How to pull SSL certificates from an external server

# Pull a server's certificate:
#
openssl s_client -connect ${SERVER}:${PORT}
 
# When dealing with a mail server using STARTTLS, we need
# to modify this a bit:
#
openssl s_client -connect ${SERVER}:${PORT} \
                 -starttls smtp
 
# Pull the entire certificate chain:
#
openssl s_client -connect ${SERVER}:${PORT} -showcerts
 
# Get certificate information:
#
openssl x509 -in $CERT -text -noout
 
# Calculate a SHA1 fingerprint:
#
openssl x509 -noout -in $CERT -fingerprint
 
# Calculate a MD5 fingerprint:
#
openssl x509 -noout -in $CERT -fingerprint -md5