Disable GDM at bootup on Ubuntu Lucid

on ubuntu 10.04

Ubuntu lucid replaces the old init system with upstart, this means you can't use update-rc.d gdm -f remove  to stop it starting up at bootup. So to disable it we need to edit the upstart files in /etc/init (note not /etc/init.d!) thanks to sisco311 on the ubuntu forums the solution is to edit /etc/init/gdm.conf and change

start on (filesystem

          and started hal

          and tty-device-added KERNEL=tty7

          and (graphics-device-added or stopped udevtrigger))

stop on runlevel [016]

to

start on (runlevel [3]

          and filesystem

          and started hal

          and tty-device-added KERNEL=tty7

          and (graphics-device-added or stopped udevtrigger))

stop on runlevel [0126]

Then reboot!

You can start gdm via service gdm start

on Ubuntu 10.04.1

booting with the text kernel parameter will also prevent display managers managed by Upstart (e.g. gdm, kdm and lxdm) from being started at boot time.
If you are using Grub2, then in /etc/default/grub replace:
Code:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
with
Code:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash text"
then run:
Code:
sudo update-grub
Remove splash to disable the splash screen and/or quiet to make the boot process verbose.