---
module: [kind=event] peripheral
see: peripheral_detach For the event fired when a peripheral is detached.
---

<!--
SPDX-FileCopyrightText: 2021 The CC: Tweaked Developers

SPDX-License-Identifier: MPL-2.0
-->

The [`peripheral`] event is fired when a peripheral is attached on a side or to a modem.

## Return Values
1. [`string`]: The event name.
2. [`string`]: The side the peripheral was attached to.

## Example
Prints a message when a peripheral is attached:
```lua
while true do
  local event, side = os.pullEvent("peripheral")
  print("A peripheral was attached on side " .. side)
end
```