Python Subprocess or BAT script splits argument on equal sign

Question

How do I add this: -param:abc=def as a SINGLE command line argument?

Module subprocess splits this up in TWO arguments by replacing the equal sign with a space.

Here is my python script:

import subprocess

pa=['test.bat', '--param:abc=def']
subprocess.run(pa)

Here is the test program test.bat:

@echo off
echo Test.bat
echo Arg0: %0
echo Arg1: %1
echo Arg2: %2
pause

and here the output:

Test.bat
Arg0: test.bat
Arg1: --param:abc
Arg2: def
Press any key to continue . . .

Because the equal sign is gone, the real app will not be started correctly. By the way, this problem also seems to happen when running on linux, with a sh script instead of a bat file.

I understand that removing the equal sign is a 'feature' in certain cases, e.g. with the argparse module, but in my case I need to keep the equal sign. Any help is appreciated!

Answer 1

Welcome to .bat file hell

To preserve equal sign, you'll have to quote your argument (explained here Preserving "=" (equal) characters in batch file parameters) ('"--param:abc=def"'), but then subprocess will escape the quotes

Test.bat
Arg0: test.bat
Arg1: \"--param:abc=def\"
Arg2:

Good old os.system won't do that

import os

os.system('test.bat "--param:abc=def"')

result

Test.bat
Arg0: test.bat
Arg1: "--param:abc=def"
Arg2:

Damn, those quotes won't go off. Let's tweak the .bat script a little to remove them manually

@echo off
echo Test.bat
echo Arg0: %0
rem those 2 lines remove the quotes
set ARG1=%1
set ARG1=%ARG1:"=%

echo Arg1: %ARG1%
echo Arg2: %2

now it yields the proper result

Test.bat
Arg0: test.bat
Arg1: --param:abc=def
Arg2:

Alternatively, stick to subprocess and remove quotes AND backslashes.