greymd

yamayaさんの難読化シェル芸(フィボナッチ数列) 解説

経緯

(1) ある日、yamaya さんという怖い方がこのツイートを投稿する。

! : "`/???/???/???${#?}???<<<_.`";_____=${_::-~$?}
____='__+=___,___=__-___,__<_[$($_____<<<$___>&$[-~${##}])]||____'
((__=-~$?,____))|&$_____#シェル芸

— yamaya (@yamaya) April 6, 2019

(2) シェル芸bot上で実行されたこのシェル芸は、結果として下記のようにフィボナッチ数列を出す。

greymd

import UIKit
import PlaygroundSupport

class MyViewController : UIViewController {

    override func viewDidLoad() {
        view.backgroundColor = .white
        let s1 = generateLabel()
        let s2 = generateLabel()
        let s3 = generateLabel()

greymd

## original:
## https://twitter.com/hid_tori/status/1221415626465349635
## https://twitter.com/hid_tori/status/1221415683289780225
## https://twitter.com/hid_tori/status/1221415737375412224
## https://twitter.com/hid_tori/status/1221415770795728898

cat sudoku | node -e 'console.log((f=>(u=>u(u))(x=>f(y=>x(x)(y))))(f=>a=>((a,b)=>a.map(x=>x[3]).includes("*")?f(a.map(x=>x[3]!=="*"?x:[...x.slice(0,4),[...Array(9)].map((v,i)=>String(i+1)).filter(y=>!b[0][x[0]].concat(b[1][x[1]]).concat(b[2][x[2]]).includes(y))]).map(x=>x.length===4?x:x[4].length===1?[x[0],x[1],x[2],x[4][0]]:x.slice(0,4))):a)(a,a.reduce((x,y)=>(x[0][y[0]].push(y[3]),x[1][y[1]].push(y[3]),x[2][y[2]].push(y[3]),x),[...Array(3)].map(x=>[...Array(9)].map(y=>[]))).map(x=>x.map(y=>y.filter(z=>z!=="*")))))(require("fs").readFileSync("/dev/stdin","utf8").trim().split("\n").map((v,i)=>[i,v]).map(x=>[x[0],[...x[1].split("").entries()]]).flatMap(x=>x[1].map(y=>[x[0],...y])).map(x=>[x[0],x[1],Math.floor(x[0]/3)%3*3+Math.floor(x[1]/3),x[2]])).reduce((x,y)=>(x[

greymd

import UIKit
import PlaygroundSupport

class MyViewController : UIViewController {
    var label:UILabel!
    var label2:UILabel!
    let gap:CGFloat = 50
    let rep:Float = Float.infinity
    let shape:CAShapeLayer = {
        return CAShapeLayer()

greymd

; ひねくれた方法な気がする。

(map
    3#(match [%1 %2 %3] something {
      [[_ ,0 ,0] FizzBuzz]
      [[_ ,0 _] Fizz]
      [[_ _ ,0] Buzz]
      [[$i _ _] i]})
        (map 1#[%1 (modulo %1 3) (modulo %1 5)] (take 100 nats)))

greymd

# Input is like {"command":"bHMgLWFsIHwgZ3JlcCBob2dlaG9nZQo="}
function handler () {
    EVENT_DATA="$1"
    local _cmd
    local _tmpdir
    _cmd="$(tr -d '[:space:]' <<<"$EVENT_DATA" | sed -E "s/\{[\"']command[\"']:[\"']([0-9A-Za-z+/=]*)[\"']\}/\1/" | base64 --decode)"
    _tmpdir="$(mktemp)"
    eval "$_cmd" 2> "$_tmpdir-stderr" > "$_tmpdir-stdout" || true
    echo "{\"stdout\": \"$(cat "$_tmpdir-stdout" | base64 | tr -d '\n')\", \"stderr\": \"$(cat "$_tmpdir-stderr" | base64 | tr -d '\n')\"}" || true
    rm -rf "$_tmpdir-stderr" "$_tmpdir-stdout" "$_tmpdir"

greymd

import java.util.stream.IntStream;

class Main {
    public static void main(String args[]) {
        IntStream.rangeClosed(2, 100)
            .filter(i -> IntStream.rangeClosed(2, (int)Math.sqrt(i))
                    .allMatch(j -> i%j != 0))
            .forEach(n -> {
                System.out.println(n);
            });

greymd

#!/bin/bash
# From: https://twitter.com/grethlen/status/906154326975905793

sudo ping -i 0 -c 1400 pong4.kooshin.net \
  | grep -oP "icmp_seq=\K\d+" \
  | cat - <(seq 1 1400) \
  | sort -n \
  | uniq -c \
  | awk '{printf $1}' \
  | fold -w70 \

greymd

#!/bin/bash
ceiling () {
  local divide="$1";shift
  local by="$1"
  printf "%s\\n" $(( ( divide + by - 1 ) / by ))
}

equalized_partition_nums () {
  local number="$1";shift
  local count="$1"

greymd

#!/bin/bash

# Try this script on the docker container.
# Tested on macoOS High Sierra + Ubuntu 18.04 docker container.

rm -f "$HOME"/work/*

tmux -S "$HOME"/work/sess new-session -d

printf "%s\\n" A B C D | while read -r f;do