How to boot into single-user mode (runlevel 1) without entering root password?

Question

In Fedora 22 and Ubuntu 15.04, whenever I boot into "single-user"/"recovery" mode, I'm asked for the root password. This is a new behavior; I remember that it used to drop me straight into the root shell. I'm not asking how to reset root password, I already know how to do this. I'm asking how to restore the old behavior in newer releases. I think that it's somehow related to systemd, but I don't know the details.

Answer 1

Using GRUB, you can manually edit the proposed menu entry[single usermode/recovery mode] at boot time. To do so, when GRUB is presenting the menu list (you might need to press ESC first), follow those instructions:

use the arrows to select the boot entry you want to modify.

press e to edit the entry

use the arrows to go to kernel line

press e to edit this entry

at the end of the line add the word single

press ESC to go back to the parent menu

press b to boot this kernel

hope it helps