Mine

#!/bin/sh


if [ "$1" = "config" ]; then

        echo 'graph_title Failed logins'
        echo 'graph_vlabel Number of failed logins'
        echo 'graph_category Auth'
        echo 'graph_info This graph shows the number of failed logins in the system.'
        echo 'Auth.label auth'
        echo 'Auth.info Number of failed logins.'
        exit 0
fi


echo -n 'Failed.value '
echo `cat /var/log/auth.log | grep Failed | wc -l `