Check CPU Usage (by Nestor@Toront)

I have updated some syntax to use new methods but the functional change is located on line 11 (12 in the below as I have a comment on line 11).

#!/bin/sh
# Version 0.2
#
# ### History ###
# V0.1 Created script from CPU Idle script
# V0.2 Handle dicimal compare and output

if [ "$1" = "-w" ] && [ "$2" -gt "0" ] && [ "$3" = "-c" ] && [ "$4" -gt "0" ] ; then
warn=$2
crit=$4
#>Main Modification CPU Usage = $USAGE %|CPU Usage=$USAGE%;;;;"
exit 2
else
echo "WARNING - CPU Usage = $USAGE %|CPU Usage=$USAGE%;;;;"
exit 1
fi
else
echo "OK - CPU Usage = $USAGE %|CPU Usage=$USAGE%;;;;"
exit 0
fi
else
echo "$0 - Nagios Plugin for checking CPU Usage in percentage "
echo ""
echo "Usage: $0 -w -c "
echo " = warnlevel and critlevel is warning and critical value for alerts. "
echo ""
echo "EXAMPLE: /usr/lib64/nagios/plugins/$0 -w 80 -c 90 "
echo " = This will send warning alert when CPU Usage percentage is higher than 80%, and send critical when higher than 90%"
echo ""
exit 3
fi