cat / etc / apt / sources.list deb http: // mirrors.aliyun.com/ubuntu-ports/ great main deb-src http: // mirrors.aliyun.com/ubuntu-ports/ great main deb http: // mirrors.aliyun.com/ubuntu-ports/ great-updates main deb-src http: // mirrors.aliyun.com/ubuntu-ports/ great-updates main deb http: // mirrors.aliyun.com/ubuntu-ports/ great universe deb-src http: // mirrors.aliyun.com/ubuntu-ports/ great universe deb http: // mirrors.aliyun.com/ubuntu-ports/ great-updates universe deb-src http: //mirrors.aliyun.com/ubuntu-ports/ great-updates universe deb http: // mirrors.aliyun.com/ubuntu-ports/ great-security main deb-src http: // mirrors.aliyun.com/ubuntu-ports/ great-security main deb http: // mirrors.aliyun.com/ubuntu-ports/ great-security universe deb-src http: // mirrors.aliyun.com/ubuntu-ports/ great-security universe