- Nothing new in this lecture.  Just a reinforcement which will help you write tar.

- Goal -- write a program to print the total number of bytes stored in all files/directories
  reachable from the current directory.

- Write in parts.  1st: just sum up all files in current directory.  Test on test1.

2nd: Turn it into a procedure so you'll be able to call it recursively.  Test non-recursive.

3rd: Make it recursive and test.  It will fail because of . and ..

4th: Special-case . and .. -- Now it fails on d1/f3.

5th: Build the filename.  Make sure you hold the directory size, so that your strcpy's
     are efficient.

     Test and see that you're double-counting directories.
     Use test2 and you'll see you're double-counting the hard link.

6th: Red-black tree for inodes.  Have to write a comparison function (or do you?)

     test3 -- friggin soft links.  Fix.

7th: Go to test4, and change the number of open fd's to 10: 

     ulimit -a | grep open
     ulimit -n 10

     Fix it.    Muse.