[SOLVED] Get path to original python executable (not the virtualenv)

Issue

Inside a virtualenv, sys.executable gives /path/to/venv/bin/python. How do I get the path of the python that the virtualenv was created from, such as /usr/bin/python3?

For example,

$ cd /tmp
$ virtualenv -p /usr/bin/python3 venv
Already using interpreter /usr/bin/python3
Using base prefix '/usr'
New python executable in /tmp/venv/bin/python3
Also creating executable in /tmp/venv/bin/python
Installing setuptools, pip, wheel...
done.
$ venv/bin/python -c 'import sys; print(sys.executable)'
/tmp/venv/bin/python

The answer that I want is /usr/bin/python3.

Solution

In a virtualenv, sys.real_prefix is the directory of the actual Python installation being used by the virtualenv.
Other variables worth checking are sys.base_prefix and sys.base_exec_prefix.
Example code to run in virtualenv:

import sys
print(sys.base_prefix)

Answered By - Ned Batchelder

Answer Checked By - Dawn Plyler (WPSolving Volunteer)