Boot to text mode in Ubuntu

Installing the GUI will probably cause it to start automatically, but it's very easy to boot to text mode in Ubuntu. Just open /etc/default/grub as root and add text to the

GRUB_CMDLINE_LINUX_DEFAULT=

line. Then run:

sudo update-grub

Your system will then always boot to text mode.

If you want to boot to the GUI, just press e in the boot menu and remove text from the kernel line.

If you want to start the GUI after boot, just run:

sudo /etc/init.d/lightdm start

Source: http://askubuntu.com/questions/74645/possible-to-install-ubuntu-desktop-and-then-boot-to-no-gui