How to do it...

In this recipe, we will run PowerTOP in interactive mode and analyze its output:

1. Log in to your Raspberry Pi system as user pi, using the password raspberry.
2. Run sudo to gain root access:

$ sudo bash
#

3. Install PowerTOP from the repository:

 # apt-get install powertop

4. Staying in a root shell, run PowerTOP:

 # powertop

The PowerTOP UI will show up in your Terminal. Use the Tab key to navigate between its screens.