Nagios Bash script which checks the Steal and reports back if threshholds are reached

Nagios check CPU steal

#!/bin/bash
##Author: James Eaton, [email protected]
#Adopted from http://stackoverflow.com/questions/26791240/how-to-get-percentage-of-processor-use-with-bash
##Created: 02/03/2015

### HELP/INFO
if [ $1 = -h ]; then
echo "Description: Checks steal for instance";
exit 1;
fi

# Read /proc/stat file (for first datapoint)
read cpu user nice system idle iowait irq softirq steal guest< /proc/stat

# compute active and total utilizations
cpu_steal_prev=$((steal))
cpu_total_prev=$((user+system+nice+softirq+steal+idle+iowait))

sleep 0.05

# Read /proc/stat file (for second datapoint)
read cpu user nice system idle iowait irq softirq steal guest< /proc/stat

# compute active and total utilizations
cpu_steal_cur=$((steal))
cpu_total_cur=$((user+system+nice+softirq+steal+idle+iowait))

# compute CPU steal (%)
if [ $(( cpu_steal_cur-cpu_steal_prev )) -eq 0 ]; then
steal_pct=0
else
steal_pct=$((100*( cpu_steal_cur-cpu_steal_prev ) / (cpu_total_cur-cpu_total_prev) ))
fi

#printf " Current CPU Steal : %s\n" "$steal_pct"

if [[ $steal_pct -gt 50 ]]; then
        echo "CRITICAL - Steal "$steal_pct"%"
        exit 2
fi

if [[ $steal_pct -gt 20 ]]; then
        echo "WARNING - Steal "$steal_pct"%"
        exit 1
fi

if [[ $steal_pct == 0 ]]; then
        echo "OK - Steal "$steal_pct"%"
        exit 0
fi

if [[ $steal_pct -lt 5 ]]; then
        echo "OK - Steal "$steal_pct"%"
        exit 0
fi

exit 0