lscpu | grep "Architecture:"

ip addr show dev eth0

const express = require('express');
const app  = express();
const port = 3000;
app.use('/aaaaa', express.static(__dirname + '/public'));
app.listen(port, () => {
  console.log(`http://localhost:${port}/aaaaa de /public no nakami ga deru-`);
});

free -h

df -h

type RemoveReadonly<T> = {
  -readonly [P in keyof T]: T[P];
};

type RemoveUndefined<T> = {
  [P in keyof T]-?: T[P];
};

type Unvalidated<T> = {
  [P in keyof T]?: any;
};

console.log(`npm i -s ${Object.keys(require('./package.json').dependencies).join(' ')}`);
console.log(`npm i -D ${Object.keys(require('./package.json').devDependencies).join(' ')}`);

.image-wrapper {
  position: relative;
}
.image-wrapper::after {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  content: "";
}

webpack --display-modules

aws s3api create-bucket --bucket <名前> --create-bucket-configuration LocationConstraint=ap-northeast-1
aws s3api put-public-access-block --bucket <名前> --public-access-block-configuration BlockPublicAcls=true,IgnorePublicAcls=true,BlockPublicPolicy=true,RestrictPublicBuckets=true

nslookup
> server 8.8.8.8
> note.kiriukun.com

sudo apt autoremove piyopiyo

sudo apt --purge autoremove piyopiyo

apt list piyopiyo

apt search piyopiyo

sudo dpkg -l

const obj = { a: 1, b: 2 };
let a, b;
({a, b} = obj);
console.log(a, b);  // -> 1 2

aws sts get-caller-identity

rm -rf ~/.anyenv
rm -rf ~/.config/anyenv

export PATH="$HOME/.anyenv/bin:$PATH"
eval "$(anyenv init -)"

unlink /path/to/link

cat /etc/os-release | grep VERSION

sudo dpkg --force-all -r mariadb-server-10.1
sudo apt --purge remove mysql-server*
sudo apt --purge remove mysql-common*
sudo apt --purge remove mariadb-server*

ln -s /path/to/target linkname

  MyAliasRecordSetIPv4:
    Type: "AWS::Route53::RecordSet"
    Properties:
      HostedZoneId: "追加先のホストゾーンID"
      Name: "ドメイン名"
      Type: "A"
      AliasTarget:
        DNSName: "CloudFrontディストリビューションのドメイン名"
        HostedZoneId: "Z2FDTNDATAQYW2"  # CloudFrontならこれ固定

  MyAliasRecordSetIPv6:
    Type: "AWS::Route53::RecordSet"
    Properties:
      HostedZoneId: "追加先のホストゾーンID"
      Name: "ドメイン名"
      Type: "AAAA"
      AliasTarget:
        DNSName: "CloudFrontディストリビューションのドメイン名"
        HostedZoneId: "Z2FDTNDATAQYW2"  # CloudFrontならこれ固定

list.sort((a, b) => {
  if (a.id > b.id) return 1;
  if (a.id < b.id) return -1;
  return 0;
});

webpack --config webpack.config.js

webpack-dev-server --config webpack.config.js

mklink /D %リンク置きたい場所% %リンク先%

function toQueryString(params) {
    var ret = '';
	Object.keys(params).forEach(function(key) {
		if (ret !== '') {
			ret += '&';
		}
		var value = params[key];
		if (value === '' || value === null) {
			ret += key;
		} else {
			ret += key +'='+ encodeURIComponent(value);
		}
	});
    return ret;
}

function getCookies() {
	var ret = {};
	var tmp = document.cookie.split(';');
	for (var i = 0, len = tmp.length; i < len; ++i) {
		var arr = tmp[i].split('=');
		if (arr[1] === undefined) {
			arr[1] = '';
		}
		ret[arr[0]] = arr[1];
	}
	return ret;
}

# ローカル
npm list --depth=0
# グローバル
npm list -g --depth=0

pip list --not-required

magick mogrify -crop 1600x900+1+26 +repage -resize 640x360 *.png

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto ens33
#iface ens33 inet dhcp
iface ens33 inet static
address 192.168.1.200
netmask 255.255.255.0
gateway 192.168.1.1
dns-nameservers 192.168.1.1

npm install --save-dev @babel/core @babel/preset-env @babel/cli

{
    "presets": [
        "@babel/preset-env"
    ]
}

npx babel src -d lib

function runlength(text) {
	let compressed = '';
	let n = 0;
	let pc = null;
	for (let i = 0, len = text.length; i < len; ++i) {
		const c = text.charAt(i);
		if (pc !== null && c !== pc) {
			compressed += n + pc;
			n = 0;
		}
		pc = c;
		++n;
	}
	if (n > 0) {
		compressed += n + pc;
	}
	return compressed;
}

console.assert( runlength('') === '' );
console.assert( runlength('a') === '1a' );
console.assert( runlength('aaabbbb') === '3a4b' );
console.assert( runlength('aaabbbbcccccabbaaaacc') === '3a4b5c1a2b4a2c' );

npm install --save-dev webpack webpack-cli
npm install --save-dev @babel/core @babel/preset-env babel-loader

{
    "presets": [
        "@babel/preset-env"
    ]
}

const path = require('path');

module.exports = {
  mode: 'development',  // productionにすると難読化＆minifyされる
  entry: './src/index.js',
  output: {
    path: path.join(__dirname, 'public/js'),  // ここはフルパスで指定
    filename: 'bundle.js',
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        loader: ['babel-loader']
      }
    ],
  }
};

npx webpack

npm install --save-dev less gulp gulp-less

const gulp = require('gulp');
const less = require('gulp-less');

// lessをコンパイルするタスク
gulp.task('less', function(done) {
  gulp.src('./src/less/*.less').pipe(less()).pipe(gulp.dest('./public/css'));
  done();  // done()しないと終わらない
});

// ファイルの変更を監視してlessタスクを起動するタスク
gulp.task('watch', function() {
  gulp.watch('./src/less/*.less', gulp.series('less'));
});

// デフォルトのタスク (lessタスクとwatchタスクを両方やる)
gulp.task('default', gulp.series('less', 'watch'));  // gulp.series()に渡したタスクは左から順に流れる

# lessタスクだけ実行
npx gulp less

# watchタスクだけ実行
npx gulp watch

# defaultタスクだけ実行
npx gulp

# 説明
description "hello"

# ランレベル3,4,5かつnetworkが開始したら動き出す
start on (runlevel [345] and started network)

# ランレベル3,4,5以外またはnetworkが停止したら止まる
stop on (runlevel [!345] or stopping network)

# プロセスが死んだら自動で復活する
respawn

# やること (例: ユーザー kiriukun で /my/terrible/program.sh を叩く)
exec sudo -u kiriukun /my/terrible/program.sh

sudo initctl reload-configuration

sudo initctl start piyopiyo
sudo initctl restart piyopiyo
sudo initctl stop piyopiyo

yum install postgresql96.x86_64

psql -h ${RDSのエンドポイント} -U ${データベース作成時に設定したユーザー名} -d postgres

sudo useradd kiriukun
sudo passwd kiriukun
sudo visudo

kiriukun    ALL=(ALL)       ALL

sudo useradd -s /sbin/nologin kiriukun