check_rpi_temperature/check_rpi_temperature.sh

#!/bin/bash
#
# Created by Jonny007-MKD 2020-10-03

echoerr() { echo "$@" 1>&2; }

pathToBc=$(command -v bc)
if [ $? -ne 0 ]; then
	echoerr Please install bc
	exit -2
fi

pathToVcGenCmd=/usr/bin/vcgencmd
if [ ! -x "$pathToVcGenCmd" ]; then
    pathToVcGenCmd=/opt/vc/bin/vcgencmd
fi
if [ ! -x "$pathToVcGenCmd" ]; then
    pathToVcGenCmd=$(which vcgencmd 2> /dev/null)
fi
if [ ! -x "$pathToVcGenCmd" ]; then
    echoerr Cannot find vcgencmd
    exit -3
fi

WARN=50
CRIT=70
FAHRENHEIT=false
DEBUG=false
while [[ $# -gt 0 ]]; do
	case $1 in
		-w|--warn|--warning)
			case "$2" in
				''|*[!0-9]*) echoerr "Value for \"$1\" has to be a number"; exit -3;;
			esac
			WARN=$2
			shift
			;;
		-c|--crit|--critical)
			case "$2" in
				''|*[!0-9]*) echoerr "Value for \"$1\" has to be a number"; exit -3;;
			esac
			CRIT=$2
			shift
			;;
		-f|--fahrenheit)
			FAHRENHEIT=true
			;;
		-d|--debug)
			DEBUG=true
			;;
		-?|--help)
			echo "Check /proc/mdstat. Arguments:"
			echo "--warning $WARN: Temperature above which the result is warning"
			echo "--critical $CRIT: Temperature above which the result is critical"
			echo "--fahrenheit: All temperatures in Fahrenheit (°F)"
			exit 0
			;;
	esac
	shift
done

if [ $CRIT -le $WARN ]; then
	echoerr "Critical threshold ($CRIT) has to be greater than Warning threshold ($WARN)"
	exit -3
fi


function log {
	if $DEBUG; then
		echo "  > $@"
	fi
}
NL=$'\n'


output=$($pathToVcGenCmd measure_temp)
result=$?
log vcgencmd: $result. $output
if [ $result -ne 0 ]; then
	echoerr "vcgencmd returned $result"
	exit $result
fi

temp=${output/temp=/}
temp=${temp/\'C/}

unit="C"
if $FAHRENHEIT; then
	temp=$(bc <<< "scale=1; ($temp * 1.8) + 32")
	unit="F"
fi


log "$temp'$unit. Warn: $WARN'$unit, Crit: $CRIT'$unit"

c=$(bc <<< "$temp > $CRIT")
w=$(bc <<< "$temp > $WARN")
if [ $c -eq 1 ]; then
	result="CRITICAL"
elif [ $w -eq 1 ]; then
	result="WARNING"
else
	result="OK"
fi
echo "$result. $temp'$unit | 'temperature'=$temp$unit;$WARN;$CRIT;-40;85"


case $result in
	OK)       exit 0;;
	WARNING)  exit 1;;
	CRITICAL) exit 2;;
esac