Why can't I print the user input data in NASM assembly?

Question

I am trying to verify the length of user input in this example (NASM):

section .bss
    user_input resb 10

section .text
    push ebp
    mov ebp, esp

    mov eax, 3 ;sys_read
    mov ebx, 0 ;stdin
    mov ecx, user_input
    mov edx, 10
    int 80h

    cmp eax, 10
    jg overflow
    jmp done 
overflow:
    .
    .
    .
done:
    mov eax, 1
    int 80h

Why isn't this working?

Answer 1

Since your buffer is 10 bytes and you put the length into edx, the return can never be greater than 10 and you jump to label done: and exit.

There's nothing in the code you've shown that prints anything out.