You don't need a multi-dimensional array to do that. You could get the same effect without the complexity by taking advantage of the regular syntax of Unix name:

• sort list ascibetically
• loop through each path in order. When outputing each item,
  • use split to convert each path into an array of names, e.g. ['var', 'www', 'data', 'misc']
  • use size of array to determine amount of indentation, e.g. 4 path components = 3 tabs, 3 path components = 2 tabs, and so on.
  • display only the last array element on each line after the space.

Presto, there you have your output. I'm not posting code on purpose. Without context for why you are interested in this question, it smells a lot like homework or a search for hints in a golf contest. If I'm providing help for that sort of thing, I generally like to know that I'm doing so, so I can make a judgment about how much help is too much (or too little) help. Perhaps you could add a few words about why you care about this?

Best, beth