https://fonts.google.com/?selection.family=Open+Sans
cd /usr/share/fonts
sudo mkdir googlefonts
sudo unzip -d ./googlefonts ~/Downloads/Open_Sans.zip
cd ..
sudo chmod -R --reference=opentype googlefonts
sudo fc-cache -fv
fc-match OpenSans
http://www.binarytides.com/gorgeous-looking-fonts-ubuntu-linux
http://ubuntuhandbook.org/index.php/2016/05/manually-install-fonts-ubuntu-16-04