Raspberry Pi-UbuntuMate environment configuration 1

1. install ssh

1.1 Input command: sudo apt-get install openssh-server, install ssh (key)
1.2 Input command: ps -e|grep ssh, check whether Raspberry Pi SSH service is enabled
1.3 Input command: sudo /etc/init.d/ssh start , start SSH service (key)
1.4 Input commands: sudo service ssh start, sudo service ssh status

2. Change the download source

1. cd /etc/apt, vim sources.list
2. Replacement source
   Ali: https://mirrors.aliyun.com/ubuntu-ports/ & University of Science and Technology of China: http://mirrors.ustc.edu.cn/ubuntu-ports
3. 
   sudo apt update
   sudo apt upgrade