printToFile.swift

// kg: Xcode 8, Swift 3

extension FileHandle : TextOutputStream {
  public func write(_ string: String) {
    guard let data = string.data(using: .utf8) else { return }
    self.write(data)
  }
}

// now something like:

let url:URL = // url to file here
let path = url.path
guard let handle = FileHandle(forWritingAtPath:path) else { return }
defer { handle.closeFile() }
print(1,2,3,to:&handle)