I am running Debian Jessie which uses SystemD. I have so far been unable to find a way to stop X11 from starting on bootup. The raspi-config setting apparently does not do anything.
Can anyone help?
Systemd users "service bunlde" named target, to achieve different system states while booting the system. You need to change the desired state of the system, from graphical to multi-user.
Will show you
You could change it with
sudo systemctl set-default multi-user.target
I could recommend this article to understand how to work with systemd https://www.digitalocean.com/community/tutorials/how-to-use-systemctl-to-manage-systemd-services-and-units
The GUI login is
dm is for display manager). This is started as an init service, and the init system on Jessie is systemd.
I believe the name of the service is also "lightdm". You can confirm that:
systemctl list-units | grep lightdm
The middle columns should say "loaded active" and the first one "lightdm.service". Presuming that's it, to disable on boot:
sudo systemctl disable lightdm
The Debian way to enable or disable services is to use update-rc.d. You can use
update-rc.d lightdm disable
if in fact lightdm is the display manager installed.
If you need to run it once, you can
service lightdm start
update the systemd way to do it is in fact to use systemctl disable like indicated in the other answer