How do I find the full path of the currently running Python interpreter from within the currently executing Python script?
See How do I check which version of Python is running my script? if you are specifically interested in the version of Python for the currently running interpreter - for example, to bail out with an error message if your script doesn't support that Python version, or conditionally disable certain modules or code paths.
sys.executable contains full path of the currently running Python interpreter.
import sys print(sys.executable) which is now documented here
/usr/bin/env python executed as env -i ./script. In that case it returns the current working directory.
#!/usr/bin/env python3 will return the correct full binary path via sys.executable. Perhaps your OS or Python version behaves slightly differently.
python and python3 commands and it printed the correct executable.
Just noting a different way of questionable usefulness, using os.environ:
import os python_executable_path = os.environ['_'] e.g.
$ python -c "import os; print(os.environ['_'])" /usr/bin/python 
_ is set by the shell. But it need not be set, so this could give the wrong answer.
_ can be /usr/bin/screen if Python is run inside a GNU Screen.
_ is not set.There are a few alternate ways to figure out the currently used python in Linux is:
which python command.command -v python commandtype python commandSimilarly On Windows with Cygwin will also result the same.
kuvivek@HOSTNAME ~ $ which python /usr/bin/python kuvivek@HOSTNAME ~ $ whereis python python: /usr/bin/python /usr/bin/python3.4 /usr/lib/python2.7 /usr/lib/python3.4 /usr/include/python2.7 /usr/include/python3.4m /usr/share/man/man1/python.1.gz kuvivek@HOSTNAME ~ $ which python3 /usr/bin/python3 kuvivek@HOSTNAME ~ $ command -v python /usr/bin/python kuvivek@HOSTNAME ~ $ type python python is hashed (/usr/bin/python) If you are already in the python shell. Try anyone of these. Note: This is an alternate way. Not the best pythonic way.
>>> import os >>> os.popen('which python').read() '/usr/bin/python\n' >>> >>> os.popen('type python').read() 'python is /usr/bin/python\n' >>> >>> os.popen('command -v python').read() '/usr/bin/python\n' >>> >>> If you are not sure of the actual path of the python command and is available in your system, Use the following command.
pi@osboxes:~ $ which python /usr/bin/python pi@osboxes:~ $ readlink -f $(which python) /usr/bin/python2.7 pi@osboxes:~ $ pi@osboxes:~ $ which python3 /usr/bin/python3 pi@osboxes:~ $ pi@osboxes:~ $ readlink -f $(which python3) /usr/bin/python3.7 pi@osboxes:~ $ 
python from the shell. If you start with an explicit different path (e.g. /opt/python/2.5/bin/python), or use python3 and then run those python commands, all of them produced incorrect answers and that has nothing to do with not being the most pythonic way, it is just plain wrong.
python (i.e., the absolute filename of the python command in the current ${PATH}) and the command the active Python interpreter is actually running under. Yikes.