Boot into console mode in Linux

Step 1 First update your repository by running

sudo apt-get update

Step 2 There is some bug in old version of lightdm, so we need to upgrade the same. To do so run,

sudo apt-get install lightdm

Step 3 Now we have to modify grub config. Step 3a Open /etc/default/grub with your faviourite editor and change

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

to

GRUB_CMDLINE_LINUX_DEFAULT="text"

Step 3b Also comment GRUB_HIDDEN_TIMEOUT=0 This line is for unhiding the GRUB menu

Step 4 Now we will upgrade GRUB configuration

sudo update-grub

Step 5 Ubuntu 11.10 Desktop edition use lightdm for GUI. We need to disable the same

sudo update-rc.d -f lightdm remove

Step 6 Now restart your machine.