Ubuntu can monitor CPU and other system temperatures, fan speeds, and voltages via command line, using the package lm-sensors, or via GUI applets in your desktop.
Monitoring sensors via the command line with lm-sensors
Install the lm-sensors package (see InstallingSoftware).
Run sudo sensors-detect and choose YES to all YES/no questions.
- At the end of sensors-detect, a list of modules that needs to be loaded will displayed. Type "yes" to have sensors-detect insert those modules into /etc/modules, or edit /etc/modules yourself.
Next, run sudo service module-init-tools restart This will read the changes you made to /etc/modules in step 3, and insert the new modules into the kernel.
Next, you should test that lm-sensors works correctly. Run the "sensors" command and check the output. Example output is below:
w83627dhg-isa-0290 Adapter: ISA adapter VCore: +1.13 V (min = +0.00 V, max = +1.74 V) in1: +11.30 V (min = +0.90 V, max = +0.05 V) ALARM AVCC: +3.28 V (min = +2.11 V, max = +2.40 V) ALARM 3VCC: +3.28 V (min = +2.05 V, max = +0.37 V) ALARM in4: +1.41 V (min = +0.00 V, max = +1.57 V) in5: +1.65 V (min = +0.02 V, max = +0.14 V) ALARM in6: +4.45 V (min = +3.28 V, max = +1.64 V) ALARM VSB: +3.28 V (min = +0.14 V, max = +3.07 V) ALARM VBAT: +3.22 V (min = +2.06 V, max = +1.02 V) ALARM Case Fan: 0 RPM (min = 2636 RPM, div = 128) ALARM CPU Fan: 1117 RPM (min = 1591 RPM, div = 8) ALARM Aux Fan: 0 RPM (min = 1171 RPM, div = 128) ALARM fan5: 0 RPM (min = 659 RPM, div = 128) ALARM Sys Temp: +31.0°C (high = +18.0°C, hyst = +96.0°C) sensor = thermistor CPU Temp: +33.0°C (high = +80.0°C, hyst = +75.0°C) sensor = diode AUX Temp: +124.5°C (high = +80.0°C, hyst = +75.0°C) ALARM sensor = thermistor cpu0_vid: +1.163 V coretemp-isa-0000 Adapter: ISA adapter Core 0: +43.0°C (high = +82.0°C, crit = +100.0°C) coretemp-isa-0001 Adapter: ISA adapter Core 1: +43.0°C (high = +82.0°C, crit = +100.0°C) coretemp-isa-0002 Adapter: ISA adapter Core 2: +40.0°C (high = +82.0°C, crit = +100.0°C) coretemp-isa-0003 Adapter: ISA adapter Core 3: +43.0°C (high = +82.0°C, crit = +100.0°C)
This sensors output shows four devices: w83627dhg-isa-0290 (motherboard sensors) and coretemp-isa-0000 through 0004 (Intel Core sensors). The motherboard sensor device has information on the voltages received from the power supply unit by the motherboard (in1-6), the fan speeds (entries with RPM), and various internal temperatures. As you can see, some sensors are obviously incorrect (e.g. AUX Temp and Case/Aux Fan); this tends to be the case with at least some of the sensors on most motherboards.
The sensor output may be tweaked by editing the "/etc/sensors.conf" file. It is possible to correct inaccurate scaling too. For details check "man sensors.conf".
Monitoring sensors on your desktop
Ksensors seems to work better for many people, and be easier to configure. Install the ksensors package (see InstallingSoftware). Start it from terminal with ksensors, and you should be able to choose which temperature, fan RPM, or other displays you want.
To get Ksensors to start when your computer starts, go System menu --> Preferences --> Sessions, and in the last tab, Startup Programs, add ksensors.
Unity Oneiric and above System Load Indicator
As of Ubuntu 11.10, in Unity one may use System Load Indicator via the Ubuntu Software Center.
For Lucid, you can apt-get or Synaptic search/install of sensors-applet, a GNOME panel applet that displays temperature, voltage, and fan speeds.
During installation, you'll be presented with the option to start the hddtemp daemon at startup. Choose "no" here if there was a sensor detected previously that reports your hard drive temperature, otherwise choose "yes".
After installation, you can right click on any panel that you want to have sensor information displayed on, and click "Add to Panel..." . In the "Add to Panel" window, there should be a icon with the text "Hardware Sensors Monitor" (You may need to restart before the option appears). Click on this entry, then click "Add". You can change the applet's settings by right-clicking on the applet and choosing "Preferences".
After installation, you can secondary click on any panel that you want to have sensor information displayed on, and click "Add to Panel...". In the "Add to Panel" window, there should be a icon with the text "Sensor plugin". Click on this entry, then click "Add". You can change the plugin settings by right-clicking on the plugin and choosing "Properties".
lm-sensor's homepage http://www.lm-sensors.org/