#!/bin/sh
# Given a list of host names as arguments, generate a known_hosts file
# Copyright (C) 2013 Ryan Kavanagh <rak@debian.org>
# All rights reserved.
# 
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#  1. Redistributions of source code must retain the above copyright
#     notice, this list of conditions and the following disclaimer.
#  2. Redistributions in binary form must reproduce the above copyright
#     notice, this list of conditions and the following disclaimer in the
#     documentation and/or other materials provided with the distribution.
#  3. The name of the author may not be used to endorse or promote products
#     derived from this software without specific prior written permission.
# 
# THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
# AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
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for i in "$@"; do
    IP4=$(host -t A "$i" | awk '{ print "," $NF }');
    IP6=$(host -t AAAA "$i" | awk '{ print "," $NF }');
    if test "${IP4}" = ",record"; then
        IP4="";
    fi
    if test "${IP6}" = ",record"; then
        IP6="";
    fi
    HOST=$(echo "${i}${IP4}${IP6}" | sed -e 's/ //g');
    KEYS=$(ssh -q "$i" cat /etc/ssh/ssh_host_rsa_key.pub /etc/ssh/ssh_host_ecdsa_key.pub);
    echo "${KEYS}" | sed -e 's/^/'"${HOST}"' /g';
done