Pass arguments to executable in Python

Question

I am using os.startfile('C:\\test\\sample.exe') to launch the application. I don't want to know the application’s exit status and I just want to launch the exe.

I need to pass the argument to that exe like 'C:\\test\\sample.exe' -color

Please suggest a method to run this in Python.

• Hackaholic: use os.system("command")

Answer 1

You should use the subprocess module instead of os.startfile or os.system in every case that I'm aware of.

import subprocess
subprocess.Popen([r'C:\test\sample.exe', '-color'])

You could, as @Hackaholic suggests in the comments, do

import os
os.system(r'C:\test\sample.exe -color')

But this is no simpler, and the docs for os recommend the use of subprocess instead.

• Bala: subprocess is waiting for the new exe to complete but my objective is just to launch new exe. below code is not working. os.system(r'c:\\Program Files\\bin\\winx64\\sample.exe -b -color')
• senshin: @Bala Ah, right, forgot that os.startfile opens in a new process. I've edited my answer; you should use subprocess.Popen if you don't want the call to block.
• senshin: @Bala Note also: you should either use double slashes 'C:\\foo' OR raw strings r'C:\foo'. Not both. If you use both, you will have too many backslashes in your file paths. That is probably why the os.system call in your comment is failing.
• Bala: The following options are not working. Please suggest: subprocess.Popen(['C:\data\ANSYS.exe -b -i cdb_wb.txt']) subprocess.check_call([r'C:\data\ANSYS.exe', '-b -i cdb_wb.txt'])
• senshin: @Bala You should probably pass each flag and argument separately, so that your argument list looks something like [r'C:\data\ANSYS.exe', '-b', '-i', 'cdb_wb.txt']. If this doesn't work for you, please ask a new question.

Answer 2

Create a batch file sam_ple.bat with the following commands and arguments

cd C:\test\
start sample.exe -color

Then put sam_ple.bat in the same directory as your script.py file

Enter the following line of code in python to launch the exe:

os.startfile('.\sam_ple.bat')