# Interacting via CLI

### **Introduction**

For advanced developers, interacting with Studio Blockchain via the Command Line Interface (CLI) offers powerful tools to deploy contracts, query blockchain data, and manage transactions programmatically. This guide covers setting up the CLI, executing essential commands, and leveraging Web3 libraries for seamless interaction.

***

### **1. Setting Up CLI Tools**

#### **Prerequisites**

Ensure the following are installed on your system:

1. **Node.js:** For running JavaScript-based CLI tools (download [here](https://nodejs.org)).
2. **npm or yarn:** For managing packages and dependencies.
3. **web3.js or ethers.js:** Libraries to interact with the blockchain.

#### **Installing Web3.js or Ethers.js**

Install the library of your choice globally:

```bash
bashCopy codenpm install -g web3 ethers
```

***

### **2. Configuring the RPC Endpoint**

To interact with Studio Blockchain, you need to configure the RPC endpoint in your scripts or CLI environment.

#### **Testnet Details:**

* **HTTP RPC URL:** `https://rpc.studio-blockchain.com`
* **WebSocket URL:** `wss://ws.studio-blockchain.com`
* **Chain ID:** \[Insert Chain ID here]

#### **Example Configuration in JavaScript**

```javascript
javascriptCopy codeconst Web3 = require('web3');
const web3 = new Web3('https://rpc.studio-blockchain.com');

// Check network ID
web3.eth.net.getId().then(console.log);
```

***

### **3. Common CLI Commands**

#### **Querying Blockchain Data**

1. **Get Latest Block:**

   ```bash
   bashCopy codecurl -X POST -H "Content-Type: application/json" \
   --data '{"jsonrpc":"2.0","method":"eth_getBlockByNumber","params":["latest", true],"id":1}' \
   https://rpc.studio-blockchain.com
   ```
2. **Get Block by Number:** Replace `0x10` with the block number in hexadecimal.

   ```bash
   bashCopy codecurl -X POST -H "Content-Type: application/json" \
   --data '{"jsonrpc":"2.0","method":"eth_getBlockByNumber","params":["0x10", true],"id":1}' \
   https://rpc.studio-blockchain.com
   ```
3. **Check Wallet Balance:** Replace `0xYourAddress` with the wallet address.

   ```bash
   bashCopy codecurl -X POST -H "Content-Type: application/json" \
   --data '{"jsonrpc":"2.0","method":"eth_getBalance","params":["0xYourAddress", "latest"],"id":1}' \
   https://rpc.studio-blockchain.com
   ```

***

#### **Deploying a Contract via CLI**

Use the `web3` library to deploy smart contracts programmatically.

**Example: Deploying an ERC-20 Token**

```javascript
javascriptCopy codeconst Web3 = require('web3');
const web3 = new Web3('https://rpc.studio-blockchain.com');

// Replace with your compiled contract ABI and bytecode
const abi = [ /* ABI array */ ];
const bytecode = '0x...'; // Contract bytecode

const deployContract = async () => {
    const account = web3.eth.accounts.privateKeyToAccount('0xYourPrivateKey');
    web3.eth.accounts.wallet.add(account);

    const contract = new web3.eth.Contract(abi);

    const deployTx = contract.deploy({ data: bytecode });
    const gas = await deployTx.estimateGas();
    const result = await deployTx.send({
        from: account.address,
        gas,
    });

    console.log('Contract deployed at:', result.options.address);
};

deployContract();
```

***

#### **Monitoring Transactions**

1. **Get Transaction by Hash:** Replace `0xTxHash` with the transaction hash.

   ```bash
   bashCopy codecurl -X POST -H "Content-Type: application/json" \
   --data '{"jsonrpc":"2.0","method":"eth_getTransactionByHash","params":["0xTxHash"],"id":1}' \
   https://rpc.studio-blockchain.com
   ```
2. **Get Transaction Receipt:**

   ```bash
   bashCopy codecurl -X POST -H "Content-Type: application/json" \
   --data '{"jsonrpc":"2.0","method":"eth_getTransactionReceipt","params":["0xTxHash"],"id":1}' \
   https://rpc.studio-blockchain.com
   ```

***

#### **Subscribing to Events via WebSocket**

Leverage the WebSocket endpoint for real-time updates.

**Example: Subscribe to New Blocks**

```javascript
javascriptCopy codeconst Web3 = require('web3');
const web3 = new Web3('wss://ws.studio-blockchain.com');

web3.eth.subscribe('newBlockHeaders', (error, blockHeader) => {
    if (!error) {
        console.log('New block:', blockHeader);
    } else {
        console.error(error);
    }
});
```

***

### **4. Best Practices for CLI Usage**

1. **Secure Private Keys:**
   * Avoid hardcoding private keys in your scripts.
   * Use environment variables or secure key management tools.
2. **Monitor Gas Usage:**
   * Use `web3.eth.getGasPrice()` to get the current gas price.
   * Monitor gas usage metrics via the API (`/blocks`, `/transactions/latest`).
3. **Use Testnet for Experimentation:**
   * Always test your scripts on the Studio Blockchain Testnet before deploying to the mainnet.
4. **Automate Tasks:**
   * Use scripts to automate repetitive tasks like deploying contracts or querying balances.