Async/await command line tool in Xcode 14.3

Update 10/4/2024: It appears in Xcode 15.3 nothing special is required and can use await right next to the hello world print.

TLDR: add @main and rename main.swift

To create a command line tool in Xcode 14.3 that uses async/await there are a few tweaks required. When we create the project using the Command Line Tool template we are left with a main.swift and the code below:

import Foundation

print("Hello, World!")

To use async/await we need to replace this with @main as follows:

import Foundation

@main
struct AsyncCommandLine {
    static func main() async throws {
        try await Task.sleep(for:.seconds(1)) // just to test async/await
        print("Hello, World!")
    }
}

Now when we compile we get the error:

'main' attribute cannot be used in a module that contains top-level code

To fix this you can simply rename main.swift to AsyncCommandLine.swift I hope this helped!