Isabella Bosia izabera

This script exploits bash's weird interpretation of POSIX's requirement that declaration builtins overloaded by functions must not modify the parsing of the arguments. Bash even extends this requirement to nonstandard extensions such as arrays. This typeset wrapper parses options by stealing the (approximately correct) optstring from ksh. It modifies each assignment then prints the effect of the command as a side-effect.

Code:

ELF Format Cheatsheet

Introduction

Executable and Linkable Format (ELF), is the default binary format on Linux-based systems.

Compilation

Internal Bash functions, useful when writing loadable builtins

Find an environment variable
Set an environment variable to a string value
Set an environment variable to a string value if it's not already set
Check if an environment variable is set
Check if an environment variable is an array
Get an environment variable that's an array
Unset an environment variable
Create an array

korn.c is the "Best One Liner" winner of the 1987 International Obfuscated C Code Contest, by David Korn (yes, the author of the Korn Shell).

korn.hint, as the name implies, offers some hints.

A commenter on Stack Overflow asked for some clarification. I didn't want to post spoilers on the site, so I'm posting them here instead. If you haven't already (and if you're familiar with the rules of C) I encourage you to study the program for a while first.

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Here's the code:

	// -- mode:c;indent-tabs-mode:nil;c-basic-offset:4;coding:utf-8 --
	// vi: set et ft=c ts=4 sts=4 sw=4 fenc=utf-8 :vi

	#define _GNU_SOURCE
	#include <pthread.h>
	#include <stdatomic.h>
	#include <stdbool.h>
	#include <stdio.h>
	#include <threads.h>
	#include <unistd.h>

	#!/usr/bin/env bash
	# solve Rubik's cube using the Tperm blindfold method. input: http://tomas.rokicki.com/cubecontest/
	# idea from Stefan Pochmann's second entry: http://tomas.rokicki.com/cubecontest/winners.html
	n=0 tperm="R2 U' R2 D B2 L2 U L2 D' B2 U "
	cube=("$@") solved=(UF UR UB UL DF DR DB DL FR FL BR BL UFR URB UBL ULF DRF DFL DLB DBR)
	declare -A inverse=([\']=\ [2]=2 [\ ]=\') setups=(
	[UF]="R2 U R2 " [UR]="" [UB]="R2 U' R2 " [UL]=""
	[DF]="D' L2 " [DR]="D2 L2 " [DB]="D L2 " [DL]="L2 "
	[FR]="U2 R U2 " [FL]="L' " [BR]="U2 R' U2 " [BL]="L "
	[FU]="R F' L' R' " [RU]="" [BU]="R' B L R " [LU]="L F' D' F L2 "

	#!/bin/bash

	save=$(bind -p; bind -X)
	function clean-up {
	bind -r '\C-i'
	bind -f /dev/stdin <<< "$save"
	}
	trap 'clean-up' RETURN

	function write-options {

	#include <stdio.h>
	#include <magic.h>

	int main(void)
	{
	char *actual_file = "/file/you/want.yay";
	const char *magic_full;
	magic_t magic_cookie;

	/* MAGIC_MIME tells magic to return a mime of the file,