使用他们的API干净地做到这一点：

#!/usr/bin/env sh

API='https://markets.businessinsider.com/ajax/'

implode() { printf %s "$*";}

ExchangeRate_GetConversionForCurrenciesNumbers() {
  isoCodeForeign=$1
  isoCodeLocal=$2
  amount=$3
  date=$4
  cacheFile="/tmp/$date-$amount-$isoCodeForeign-$isoCodeLocal.json"

  # Check if we have cached the result to avoid front-running the API
  if ! [ -e "$cacheFile" ]; then
    post_vars=$(
      IFS=\& implode \
        "isoCodeForeign=$isoCodeForeign" \
        "isoCodeLocal=$isoCodeLocal" \
        "amount=$amount" \
        "date=$date"
    )

    method='ExchangeRate_GetConversionForCurrenciesNumbers'
    url="$API$method?$post_vars"
    if ! http_code=$(
      curl -s -w '%{http_code}' \
        -H 'Accept: application/json' \
        -X POST "$url" -o "$cacheFile"
    ); then
      printf 'Failed to connect to %s\n' "$API"
      rm -f "$cacheFile"
      return 1
    fi >&2
    if ! [ "$http_code" = '200' ]; then
      printf 'Unexpected http_code=%s from %s:\n' "$http_code" "POST $url"
      cat "$cacheFile"
      echo
      rm -f "$cacheFile"
      return 1
    fi >&2
  fi
  jq -r '.ConvertedAmountFourDigits' "$cacheFile"
}

getRateEURO_USToday() {
  ExchangeRate_GetConversionForCurrenciesNumbers EUR USD 1 "$(date '+%Y-%m-%d')"
}

exchange_rate=$(getRateEURO_USToday) || exit 1
# Set LC_NUMERIC=C because the float format returned is using . as decimal
LC_NUMERIC=C printf 'The exchange rate for EUR to USD today is: %.4f\n' \
  "$exchange_rate"