.devcontainer.json

{
	"name": "example",
	"build": {
		"dockerfile": "Dockerfile",
	},
	"remoteUser": "user"
}

Dockerfile

FROM buildpack-deps:focal

RUN useradd -m user

USER user

# Uncomment this in order to get the script executed when dotfiles are installed
# ENV HACKED="'; echo hacked >> /home/user/hacked.txt; '"

# Uncomment this to observe "Syntax error: redirection unexpected" error
# dotfiles won't be installed, .gitconfig won't be copied from host
ENV COMP_WORDBREAKS=" \n\"'@><=;|&("