emerge 명령어를 쳤더니...

!!! Invalid PORTDIR_OVERLAY (not a dir): '/usr/portage'
!!! main-repo not set in DEFAULT and PORTDIR is empty.


!!! /etc/portage/make.profile is not a symlink and will probably prevent most merges.
!!! It should point into a profile within /usr/portage/profiles/
!!! (You can safely ignore this message when syncing. It's harmless.)


!!! Your current profile is invalid. If you have just changed your profile
!!! configuration, you should revert back to the previous configuration.
!!! Allowed actions are limited to --help, --info, --search, --sync, and
!!! --version.

이렇게 나오네요. 어떻게 해야 하나요?