Dockerfile Error 2, cannot cd to /root/rpi-rgb-led-matrix

Open Source Projects DockerEngine
1

Client: RASPIAN PI
Version: 18.06.1-ce**
API version: 1.38**
Go version: go1.10.3**
Git commit: e68fc7a**
Built: Tue Aug 21 17:30:52 2018**
OS/Arch: linux/arm**
Experimental: false**

Updated: this topic question is also asked here with, I think a bit more tidy on the questions and results I have gotten thus far: Docker MQTT Panel (Overstack)

Hi,
I receive an [build] error 2 commands: /bin/sh: cd: line 1: can’t cd to /root/rpi-rgb-led-matrix during “make build” with this dockerfile

Is the line "cd /root/rpi-rgb-led-matrix && " legal in Dockerfile?

I tried WORKDIR /root/rpi-rgb-led-matrix" and it would build without error 2 but not sure if this is what the author intended. How can I solve this?

Dockerfile:

RUN apk update && \
	apk add --no-cache python py-paho-mqtt py-pillow libstdc++ make rsync g++ \
		ttf-freefont ttf-opensans ttf-dejavu ttf-inconsolata ttf-ubuntu-font-family ttf-droid ttf-liberation ttf-linux-libertine \
		graphicsmagick-dev zlib-dev freetype-dev mosquitto-dev python-dev json-c-dev python2-dev && \
	cd /root/rpi-rgb-led-matrix && \
	HARDWARE_DESC=adafruit-hat-pwm make && \
	mkdir -p /usr/local/include/rgbmatrix && \
	cp include/* /usr/local/include/rgbmatrix && \
	cp lib/librgbmatrix.* /usr/local/lib && \
	ln -s librgbmatrix.so.1 /usr/local/lib/librgbmatrix.so && \
	HARDWARE_DESC=adafruit-hat-pwm make install-python
	#mkdir -p /usr/local/share/fonts/rgbmatrix && \
	#cp fonts/* /usr/local/share/fonts/rgbmatrix


# ttf-cantarell ttf-font-awesome ttf-mononoki
WORKDIR /root

Thank you for you consideration in helping me with this.
Climy