I currently run Nagios on Ubuntu and I am trying to figure out how to add logic to the following scenario:

For example here is my sensors output:

root@ubunag:/usr/local/nagios/etc/keys# sensors -f
Adapter: ISA adapter
Vcore: +1.82 V (min = +0.06 V, max = +3.10 V)
in1: +0.40 V (min = +0.06 V, max = +3.10 V)
+3.3V: +3.45 V (min = +2.98 V, max = +3.63 V)
+5V: +4.83 V (min = +4.51 V, max = +5.50 V)
+12V: +12.72 V (min = +10.81 V, max = +13.20 V)
fan1: 5578 RPM (min = 0 RPM, div = 2) ALARM
fan2: 0 RPM (min = 0 RPM, div = 2)
temp1: +110.8°F (high = +295.2°F, hyst = -95.6°F)
temp2: +88.9°F (high = +295.2°F, hyst = -95.6°F)
temp3: +73.4°F (high = +4.6°F, hyst = +54.5°F) ALARM

Now what I do currently with Nagios is the following command to simply output this information:

define service{
use local-service ; Name of service template to use
host_name SkunkWerkz
service_description SENSORS MB Temperature
check_command mbtemp
notifications_enabled 0
define command{
command_name mbtemp
command_line sensors -f | grep 'temp2'

There is no logic to this as its only displaying the output. What I would like todo is add logic to this to where if the temperature for example runs past a certain range then I get a critical warning, etc etc.

So for example with 'temp2' which is the MB temp I would like it to throw a warning at lets say 100 F and a critical at 120 F for example.

Any help is appreciated in Advance,..