Answer by user181713 for Displaying a remote SSL certificate details using CLI tools

Basic certificate info

That's my everyday script:

curl --insecure -vvI https://www.example.com 2>&1 | awk 'BEGIN { cert=0 } /^\* SSL connection/ { cert=1 } /^\*/ { if (cert) print }'

Output:

* SSL connection using TLSv1.3 / TLS_AES_256_GCM_SHA384* ALPN, server accepted to use h2* Server certificate:*  subject: C=US; ST=California; L=Los Angeles; O=Verizon Digital Media Services, Inc.; CN=www.example.org*  start date: Dec 10 00:00:00 2021 GMT*  expire date: Dec  9 23:59:59 2022 GMT*  issuer: C=US; O=DigiCert Inc; CN=DigiCert TLS RSA SHA256 2020 CA1*  SSL certificate verify ok.* Using HTTP2, server supports multi-use* Connection state changed (HTTP/2 confirmed)* Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0* Using Stream ID: 1 (easy handle 0x5588e1f5ae30)* TLSv1.3 (IN), TLS handshake, Newsession Ticket (4):* TLSv1.3 (IN), TLS handshake, Newsession Ticket (4):* old SSL session ID is stale, removing* Connection state changed (MAX_CONCURRENT_STREAMS == 100)!* Connection #0 to host www.example.com left intact

Full certificate info

openssl s_client -connect www.example.com:443 </dev/null 2>/dev/null | openssl x509 -inform pem -text