How Small Can A Linux Executable Be?

An exploration of how small a Linux ELF executable can be made, starting from a naive C 'Hello, World!' at 12-15KB and progressively shrinking it. By rewriting in x86_64 assembly with Linux syscalls, removing section headers, applying aggressive instruction-level size optimizations, and exploiting unused space within the ELF and program headers to store code, the final binary reaches just 120 bytes.