linux cmd

ip link show (ip s)
ip route show (ip r)
ip addr show (ip a)

vim key
chmod 600 key
ssh -i key root@10.0.0.1
ssh -v -i key root@10.0.0.1

/etc/network/interfaces

/etc/netplan/01-netcfg.yaml
sudo netplan try
sudo netplan apply

sudo su

sudo reboot
sudo shutdown -h now