gui () {
  sudo systemctl isolate graphical.target
  sudo systemctl start lightdm
  sudo systemctl start nxserver
}

tui () {  
 sudo systemctl stop lightdm
 sudo systemctl stop nxserver
 sudo systemctl isolate multi-user.target
 sleep 3
 sudo chvt ${VTTY:-2}
}

dtui () {  
 sudo systemctl disable lightdm
 sudo systemctl set-default multi-user.target
}

dgui () {  
 sudo systemctl enable lightdm
 sudo systemctl set-default graphical.target
}