title: Recommended way to copy arbitrary files using Cocoa
body: <p>I need to copy file from one OS X volume to another OS X volume. While an *.app isn't strictly speaking a file but a folder, user expect them to be a unit. Thus, if user selects a file, the app should not show its folder's contents, but copy it as a unit.</p>
  
  <p><strong>Therefore I ask, if there exists a recommended way to copy files using pure Cocoa code.</strong></p>
  
  <p><strong>Optional:</strong> Which <strong>command line tool</strong> provides help and could be utilized by a Cocoa application.</p>