I see that Greg just submitted a few PRs about NetBSD's shell.  This
added to the PRs that have already been submitted and the problems I
know about but haven't submitted PRs about, got me to thinking about
alternatives to our ash-based shell again.  

I actually think about this quite often --- most of the time when I'm
trying to find and fix a bug --- but haven't expressed it to the list
until now.

I think that we should consider replacing our shell with pdksh.  The
latest pdksh release (5.1.0) is much closer than ash to being POSIX.2
compliant, it's compiled executable is about the same size, it is only
slightly slower, and most importantly, it is being actively maintained
outside of NetBSD.

The reason I think the last point is the most important is because we
can expect drawbacks like the performance issues, and the remainder of
POSIX.2 work, to be addressed by others.  Ash is what it is today, and
I don't see any volunteers lining up to fix it's defects.  I know that
the pdksh maintainer is busy just like the rest of us, but he has been
very responsive to the the patches that I submitted and performance
issues I discovered during the alpha and beta process.

Thoughts?

	--jtc