how to open a cmd shell in windows and issue commands to that shell using python

Question

I've tried

import os
os.system('cmd.exe')

great it opens up a cmd shell

but how do I write commands from my python script so that the opened shell executes it?

basically it's like this

open up a cmd shell and somehow get a hold of the instance of the opened shell and issue commands to it. the subprocess module doesn't seem to open a cmd shell im not trying to view the contents of the shell via the interpreter but actually but that's what subprocess does?

so how can we open up a cmd shell and pass commands to that opened shell?

Answer 1

to anyone having the same problems as me

I needed to get a handle on the command prompt window and and wanted to activate my virtualenv and run my .py file programatically.

I used pywin32com and after hours of researching stackoverflow and the web

I managed to get a working solution

I don't know much about the subprocess module but and I don't know if it let's you send different commands to the opened command prompt

but here is my working solution

import time
import os
from win32com import client
from  win32gui import GetWindowText, GetForegroundWindow, SetForegroundWindow, EnumWindows
from win32process import GetWindowThreadProcessId


class ActivateVenv:

    def set_cmd_to_foreground(self, hwnd, extra):
        """sets first command prompt to forgeround"""

        if "cmd.exe" in GetWindowText(hwnd):
            SetForegroundWindow(hwnd)
            return

    def get_pid(self):
        """gets process id of command prompt on foreground"""

        window = GetForegroundWindow()
        return GetWindowThreadProcessId(window)[1]

    def activate_venv(self, shell, venv_location):
        """activates venv of the active command prompt"""

        shell.AppActivate(self.get_pid())
        shell.SendKeys("cd  {ENTER}")
        shell.SendKeys(r"cd %s {ENTER}" % venv_location)
        shell.SendKeys("activate {ENTER}")

    def run_py_script(self,shell):
        """runs the py script"""

        shell.SendKeys("cd ../..{ENTER}")
        shell.SendKeys("python run.py {ENTER}")

    def open_cmd(self, shell):
        """ opens cmd """

        shell.run("cmd.exe")
        time.sleep(1)


if __name__ == "__main__":

    shell = client.Dispatch("WScript.Shell")
    run_venv = ActivateVenv()
    run_venv.open_cmd(shell)
    EnumWindows(run_venv.set_cmd_to_foreground, None)
    run_venv.activate_venv(shell, "flask3.5/venv/scripts")
    run_venv.run_py_script(shell)