Determine SSL cert expire date from the cert file (.p12)

1. Use openssl to extract the certificate from the .p12 file to a .pem file

openssl pkcs12 -in certificate.p12 -out certificate.pem -nodes

2.  You can extract the expiration date from the certifcate in the .pem file 

cat certificate.pem | openssl x509 -noout -enddate

References:https://stackoverflow.com/questions/28373771/how-to-determine-ssl-cert-expire-date-from-the-cert-file-itself-p12