Split requirements files in pip

The -r flag isn't restricted to command-line use only, it can also be used inside requirements files. So running pip install -r req-1-and-2.txt when req-1-and-2.txt contains this:

-r req-1.txt
-r req-2.txt

will install everything specified in req-1.txt and req-2.txt.

Just on a note, you can also split the requirements based on your groupings and embed them in a single file ( or again can prepare multiple requirements file based on your environment), that you can execute.

For example, the test requirements here:

requirements-test.txt

pylint==2.4.4
pytest==5.3.2

The dev requirements here:

requirements-dev.txt

boto3>=1.12.11

Master requirements file containing your other requirements:

requirements.txt

-r requirements-dev.txt
-r requirements-test.txt

Now, you can just install the requirements file embedding your other requirements

pip3 install -r requirements.txt