# 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

enable and disable sites and modules in apache 2

apache2 - enabling and disabling sites

module

Apache