check SSL

TARGET="mysite.example.net"; \
RECIPIENT="[email protected]"; \
DAYS=7; \
echo "checking if $TARGET expires in less than $DAYS days"; \
expirationdate=$(date -d "$(: | openssl s_client -connect $TARGET:443 -servername $TARGET 2>/dev/null \
                              | openssl x509 -text \
                              | grep 'Not After' \
                              |awk '{print $4,$5,$7}')" '+%s'); \
in7days=$(($(date +%s) + (86400*$DAYS))); \
if [ $in7days -gt $expirationdate ]; then \
    echo "KO - Certificate for $TARGET expires in less than $DAYS days, on $(date -d @$expirationdate '+%Y-%m-%d')" \
    | mail -s "Certificate expiration warning for $TARGET" $RECIPIENT ; \
else \
    echo "OK - Certificate expires on $expirationdate"; \
fi;