📜 Etherscript

A collection of useful scripts for interacting with EVM compatible blockchains from the command line

• Environment Variable Management
  • Usage
• Hardhat Guide
  • Scripts
  • Tasks
• Script Glossary
  • swap
  • get-price
  • get-abi

Environment Variable Management

This repository uses the NPM package @chainlink/env-enc to keep private keys, RPC URLs, and other secrets encrypted at rest. This helps reduce the risk of leaking your private key.

By default, the @chainlink/env-enc package will store your encrypted environment variables in a file named .env.enc in the root directory of this repository. Ensure that your .gitignore file includes.env.enc

Usage

Set the encryption password by running the command

npx env-enc set-pw

Set a new environment variable by running the command

npx env-enc set

See all your currently set environment variables

npx env-enc view

Remove an environment variable

npx env-enc remove SOME_ENV_VAR_NAME

Hardhat Guide

• hardhat.config.ts specifies the settings like imports, networks, solidity verions, etc that will all be made available through the hre (hardhat runtime environment)

• all scripts and tasks are by default executed on the local hardhat network, but can be configured to run on other networks by passing the --network flag .i.e. yarn hardhat NAME_OF_TASK --network arbitrum

Scripts

• good for executing code that doesnt require parameters

yarn hardhat run scripts/PATH_TO_SCRIPT.ts

Tasks

• good for executing scripts that require parameters passed on the command line
• to see all availalble tasks run yarn hardhat
• to see which flags you need to pass run yarn hardhat NAME_OF_TASK --help
• not allowed to import hre into scripts that are imported and used by tasks

yarn hardhat NAME_OF_TASK --NAME_OF_FLAG VALUE_OF_FLAG

Script Glossary

swap

Swap tokens using uniswap's smart order router that computes the optimal route before executing the swap.

Required flags

Parameter	Description
amount	The human readable amount of the token to swap in
in	The symbol of the token to swap in
out	The symbol of the token to swap out

Example usage

Execute a swap on the local hardhat network that is configured as fork of arbitrum

yarn hardhat swap --in USDC --amount 100 --out rETH

get-abi

Fetches abi from etherscan API and outputs the result to a .json file inside the ./abis directory

Required flags

Parameter	Description
contract	The target contract address (must be verified on etherscan)
file-name	The name for the file that will be output into abis directory

Example usage

yarn hardhat get-abi --contract 0x514910771AF9Ca656af840dff83E8264EcF986CA --file-name link-token-abi --network mainnet

get-price

Gets the price for a base asset in terms of a quote asset using chainlink price feeds

Required flags

Parameter	Description
contract	The chainlink price feed contract address

Example usage

Fetch the price of ETH in USD on mainnet

yarn hardhat get-price --contract 0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419 --network mainnet