Turning to apple is a good solution, but I don't believe that all things are in the same place as they are on a standard PC Linux install (correct me if I'm wrong). but all the commands are there.

While it's nix under the hood, it's pretty far under the hood, and most of the standard Unix conventions are thrown out the window. It has many if not most of the Unix user commands, but I don't know if it'd really get you anywhere useful if your intent was to learn Unix.