greymd

## From: https://en.wikipedia.org/wiki/Dc_(computer_program)
## prime number

2p  # A = 2; print A
3p  # A = 3; print A

## スタックの先頭にある数とsqrt(処理中の数)を計算
[          # func f-# (int n) int {
    d      # A = n(試す数)
    l!     # B = ! -- nと試し割りの割る数を用意

greymd

[響] 0:a [け] 1:a [！] 2:a [ユ] 3:a [ー] 4:a [フ] 5:a [ォ] 6:a [ニ] 7:a [ア] 8:a [ム] 9:a
0sc
[
  lc
  lC+
  10%;an
  lC
  1+
  d
  sC

greymd

# https://unix.stackexchange.com/questions/205936/how-can-i-quickly-sum-all-numbers-in-a-file/205939
perl -pe 's/\d*/$s+=$&/ge}{$_=$s' file
perl -F= -pe '$s+=$F[1]}{print $s' file
awk -F= '{sum+=$2};END{print sum}'

greymd

2017-05-09 20:53:26 INFO --- [thread-1] myapp.logic : Register records
2017-05-09 20:53:26 INFO --- [thread-1] myapp.logic : --> POST https://api.example/v2/records http/1.1
2017-05-09 20:53:27 INFO --- [thread-1] myapp.logic : response: <?xml version="1.0" encoding="UTF-8"?>
<root>
  <records>
    <record>
      <id>A001</id>
      <date>1990-01-04</date>
      <status>0</status>
    </record>

greymd

sed '/response:/{:loop;N;/<\/root>/!b loop;s/\n//g}' app.log | \
 # 特定の時間帯のログだけをgrep
  grep '^2017-05-09 20:5[0-9]' | \
 # あとはgrepなりsedなりawkなりで自由に抽出
  grep -oP '<record> *\K.*?(?= *</record>)' | sed 's/<\/[^>]*> *<[^>]*>/,/g;s/<[^>]*>//g'

# 同じディレクトリにapp.logを置いて実行
# $ bash script.sh
# 出力結果:
# A001,1990-01-04,0

greymd

Q1:
<welcome.txt tr '\0' '*' | fold -w 70

初っ端からひどい

Q2:
ls | perl -C -Mutf8 -nle 'printf "mv $_ ";$_ =~ tr/０-９/0-9/ ;$_ =~ tr/A-Z/Ａ-Ｚ/;$_ =~ m/([0-9]).*([Ａ-Ｚ])/; print " $1年$2組.doc"'

Q3:
echo 2018{01..12}{01..31}$'\n' | date -f- +'%Y%m%d' 2>/dev/null | grep -P '([2357].*){4}'

greymd

--------------------
bash 3.2.0
--------------------
~$ bash --version
GNU bash, version 3.2.0(1)-release (x86_64-unknown-linux-gnu)
Copyright (C) 2005 Free Software Foundation, Inc.

~$ [[ "hoge" =~ ho.. ]] && echo "${BASH_REMATCH[0]}"
hoge

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

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

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。