title: Swift command hangs
body: <p>I'm trying to write a simple Hello World program, and run it from the command line. The code is simple.</p>
  <pre><code>import Foundation
  
  print(&quot;Hello World&quot;)
  </code></pre>
  <p>When I run <code>swift HelloWorld.swift</code> the program just hangs, and outputs nothing, until I hit CTRL-Z to kill it. Any ideas on what the problem might be. It's such a simple example, I can't figure out what the problem is.</p>
  <p>I know I'm putting in the right file name. When I put the wrong file name in it says &quot;error: unable to invoke subcommand: /Library/Developer/CommandLineTools/usr/bin/swift-WrongFileName (No such file or directory)&quot;</p>