Create and prepare a smart contract

First of all, you need to create and prepare your smart contract to work with it. To do this:

Install Solidity compiler by running the following command:
```
npm install -g solc
```
Create a smart contract file greeter.sol, which contains the following code:
```
//SPDX-License-Identifier: Unlicense
pragma solidity ^0.8.13;
contract Greeter {
string private greeting;

 constructor() {
     greeting = 'Hello World!';
 }
function greet() public view returns (string memory) {
return greeting;
}
function setGreeting(string memory _greeting) public {
greeting = _greeting;
}
}
```
The main actions in this code example:
1. Declaration of a new contract variable, where the greeting variable will be stored:
```
string private greeting;
```
2. Declaration of contract inner variable, where the greeting variable will be stored:
```
constructor() {
  greeting = 'Hello World!';
}
```
  When you create a smart contract, the greeting variable is initialized with a classical Hello World! text.
3. The greet() function returns the current greeting.
4. The setGreeting() function replaces the current greeting with a new one.
Compile the given code. You will receive an .abi file:
Run the following commands in the directory, where the greeter.sol file is stored:
1. ```
  solcjs --bin greeter.sol
```
  As a result you will get a greeter_sol_Greeter.bin file.
2. ```
  solcjs --abi greeter.sol
```
  As a result you will get a greeter_sol_Greeter.abi file.
Replace the greeter_sol_Greeter.abi file extension from .abi to .json to let the code recognize it right.