A simple script to control the temperature of our raspberry pi. This script save the temperature in a log file and if it's greater than 70 ºC, our raspberry will be shutdown for security

checktemp.sh

#!/bin/bash
cpuTemp0=$(cat /sys/class/thermal/thermal_zone0/temp)
cpuTemp1=$(($cpuTemp0/1000))
cpuTemp2=$(($cpuTemp0/100))
cpuTempM=$(($cpuTemp2 % $cpuTemp1))
gpuTemp=$(/opt/vc/bin/vcgencmd measure_temp)

# Function to write the temperature into the log
function writeToLog() {
	# The direction of the file
	# you can put here another route
	file="/home/pi/temp.log"

	# Check if the file exists
	if [ ! -f "$file" ] ; then
         	# if not create the file
        	touch "$file"
     	fi

	echo "$1" >> "$file"
}

# Save the value
writeToLog "$(date): CPU temp - $cpuTemp1.$cpuTempM'C, GPU temp - $gpuTemp;"

# Check the temperature
if [ "$cpuTemp1" -gt  "70" ]
        then writeToLog "Shutdown.......;"; `shutdown -h now`
fi

INSTALL.md

INSTALL

The installation is very easy. First, you need to download the file below: checkTemp.sh. To complet this task, open a terminal an execute this command:

wget https://gist.github.com/Angelmmiguel/e13fed981e91bf6a298c/raw/0c33849753f17bd3b70d3aa2a4cfc06e05abafb3/checktemp.sh

The second step is to copy this file to the Crontab folder (Crontab is an application to schedule scripts in Unix systems):

sudo cp checktemp.sh /etc/cron.d/

The last step is to initialize the crontab task. You must open the crontab file to save the task with this command:

sudo crontab -e

We need to use sudo because the command shutdown needs root privileges. When the file is open, go to the bottom and, after the comments (# lines), and write this line:

*/5 * * * * /etc/cron.d/checktemp.sh

This task will execute checkTemp every 5 minutes. More info about schedule time options in this nice post :)