Question

I have a Python script that needs to execute an external program, but for some reason fails.

If I have the following script:

import os; os.system('C:\\Temp\\a b c\\Notepad.exe'); raw_input(); 

Then it fails with the following error:

‘C:\Temp\a’ is not recognized as an internal or external command, operable program or batch file.

If I escape the program with quotes:

import os; os.system(''C:\\Temp\\a b c\\Notepad.exe''); raw_input(); 

Then it works. However, if I add a parameter, it stops working again:

import os; os.system(''C:\\Temp\\a b c\\Notepad.exe' 'C:\\test.txt''); raw_input(); 

What is the right way to execute a program and wait for it to complete? I do not need to read output from it, as it is a visual program that does a job and then just exits, but I need to wait for it to complete.

Also note, moving the program to a non-spaced path is not an option either.

---

This does not work either:

import os; os.system(''C:\\Temp\\a b c\\Notepad.exe''); raw_input(); 

Note the swapped single/double quotes.

With or without a parameter to Notepad here, it fails with the error message

The filename, directory name, or volume label syntax is incorrect.

Answer 1

subprocess.call will avoid problems with having to deal with quoting conventions of various shells. It accepts a list, rather than a string, so arguments are more easily delimited. i.e.

import subprocess subprocess.call(['C:\\Temp\\a b c\\Notepad.exe', 'C:\\test.txt'])