#Writing scripts with Hardhat

In this guide we will go through the steps of creating a script with Hardhat. For a general overview of using Hardhat refer to the Getting started guide.

You can write your own custom scripts that can use all of Hardhat's functionality; for example, in this guide, we will work through scripts that print the list of available accounts.

There are two ways of writing a script that accesses the Hardhat Runtime Environment.

# Running scripts with the Hardhat CLI

You can write scripts that access the Hardhat Runtime Environment's properties as global variables.

These scripts must be run through Hardhat: npx hardhat run script.js.

This makes it easy to port scripts that were developed for other tools and that inject variables into the global state.

# Standalone scripts: using Hardhat as a library

The second option leverages Hardhat's architecture to allow for more flexibility. Hardhat has been designed as a library, allowing you to get creative and build standalone CLI tools that access your development environment. This means that by simply requiring it:

const hre = require("hardhat");

You can get access to all your tasks and plugins. To run these scripts you simply go through node: node script.js.

To try this out, create a new directory called scripts in your project's root directory. Then, inside that directory, create a file called accounts.js with the following content:

const hre = require("hardhat");

async function main() {
  const accounts = await hre.ethers.getSigners();

  for (const account of accounts) {
    console.log(account.address);
  }
}

main().catch((error) => {
  console.error(error);
  process.exitCode = 1;
});

Now run the script:

node scripts/accounts.js

By accessing the Hardhat Runtime Environment at the top, you are allowed to run the script in a standalone fashion.

#Hardhat arguments

You can still pass arguments to Hardhat when running a standalone script. This is done by setting environment variables. Some of these are:

• HARDHAT_NETWORK: Sets the network to connect to.

• HARDHAT_SHOW_STACK_TRACES: Enables JavaScript stack traces of expected errors.

• HARDHAT_VERBOSE: Enables Hardhat verbose logging.

• HARDHAT_MAX_MEMORY: Sets the maximum amount of memory that Hardhat can use.

For example, instead of doing npx hardhat --network localhost run script.js, you can do HARDHAT_NETWORK=localhost node script.js. Check our Environment variables reference to learn more about this.