With the NetBSD package system, is there an easy way to look at what
ports I currently have installed, and then re-make and re-install all
of them either unconditionally, or only if a newer version exists?

Also, is there a way to query where an installed port came from within 
/usr/pkgsrc?
(i.e, zsh-3.0.7 = "shells/zsh", autoconf-2.13 = "devel/autoconf", etc.)

Thanks.