exchange_rates_nbp.sh

exchange-rates() {
  DATE="${1:-}"

  FILTER=".[] | {"
  FILTER+="table: .table,"
  FILTER+="no: .no,"
  FILTER+="date: .effectiveDate,"
  FILTER+='"EUR": .rates[] | select(.code == "EUR").mid,'
  FILTER+='"USD": .rates[] | select(.code == "USD").mid'
  FILTER+="}"

  URL="http://api.nbp.pl/api/exchangerates/tables/a/${DATE}"

  STATUS_CODE=$(curl -s -o /dev/null -w "%{http_code}" "${URL}")

  if [[ "${STATUS_CODE}" == "404" ]]
  then
    echo "There is no data for ${DATE}"
  else
    curl -s "http://api.nbp.pl/api/exchangerates/tables/a/${DATE}" | jq "${FILTER}"
  fi
}