openssl rsa -text -in <path to private key>
openssl x509 -text -in <path to public key>
openssl req -text -in <path to csr>
openssl x509 -text -noout -in <path to crt>
openssl s_client -connect <host>:<port>
openssl s_client -connect 127.0.0.1:smtp -starttls smtp
Find CRL Url, Get CRL, get Serial from to check certificate, find serial in CRL list
openssl x509 -in <path to crt> -noout -text | grep -A 4 CRL
wget '<url to crl>'
openssl x509 -in <crt file> -noout -serial
openssl crl -inform DER -text -in <crl file>