I just got my system to boot up (Scientific Linux), but at the login screen I can't login as root. It doesn't even ask for a password, just says .

So what I see is:

Then:

How can I go about finding the cause? E.g. I'm referring to this post here where I should do:

But I don't really understand this command. Doing that at runlevel 1 brought me back to the login screen, but also kept me as root, so there was some weird glitching. I'm trying to check the system logs from the login prompt, but I'm not sure how to do that from here.

I'm also doing a network boot, so I'm working with a root fs image that isn't written to upon booting. So maybe I can't check system logs after all?

Does PAM have any dependencies in /usr/lib? Is anything in /usr/bin required for a basic boot? Those directories are both basically empty in my root fs. I was thinking of adding things to them later. For now I just need to get this boot and login working.

Ah, the issue was actually with the login binary's libraries. I checked another, similar system that I had, and it showed that login depended on some libraries in /usr/lib, namely libcrack.so.2.8.0 and some version of libglib. My own /usr/lib in this image I'm creating was empty. After copying in libcrack* and libglib*, I was able to log in just fine.