<!-- Do you have a question instead of a bug report or enhancement request? Please ask it on https://stackoverflow.com/questions/tagged/visual-studio-code+python. Unable to install a linter or formatter? 'No installers available'? Windows - https://stackoverflow.com/questions/4750806/how-do-i-install-pip-on-windows Linux - https://www.cyberciti.biz/faq/debian-ubuntu-centos-rhel-linux-install-pipclient/ , https://www.tecmint.com/install-pip-in-linux/ Python configuration issues? Please check https://code.visualstudio.com/docs/python/python-tutorial#_prerequisites Otherwise **please** fill in the requested details below. "XXX" markers should not be present in the final bug report. If you think a GIF of what is happening would be helpful, consider tools like https://www.cockos.com/licecap/, https://github.com/phw/peek or https://www.screentogif.com/ . --> ## Environment data - VS Code version: Code 1.34.0 (a622c65b2c713c890fcf4fbf07cf34049d5fe758, 2019-05-15T21:59:37.030Z) - Extension version (available under the Extensions sidebar): 2019.4.12954 - OS and version: Windows x64 10.0.17763 - Python version (& distribution if applicable, e.g. Anaconda): 3.6 - Type of virtual environment used (N/A | venv | virtualenv | conda | ...): venv ## Expected behaviour According to [documentation](https://github.com/microsoft/vscode-docs/blob/master/docs/python/environments.md#variable-substitution) the value of any existing environment variable could be used when defining an environment variables. ## Actual behaviour Value of PATH environment variable is not being substituted. ## Steps to reproduce: 1. Create ```.env``` file with a single line ```PATH="${PATH};Blah-blah-blah"```. 2. Print ```PATH``` value with ```print(os.environ.get('PATH'))``` 3. ```;Blah-blah-blah``` gets printed.