Directories treated by OS X as executable Under OS X, there seem to be two different types of directory. One is an ordinary directory, as in Unix. The other is an "executable directory", on which you can double-click to start up an app.


Are there standard names for these two different types of directory?
Using Unix tools (perhaps downloaded from MacPorts), how would one distinguish between these?
They are called Packages or bundles.

From Apple's Documentation:


  
  A package is any directory that the Finder presents to the user as if it were a single file.
  A bundle is a directory with a standardized hierarchical structure that holds executable code and the resources used by that code.
  


Apparently there is a special "Package Bit" that's set on those directories.