Hello sir i am new to docker, i am using ubuntu budgie(linux) 20.04 my docker version is
Docker version 18.09.9, build 1752eb3
i have install docker using snap pac
This error originates from the fact, that your current user does not have enough permission to access the npm cli file.
Did you try the minimal Dockerfile:
FROM node:lts
WORKDIR /home/node
COPY . .
RUN npm install
CMD ['npm', 'start']
Does it work for you? If so, the problem in your Dockerfile, I assume in user node
or you have some other script we don't see in OP.