How do I disable X at boot time so that the system boots in text mode?

Edit /etc/default/grub with your favourite editor, e.g. nano:

sudo nano /etc/default/grub

Find this line:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

Change it to:

GRUB_CMDLINE_LINUX_DEFAULT="text"

Update GRUB:

sudo update-grub

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For systems that use systemd

^{This is an additional step for systemd releases, e.g. Ubuntu 15.04, the steps above for grub are still necessary.}

You need to tell systemd to not load the graphical login manager:

sudo systemctl enable multi-user.target --force
sudo systemctl set-default multi-user.target

You will still be able to use X by typing startx after you logged in.

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

Hope this helps :)

For 11.04 and previous versions (and perhaps later)

If you want to boot into text mode:

Edit /etc/default/grub. For example:

sudo gedit /etc/default/grub

Find this line:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

Add text:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash text"

Then update Grub:

sudo update-grub

Note: Removing quiet splash (i.e. GRUB_CMDLINE_LINUX_DEFAULT="") will show text during boot but then show a graphical login screen as usual. Replacing quiet splash with text will leave you at a login prompt; to start a GNOME session, use sudo /etc/init.d/gdm start or startx.

To disable GDM:
Install bum .

After installation it will be found under System>>Administration>>Bootup-Manager

Uncheck Gnome Display Manager