redis commands

start cli
redis-cli

show keys
KEYS

showo keys starting with blog
KEYS blog*

clear all keys (delete all from redis)
flushall

change jvm options

sudo vi jvm.options

Elastic search start stop

Start
sudo service elasticsearch start
Stop
sudo service elasticsearch stop

show process memory usage ubuntu

ps aux --sort=-%mem | awk 'NR<=10{print $0}'

remove (delete) folder and its coontent in ubuntu terminal

sudo rm -r

copy content of folder to another folder

see what owner of files is (for sake).

sudo cp -a /source/. /dest/

this should copy all files and in my case assign right owner.
If not cd to the dest folder and use

sudo chown www-data:www-data *

Nginx test && reload

sudo nginx -t && sudo nginx -s reload