CODEWITHSUNDEEP
pythonsubprocess
Vamsi Emani
Vamsi Emani

Reputation: 10302

Get control over an external process into current python program?

I have an executable xyz.exe that is purely driven by command prompt/shell. It interactively takes input and displays output. Assume xyz.exe is somewhat like the typical python shell on windows. It waits for user to type something >>> and thereby proceeds to process the input.

Now, I want to get control over this xyz.exe process and bring it entirely into the context of my current python console/shell. How can I do this?

I referred Assign output of os.system to a variable and prevent it from being displayed on the screen and tried doing the same using subprocess: 

import subprocess

cmd = r"\\sharedLocation\path\xyz.exe"
proc = subprocess.Popen([cmd], stdout=subprocess.PIPE, shell=True)
(out, err) = proc.communicate()
print("program output:", out)

but that only gets the immediate (first time) output of xyz.exe when it starts, more like the welcome message. But after the first time output/welcome message, the xyz.exe actually waits for user input ">>>"... I want my current execution of the python script to wait() and bring-in the entire context of xyz.exe inside the scope of my script output. Is there a way to do this in python?

Upvotes: 0

Views: 701

Answers (1)

Ramchandra Apte
Ramchandra Apte

Reputation: 4079

Actually, whatever you input will be fed to xyz.exe but you won't see any further messages as stdout=subprocess.PIPE has been passed to Popen's constructor, which will make the output of the command not be outputted; instead it is fed to the file-like proc.stdout. The welcome message is printed because of print("program output:", out). To make the output of xyz.exe show up in the console remove stdout=subprocess.PIPE, from the Popen constructor arguments. Then print("program output:", out) is unnecessary.

Upvotes: 1

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