nix package manager from alpine with sudo and admin user

alpine-with-admin-user.sh

# set up base alpine image
ADMINUSER=$1
if [ ! -e nixos-docker ]; then
    git clone https://github.com/NixOS/docker nixos-docker
fi
pushd nixos-docker > /dev/null
    git checkout Dockerfile
    cp Dockerfile Dockerfile.orig
    cat Dockerfile.orig |
        sed "s/addgroup/sudo addgroup/" |
        sed "s/adduser/sudo adduser/" |
        sed "s/mkdir/sudo mkdir/" |
        sed "s/ln /sudo ln /" |
        sed "s/rm /sudo rm /" |
        sed "s|rm -r /nix|rm -r /tmp/nix|" |
        sed "s|/profiles/default|/profiles/per-user/$ADMINUSER/profile|" |
        sed "s|/profiles/per-user/root|/profiles/per-user/$ADMINUSER|" |
        sed "s/0755/0777/" |
        sed "s/USER=root/USER=$ADMINUSER/" |
        sed "/# Download/i RUN apk add sudo" |
        sed "/# Download/i RUN adduser -D $ADMINUSER && echo '$ADMINUSER ALL=(ALL) NOPASSWD: ALL' >> /etc/sudoers" |
        sed "/# Download/i USER $ADMINUSER" |
        sed "/# Download/i WORKDIR /tmp" |
        sed "/^ENV/i WORKDIR /home/$ADMINUSER" |
        tee Dockerfile
    sudo su -c "$(which docker) build -t alpine-with-admin-user ."
popd > /dev/null