2 examples for equery
# Which Portage packages do require media-libs/libvorbis-1.3.3 ? equery d media-libs/libvorbis-1.3.3
# Tell which gentoo package installed the executeable "php" to your system... equery b `which php`
# Which Portage packages do require media-libs/libvorbis-1.3.3 ? equery d media-libs/libvorbis-1.3.3
# Tell which gentoo package installed the executeable "php" to your system... equery b `which php`