For this, You must use hook_entity_delete.
Welcome To Drupal 8
Drupal is a CMS (Content Management System) open-source written in PHP. Drupl 8 is the latest version of Drupal successor of Drupal 7 popular for its security, flexibility and scalability, used on the complex high traffic web applications as well as small showcase sites. Drupal 8 is comes with over 200 new features and improvements including native full responsive support, multilingual support, REST Full web service. Drupal 8 was created in PHP using Symfony 2 Framework and TWIG templating system.
This web site is a set of tutorials help to new Drupal 8 developers and persons who want to be a Drupal 8 developer or a webmaster. The level of the tutorials are start from very basic (beginners) and can be very complex (Experts). I hope the site is useful for you and you are welcome to share your knowledge, ideas and experience. Thank you.
Zip and Unzip Files on Linux (With zip and unzip)
zip file *
zip -r file *
extract a file
unzip file.zip file.doc
$user = User::load($uid);