.' is not recognized as valid command

Question

On Windows (11), I'm trying to activate a python virtualenv inside a subprocess.run, but, I'm not able to execute the activate script :

import subprocess

p = subprocess.run(".\venv\Scripts\activate.bat", shell=True, stderr=subprocess.PIPE)
print(p.stderr)

Produce :

b"'.' n'est pas reconnu en tant que commande interne\r\nou externe, un programme ex\x82cutable ou un fichier de commandes.\r\n"

Note: .\venv\Scripts\activate.bat is working in a shell prompt.

How am I supposed to activate a virtual env inside a subprocess.run ?

Answer 1

Remember that \ is used to escape special characters. \v is a ASCII Vertical Tab, so that the first part of your command line is just .. To fix this, add an r to your string.

p = subprocess.run([r".\venv\Scripts\activate.bat"], stderr=subprocess.PIPE)

Note that I've also removed the shell=True. It's not necessary and so shouldn't be used.

Oh, and remember that you cannot change one process' environment from a subprocess. So, whatever you're trying to do, probably won't work anyways.