The following tutorial requires root terminal access. It also will not work on virtual servers, only on dedicated machines.
This program lets you access temperature sensors and fan speed sensors on your system. Root access is required to detect the sensors, but not to read them.
This will only work for systems running on bare metal, as opposed to a virtual server. Install the lm-sensors package with the following:
$ sudo apt-get install lm-sensors
Then, let sensors find which temperature sensors are available on your system with:
$ sudo sensors-detect
Accept the defaults to the prompts. If sensors-detect fails, check to make sure you are running as root and that you are not running on a virtual machine. Then, get readings from the sensors with:
$ sensors
Reading sensors does not require root privileges.