# Argument Format

There are a few special ways to provide arguments to bw commands.

# Decimals

A lot of numbers on Ethereum use a large number of decimals which need to be converted. Most tokens and ETH itself have 18 decimals for every day use, but the blockchain itself doesn't know about decimals.

For example, when you say 1 ETH, the blockchain thinks 1000000000000000000, in other words 1 followed by 18 zeroes for 18 decimals. If you tell the blockchain 1 for ETH, it will think you meant 0.000000000000000001 ETH.

Some bw commands already convert this automatically (send, ether), but it's more complicated with more generic commands like contract-call, contract-send and contract-deploy.

For those commands, there is a special decimal format you can use to make it easier:


Where <number> is the number you want to use, and [options] specify how the decimals are determined.

Here are some examples:


this will use the number 1.2, and gets the number of decimals from the contract you're using. For example:

./eth-tool -f acc.key contract-send approve address 1.2d

This will use the decimals of the contract you're calling approve on.


this will call a function on the contract called "token", and then use the number of decimals from the contract address that provides.


this will load a contract address from the file called "foodcoin", and use that contract's decimals. For example:

./eth-tool -f acc.key contract-send setTokenPrice foodcoin 1.2d:foodcoin


this will use the contract address in the argument # 1, and get decimals from that. For example:

./eth-tool -f acc.key contract-send setTokenPrice foodcoin 1.2d:1

You can also use scientific notation. For example 1e18 would be 1 and 18 decimals.

# Addresses

Any command that accepts an address can instead read it from a file. When providing an address if the value doesn't match an address' format, it will be treated as a file.

For example, if the file foodcoin has the following content:

Address: 0xe8340fdfe79851e9e117b3033e147a654dbdb0ae

Then, instead of doing this:

./bw token-balances 0xe8340fdfe79851e9e117b3033e147a654dbdb0ae

You can use the file like this:

./bw token-balances foodcoin

It even works with the --address option:

./bw --address foodcoin contract-call name