A preventative fix for bug 557177 (the "... erased all my data in /" one)

[Gavin Panella]

I read mdz's post
<http://mdzlog.alcor.net/2010/04/08/a-story-in-numbers/> and saw the
one line fix:

-    cd "${MOUNTPOINT}"
+    cd "${MOUNTPOINT:?mount point not specified}"

and wondered if there might be a better long-term preventative fix for
this: run all init scripts with "set -o errexit -o nounset" shell
options. Is this feasible? My guess is that converting all scripts to
work with these options is a pretty big task.

(From past experience as a sysadmin, putting these options at the top
of every script is a total win; I was forced to consider failure
scenarios, and even when I didn't the damage was limited. Over time it
made me write cleaner and more robust scripts.)

Gavin.