Piping commands till it hurts

(Just to save a useful and complex construct for future reference)

List all the overlay maintainers who hasn’t migrated their packages to virtual/pkgconfig:

ag --files-with-matches dev-util/pkgconfig | xargs dirname | uniq \
       | xargs -I {} grep '<name>' '{}/metadata.xml' \
       | sed 's:\s\+<name>\(.\+\)</name>:\1:' | sort -u

Yes, I use ag instead of grep, being too lazy to add all the necessary options. And wait. And ag is so much better however you look at it.