How to run external executable using Python?

Question

I have an external executable file which i am trying to run from a Python script. CMD executable runs but without generating output. Probably it exit before output can be generated. Any suggestion about how to delay exit until outputs are generated?

import subprocess, sys
from subprocess import Popen, PIPE
exe_str = r"C:/Windows/System32/cmd C:/temp/calc.exe"

parent = subprocess.Popen(exe_str,  stderr=subprocess.PIPE)

Answer 1

option 1:

import subprocess

subprocess.call('C:\Windows\System32\calc.exe')

option 2:

subprocess.Popen(['C:\Windows\System32\calc.exe'],stdout=subprocess.PIPE,stderr=subprocess.PIPE,shell=True).communicate()

option 3:

import os os.system('C:\Windows\System32\calc.exe')

Answer 2

use subprocess.call, more info here:

import subprocess
subprocess.call(["C:\\temp\\calc.exe"])

or

import os
os.system('"C:/Windows/System32/notepad.exe"')

i hope it helps you...

Answer 3

The os.system method is depreciated and should not be used in new applications. The subprocess module is the pythonic way to do what you require.

Here is an example of some code I wrote a few weeks ago using subprocess to load files, the command you need to use to delay exit until data has been received and the launched program completes is wait():

import subprocess

cmd = "c:\\file.exe"
process = subprocess.Popen(cmd, stdout=subprocess.PIPE, creationflags=0x08000000)
process.wait()

creationflags=0x08000000 is an optional parameter which suppresses the launch of a window, which can be useful if the program you are calling does not need to be directly seen.