Install

sudo add-apt-repository ppa:certbot/certbot
sudo apt-get update
sudo apt-get install certbot python-certbot-nginx 

Setup

Running this command will get a certificate for you and have Certbot edit your Nginx configuration automatically to serve it.

sudo certbot --nginx

# for a specific name
sudo certbot --nginx -d example.com

Renew

The Certbot packages on your system come with a cron job that will renew your certificates automatically before they expire.
You can test automatic renewal for your certificates by running this command:

sudo certbot renew --dry-run

Images

docker images
docker build -t image_name .
docker rmi $(docker images | grep "^<none>" | awk "{print $3}")  # remove all untagged images
docker save image_name > image_name.tar  # save image as a tar file
docker load < busybox.tar.gz  # load image

Containers

docker run -p 27017:27017 -v mongodbdata:/data/db mongo
docker ps -a
docker exec -it ubuntu_bash bash
docker rm container_name
docker rm $(docker ps -a -q)  # remove all stopped containers

Volumes

docker volume create mongodbdata
docker volume ls
docker volume inspect mongodbdata

Networks

docker network ls
docker network create network_name
docker network inspect network_name
docker network rm network_name

Sample Code: https://github.com/guangningyu/react-skeleton

1. set proxy

wget http://downloads.lightbend.com/scala/2.11.8/scala-2.11.8.rpm

3.

Create the directory structure

mkdir -p src/main/java/hello
mkdir -p src/test/java/hello

Create classes

src/main/java/hello/HelloWorld.java

package hello;
import org.joda.time.LocalTime;
public class HelloWorld {
    public static void main(String[] args) {
        LocalTime currentTime = new LocalTime();
        System.out.println("The current local time is: " + currentTime);
        Greeter greeter = new Greeter();
        System.out.println(greeter.sayHello());
    }
}

src/main/java/hello/Greeter.java

package hello;
public class Greeter {
    public String sayHello() {
        return "Hello world!";
    }
}

Write a test

src/test/java/hello/GreeterTest.java

package hello;
import static org.hamcrest.CoreMatchers.containsString;
import static org.junit.Assert.*;
import org.junit.Test;
public class GreeterTest {
    private Greeter greeter = new Greeter();
    @Test
    public void greeterSaysHello() {
        assertThat(greeter.sayHel

• every 30 minutes

0,30 * * * * ...

• loop through object

> var _ = require('lodash');
> foo
{ a: { num: 1 }, b: { num: 2 }, c: { num: 3 } }
> _.forEach(foo, (vlu, key) => {console.log(vlu, key);})
{ num: 1 } 'a'
{ num: 2 } 'b'
{ num: 3 } 'c'
{ a: { num: 1 }, b: { num: 2 }, c: { num: 3 } }

• filter object of objects

> foo
{ a: { num: 1 }, b: { num: 2 }, c: { num: 3 } }
> _.pickBy(foo, (i) => i.num>=2)
{ b: { num: 2 }, c: { num: 3 } }

• assign default value to variable

DEFAULT=5
RESULT=${VAR:-$DEFAULT}

• trap error exit

function rollback() {
  if [[ $? -ne 0 ]]; then
    echo "rollback"
  fi
}
set -ueo pipefail
trap rollback EXIT

• if file exists

#!/bin/bash
FILE="/etc/passwd"
if [[ -f $FILE ]];then
    echo "$FILE exists"
else
    echo "$FILE doesn't exist"
fi

• if directory exists

#!/bin/bash
DIR="/var/log"
if [[ -d $DIR ]]; then
   echo "$DIR exists"
else
   echo "$DIR doesn't exist"
fi

• eval

function assert_var_exists() {
    local condition="[[ ! -n \"\${$1+set}\" ]]"
    if eval $condition; then
        echo "The variable ${1} does not exist. Exit."
        exit 1
    fi
}
function export_var() {
    assert_var_exists $1
    local var_value=$(($1))
    eval "export $1=\$var_value"
    echo "$1=$var_value"
}

• Setting user name and email

git config --global user.name "Guangning Yu"
git config --global user.email "hi@guangningyu.com"

• Showing remotes

git remote -v

• Changing a remote’s URL

git remote set-url origin git@github.com:guangningyu flasky.git

• Pulling from remotes

git pull origin master

• Pushing to remotes

git push origin master

• Commit using default message

git commit —no-edit

• Cancel last commit

git reset HEAD~

• Undo a git add

git reset filename.txt

• Define author & committer

GIT_COMMITTER_NAME='Jane Doe' GIT_COMMITTER_EMAIL='jane@doe.com' git commit —author="John Doe <john@doe.com>" -m "This is authored by John Doe and committed by Jane Doe."

• Undo git rm

git checkout HEAD path/to/file

• Check out a remote branch

git branch -a
git checkout test_branch

• Create a new branch

git checkout -b [name_of_your_new_branch]

• Push a local branch to remote

git push -u origi

select last element in array

my_array.slice(-1)[0]

my_array.pop()

#!/usr/bin/env python
import urllib2
import numpy as np
from keras.models import Sequential
from keras.layers import Dense
from keras.wrappers.scikit_learn import KerasRegressor
from sklearn.model_selection import cross_val_score
from sklearn.model_selection import KFold
from sklearn.preprocessing import StandardScaler
from sklearn.pipeline import Pipeline
def load_data():
    X = []
    Y = []
    data_url = 'https://archive.ics.uci.edu/ml/machine-learning-databases/housing/housing.data'
    for line in urllib2.urlopen(data_url).readlines():
        line = map(float, line.split())
        X.append(line[0:13])
        Y.append(line[13])
    return X, Y
def basic_model():
    # create model
    model = Sequential()
    model.add(Dense(13, input_dim=13, kernel_initializer='normal', activation='relu'))
    model.add(Dense(1, kernel_initializer='normal'))
    # compile model
    model.compile(loss='mean_squared_error', optimizer='adam')
    return model
d

逾期天数（days past due, DPD）

已逾契约书约定缴款日的延滞天数，贷放型产品自缴款截止日（通常为次一关账日）后第一天开始计算；信用卡比较特别，虽然缴款截止日约为关账日后20天，但逾期天数亦是由次一关账日后起算。

逾期期数（bucket）

逾期1期称为M1，2期称为M2，3期称为M3……以此类推。信用卡缴款截止日与次一关账日之间虽然不计算逾期天数，但其bucket称为M0。
注意，因为每月天数不一定相同，所以各期的长短会有不同。

逾期阶段（stage）

依bucket可分为前期（front end）、中期（middle range）、后期（hot core）、转呆账（write-off）。
stage的划分方式并无硬性规定，可依各银行的催收策略、转呆账政策与产品特性决定。以信用卡为例，一般将M1列为前期，M2-M3列为中期，M4以上列为后期，若已转列呆账者则列入转呆账。

即期指标（coincidental）

即期指标 = 当期各bucket延滞金额 / 当期应收账款

即期指标是计算延滞率时常用的两种方法之一，其概念为分析当期应收帐款的质量结构。一般公开信息所显示的延滞率，若无特别注明，皆是以coincidental的概念计算的。

递延指标（lagged）

递延指标 = 当期各bucket延滞金额 / 各bucket对应的历史月份应收帐款

即期指标的分母一律是当期应收账款，不过其分子实际上是由之前的应收账款产生的；因为为了回溯逾期起源，递延指标将分母改成了相对应的之前月份的应收账款。

期末结算（cycle end）

期末结算为信用卡特有的结算方式。因为信用卡客群最为庞大，作业处理相当耗时，许多银行会将其客户划分至不同账务周期（cycle），因此信用卡产品下通常有多个关账日。
银行必须就各个cycle客户分别管理，尤其是账务及催收单位皆以cycle为作业周期。

月底结算（month end）

月底结算报表主要表达各月月底结算数据，适用于消费金融所有产品，尤其在跨产品并列分析时，为实现资料切点一致，多采用月底结算数据。

参考：《互联网金融时代：消费信贷评分建模与应用》

• Date functions

-- change date format
from_unixtime(unix_timestamp('20150101' ,'yyyyMMdd'), 'yyyy-MM-dd')
-- add n days
date_add('2015-11-01', 30)  -- will return '2015-12-01'
-- calculate date difference
datediff('2015-12-01', '2015-11-01') -- will return 30

• Generate row number

row_number() over (DISTRIBUTE BY... SORT BY... DESC)

• Get partition information

analyze table xxx.yyy partition(dt = '2015-12-11') compute statistics;
describe formated xxx.yyy partition (dt = '2015-12-11');