Problems with freebsd assembly

[David Jackson]

I am having great difficulty running a very simple assembler program on 
FreeBSD on x86 in my efforts to learn some assembly programming on 
FreeBSD.  I have tried to compile the following with nasm, however i get 
nothing in response when I attempt to run this program:

       section .data
       hello   db      'Hello, World!', 0xa
       hbytes  equ     $ - hello

       section .text
       global  _start
       _start:
       push    dword hbytes
       push    dword hello
       push    dword 1
       mov eax,0x4
       int 0x80
       add esp,12

       push    dword 0
       mov eax,0x1
       int 0x80

nasm -f elf -o hello1s.o hello1.s
ld -s -o hello1s hello1s.o

./hello1s prints nothing.

What is wrong here? It should print "hello world".
Thanks in advance for   your help, it is greatly appreciated.