update_known_host.sh

#!/bin/sh
set -e

echo "Updating known host for $1 ..."
KEY=$(ssh-keyscan -t ecdsa-sha2-nistp256 $1 2> /dev/null)

if grep -q $1 ~/.ssh/known_hosts;
then
    ESCAPED_KEY=${KEY//\//\\\/}
    sed -i "" "s/$1.*$/$ESCAPED_KEY/g" ~/.ssh/known_hosts
    echo "updated $1 to $ESCAPED_KEY"
else
    echo $KEY >> ~/.ssh/known_hosts
    echo "added $1 and set to $KEY"
fi