1.连接wifi，在Ubuntu Server中使用netplan连接

    1. $ sudo vim /etc/netplan/50-cloud-init.yaml //末尾添加，注意缩进使用空格，wifis:前有缩进
    2. wifis:
    3.     wlan0:
    4.         dhcp4: true
    5.         access-points:
    6.             "wlan-name":
    7.                 password: "password here" 
    8. $ sudo netplan --debug apply

    2.树莓派换源

    1. $ sudo sed -i 's/ports.ubuntu.com/mirrors.ustc.edu.cn/g' /etc/apt/sources.list

    3.开启ssh

    1. $ sudo apt search openssh-server
    2. $ sudo apt install opessh-client openssh-server
    3. $ sudo dpkg-reconfigure openssh-server
    4. $ sudo service ssh restart
    5. $ sudo service ssh status
    6. $ sudo systemctl enable ssh