zaster

zaster is a simple double account book keeping software. Main features:

• Double account book keeping
• Simple XML file format makes for easy transfer to or from other tools
• Supports account hierarchies (transactions on child accounts will be added to the parents; useful for grouped reporting)

XML file format

Create an XML file from the following template:

<?xml version="1.0" encoding="utf-8"?>
<zaster>
  <accounts>
    <!-- account elements will go here -->
  </accounts>
  <transactions>
    <!-- transaction elements will go here -->
  </transactions>
</zaster>

Account elements

Each account element has the following attributes:

• id: ID of the account. Must be unique. Required.
• parent: ID of the parent account (if any). The definition of the parent must precede the definition of the child. Optional.
• description: Any description you'd like. Optional.

Transaction elements

Each transaction element has the following attributes:

• id: ID of the transaction. Must be unique. Required.
• date: Date (in ISO8601 format, although that is not enforced) of the transaction. Required.
• amount: The amount of currency being transferred in the transaction. Required.
• from: The ID of the account, where the amount is subtracted. Required.
• to: The ID of the account, where the amount is added. Required.
• comment: Any description you'd like. Optional.

Usage tips

Use account hierarchies for reporting

If you decided you want to differentiate your expenses between categories "food", "house", "car" and "other", and for the car you want to see reports separately for "repairs" and "fuel", you might create the following XML structure:

<?xml version="1.0" encoding="utf-8"?>
<zaster>
  <accounts>
    <account id="expenses" />
    <account id="food" parent="expenses" />
    <account id="house" parent="expenses" />
    <account id="car" parent="expenses" />
    <account id="fuel" parent="car" />
    <account id="repairs" parent="car" />
    <account id="other" parent="expenses" />
  </accounts>
<!-- ... -->
</zaster>

With this setup, you can show reports on "expenses" in general, "car" (a bit more specific, but still a group) or "repairs" (very specific).

Note that it would not be possible to have another "repairs" account for the house. (The next section presents a possible solution.)

Use alphabitcally sortable identifiers

By default, zaster's commands will sort outputs in lexicographical order. The balance command will list all accounts in this order. If you want all accounts of a parent to be listet below that parent, make the parent's name a part of the account's name. It would be easiest to use a separator token, e.g. any of /, \, ., ::, ...

Actually, zaster does not care about the name of accounts or IDs of transactions. But to you this may make it more comfortable when the balances for accounts "car", "fuel" and "repairs" appear under each other. So, drawing on our previous example, a possible solution would be to use something like this:

<?xml version="1.0" encoding="utf-8"?>
<zaster>
  <accounts>
    <account id="expenses" />
    <account id="expenses/food" parent="expenses" />
    <account id="expenses/house" parent="expenses" />
    <account id="expenses/house/repairs" parent="expenses/house" />
    <account id="expenses/house/mortgage" parent="expenses/house" />
    <account id="expenses/car" parent="expenses" />
    <account id="expenses/car/fuel" parent="expenses/car" />
    <account id="expenses/car/repairs" parent="expenses/car" />
    <account id="expenses/other" parent="expenses" />
  </accounts>
<!-- ... -->
</zaster>

Then the balance command would then e.g. print out lines like that:

ACCOUNT;TOTAL OUT;TOTAL IN;BALANCE
expenses;0.00;920.00;920.00
expenses/car;0.00;130.00;130.00
expenses/car/fuel;0.00;50.00;50.00
expenses/car/repairs;0.00;80.00;80.00
expenses/food;0.00;240.00;240.00
expenses/house;0.00;450.00;450.00
expenses/house/mortgage;0.00;150.00;150.00
expenses/house/repairs;0.00;300.00;300.00
expenses/other;0.00;100.00;100.00

A primer on double account book keeping

I had only little training on accounting in general, so this can only be a very shallow introduction.

The underlying idea for double account book keeping is, that everything must be nicely balanced. You can only move amounts of money from one place to another. This is very simple to understand, if you consider withdrawing money from your bank account at an ATM. In that case a certain amount of money will be moved from your bank account to your wallet, which also serves as an account.

Things may get confusing when you consider income (at least it was the case for me): You define an artificial "income" account and transfer money from there to the bank account. That means, that the accumulated balance (as per the bank statement) on the "income" account will be negative and continue growing towards negative infinity.

This is mathematically required, so on your bank account the balance can go up. That's all there is to it. It's just an artificial counterweight, so in the end it all adds up to 0.

Expenses, on the other hand, although you give money away, will continue to grow towards positive infinity. Again, the same "mind trick" is at work.