nagios监控shadow文件

#!/bin/bash
Modify=$(stat /etc/shadow|awk NR==6'{print $2,$3}'|md5sum|awk '{print $1}')
Change=$(stat /etc/shadow|awk NR==7'{print $2,$3}'|md5sum|awk '{print $1}')
oldmd5=$(cat /tmp/shadow)
newmd5=${Modify}${Change}
if [ $newmd5 != $oldmd5 ];then
echo passwd is changed
exit 1
else
echo passwd is ok
echo ${Modify}${Change} >  /tmp/shadow
exit 0
fi