How do I execute a program from python? os.system fails due to spaces in path

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.

---

Edit 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

I suspect it's the same problem as when you use shortcuts in Windows... Try this:

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

Answer 2

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. ie

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

Answer 3

Here's a different way of doing it.

If you're using windows the following acts like double-clicking the file in Explorer, or giving the file name as an argument to the DOS "start" command: the file is opened with whatever application (if any) its extension is associated.

import os
os.startfile(filepath)

Example:

import os
os.startfile(textfile.txt)

This will open textfile.txt with notepad if notepad is associted with .txt files.

Answer 4

The outermost quotes are consumed by Python itself, and the Windows shell doesn't see it. As mentioned above, Windows only understands double-quotes. Python will convert forward-slashed to backslashes on Windows, so you can use

os.system('"C:/Temp/a b c/Notepad.exe"')

The ' is consumed by Python, which then passes "C:\Temp\a b c\Notepad.exe" (as a Windows path, no double-backslashes needed) to CMD.EXE

Answer 5

At least in Windows 7 and Python 3.1, os.system in Windows wants the command line double-quoted if there are spaces in path to the command. For example:

  TheCommand = '\"\"C:\\Temp\\a b c\\Notepad.exe\"\"'
  os.system(TheCommand)

A real-world example that was stumping me was cloning a drive in Virtual box. The subprocess.call solution above didn't work because of some access rights issue, but when I double-quoted the command, os.system became happy:

  TheCommand = '\"\"C:\\Program Files\\Sun\\VirtualBox\\VBoxManage.exe\" ' \
                 + ' clonehd \"' + OrigFile + '\" \"' + NewFile + '\"\"'
  os.system(TheCommand)

Answer 6

import win32api # if active state python is installed or install pywin32 package seperately

try: win32api.WinExec('NOTEPAD.exe') # Works seamlessly except: pass