Raspberry Pi 3 stuck trying to login after configured for autologin in 60-lightdm-gtk-greeter.conf


I have a raspberry pi 3 running ubuntu mate.

I wanted to upon power up auto login into the GUI.

I followed the steps outlined here:

To configure the Desktop to auto-login (Ubuntu MATE 14.04) add an autologin-user line specifying your user name to the /usr/share/lightdm/lightdm.conf.d/60-lightdm-gtk-greeter.conf file. For example: [SeatDefaults] greeter-session=lightdm-gtk-greeter autologin-user=srackham Conf files in the /usr/share/lightdm/lightdm.conf.d/ directory are cascaded into the lightdm login manager in alpha order.

When I re-power I see the initial bootup sequence followed by going to the login screen where it is stuck.

I am not sure how to get out of this mode and back to what I had before?

Is there a way now that I am in this state to get into a command line mode where I can go back into the 60-lightdm-gtk-greeter.conf and remove what I had added?

Any help would be appreciated,