function cert -d "Retrieve the SSL certificat of a HTTPS website from the servername"
    # PEM format
    echo "Certificat of $argv[1] on port 443 (PEM format)"
    openssl s_client -servername $argv[1] -connect $argv[1]:443 2>/dev/null </dev/null |  sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p'
end