Blanche allows Linux users to define a whitelist of domains, thus blocking all others.
To install Blanche on your system, just run these commands:
git clone https://github.com/mariavillosa/Blanche.git
cd Blanche
sudo ./install.sh
Viola! Now you can start the app via the blanche
command on your terminal.
The app is a native GUI that lets you specify a newline separated list of domains, like so: