How to determine SSL cert expire date from the cert file itself(.p12)

You can use openssl to extract the certificate from the .p12 file to a .pem file using the following command:

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

Then, you can extract the expiration date from the certificate in the .pem file using the following command:

cat certificate.pem | openssl x509 -noout -enddate