Isaac Young ibreathebsb

SUID

只对二进制程序有效,对shell脚本或者目录无效
拥有者的权限执行位改为s
执行者拥有x权限
执行者在运行程序过程中将获得改文件拥有者的权限

SGID

which

在用户的目录($PATH)下查找指定的可执行文件

➜  ~ which ifconfig
/sbin/ifconfig

组成

inode 用于记录文件的权限信息，以及对应的data block编号，每个文件占用一个inode
data block 用于存放文件的内容，每个文件至少占用一个
superblock 用于记录整个文件系统的inode block用量以及文件系统相关信息

索引式文件系统，inode和block都有自己的编号，可以根据inode直接获取所有data block 的编号并直接访问，访问效率高

filesystem = boot sector + block group * n

df

df 列出文件系统的使用情况 df /somepath 会自动匹配该目录对应的文件系统并列出该文件系统的使用情况

du

du 列出文件大小

配置文件

cat /etc/fstab

# filesystem | mount point | type | mount option | dump | fsck
/dev/loop15 /snap/gnome-logs/37 squashfs ro,nodev,relatime 0 0
/dev/nvme0n1p1 /boot/efi vfat rw,relatime,fmask=0077,dmask=0077,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro 0 0
/dev/nvme0n1p2 / ext4 rw,relatime,errors=remount-ro,data=ordered 0 0

	{
	"name": "whitealbum.io",
	"description": "whitealbum.io",
	"version": "1.0.0",
	"keywords": [
	"blog"
	],
	"main": "index.js",
	"scripts": {
	"dev": "webpack-dev-server",

	// Note: only for modern browser
	import axios from 'axios'

	// helper function: generate a new file from base64 String
	const dataURLtoFile = (dataurl, filename) => {
	const arr = dataurl.split(',')
	const mime = arr[0].match(/:(.*?);/)[1]
	const bstr = atob(arr[1])
	let n = bstr.length
	const u8arr = new Uint8Array(n)

	/**
	* Copyright 2015 Google Inc. All rights reserved.
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software

	// NumberFlip.ts
	import * as React from 'react';
	import cStyle from './NumberFlip.scss'

	class NumberFlip extends React.Component {
	private static Nums = Array.from({ length: 11 }).map((v, i) => i % 10);
	private num: number = 0;
	private $content: HTMLElement \| null;
	private $scroller: HTMLElement \| null;
	private height: number = 0;

	// tree node
	class TreeNode {
	constructor(value) {
	this.value = value
	this.parent = null
	this.left = this.right = null
	}
	insert(newNode) {
	const {
	value