Improper shutdown - weird results

[Hugo van der Merwe <hugo@mailroom.com>]

Hi,

A friend of mine, for whom I installed Debian, recently accidentily turned
off his computer before the shutdown process was complete. When he booted
back up, the whole thing was messed up... (He had to run fsck manually,
and probably said "y" to all questions.)

It turned out that his /etc/group file was incorrect (out dated, or
something weird, but still recognisable), his /etc/shadow file contained
what should have been the current /etc/group, his /etc/passwd contained
what should have been /etc/shadow! Needless to say, he couln't log in.
(There was some error message that looked something like "::: No such file
or directory" - not that I'm 100% sure of the formatting, this was all
told over the telephone...). After moving the files around (in single user
mode), and copying /etc/passwd- to /etc/passwd, he could log in again, but
instead of the login prompt:

user@hostname:~$

he had:

I have no name!@hostname:~$

(Or so he explained over the telephone...) I suggested deleting the user
and recreating it, out of laziness. (Oops, I just realize that that
probably took him out of the groups as well, but he'll figure that out
quickly and fix it.)

What I was wondering, firstly, is how these files could have been moved
around... he logged out all the users, and it didn't sound like he was
running anything strange just before it.

The second thing is, why the "I have no name"? Anyone have any idea where
that info is supposed to be? I'd think it simply uses the login name...

Anyway, just sharing an "incomplete shutdown experience"...
Hugo van der Merwe