If you update a routes file in Drupal 8 how do you clear the cache? Having worked with Drupal 7 since its launch, I'm learning Drupal 8. At the moment I'm finding that whenever I change anything I have to do drush cache-rebuild to get things working again.

On my VPS this takes 15 seconds (and then the next page load also is slow). I have a feeling this may be a sledge hammer to crack a nut situation.

Is there a more efficient way to get Drupal to recompile the (changed) routes from {module}.routing.yml files?
You can use

drush ev '\Drupal::service("router.builder")-&gt;rebuild();'


to rebuild the routing information without clearing all the caches.