Generate a private key (.key file) a certificate (.crt file) and a .pem file (containing the private key and a certificate)

generate-pem-certificate-and-key.sh

#!/bin/bash
# Generate a private key (.key file) a certificate (.crt file) and 
# a .pem file (containing the private key and a certificate)
# author: mariogasparoni.
# Usage: ./generate-pem-certificate-and-key.sh <HOSTNAME|IP-ADDRESS>

set -e
HOSTNAME=$1

if [ -z "$HOSTNAME" ]
then
        echo "Usage: ./generate-pem-certificate-and-key.sh <HOSTNAME|IP-ADDRESS>"
        exit 1;
fi

CERTNAME=$HOSTNAME

sudo apt-get install -y gnutls-bin

#Generate private key
certtool --generate-privkey --outfile $CERTNAME.key
echo 'organization = '$HOSTNAME > /tmp/certtool.tmpl
echo 'cn = '$HOSTNAME >> /tmp/certtool.tmpl
echo 'unit = '$HOSTNAME >> /tmp/certtool.tmpl
echo 'dns_name = '$HOSTNAME >> /tmp/certtool.tmpl


# Bypass Java Exception: "javax.net.ssl.SSLHandshakeException: java.security.cert.CertificateException: No subject alternative names present"
if [[ $HOSTNAME =~ ^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$ ]]
then
        echo 'ip_address = '$HOSTNAME >> /tmp/certtool.tmpl
fi

#Generate certificate using private key
certtool --generate-self-signed --load-privkey $CERTNAME.key --template /tmp/certtool.tmpl > $CERTNAME.crt

#Generate PEM's container, using both private key and certificate
cat $CERTNAME.key $CERTNAME.crt > $CERTNAME.pem