Python's os.system(command) and dashes inside a string

Question

I want to run some command with os.system(). I have prepared string "command" (includes some dashes, slashes) and try to do:

print(command)
os.system(command)

My output:

"C:\Program Files (x86)\SimInTech\bin\mmain.exe" "Aux Systems.prt" /saveas "Aux Systems.xprt" /exit
"C:\Program" не является внутренней или внешней
командой, исполняемой программой или пакетным файлом.

("C:\\Program" is not an inner or outter command, executable program or package file.)

If I copy+paste in a command line this (output of print(command)):

"C:\Program Files (x86)\SimInTech\bin\mmain.exe" "Aux Systems.prt" /saveas "Aux Systems.xprt" /exit

It works fine. So, what is the problem and how to avoid it?

Some details of how I prepare my "command" string:

import sys
import os
import codecs
simintech = '"C:\\Program Files (x86)\\SimInTech\\bin\\mmain.exe"'
argfile = sys.argv[1:len(sys.argv)]
file = ' '.join(argfile)
file = file.strip()
filepath, filename = os.path.split(file)
if filepath !='':
    filepath = filepath+"\\"
oldname = filename
newname = filename.replace('.prt','.xprt')
command = simintech + ' "' + filepath +oldname+'" /saveas "'+filepath+newname+'" /exit'

Explanation: I run my script with filename as an argument. Filename could contain spaces, so I collect all args and put it in one string using ' '.join(argfile) After that I separate flepath and filename (if filename was full - with absolute path). And finally I form my command with path to my program, dash, fullname of a file, option \\saveas, again fullname with path but with other file extension, dash and option \\exit.

Answer 1

You should not use os.system, but subprocess.call:

import subprocess
subprocess.call(["C:\Program Files (x86)\SimInTech\bin\mmain.exe", "Aux Systems.prt", "/saveas", "Aux Systems.xprt", "/exit"]

It will make sure that all spaces are escaped properly and will call the according program with the according arguments. (First of list is program, rest is arguments)