打印出在两个文件中都不存在元素

#!/bin/sh
echo "下面为那些没有在联系人组里面的人" >/opt/tmp/check_person_notingroup.out
file="contacts.cfg contacts_level2.cfg contacts_level3.cfg contacts_level4.cfg contacts_level5.cfg contacts_level6.cfg"
for h in $file
do
        for i in `find /usr/local/nagios/etc/ -type f -name $h |xargs -i cat {} | grep contact_name | awk '{print $2}'`
        do
        grep $i /usr/local/nagios/etc/contactgroups.cfg 2>/dev/null 1>/dev/null || grep $i /usr/local/nagios/etc/contactgroups_charge.cfg 2>/dev/null 1>/dev/null
                if [ $? -ne 0 ]
                then
                echo $i >>/opt/tmp/check_person_notingroup.out
                fi
        done
done

打印出在两个文件中都不存在元素