bash function to update host keys

hostkey.sh

hostkey () {
  for HOST in "$@"; do
    LIST=$HOST
    PARTS=(${HOST//./ })
    if [[ ${#PARTS[*]} -gt 2 && "${PARTS[0]}" != "$HOST" ]]; then
      LIST="$LIST ${PARTS[0]}"
    fi
    IP=$(dig +short $HOST)
    if [ -n "$IP" ]; then
      LIST="$LIST $IP"
    fi
    for ITEM in $LIST; do
      echo "removing old key for <$ITEM>..."
      ssh-keygen -f ~/.ssh/known_hosts -R $ITEM
      echo "adding new key for <$ITEM>..."
      ssh-keyscan $ITEM >> ~/.ssh/known_hosts
    done
  done
}