Option A: pwntools shellcraft + asm

• pwntools can generate and assemble shellcode for you.
• shellcraft is a library of ready-made snippets; asm() assembles raw assembly to bytes.

from pwn import *
context.arch = 'amd64'          # target architecture

# Ready-made execve("/bin/sh") shellcode:
sc = asm(shellcraft.sh())
print(len(sc), "bytes")
print(enhex(sc))                # inspect the byte string

# Assemble your own snippet:
mine = asm('xor rax, rax; mov al, 59; syscall')