swift – 错误：使用未解析的标识符“进程”

Swift版本：3.0预览版6

我正在关注这个getting started page

在greeter.swift

func sayHello(name: String) {
  print("Hello,(name)!")
}

在main.swift中

if Process.arguments.count != 2 {
    print("Usage: hello NAME")
} else {
    let name = Process.arguments[1]
    SayHello(name: name)
}

我收到错误

$swift build
Compile Swift Module 'myapp' (2 sources)
/Sources/main.swift:1:4: error: use of unresolved identifier 'Process'
if Process.arguments.count != 2 {
   ^~~~~~~
/Sources/main.swift:4:16: error: use of unresolved identifier 'Process'
    let name = Process.arguments[1]
               ^~~~~~~
<unknown>:0: error: build had 1 command failures
error: exit(1): swift/bin/swift-build-tool -f .build/debug.yaml