Shell scripts breaking in Ubuntu

Ubuntu Bug 61463 is a reasonably large issue. I talked with some folks about it a while back, and decided to lay off because it was a bit of a hot rock.

I think it's worth noting here that the correct procedure after installing Ubuntu Edgy or later is:
dpkg-reconfigure dash
In order to get /bin/sh pointing to something that won't break you configure scripts and shell scripts written by vendors. As the 'POSIX Compliant' shell that ubuntu now uses by default in Edgy and later (called 'dash') causes various breakages just about everywhere.

Read the linked (and closed) bug for more information.