SSL certificate expiration check script

certcheck.sh

#!/bin/bash

# ./certcheck.sh [domain name]

DOMAIN=$1

notAfter=$(echo -n Q | openssl s_client -connect ${DOMAIN}:443 -servername ${DOMAIN} 2>/dev/null | openssl x509 -noout -enddate | grep notAfter | sed 's/notAfter=//')
notAfterEpic=$(date -d "${notAfter}" +\%s)
twoWeeksLaterEpic=$(date -d 'now + 2 weeks' +\%s)
nowEpic=$(date +\%s)

echo "now    = "$(date)
echo "expiry = "$(date -d @${notAfterEpic})

if [ $notAfterEpic -le $nowEpic ]; then
  echo "The SSL cert for ${DOMAIN} has expired."
  exit 1
elif [ $notAfterEpic -le $twoWeeksLaterEpic ]; then
  echo "The SSL cert for ${DOMAIN} will expire in two weeks."
  exit 1
else
  exit 0
fi