1.输入该命令按回车键：apt-get update && apt-get upgrade -y
2.输入该命令按回车键：sed -i 's/stretch/buster/g' /etc/apt/sources.list
3.输入该命令按回车键：apt-get update && apt-get upgrade -y
4.输入该命令按回车键：apt-get dist-upgrade -y
5.依照默认选项按回车键，完成后重启系统
6.输入该命令按回车键可查看当前系统版本：cat /etc/os-release
