“Hello world” written using NASM assembly

hello.S

section .data
hello:  db "Hello world!",0xa
length: equ $-hello

section .text
global  _start
_start:
    mov eax, 4 ; write(1, hello, length)
    mov ebx, 1
    mov ecx, hello
    mov edx, length
    int 0x80

    mov eax, 1 ; exit(0)
    mov ebx, 0
    int 0x80