更新源，但是由于不能使用vi，如下用echo
cp /etc/apt/sources.list /etc/apt/sources.list.bak # 备份原先的
echo "deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse" >> sources.list
echo "deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse" >> sources.list
echo "deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse" >> sources.list
echo "deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse" >> sources.list
echo "deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse" >> sources.list
echo "deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse" >> sources.list
echo "deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse" >> sources.list
echo "deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse" >> sources.list
echo "deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse" >> sources.list
echo "deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse" >> sources.list
apt-get update
apt-get install vim