Bash script to create a frozen set of a requirements from a requirements.txt using pip

update_frozen.sh

#!/usr/bin/env bash

set -ex

if [ "$1" = "build" ]; then
	cd /tmp/build
	mkdir -p cache
	pip install --cache-dir cache -r requirements.txt
	pip freeze > requirements_frozen.txt
	pip list --outdated --format columns
else
	mkdir -p build
	cp requirements.txt build
	cp scripts/update_frozen.sh build
	docker run --rm -it -v $(pwd)/build:/tmp/build python:3.5 /tmp/build/update_frozen.sh build
	cp build/requirements_frozen.txt requirements_frozen.txt
fi