I have tried to boot into command line in Ubuntu 18.10 using ‘sudo systemctl set-default multi-user.target’, however on reboot I get nothing...no GUI, no command line, just a black screen...now I cannot boot up at all! Is there anything I can do?
I faced the same problem. I did
f2 on the keyboard as given in this question. This automatically takes one to the command line login...and from there it is easy. Adding this answer, just in case if someone got stuck and looking for an answer.
I faced this problem with 20.04 in UEFI mode (the problem not occours in BIOS Legacy mode), but, when I disabled the splash screen, I can have tty1 at boot process ends. Here is the workarround:
systemctl set-default multi-user.target && sed -i "s/GRUB_CMDLINE_LINUX_DEFAULT=\"quiet\ splash\"/GRUB_CMDLINE_LINUX_DEFAULT=\"\"/g" /etc/default/grub && update-grub
I don't like splash screens, so for me it fits perfectly!