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How do I find the full path of the currently running Python interpreter from within the currently executing Python script?

Peter Mortensen
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vy32
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3 Answers3

933

sys.executable contains full path of the currently running Python interpreter.

import sys

print(sys.executable)

which is now documented here

Flair
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Imran
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    This does not seem to work from scripts with a shebang `/usr/bin/env python` executed as `env -i ./script`. In that case it returns the current working directory. – John Freeman Apr 28 '15 at 21:50
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    @JohnFreeman: I tried this on a GNU/Linux box w/ GNU coreutils 8.4 (env) and Python 3.4.2. `#!/usr/bin/env python3` will return the correct full binary path via `sys.executable`. Perhaps your OS or Python version behaves slightly differently. – kevinarpe May 22 '15 at 12:56
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    Note that this will not return the name of the Python interpreter if Python is embedded in some application. – mic_e Jul 14 '15 at 00:30
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    I tried this with the shebang for python2 and python3 and it printed the correct executable. I also tried with no shebang and called the script with the `python` and `python3` commands and it printed the correct executable. – David Baucum Oct 10 '19 at 13:18
  • It doesnt seem to work, if you have created an alias for python through alternatives, i.e. alternatives --install /usr/bin/python python /usr/bin/python2 50 alternatives --install /usr/bin/python python /usr/bin/python3.5 60 alternatives --config python In this case, sys.executable still prints python2 path. – vhora Jul 01 '20 at 02:50
  • typing ```type -a python3``` into the console gives me /usr/local/bin/python3, /usr/bin/python3. Yet running ```import sys print(sys.executable)``` gives me /usr/local/opt/python@3.8/bin/python3.8 So the paths do not match. What's up with that? – Tea Tree Aug 12 '20 at 17:30
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    @mic_e, this may have been true in 2015, but I just tried it today and it behaves as expected (it returns the absolute file of the executable that embeds Python). – Shmuel Kamensky Oct 02 '20 at 17:20
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    @mic_e how to find python executable when embedded in an interpreter? – Fred Zimmerman Nov 14 '20 at 18:27
14

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
famousgarkin
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3

There are a few alternate ways to figure out the currently used python in Linux is:

  1. which python command.
  2. command -v python command
  3. type python command

Similarly 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:~ $
Tiago Martins Peres
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kvivek
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    "from within the currently executing Python script" wrote the OP – nodakai Dec 12 '16 at 07:15
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    Your "already in the python shell" examples, all assume that the python shell started is what you get if you type `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. – Anthon Aug 24 '17 at 07:17
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    Does not answer the question of "How do I find the full path of the currently running Python interpreter from within the currently executing Python script?" – Dwight J. Browne Jul 11 '21 at 14:51
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    **Dumpster fire answer.** There's *no* deterministic relation between what the external shell considers to be `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.* – Cecil Curry Nov 29 '21 at 23:19