Openssl

1. Display Certificate

See https://unix.stackexchange.com/questions/696224/using-openssl-to-display-all-certificates-of-a-pem-file.

# List only first certificate.
openssl x509 -in cert.pem -text

# List all certificates.
openssl crl2pkcs7 -nocrl -certfile cert.pem | openssl pkcs7 -noout -print_certs -text