1// capture requirements to install
2pip freeze > requirements.txt
3
4// install requirements from requirements.txt
5pip install -r requirements.txt
6
7// or
8$ env1/bin/pip freeze > requirements.txt
9$ env2/bin/pip install -r requirements.txt1For Unix families: pip3 freeze > requirements.txt
2For Windos: pip freeze > requirements.txt1note: yor should be on the same dir as requirements.txt file 
2
3pip install -r requirements.txt1pip3 freeze > requirements.txt  # Python3
2pip freeze > requirements.txt  # Python2
31pip3 freeze > requirements.txt  # Python3
2pip freeze > requirements.txt  # Python2