I have a directory, t:
ronsexcllentmbp:t rminnich$ ls -li
total 0
23801442 -rw-r--r--  1 rminnich  wheel  0 Jun 26 20:21 a
23801443 -rw-r--r--  2 rminnich  wheel  0 Jun 26 20:21 b

23801443 -rw-r--r--  2 rminnich  wheel  0 Jun 26 20:21 c

note that b and c are the same inode.

let's make a cpio.

ronsexcllentmbp:t rminnich$ cpio -o >../t.cpio
a
b
c

^D
1 block

what's in it?
ronsexcllentmbp:t rminnich$ cpio -ivt < ../t.cpio
-rw-r--r--   1 rminnich wheel           0 Jun 26 20:21 a
-rw-r--r--   2 rminnich wheel           0 Jun 26 20:21 b
-rw-r--r--   2 rminnich wheel           0 Jun 26 20:21 c link to b

"c link to b"? wtf? Who thought that was a good idea? because ...

ronsexcllentmbp:t rminnich$ touch 'c link to b'
ronsexcllentmbp:t rminnich$ ls -l
total 0
-rw-r--r--  1 rminnich  wheel  0 Jun 26 20:21 a
-rw-r--r--  2 rminnich  wheel  0 Jun 26 20:21 b
-rw-r--r--  2 rminnich  wheel  0 Jun 26 20:21 c
-rw-r--r--  1 rminnich  wheel  0 Jun 26 20:22 c link to b

and

ronsexcllentmbp:t rminnich$ cpio -o >../t.cpio
a
b
c
c link to b

^D

ronsexcllentmbp:t rminnich$ cpio -ivt < ../t.cpio
-rw-r--r--   1 rminnich wheel           0 Jun 26 20:21 a
-rw-r--r--   2 rminnich wheel           0 Jun 26 20:21 b
-rw-r--r--   2 rminnich wheel           0 Jun 26 20:21 c link to b
-rw-r--r--   1 rminnich wheel           0 Jun 26 20:22 c link to b

so ... it looks like a file is there twice, because somebody thought it was a good idea to confuse a file name and file metadata. And, anyway, it's just as accurate to have it say

-rw-r--r--   1 rminnich wheel           0 Jun 26 20:21 a
-rw-r--r--   2 rminnich wheel           0 Jun 26 20:21 b link to c
-rw-r--r--   2 rminnich wheel           0 Jun 26 20:21 c link to b
-rw-r--r--   1 rminnich wheel           0 Jun 26 20:22 c link to b

Right? :-)

From the same people who brought you this:

ronsexcllentmbp:t rminnich$ bc
>>>

Somebody needs to get the osx folks a unix manual set :-)