Correct way to book an auto loan

[Aaron Goldblatt]

> Based on my calculations, your monthly principal/interest splits would be:

Is there an automated way to do these kinds of split calculation (under 
Linux)?

I'd like to be able to run these kinds of accounts, but do not know how to 
do the math myself, and the number of accounts I'd like to keep like this 
(two credit cards, two car notes, and a mortgage) make the prospect of 
setting it up myself manually ... daunting.

ag