Screen resolution and font size in text mode

vi /etc/defaults/grub
GRUB_GFXMODE=800x600
update-grub2

vi /etc/defaults/console-setup
FONTFACE="Terminus"
FONTSIZE="12x6"
/etc/init.d/console-setup restart

or 
dpkg-reconfigure console-setup

then
/etc/init.d/console-setup restart