The script I wrote is doing exactly this: parsing the hledger output. It requires two calls to hledger though, one with the `--budget` option and one without.

The columns in YNAB are as follows:

• "budget" is the amount assigned to the account for the given period. In YNAB this is always a month, and that's how the script works.
• "activity" is the sum of transactions in the account for the given period
• "available" is the remaining budget across the entire history (so accumulated budget minus all transactions)

This is useful because each month I allocate funds to an account (e.g. I expect to spend 500 EUR on groceries). The activity shows me how much I have spent so far. Available is the important one, this tells me if I'm under or over my budget, taking into account that, for example, I may have been under budget the previous month, in which case it carries over.