadTree($vid, $parent, NULL, TRUE);
/** @var \Drupal\taxonomy\Entity\Term $term */
foreach($terms as $term) {
  $label = $term->label();
  echo "Deleting: $label\n";
  $term->delete();
}
echo "Done\n";