[luau] interactive bootup - how?

[Charles Lockhart]

Ok, for the record, I am part Irish, and hence I don't think I've ever 
had a problem with one of MY systems booting.  But I do get called over 
whenever someone else has a problem, which is why I'm asking this.

I'm looking for a fairly simple how-to/faq/tutorial document for how to 
go in and control the bootup of most linuxes (well, something that would 
cover RedHat/Slackware/Mandrake installs at least), and let me do some 
diagnostic stuff to figure out what's going wrong, and let me bypass and 
continue booting.  Something that would explain (not extensively) what 
all that stuff it's doing is actually, uh, doing.

For instance, the hardware engineer guy this morning comes to me and 
says that one of his instrumentation computers isn't coming up, can I 
fix it.  So I go look at it, it's stuck trying to mount NFS stuff.  Most 
likely something is down on our oh so flakey network, and it's stalling 
on that.  But I'd like to look all sharp and wizardly by typing in some 
truly esoteric commands to let me figure out exactly what isn't working, 
and maybe bypass that stage if it's beyong my control.

So where can I learn to do this?

Dammit Jim, I'm a software engineer, not a sys admin!

-Charles