curl -X OPTIONS 'https://test.com/index.html' -H "Origin: https://www.google.com" -H "Access-Control-Request-Method: GET" -v

sudo chmod -R u=rwX,go=rX ./app

CREATE USER 'kevinkhew'@'%' IDENTIFIED BY 'KevinKhew';
GRANT ALL PRIVILEGES ON dbname.* TO 'kevinkhew'@'%';
FLUSH PRIVILEGES;

SHOW GLOBAL STATUS
WHERE Variable_name = 'Com_insert'
OR Variable_name = 'Com_select'
OR Variable_name = 'Com_Update'
OR Variable_name = 'Com_delete';

SELECT * FROM `recipes` WHERE JSON_EXTRACT(`filter_type`, '$[0]') = 99;
SELECT * FROM `api_logs` WHERE json_extract(response, '$.status') <> 200;

SHOW SESSION VARIABLES LIKE 'wait_timeout'; -- set to 3600
SHOW GLOBAL VARIABLES LIKE 'wait_timeout'; -- set to 3600
SHOW SESSION VARIABLES LIKE 'interactive_timeout'; -- set to 28800
SHOW GLOBAL VARIABLES LIKE 'interactive_timeout'; -- set to 28800

== install docker ==
curl -fsSL https://get.docker.com -o get-docker.sh
sudo sh get-docker.sh
sudo groupadd docker
sudo usermod -aG docker $USER
==

sudo systemctl status
sudo systemctl list-units --failed

openssl rand -base64 12

s6-setuidgid www-data php /var/www/html/artisan queue:work

wrk -t2 -c50 -d60s https://test.com/status --header 'x-api-key: abc'

git clone --single-branch --branch <branch-name> <repo-address>

docker exec -i conainer_name sh -c 'exec mysqldump --single-transaction -h db -u root -pSecret db_name' > ./db_name_2021-03-03.sql
docker exec -i conainer_name sh -c 'exec mysql -h db -u root -pSecret db_name' < ./db_name_2021-03-03.sql

# view all docker env secret
docker exec mycontainer /usr/bin/env

# cpu full load
sha1sum /dev/zero &

# 2022-10-18 15:27:38
echo `date +%Y-%m-%d\ %H:%M:%S`

youtube-dl -F https://youtu.be/???
youtube-dl -f 140 https://youtu.be/??? -o file_name

SCRIPT_FILENAME=/var/www/html/public/index.php \
REQUEST_URI=/api/status \
REQUEST_METHOD=GET \
cgi-fcgi -bind -connect 10.42.0.43:9000

# The submit event will no longer reload the page
<form v-on:submit.prevent="onSubmit"></form>

# make log method
methods: {
    log(message) {
      console.log(message);
    },
},

Center Div
==========
# for child div
.classic {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}
---
# for parent div
.flex {
    display: flex;
    align-items: center;
    justify-content: center;
}
---
# for parent div
.grid {
    display: grid;
    place-items: center;
}

sudo docker run -it --rm --name certbot \
-v "/etc/letsencrypt:/etc/letsencrypt" \
-v "/var/lib/letsencrypt:/var/lib/letsencrypt" \
-p 80:80 \
certbot/certbot certonly

# ssh tunneling for local access to remote database
ssh micro-kevin.khew@202.165.22.18 -NL 127.0.0.1:33069:172.16.2.111:3306 -f -o ServerAliveInterval=180

list all = wsl -l -v
shut one = wsl -t <DistroName>
shut all = wsl --shutdown
boot one = wsl -d <DistroName>

kubectl config view
KUBECONFIG=~/.kube/config:~/.kube/kubconfig2
kubectl config get-contexts
kubectl config use-context my-cluster-name
kubectl config set-context --current --namespace=ggckad-s2

kubectl get cronjob --all-namespaces
kubectl get job --all-namespaces
kubectl create cronjob hello --image=busybox --schedule="* * * * *" -- echo "Hello World"
kubectl create cronjob laravel --schedule="* * * * *" -- php /var/www/html/artisan schedule:run >> /dev/null 2>&1

kubectl exec -it $(kubectl get pods -o name | grep admin-portal) -- bash
kubectl exec $(kubectl get pods -o name | grep admin-portal) -- php /var/www/html/artisan schedule:run >> /dev/null 2>&1
kubectl exec econnote-5bf8d74f49-kqf26 -- php /var/www/html/artisan schedule:run
kubectl exec $(kubectl get pods -o name | grep admin-portal) -- php /var/www/html/artisan renew:token

Cassandra = multi master, consistent for write, better read throughput
MongoDB   = high availability, single master, better read latency
RocksDB   = single node, good for log

docker stack deploy -c t1.yml local
===================================
version:          "3"
services:
  app:
    image:        t1:v3
    deploy:
      mode: replicated
      replicas: 2
    ports:
      - "80:80"