Based on the Rabobank script by @EddoKloosterman I've made some changes so it works with ASN bank exports as well.
- Create an export from your bank account on the ASN website. Make sure you tick the box 'CSV met IBAN'.
- Download the script to your machine and run from terminal:
php YnabCsvConverterASN.php ~/Downloads/yourASNexport.csv
- The script will create a new .csv file on your Desktop.
- Import that file in YNAB.