Brain Teaser

[Leonard Cuff]

In article <Oct90.150551.3649 at x.co.uk> mike at x.co.uk (Mike Moore) writes:
>Here's one (do NOT actually do this, it appears to be lethal):
>now assume that *everyone* is set to use /bin/sh (including root), how
>do you get out of this without rebuilding the operating system?  I don't
>think there actually is one..... but....

Some versions of UNIX are distributed on floppies and the boot
floppy can be used to mount the hard disk (after stopping the
installation process early on).  The password file could then
be edited, or whatever other hacks come to mind.  I have recovered
System V/386 systems from AT&T, 386 systems from Interactive (ISC) 
and ancient Callan systems (SVR2) using this technique.  It tends
to be ugly, because you have to know the device name(s) of your partitions 
and you must use full paths that have this ugly prefix, and an editor like vi
doesn't typically work 'cos it can't find its termcap or terminfo files, but
one can muddle along with sed.  This technique is helpful in
a variety of scenarios, most of them involving badly munched hard
disks: bad boot block on the hard disk, bad fsck, bad passwd file, you
get the idea.....

Lots of fun.  :-)
-- 
Leonard Cuff                 if ( my_words == Rockwells_words )
lcuff at cmc.com                         hell_freezes_over = now;

"I feel like a fugitive from th' law of averages" - Bill Mauldin