Checks for upcoming expiry of SSL certificates, e.g. HTTPS or LDAPS. Useful for cron jobs and server monitoring.

check-ssl-expiry.sh

#!/bin/bash

SERVER=my.example.com:443
WARNDAYS=30

EXPIRE=$(openssl s_client -connect $SERVER 2>/dev/null </dev/null | openssl x509 -noout -enddate | cut -d= -f2)
DAYS=$((( $(date --date "${EXPIRE}" +%s) - $(date +%s) ) / 86400));
[ $DAYS -lt $WARNDAYS ] && echo "WARNING: SSL certificate for $SERVER expires in $DAYS days"