pythonmux is a binary intended to be installed at /usr/bin/python to
multiplex between Python 2 and 3 in a backwards-compatible way. Notably,
it will default to running Python 2 to match the historical interface of
/usr/bin/python, but scripts can specify that they can run on either
Python 2 or 3. Such scripts can be run on a system that only has Python
3 installed, if this launcher is present.
For more details, see my blog post, A proposal for /usr/bin/python
between Python 2 and Python
3.
pythonmux is free software licensed under the 2-clause BSD license.