---
title: NSUserUnixTask.CompletionHandler
framework: foundation
role: symbol
role_heading: Type Alias
path: foundation/nsuserunixtask/completionhandler
---

# NSUserUnixTask.CompletionHandler

Implement this block to retrieve an error from the Unix scripted executed by execute(withArguments:completionHandler:).

## Declaration

```swift
typealias CompletionHandler = @Sendable ((any Error)?) -> Void
```