Yesterday, Gentoo marked KDE 3.5.10 as stable on amd64. I looked for a way to upgrade all of the KDE-related packages without manually specifying each one of them. Normally, one could do
emerge -avu world
but I encountered some nasty conflicts that I didn’t have time, nor would I, to resolve at that time. So I looked for a different solution. To my rescue came qlist from the great app-portage/portage-utils package. This package provides a set of very fast utilities to query portage. I used qlist to list all of my installed packages, grep‘ed the list, and piped the result as arguments to emerge using xargs.
qlist -I --nocolor | grep kde | xargs emerge -pvu1
Take a look at the package list that will be merged. If everything looks fine, then do the actual merge.
qlist -I --nocolor | grep kde | xargs sudo emerge -vu1
The --nocolor option is important, or else emerge will complain about the benign-looking atoms such as dev-util/kdevelop because there are invisible terminal formatting characters around them.