修改阿里源為Ubuntu 18.04默認的源
sudo gedit /etc/apt/sources.list
添加如下條目
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ hirsute main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ hirsute-updates main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ hirsute-backports main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ hirsute-security main restricted universe multiverse
最后執行如下命令更新源
sudo apt-get update
sudo apt-get upgrade