Hello Docker World in 69 bytes

gistfile1.txt

BITS 32

      org 0x05000000
       db 0x7F, "ELF"
       dd 1
       dd 0
       dd $$
       dw 2
       dw 3
       dd 0x0500001B
       dd 0x0500001B
       dd 4
       mov dl, 19
       mov ecx, msg
       int 0x80
       db 0x25
       dw 0x20
       dw 0x01
       inc eax
       int 0x80
msg db 'Hello Docker world!', 10


---------------

$ nasm -f bin -o hello <above_asm>.asm
$ chmod +x hello
$ ./hello

Lines 3 - 12 are a static ELF header format, which identifies it to the OS as a binary it understands. Lines 13-15 point to the data and perform a sys call to write to stdout. Lines 19-20 set the exit function and call it.

So great!

Fantastic!