This will add a web server's SSL certificate to your Ubuntu System-wide keystore

add-host-to-ubuntu-keystore.sh

#!/bin/bash

host=$1
port=$2

# Make sure we got the host name
if (( ${#host} == 0 )); then
    echo "usage: $0 <hostname> [port]"
    exit 1
elif (( ${#port} == 0 )); then
    # Set default port if it wasn't passed
    port=443
fi

# Check for root/sudo access
if ( ! sudo -n echo -n ''); then
    echo "This script requires root access to run.  please run:"
    echo "  sudo $0 $host $port"
fi

# Make sure ca-certificates-java is installed
if (dpkg -s ca-certificates-java 2> /dev/null > /dev/null); then
    sudo apt-get install -y ca-certificates-java
fi

# check for local ca-certificates folder
if [ ! -d /usr/share/ca-certificates/local ]; then
    sudo mkdir /usr/share/ca-certificates/local/
fi

# Get the certificate, and write it to a file
echo "" | openssl s_client -showcerts -host ${host} -port ${port} 2> /dev/null \
    | openssl x509 | sudo tee /usr/share/ca-certificates/local/$host.crt

# add the new file to the configuration
echo "local/$host.crt" | sudo tee -a /etc/ca-certificates.conf

# run update-ca-certificates
sudo update-ca-certificates