Hello world (and commands to assembler)

;This is a hello world program, but seems to be really hard, and now I'm compiling in Linux x86
;and this is not by me, you can found it here
;http://en.wikipedia.org/wiki/X86_assembly_language#.22Hello_world.21.22_program_for_Linux_in_NASM_style_assembly
;I will keep shearching I try to make modifications and try to print just values and caracters
;Sorry about mistakes in last shared snippet
;In linux we need the "_start:" otherwise we will get an error
;So, keep up and sorry again


;
; This program runs in 32-bit protected mode.
;  build: nasm -f elf -F stabs name.asm
;  link:  ld -o name name.o
;
; In 64-bit long mode you can use 64-bit registers (e.g. rax instead of eax, rbx instead of ebx, etc.)
; Also change "-f elf " for "-f elf64" in build command.
;
section .data                           ; section for initialized data
str:     db 'Hello world!', 0Ah         ; message string with new-line char at the end (10 decimal)
str_len: equ $ - str                    ; calcs length of string (bytes) by subtracting the str's start address
                                            ; from this address ($ symbol)

section .text                           ; this is the code section
global _start                           ; _start is the entry point and needs global scope to be 'seen' by the
                                            ; linker --equivalent to main() in C/C++
_start:                                 ; definition of _start procedure begins here
    mov eax, 4                   ; specify the sys_write function code (from OS vector table)
    mov ebx, 1                   ; specify file descriptor stdout --in gnu/linux, everything's treated as a file,
                                             ; even hardware devices
    mov ecx, str                 ; move start _address_ of string message to ecx register
    mov edx, str_len             ; move length of message (in bytes)
    int 80h                      ; interrupt kernel to perform the system call we just set up -
                                             ; in gnu/linux services are requested through the kernel
    mov eax, 1                   ; specify sys_exit function code (from OS vector table)
    mov ebx, 0                   ; specify return code for OS (zero tells OS everything went fine)
    int 80h                      ; interrupt kernel to perform system call (to exit)