설정 파일 열기
vi /etc/apt/sources.list내용 넣기
deb http://kr.archive.ubuntu.com/ubuntu/ xenial main restricted
deb http://kr.archive.ubuntu.com/ubuntu/ xenial-updates main restricted
deb http://kr.archive.ubuntu.com/ubuntu/ xenial-updates universe
deb http://kr.archive.ubuntu.com/ubuntu/ xenial multiverse
deb http://kr.archive.ubuntu.com/ubuntu/ xenial-updates multiverse
deb http://kr.archive.ubuntu.com/ubuntu/ xenial universe