# Using Node.js REPL Terminal

The `node` command is the one we use to run our `Node.js scripts`:

```
node script.js
```

If we omit the `filename`, we use it in `REPL` (Read Evaluate Print Loop) mode:

```
node
```

> 
**Note: ** REPL also known as Read Evaluate Print Loop is a programming language environment(Basically a console window) that takes single expression as user input and returns the result back to the console after execution.

If you try it now in your `terminal`, this is what happens:

```
❯ node

>
```

the command stays in `idle mode` and waits for us to enter something.

> Tip: if you are unsure how to open your terminal, google "How to open terminal on <your-operating-system>".

The `REPL` is waiting for us to enter some JavaScript code, to be more precise.

Start simple and enter

```
> console.log('test')

test

undefined

>
```

The first value, test, is the output we told the console to print, then we get undefined which is the return value of running `console.log()`.

We can now enter a new line of JavaScript.

REPL Commands
-------------

-   ctrl + c - terminate the current command.
-   ctrl + c twice - terminate the Node REPL.
-   ctrl + d - terminate the Node REPL.
-   Up/Down Keys - see command history and modify previous commands.
-   tab Keys - list of current commands.
-   .help - list of all commands.
-   .break - exit from multiline expression.
-   .clear - exit from multiline expression.
-   .save filename - save the current Node REPL session to a file.
-   .load filename - load file content in current Node REPL session.

`So in this section, we saw the usage of Node REPL to execute Javascript code.`

​