Automatically answer to input prompt of batch script run by Python

Question

This is rather a unusual use case where I had to make a legacy system to work.

I have Windows batch script like following named 'batch_test.bat' (example only):

@echo OFF
set /P choice=Enter your choice: 

if /I "%choice%" == "N" (
    echo "Don't proceed"
)

if /I "%choice%" == "Y" (
    echo "Proceed"
)
if /I "%choice%" == "C" (
    echo "Cancel"

)
EXIT /B 0

I have following python code (sample):

import os

os.system('batch_test.bat')

Question is how do I feed the choice batch script is expecting from Python? I did some look up but could not find the appropriate answer.

thanks.

If you read the docs for os.system: "The subprocess module provides more powerful facilities… using that module is preferable to using this function…" If you want to control the stdin of a program, or capture its stdout, or run it safely without using the shell, or anything else, use subprocess, not os.system. — abarnert
– abarnert, Commented Aug 1, 2018 at 0:56
And notice that the docs linked to from that paragraph, Replacing Older Functions with the subprocess Module, include examples that feed input into other programs, exactly what you haven't been able to find. — abarnert
– abarnert, Commented Aug 1, 2018 at 0:56
Note that echo "some text" includes the quotes in the output... — aschipfl
– aschipfl, Commented Aug 1, 2018 at 8:58

blhsing · Accepted Answer · 2018-08-01 01:25:15Z

1

You can use subprocess.Popen to provide input to a process:

from subprocess import Popen, PIPE
p = Popen('batch_test.bat', stdin=PIPE, stdout=PIPE)
output, _ = p.communicate(b'Y\n')

answered Aug 1, 2018 at 1:25

blhsing

109k9 gold badges88 silver badges132 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Alsina Over a year ago

This worked! Deep within I found some doc that explains it in subtle way: docs.python.org/3/library/subprocess.html#subprocess.Popen

Collectives™ on Stack Overflow

Automatically answer to input prompt of batch script run by Python

1 Answer 1

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related