#!/bin/bash
WA=68
CR=90
cpuUsage='55%'

cpuValue=$( echo $cpuUsage | cut -d '%' -f 1 )

    case 1 in
            $(($cpuValue <= $WA-1)))
                echo "OK! CPU used: $cpuUsage";;
            $(($cpuValue <= $CR-1)))
                echo "WARRING! CPU used: $cpuUsage" && STATE=$STATE_WARN ;;
            $(($cpuValue > $CR-1)))
                echo "CRITICAL! CPU used: $cpuUsage" && STATE=$STATE_CRIT ;;
    esac