In OS X the trash can directories are:
 - ~/.Trash
 - $topdr/.Trashes/$uid 

Afert installing the `osx-trash` gem the behaviour can be described with:
 $ ls ~/.Trash
 $ touch foo
 $ trash foo
 $ ls ~/.Trash
 foo
 $ touch foo
 $ trash foo
 $ ls ~/.Trash
 foo
 foo 17-32-40

Where 17-32-40 is HH:MM:SS. If you "Put back" a file it is moved to the
original path but it still maintains the new name (e.g. "foo 17-32-40").

The deletion time is put before the last dot:
 $ touch foo.tar.gz; trash foo.tar.gz
 $ touch foo.tar.gz; trash foo.tar.gz
 $ ls ~/.Trash
 foo.tar 17-36-13.gz  
 foo.tar.gz

The original path is stored in the ~/.Trash/.DS_Store. More details in 
http://superuser.com/questions/108301/deleting-a-single-file-from-the-trash-in-mac-os-x-snow-leopard
