Open document with default OS application in Python, both in Windows and Mac OS

Use the subprocess module available on Python 2.4+, not os.system(), so you don't have to deal with shell escaping.

import subprocess, os, platform
if platform.system() == 'Darwin':       # macOS
    subprocess.call(('open', filepath))
elif platform.system() == 'Windows':    # Windows
    os.startfile(filepath)
else:                                   # linux variants
    subprocess.call(('xdg-open', filepath))

The double parentheses are because subprocess.call() wants a sequence as its first argument, so we're using a tuple here. On Linux systems with Gnome there is also a gnome-open command that does the same thing, but xdg-open is the Free Desktop Foundation standard and works across Linux desktop environments.

open and start are command-interpreter things for Mac OS/X and Windows respectively, to do this.

To call them from Python, you can either use subprocess module or os.system().

Here are considerations on which package to use:

1. You can call them via os.system, which works, but...

   Escaping: os.system only works with filenames that don't have any spaces or other shell metacharacters in the pathname (e.g. A:\abc\def\a.txt), or else these need to be escaped. There is shlex.quote for Unix-like systems, but nothing really standard for Windows. Maybe see also python, windows : parsing command lines with shlex

   • MacOS/X: os.system("open " + shlex.quote(filename))
   • Windows: os.system("start " + filename) where properly speaking filename should be escaped, too.

2. You can also call them via subprocess module, but...

   For Python 2.7 and newer, simply use

   subprocess.check_call(['open', filename])
   

   In Python 3.5+ you can equivalently use the slightly more complex but also somewhat more versatile

   subprocess.run(['open', filename], check=True)
   

   If you need to be compatible all the way back to Python 2.4, you can use subprocess.call() and implement your own error checking:

   try:
       retcode = subprocess.call("open " + filename, shell=True)
       if retcode < 0:
           print >>sys.stderr, "Child was terminated by signal", -retcode
       else:
           print >>sys.stderr, "Child returned", retcode
   except OSError, e:
       print >>sys.stderr, "Execution failed:", e
   

   Now, what are the advantages of u

I prefer:

os.startfile(path, 'open')

Note that this module supports filenames that have spaces in their folders and files e.g.

A:\abc\folder with spaces\file with-spaces.txt

(python docs) 'open' does not have to be added (it is the default). The docs specifically mention that this is like double-clicking on a file's icon in Windows Explorer.

This solution is windows only.

I am pretty late to the lot, but here is a solution using the windows api. This always opens the associated application.

import ctypes

shell32 = ctypes.windll.shell32
file = 'somedocument.doc'

shell32.ShellExecuteA(0,"open",file,0,0,5)

A lot of magic constants. The first zero is the hwnd of the current program. Can be zero. The other two zeros are optional parameters (parameters and directory). 5 == SW_SHOW, it specifies how to execute the app. Read the ShellExecute API docs for more info.

On mac os you can call open:

import os
os.open("open myfile.txt")

This would open the file with TextEdit, or whatever app is set as default for this filetype.