Passing arguments to subprocess.call

Question

I faced unpleasant situation with silent installation of some program. I am not sure that they use any convention for installation flags with values but here what should be used for installation:

"path with spaces\setup.exe" -uninst -s -f2"path with spaces\uninstall.log"

you cannot use --f2="path with spaces\uninstall.log" or -f2="path with spaces\uninstall.log" or -f2 "path with spaces\uninstall.log"

so if I use in Python following:

command = [self.setup_exe, '-uninst', '-s', fr'-f2"{uninstall_log_file}"']

command that subprocess is executing (get from subprocess.list2cmdline(command)) is:

setup.exe" -uninst -s -f2\"some path\temp build 12\uninstall.log\"

basically slashes appear and installation is failing. Theoretically I can create my own string but the same provider for another executable provides another syntax which is more compatible with subprocess. I am wondering if it is possible to setup a list of arguments to satisfy reqs of installer?

How are you actually calling the command? It looks like you may be using shell=True when you shouldn't be. — chepner
– chepner, Commented Jun 19, 2020 at 13:14
@chepner, you are right, I am using shell=True. As far as I understood this is needed in case if I need to run command as elevated user (for example with PowerShell). Or will it work any case? — Beliaev Maksim
– Beliaev Maksim, Commented Jun 19, 2020 at 13:16
No, using shell=True just switches from executing the command directly to running a shell with a constructed argument to have the shell run the command for you. — chepner
– chepner, Commented Jun 19, 2020 at 13:18
@chepner, now it is creating another layer of quotes: "-f2\"some path\uninstall.log\"" — Beliaev Maksim
– Beliaev Maksim, Commented Jun 19, 2020 at 13:29

chepner · Accepted Answer · 2020-06-22 12:21:54Z

0

If you run

"path with spaces\setup.exe" -uninst -s -f2"path with spaces\uninstall.log"

from the command line, the equivalent call to subprocess.call is

uninstall_log_file = r"path with spaces\uninstall.log"
command = [self.setup_exe, '-uninst', '-s', f'-f2{uninstall_log_file}']
subprocess.call(command)

edited Jun 22, 2020 at 12:21

answered Jun 21, 2020 at 21:49

chepner

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4 Comments

Beliaev Maksim Over a year ago

unfortunately this ill not work, I tried this already. If I put a path without spaces it will work. If I put a path with spaces then not since argument will look like "-f2path with spaces/log.log". So this does not work

Beliaev Maksim Over a year ago

I also tried this one: stackoverflow.com/questions/43022687/… however I assume difference in provider. Since there the argument will look like -f2=path with spaces. In my example from CMD equal sign is not allowed

chepner Over a year ago

I made a slight adjustment to the answer, making uninstall_log_file the raw string rather than the f-string that interpolates the value. I'm not sure if that will make a difference.

Beliaev Maksim Over a year ago

just performed the test. Unfortunately no. I executed subprocess with list but for check also ran list2cmdline. It is adding quotes around -f2 -> "-f2path". So installation fails. what is working but weird is: command = [f'"{self.setup_exe}"', '-uninst', '-s', fr'-f2"{uninstall_log_file}"'] command = " ".join(command) and then call subprocess with a string. Do you think it is possible to get the same using list?

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