linux | bash - get domain certificate fingerprint (md5, sha-1, sha-256)

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echo | openssl s_client -connect SERVER_ADDRESS_HERE:443 -servername DOMAIN_NAME_HERE 2>/dev/null | openssl x509 -noout -fingerprint -md5
echo | openssl s_client -connect SERVER_ADDRESS_HERE:443 -servername DOMAIN_NAME_HERE 2>/dev/null | openssl x509 -noout -fingerprint -sha1
echo | openssl s_client -connect SERVER_ADDRESS_HERE:443 -servername DOMAIN_NAME_HERE 2>/dev/null | openssl x509 -noout -fingerprint -sha256



# -------------------------------------------------------------
# Practical example (for gitlab.com):
# -------------------------------------------------------------

echo | openssl s_client -connect gitlab.com:443 -servername gitlab.com 2>/dev/null | openssl x509 -noout -fingerprint -md5
echo | openssl s_client -connect gitlab.com:443 -servername gitlab.com 2>/dev/null | openssl x509 -noout -fingerprint -sha1
echo | openssl s_client -connect gitlab.com:443 -servername gitlab.com 2>/dev/null | openssl x509 -noout -fingerprint -sha256


# Example output:
#
#     md5 Fingerprint=04:04:10:1C:BF:D9:A1:F6:16:49:60:5B:66:5B:88:52
#     sha1 Fingerprint=F7:4E:F9:4C:4E:B4:FF:39:A2:19:F7:5D:40:CF:10:26:D7:E7:F2:99
#     sha256 Fingerprint=A7:2B:29:21:4B:15:3C:88:4B:74:2F:8A:58:10:69:53:4D:55:B0:E2:11:CB:65:D6:94:91:6B:4B:F5:E3:37:9D