Get TLS connection information for a given server.

tls-info.sh

#!/bin/bash

function usage() {
    echo "Usage: $0 hostname [port]" >&2
    echo "    hostname   Hostname of the server to connect to." >&2
    echo "    port       Port of the server running TLS, defaults" >&2
    echo "               to 443." >&2
    echo ""
    exit 1
}

if [ -z "$1" ]; then
    usage
fi

tls_hostname="$1"
# default to 443
tls_port="${2-:443}"

echo "Q" | openssl s_client -connect $tls_hostname:$tls_port