# Standard I/O

One of Lune's most useful libraries for writing scripts is the standard I/O library, also known as
`stdio`, which will be the first one we introduce here. The pages following this one will introduce
several others.

## Prompting for User Input

The easiest way to get started and being productive using Lune is to prompt the person running your
script for some text input, which you can do using the [`stdio`](../../api-reference/stdio.md)
library. Let's make a script called `hello.luau`:

```lua copy filename="hello.luau"
local stdio = require("@lune/stdio")

local name = stdio.prompt("text", "Hello there! What's your name?")

print("Hello, " .. name .. "!")
```

Now you can place this script in your current directory, and run it using Lune:

```sh copy filename="Bash"
lune hello
```

You can also prompt for more than just text. Let's extend the above script and ask the person
running the script if that was really their name:

```lua copy filename="hello.luau"
local confirmed = stdio.prompt("confirm", "Is that really your name?")
if confirmed then
	print("Nice to meet you, " .. name .. "!")
	print("Have a great day!")
else
	print("You lied to me! Goodbye 😡")
end
```

There are more options for prompting for user input than what we covered in this example, but these
two basic prompting methods should cover most of your use cases and get you started with making
interactive scripts.

Next, head on over to the following section on [Script Arguments](./4-script-arguments.md) or check
out the bonus game below!

<details>
<summary>Bonus</summary>

## Guessing Game

Here's a tiny game you can play versus the computer, using nothing but Lune's
[`stdio`](../../api-reference/stdio.md) library and Luau's `math` library. This is a bit longer of a
script, but don't worry, it is still only using the same functions as the script above, albeit this
time together with a `while ... do` loop and a couple `if ... then` statements:

```lua copy filename="guessing-game.luau"
local stdio = require("@lune/stdio")

print("")
print("Let's play a game! Whoever guesses the correct number between 1 and 10 first will win.")
print("")

local answer = tostring(math.random(1, 10))

local guess = stdio.prompt("text", "Input a number between 1 and 10")
while guess ~= answer do
	print("Incorrect! Computer's turn...")

	local computer = tostring(math.random(1, 10))
	print("The computer guessed", computer)

	if computer == answer then
		break
	end

	print("Incorrect! Your turn...")
	guess = stdio.prompt("text", "Input a number between 1 and 10")
end

print("")
print(if guess == answer then "You won the game! 🎉" else "The computer won the game! 😭")
print("")
```

Just like before, you can place this script in your current directory, and run it using Lune:

```sh copy filename="Bash"
lune guessing-game
```

</details>
