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.