Why can't I sys_write from a pointer to stack memory, using int 0x80? [duplicate]

Answer 1

30 decimal is the code of the ASCII "record separator". Whatever that is, it's probably not a printable character.

30 hexadecimal (30h or 0x30 in NASM parlance), on the other hand, is the code of the ASCII "0".

Also, you need to use the 64-bit ABI.