Check ssl exp date script

check_ssl.sh

#!/bin/bash 
gracedays=14

result=0
for server in example.com www.example.com other-test.com; do
    data=`echo | openssl s_client -connect "${server}:443" -servername "${server}" 2>/dev/null | openssl x509 -noout -enddate | sed -e 's#notAfter=##'`

    ssldate=`date -d "${data}" '+%s'`
    nowdate=`date '+%s'`
    diff="$((${ssldate}-${nowdate}))"

	if test "${diff}" -lt "$((${gracedays}*24*3600))"; then
        if test "${diff}" -lt "0"; then
            echo "The certificate for ${server} has already expired."
            result=2
        else
            echo "The certificate for ${server} will expire in $((${diff}/3600/24)) days."
            if test "$result" != "2"; then
            	result=1
            fi
        fi
    fi
done
if test "$result" = "0"; then
	echo "All certificate valid!"
fi
exit $result