If one or more bashrc files exist in the following locations, they will be sourced before the ebuild is executed in the following order: /etc/portage/bashrc /etc/portage/env/${CATEGORY}/${PN} /etc/portage/env/${CATEGORY}/${PN}:${SLOT} /etc/portage/env/${CATEGORY}/${P} /etc/portage/env/${CATEGORY}/${PF} A phase hook function name begins with a pre_ or post_ prefix to indicate that it will be called before or after one of the ebuild phases. The prefix is followed by the name of the ebuild function that the hook will be associated with. For example, a hook named pre_src_compile will be called before src_compile, and a hook named post_src_compile will be called after src_compile.