# enable site
sudo a2ensite
# disable site
sudo a2dissite
# enable an apache2 module
sudo a2enmod
# e.g. a2enmod php4 will create the correct symlinks in mods-enabled to allow the module to be used. In this example it will link both php4.conf and php4.load for the user
# disable an apache2 module
sudo a2dismod
# force reload the server:
sudo /etc/init.d/apache2 force-reload
# https://blog.basilediougoant.com/2016/01/21/secure-apache-with-lets-encrypt-certificate/