How to workaround “the input device is not a TTY” when using grunt-shell to invoke a script that calls docker run?

Remove the -t from the docker run command:

docker run $RUN_ENV_FILE -i --rm --user node -v "$PWD":/app -w /app yaktor/node:0.39.0 $@

The -t tells docker to configure the tty, which won’t work if you don’t have a tty and try to attach to the container (default when you don’t do a -d).