Ask HN: What data structure/db should I use for storing the file tree structure?

I am trying to write an application(I am using python) to have a copy of a remote machines directory structure in my local machine (not the actual content of the files in the remote machine). Once I store it in my local machine, I want to be be able to perform the following operations on my local copy of the tree structure "ls" "ls /etc" "ls /etc/bin/yahoo" and see the listing. Also if I change/add a dir/file name in the remote machine, I want to have the ability to easily update it in my local data structure.