shell script

1. sha-bang #!

#!/bin/bash # Proper header for a Bash script.

2. define all variables (UpperCase) at top at refer them later using $

3. command line argument

• $0: command itself
• $1: 1st argument

4. `pwd`.    //everything between `` is evaluated first

5. $?           //the exit code of previous command is stored in it

6. $(command)      //run command and return value as variable

7. i/o redirection

• 0, 1, 2                    //stdin, stdout, stderr
• 1>filename            //redirect stdout to file
• 2>&1                     //redirect stderr to stdout
• >                            //redirect, overwrite
• >>                          //redirect append

8. sed (stream editor)

sed -n           //don't print input, always use

sed -i            //modify file in-place

echo "hello sed" | sed 's/sed/world/'                                       //hello world
sed 's+http://+https://www.cyberciti.biz+g' input.txt             //sed allow delimiter other than /
sed -i -e '/FOO/s/love/sick/' input.txt.                                    //if the line contain FOO
sed -i 's/foo/bar/gI' hello.txt                                                   //'I' to match all cases of foo

sed -n -e 's/^.*ch\([a-zA-Z0-9-]\{1,\}\).*$/\1/p' input.txt.     //+ does not work in sed, use \{1,\}

9. special character

• $                                              //access variable
• ${HOME}                              //return value of HOME
• $(command)                           //return output of command, maybe separated by space !!!  
• "$(command)"                        //return output of command as a whole
• [   ]                                          //condition, !!! need space after [ and before ], i.e. [ 1 -lt 2 ] 
• [ -z "$var" ]                             //$var is empty

10. awk

• program structure
  
  BEGIN {awk-commands}
  /pattern/ {awk-commands}      // body
  END {awk-commands}
  
  
• variable
  $0: a special variable in awk that represents the entire line
  
  
• command
  awk -f command.awk marks.txt
  awk '/a/{++cnt} END {print "Count = ", cnt}' marks.txt

reference
1. special char in shell scripting
2. tldp sed
3. tutorialspoint regex with sed
4. how-to-use-sed-to-find-and-replace-text-in-files

5. unix tutorials point
6. freeos unix guide

7. shell scripting crash course - beginner level

symbol

~   tilde
`   back quote, everything between ` ` is executed first
^  caret
*  star
(   left/right parenthesis
{  curly bracket
:   colon
;   semicolon
"  quote
'   single quote
<  angle bracket
|   pipe

#  hash

[   square bracket

stock

1. terminology

• ttm: trailing twelve month
• eps: earning per share
• beta: volatility of stock, if a stock move less than market, beta < 1.0
• earning date: last financial report date
• ex-dividend date: if purchase the stock after the date, will not get the next dividend
• peg ratio (<1.0 is good): pe ratio adjusted on growth
• free cash flow = operating cash flow - capital expenditure
• issuance of debt: 借债
• stop-loss order: will turn into a market order once price is hit
• short squeeze: stock price rise sharply to squeeze the shorters
• short ratio: % of stocks that are being shorted
• price/book ratio (<1.0 is good)
• equity value/market cap: # of shares * share price
• enterprise value: equity value + debt - cash
• cagr: compound annual growth rate
• operating/profit margin: profit margin only consider cost of production, operating margin consider operating expense

2. warren buffett income statement

• net income
• profit margin

 

3. 止损止盈抄底

• 设止损
• 最好不要抄底，抄底也要抄在support才有意义(1M或1Q均线)
• 根据cis散户理论，第一次下跌可以ignore，第二次下跌要离场
• 根据知乎理论，每次下跌5%要减仓一半
• 盈利不好的公司出财报前减仓一半以防大跌
• 6月份一般没有行情
• 3 day rule: never buy for at least 3 days after bad news as it will fall for 3 days 90% chance

4. 投资策略

• VIX > 30 price low考虑买，VIX < 20 price high 考虑卖
• 30%长持，30%根据vix高抛低吸或做波段，30%大跌抄底

5. 短线指标

• 下跌过程中出现锤头线或倒锤头线
• 上涨过程中出现锤头线或倒锤头线
• RSI顶背离：股价上升，RSI下降                 //RSI表示买方力量
• RSI底背离，股价下降，RSI上升
• BBI                                                                   //多空线
  
  

6. 日内指标

• VWAP 1分/3分/5分/15分，主看3分
• MAVOL

7. 均线

• 5日均线：强庄线 。个股沿着5日均线运行，表明庄家正在拉升，不破均线不用担心。
• 30日均线：庄家生命线 。个股沿着30日均线运行，表明庄家还在。
• 不同分时图如出现同一个位置的均线点，基本可以确定其具有较大的强度。比如说在60分钟图某条均线形成支撑位，而30分钟的另一条均线的支撑位恰好一样，15分钟5分钟也是，这样这个支撑点就非常强，甚至有80%机率可获支撑。 这个对于短线操作或者买卖操作很重要，是如何买在最低，卖在最高的要诀

7. do/dont

• try to buy industry leader
• don't buy at 52 week high
• don’t buy airline/cruise, be cautious with medical and telecom
• when to buy dip (缩量下跌）
• don‘t set a small amt trailing stop limit order (被恶意洗盘震荡卖出)
• 试探盘要少量，否则很难cost average down
• 盘前只高卖不买，开盘做超短线，收盘后正常操作

7. trailing stop loss sell 

• trigger is set on a dollar or % drop of market price
• example: bought a stock at $10, then set a trailing stop-loss order to 10% below market price
• trailing amount: 最大下跌幅度
• stop: 触发价
• limit: 卖出价
• limit offset: 从stop来算limit, limit = stop - limit offset, 不直接指定

8. others

• check warren buffett, soros
• check yahoo finance 'analysis' tab for rating and target price

9. leverage ETF

• it is best to hold 1X bull ETF for long term saving
• when the market corrects then convert to 2X or 3X bull until it recovers
• the market corrections will kill you and leveraged ETF have decay

10. 澳洲持有股票12月以上获利按50%交税，为避税

• 持有超过一年
• 持有一个portfolio，财年前把亏钱的仓位全部realise

reference

1. what is trailing stop loss order

2. ib intro

powerpoint

1. menu -> design to choose popular themes

2. quick access toolbar

• align objects
• align text
• distribute horizontally/vertically
• group

3. slide master and sub-master slide

• slide master: base class of all slide, change its style changes all

4. animation panel (to edit the sequence of animation)

• fade
• fly-in

5. add a grey book and send to back as background

6. smart art is useful to draw diagrams

deep learning

1. concepts

• neuron (input -> output)
• input, weight, bias      u=∑w*x+b
• activation function     y = f(u)
• cost/loss function
• overfitting: statistically correspond too closely

2. type of activation functions

• sigmoid
• relu
• softmax (convert to probabilities that sum up to 1)

3. tensorflow

• tensor: n-dimension vector
• inception v3, a neural network that's pretrained for image classification
• top layer - right most output layer
• bottleneck layer - layer just before the top layer

reference
1. 25 must know concepts
2. quickly setup google’s tensorflow image recognition
3. deep Learning with tensorflow: part 2 — image classification

useful javascript functions

1. spread operator ...

2. for ... of iterator

3. includes()

4. some()     //if some element in array pass the test

5. every()    //if every element in array pass the test

6. filter()     //filter the array that pass the test

7. map()     //convert the array

8. reduce()    //reduce to array, number, object

9. find()

ref
1. 7-javascript-methods-that-will-boost-your-skills
2. Most Useful JavaScript Array Functions
3. most-useful-javascript-methods