exit locked ssh connection

To disconnect a locked-up ssh session, type

Enter ~ .

References :

command line - How do I kill a locked SSH session? - Ask Ubuntu

kill process by port

show

fuser 8080/tcp

kill

fuser -k 8080/tcp

References :
unix - How to kill a process running on particular port in Linux? - Stack Overflow 

No module named PIL

$ pip install image

References :
python - No module named serial - Stack Overflow 

Turning off usb

power off

# echo "1-4.4.4" > /sys/bus/usb/drivers/usb/unbind

power on

# echo "1-4.4.4" > /sys/bus/usb/drivers/usb/bind

References :
Controlling a USB power supply (on/off) with linux - Stack Overflow 

Node-RED dashboard

$ cd ~/.node-red
$ npm i node-red-dashboard

http://localhost:1880/ui

References :

node-red/node-red-dashboard: A dashboard UI for Node-RED

fatal error: libxml/xpath.h: No such file or directory

# apt-get install libxml2-dev libxslt1-dev python-dev

References :

python - How to install lxml on Ubuntu - Stack Overflow

Python json.dumps 顯示中文

newjson = json.dumps(myjson, ensure_ascii=False)

References :
python 打印json格式的数据中文显示问题 - onwer3的专栏 - 博客频道 - CSDN.NET