What are the ways to terminate the operation of an Ubuntu system through the interface or command line?

There are several ways to shut down the Ubuntu system:

Via graphical interface:

• Click on the power button in the top right corner of the screen and select "Shut Down" or "Restart".

Via command line:

• Command to shut down:

  sudo shutdown -h now
  

• Command to restart:

  sudo reboot
  

• You can also use:

  sudo poweroff
  

These commands require superuser privileges and allow for a proper shutdown of all processes before turning off.