Ubuntu Development Set Up
This article show how to setup a ubuntu development with i3, oh-my-zsh and spaceVim.
Preparation
Download virtualbox if windows or mac
Download Ubuntu and install it
Set up oh my zsh
install zsh and set as default sh
sudo apt update && sudo apt install zsh # install zsh
sudo chsh $USER -s `which zsh` # also works on aws ub...
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ToyOS Development Journal - 2
This is second part of ToyOS development journal. In the first part, we successfully print “Hello World” in a naked i386 system. Now, let us move to memory management.
Pre-knowledge
Before we directly jump to memory management of 32 bit, we need to learn how memory was handled in 8086. In 8086 Registers we know 8086 is 16 bits cpu whose ALU an...
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ToyOS Development Journal - 1
This development journal collects my study notes when I develop toyOS following Viktor Engelmann’s writting your own operation system tutorial series.
ToyOS is a toy project for tutorial purpose. In this article, I will cover how to setup the environment and how to write a simple boot program.
Development Environment Setup
The first thing ...
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ELF Format
ELF represents Executable and Linkable Format, which is a common standard file format for executable files, object code, shared libraries, and core dumps. It is a standard binary file format for *nix-like systems on x86 processors.
let us make a simple program
// hello.c
#include <stdlib.h>
char str[] = "Hello World\n";
int main (int arg...
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Implement Virtual Dom In ES6
In order to understand MVVM, I was trying to revert wheel for virtual dom which is essential part for MVVM framework such as reactjs and vuejs.
To begin with, we need to know why virtual dom? This is because dom is too heavy as it must implement at least those standards:
HTMLElement - Web API Interfaces
Element - Web API Interfaces
Glob...
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Postgresql query optimization practice
Recently, I was develop a RESTful API for all business data in Australia. There are some thoughts I’d like to mark down for notes.
Guides
Denormalize if necessary
Understand sql query order
Small table join big table
Denormalize
When designing models, we tend to normalize the database into a very detailed level because it makes sense...
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Javascript Blind Spot
This is a collection of javascript blind spot.
Array
map parameters
['1', '2', '3'].map(parseInt) // [1, NaN, NaN]
['1', '2', '3'].map((currentValue, index, array) => {
console.log(currentValue)
console.log(index)
console.log(array)
})
// parseInt(1, 0) == parseInt(1, 10) 1
// parseInt(2, 1) NaN
// parseInt(3, 2) NaN
map w...
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Free Hosting Methods
In this article, I am going to introduce three way to free hosting your simple website.
Google Firebase
Firebase Hosting is a static and dynamic web hosting service that launched on May 13, 2014. It supports hosting static files such as CSS, HTML, JavaScript and other files, as well as dynamic Node.js support through Cloud Functions. The se...
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Setup postgesql cluster and install Postgis
Recently, I had upgrade ubuntu from 14.04 to 16.04. When I upgrade postgresql and try to set up postgis, I encountered a bug. This article record the process of solving it.
Background
Upgrading ubuntu from 14.04 to 16.04
sudo do-release-upgrade # will take hours depends
Then change data directory for postgresql
# make new directory and set...
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Markdown Example - MathJax
When , there are two solutions to and they are
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ES6 Variable - ES6 Study
ES6 variable study notes.
block level variable
{
let a = 10;
var b = 1;
}
a // ReferenceError: a is not defined.
b // 1
No variable lift up
console.log(foo); // 输出undefined
console.log(bar); // 报错ReferenceError
var foo = 2;
let bar = 2;
variable blind in block temporal dead zone，aka TDZ
var tmp = 123;
if (true) {
tmp = 'abc'; //...
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How To Setup Free Email Host In Zoho
This article introduce how to set up a free business email in zoho.
Preparation
Must have a domain name first
a phone number never apply zoho email before
Zoho features
10 free accounts per domain ( possible get more )
5G for each accounts
CRM, Project, Docs and other – Free version of Google business
S...
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Introduction to flexbox
Flex enable containers to adust items’ width/height/order to best fill the space in different kinds of screen sizes in a simple way.
How to use
.flex-element {
display: -webkit-flex; /* Webkit core browerer such as Safari */
display: flex;
}
Then all the children elements will lose float, clear,vertical-align properties.
The layout of a ...
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Useful Comments
Useful comments
/**
* ┏┓ ┏┓+ +
* ┏┛┻━━━━━┛┻┓ + +
* ┃ ┃
* ┃ ━ ┃ ++ + + +
* ████━████ ┃+
* ┃ ┃ +
* ┃ ┻ ┃
* ┃ ┃ + +
* ┗━┓ ┏━┛
* ┃ ┃
* ┃ ┃ + + + +
* ┃ ┃ Bug free
...
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How to build a church website
Recently, the elders in the church ask me to design a church website which need to fulfill requirements below:
Brief introduction
Location and navigation
Sermons
Calender
Groups
Easy-to-use admin board
Analysis
This is a simple website, there are two main technique stack to select here:
Wordpress
static html/css + google s...
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Code Complete Study Note Part One
Code Complete study notes.
question-definition prerequisites
production vision
vision statement
mission statement
production definition
problem definition
requirements prerequisites
requirement development
requirements analysis
analysis
requirements definition
software requirements
specification
functional specific...
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Linux Log Files
logs in linux
/var/log/boot.log：
The process of kernel detecting devices during booting and initing core functions will be record here. Only record for each booting.
/var/log/cron：
cron jobs go here
/var/log/lastlog：
last login
/var/log/maillog 或 /var/log/mail/*：
for postfix (SMTP) and dovecot (POP3)
/var/log/messages...
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Useful Regex
Useful regex
check password must include number and uppercase and lowercase no special characters
^(?=.*\\d)(?=.*[a-z])(?=.*[A-Z]).{8,10}$
check chinese
^[\\u4e00-\\u9fa5]{0,}$
check email
[\\w!#$%&'*+/=?^_`{|}~-]+(?:\\.[\\w!#$%&'*+/=?^_`{|}~-]+)*@(?:[\\w](?:[\\w-]*[\\w])?\\.)+[\\w](?:[\\w-]*[\\w])?
check url
^...
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Shell Study Notes
Linux shell variables tutorial.
Variable
don’t usually declare variables in the shell before we use them. Instead, we create them when we first use them get at the contents of a variable by preceding its name with a $ character and outputting its contents with the echo command
we need to give variables a preceding $, except when an assignment...
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Linux Program Notes
Applications under Linux / UNIX are represented by two special types of file: executables and scripts. Executable
files are programs that can be run directly by the computer and correspond to DOS .exe files. Scripts are
collections of instructions for another program, an interpreter, to follow. These correspond to DOS .bat files,
or interpreted ...
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