subprocess cwd too long: builtins.NotADirectoryError: [WinError 267] - python

I want to run subprocess.call (or any other subprocess function) with a cwd that is really long (longer than 260 characters). I am using a recent Windows 10.
I read here that in order to support long paths, you either have to set a registry key or add \\?\ in front of the path. I did both.
It works if the executable I want to run has a long path. But it does not work if the cwd is a long path:
import os, sys
import subprocess
PATH_TO_WRITE_EXE = r"C:\Windows\write.exe"
print(os.path.isfile(PATH_TO_WRITE_EXE))
# error:
my_cwd = "\\\\?\\C:\\a\\really\\long\\path\\a\\really\\long\\path\\a\\really\\long\\path\\a\\really\\long\\path\\a\\really\\long\\path\\a\\really\\long\\path"
print(os.path.isdir(my_cwd))
# no error:
#my_cwd = "\\\\?\\C:\\a\\not\\so\\long\\path"
#print(os.path.isdir(my_cwd))
o = subprocess.call([PATH_TO_WRITE_EXE], timeout=None, cwd=my_cwd)
print(o)
Note that os.path.isdir() returns True on both the short and the long path.
How can I use a long path as cwd on Windows 10?

This is just a proof of concept, and you will would probably want to do something different, but here is "an" answer that will work if you run your script as admin (which is a bad idea... maybe? (depending on the scope)).
import os
import win32file
import subprocess
long_path = '\\\\?\\C:\\Temp\\3d\\RsTYjcEwAA26\\aFmtI0e\\v\\ZZ7\\AWgMBtUP5\\JRGtyZXFj2\\f2rqXnYX3yJ4\\39X11fdRbYEA\\NtPySHqx\\htyDGAtZWv8NDK\\d2VRFFJPuBUVXET\\2QSlBOlMkgO8h\\mES\\sQfPZ1nBAKZNIogOb\\wyGm5Z0RwHV\\n54Si\\2BqDwGnK6TOxjs2P\\p4SnwEre4\\KQzs1NXu5QEZcuZOIct\\YrMfsGq5g5gnMN69ko\\QFIq\\J4IKjZ3vxNrC\\OVDWtz\\Jp1H0M1UclBJqeBuX\\bjN7dA\\lCFmKDg7G1\\OhYtim9AxgX9Bm9\\vrLaaL\\KLvkkJeI0ofdwb\\Es\\ZJi3Q54oIXbQ8NOi10\\VR\\HH3\\O\\5\\zn7\\7EKj96k3BC\\8Q1OqP\\FdX8RLhl1Ce\\mPG\\OtmJWbzFk\\AheYZ8Ypwo\\085dmIvlrg\\Y8tmeJt\\cDYqXPq\\G6EYcqVXaLxv\\XXq6tIfVDhv8WoF\\xM\\PCYkVfFT1Uam9N0e\\G9PfRMOv\\GUWbc6eot4aEuVQIMd\\0NMEq9iDzqgLGOJx09\\HpUN5rBfaq9\\Ve\\Tp0E\\wpXyehjLotcDa4x\\HlBy1LMD83sxzQF0\\1\\NH1be07kdb61aomggou\\D0\\SF\\n0NLPfYTEh\\3k1AooSmx4y2CS6Mrp\\sgAd9N6x1v31jZ\\hof1X6XGdBAU8\\zyzuxVDHuX54PiYW0\\nVJc8\\r\\ukx63N2kY\\6gf8dhUTYad\\L8w4JWwZq\\iixvKOcH13FXljY5D\\zgGuUlXFH1hd\\2Ykw1isPKOKXR4Osv1U\\ncmRIMWf\\i1ioae6pqcsfDsI\\AU7fhnbPCtpaOphXL\\Vxn\\gJFO1o6JAMBmBWP\\8EKwcdps\\JGd\\SgfwKrEd5\\pGSxLp\\DuA8th1\\YRx8u0LF8Cgs6JEfwA\\dIV0Ay\\PEc2\\CSli\\nyRaOzgBtLuM8S09st\\vMd9Ctvc8c6\\2\\H5tpHh\\K6TsNhH\\jXmon6\\BqvEDk\\gsMH20FxEgwlY'
file_name = "test_file"
symlink_name = "C:\\Temp\\long_link"
os.makedirs(long_path)
with open(os.path.join(long_path, file_name), "w") as file:
file.write("I'm some test data in a long path!")
win32file.CreateSymbolicLink(symlink_name, long_path, 0x3)
subprocess.call("type %s" % file_name, shell=True, timeout=None, cwd=symlink_name)
I'm some test data in a long path!0
As #eryksun mentioned in the comments: Creating a symbolic link requires SeCreateSymbolicLinkPrivilege, which by default is only assigned to elevated administrators. (However, it can be explicitly assigned to users and groups.) If os.symlink raises OSError, you can create a junction via _winapi.CreateJunction or CMD's mklink /j command.
Finally here is another answer which should enable the same behavior if you create a junction. I have not tested this answer in conjunction with your question, but it should work.
Edit: If you're running >= Python 3.5 you can use the CreateJunction call to replace the symlink above.
import _winapi
_winapi.CreateJunction(source, target)

Related

Literally opening a file (python) [duplicate]

I need to be able to open a document using its default application in Windows and Mac OS. Basically, I want to do the same thing that happens when you double-click on the document icon in Explorer or Finder. What is the best way to do this in Python?
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:
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.
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 using subprocess?
Security: In theory, this is more secure, but in fact we're needing to execute a command line one way or the other; in either environment, we need the environment and services to interpret, get paths, and so forth. In neither case are we executing arbitrary text, so it doesn't have an inherent "but you can type 'filename ; rm -rf /'" problem, and if the file name can be corrupted, using subprocess.call gives us little additional protection.
Error handling: It doesn't actually give us any more error detection, we're still depending on the retcode in either case; but the behavior to explicitly raise an exception in the case of an error will certainly help you notice if there is a failure (though in some scenarios, a traceback might not at all be more helpful than simply ignoring the error).
Spawns a (non-blocking) subprocess: We don't need to wait for the child process, since we're by problem statement starting a separate process.
To the objection "But subprocess is preferred." However, os.system() is not deprecated, and it's in some sense the simplest tool for this particular job. Conclusion: using os.system() is therefore also a correct answer.
A marked disadvantage is that the Windows start command requires you to pass in shell=True which negates most of the benefits of using subprocess.
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.
Just for completeness (it wasn't in the question), xdg-open will do the same on Linux.
import os
import subprocess
def click_on_file(filename):
'''Open document with default application in Python.'''
try:
os.startfile(filename)
except AttributeError:
subprocess.call(['open', filename])
If you have to use an heuristic method, you may consider webbrowser.
It's standard library and despite of its name it would also try to open files:
Note that on some platforms, trying to open a filename using this
function, may work and start the operating system’s associated
program. However, this is neither supported nor portable.
(Reference)
I tried this code and it worked fine in Windows 7 and Ubuntu Natty:
import webbrowser
webbrowser.open("path_to_file")
This code also works fine in Windows XP Professional, using Internet Explorer 8.
If you want to go the subprocess.call() way, it should look like this on Windows:
import subprocess
subprocess.call(('cmd', '/C', 'start', '', FILE_NAME))
You can't just use:
subprocess.call(('start', FILE_NAME))
because start is not an executable but a command of the cmd.exe program. This works:
subprocess.call(('cmd', '/C', 'start', FILE_NAME))
but only if there are no spaces in the FILE_NAME.
While subprocess.call method enquotes the parameters properly, the start command has a rather strange syntax, where:
start notes.txt
does something else than:
start "notes.txt"
The first quoted string should set the title of the window. To make it work with spaces, we have to do:
start "" "my notes.txt"
which is what the code on top does.
Start does not support long path names and white spaces. You have to convert it to 8.3 compatible paths.
import subprocess
import win32api
filename = "C:\\Documents and Settings\\user\\Desktop\file.avi"
filename_short = win32api.GetShortPathName(filename)
subprocess.Popen('start ' + filename_short, shell=True )
The file has to exist in order to work with the API call.
os.startfile(path, 'open') under Windows is good because when spaces exist in the directory, os.system('start', path_name) can't open the app correctly and when the i18n exist in the directory, os.system needs to change the unicode to the codec of the console in Windows.
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.
Here is the answer from Nick, adjusted slightly for WSL:
import os
import sys
import logging
import subprocess
def get_platform():
if sys.platform == 'linux':
try:
proc_version = open('/proc/version').read()
if 'Microsoft' in proc_version:
return 'wsl'
except:
pass
return sys.platform
def open_with_default_app(filename):
platform = get_platform()
if platform == 'darwin':
subprocess.call(('open', filename))
elif platform in ['win64', 'win32']:
os.startfile(filename.replace('/','\\'))
elif platform == 'wsl':
subprocess.call('cmd.exe /C start'.split() + [filename])
else: # linux variants
subprocess.call(('xdg-open', filename))
If you want to specify the app to open the file with on Mac OS X, use this:
os.system("open -a [app name] [file name]")
On windows 8.1, below have worked while other given ways with subprocess.call fails with path has spaces in it.
subprocess.call('cmd /c start "" "any file path with spaces"')
By utilizing this and other's answers before, here's an inline code which works on multiple platforms.
import sys, os, subprocess
subprocess.call(('cmd /c start "" "'+ filepath +'"') if os.name is 'nt' else ('open' if sys.platform.startswith('darwin') else 'xdg-open', filepath))
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.
I think you might want to open file in editor.
For Windows
subprocess.Popen(["notepad", filename])
For Linux
subprocess.Popen(["text-editor", filename])
I built a small library combining the best answers here for cross-platform support:
$ pip install universal-startfile
then launch a file or URL:
from startfile import startfile
startfile("~/Downloads/example.png")
startfile("http://example.com")
I was getting an error when calling my open file() function. I was following along with a guide but the guide was written in windows while I'm on Linux. So the os.statrfile method wasn't working for me. I was able to alleviate this problem by doing the following:
Import libraries
import sys, os, subprocess
import tkinter
import tkinter.filedioalog as fd
import tkinter.messagebox as mb
After the lib imports I then called the subprocess method for opening a file in unix based OS which is "xdg-open" and the file that will be opened.
def open_file():
file = fd.askopenfilename(title='Choose a file of any type', filetypes=[('All files', "*.*")])
subprocess.call(['xdg-open', file])

Is there any function to open (directly open the file itself) any file? [duplicate]

I need to be able to open a document using its default application in Windows and Mac OS. Basically, I want to do the same thing that happens when you double-click on the document icon in Explorer or Finder. What is the best way to do this in Python?
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:
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.
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 using subprocess?
Security: In theory, this is more secure, but in fact we're needing to execute a command line one way or the other; in either environment, we need the environment and services to interpret, get paths, and so forth. In neither case are we executing arbitrary text, so it doesn't have an inherent "but you can type 'filename ; rm -rf /'" problem, and if the file name can be corrupted, using subprocess.call gives us little additional protection.
Error handling: It doesn't actually give us any more error detection, we're still depending on the retcode in either case; but the behavior to explicitly raise an exception in the case of an error will certainly help you notice if there is a failure (though in some scenarios, a traceback might not at all be more helpful than simply ignoring the error).
Spawns a (non-blocking) subprocess: We don't need to wait for the child process, since we're by problem statement starting a separate process.
To the objection "But subprocess is preferred." However, os.system() is not deprecated, and it's in some sense the simplest tool for this particular job. Conclusion: using os.system() is therefore also a correct answer.
A marked disadvantage is that the Windows start command requires you to pass in shell=True which negates most of the benefits of using subprocess.
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.
Just for completeness (it wasn't in the question), xdg-open will do the same on Linux.
import os
import subprocess
def click_on_file(filename):
'''Open document with default application in Python.'''
try:
os.startfile(filename)
except AttributeError:
subprocess.call(['open', filename])
If you have to use an heuristic method, you may consider webbrowser.
It's standard library and despite of its name it would also try to open files:
Note that on some platforms, trying to open a filename using this
function, may work and start the operating system’s associated
program. However, this is neither supported nor portable.
(Reference)
I tried this code and it worked fine in Windows 7 and Ubuntu Natty:
import webbrowser
webbrowser.open("path_to_file")
This code also works fine in Windows XP Professional, using Internet Explorer 8.
If you want to go the subprocess.call() way, it should look like this on Windows:
import subprocess
subprocess.call(('cmd', '/C', 'start', '', FILE_NAME))
You can't just use:
subprocess.call(('start', FILE_NAME))
because start is not an executable but a command of the cmd.exe program. This works:
subprocess.call(('cmd', '/C', 'start', FILE_NAME))
but only if there are no spaces in the FILE_NAME.
While subprocess.call method enquotes the parameters properly, the start command has a rather strange syntax, where:
start notes.txt
does something else than:
start "notes.txt"
The first quoted string should set the title of the window. To make it work with spaces, we have to do:
start "" "my notes.txt"
which is what the code on top does.
Start does not support long path names and white spaces. You have to convert it to 8.3 compatible paths.
import subprocess
import win32api
filename = "C:\\Documents and Settings\\user\\Desktop\file.avi"
filename_short = win32api.GetShortPathName(filename)
subprocess.Popen('start ' + filename_short, shell=True )
The file has to exist in order to work with the API call.
os.startfile(path, 'open') under Windows is good because when spaces exist in the directory, os.system('start', path_name) can't open the app correctly and when the i18n exist in the directory, os.system needs to change the unicode to the codec of the console in Windows.
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.
Here is the answer from Nick, adjusted slightly for WSL:
import os
import sys
import logging
import subprocess
def get_platform():
if sys.platform == 'linux':
try:
proc_version = open('/proc/version').read()
if 'Microsoft' in proc_version:
return 'wsl'
except:
pass
return sys.platform
def open_with_default_app(filename):
platform = get_platform()
if platform == 'darwin':
subprocess.call(('open', filename))
elif platform in ['win64', 'win32']:
os.startfile(filename.replace('/','\\'))
elif platform == 'wsl':
subprocess.call('cmd.exe /C start'.split() + [filename])
else: # linux variants
subprocess.call(('xdg-open', filename))
If you want to specify the app to open the file with on Mac OS X, use this:
os.system("open -a [app name] [file name]")
On windows 8.1, below have worked while other given ways with subprocess.call fails with path has spaces in it.
subprocess.call('cmd /c start "" "any file path with spaces"')
By utilizing this and other's answers before, here's an inline code which works on multiple platforms.
import sys, os, subprocess
subprocess.call(('cmd /c start "" "'+ filepath +'"') if os.name is 'nt' else ('open' if sys.platform.startswith('darwin') else 'xdg-open', filepath))
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.
I think you might want to open file in editor.
For Windows
subprocess.Popen(["notepad", filename])
For Linux
subprocess.Popen(["text-editor", filename])
I built a small library combining the best answers here for cross-platform support:
$ pip install universal-startfile
then launch a file or URL:
from startfile import startfile
startfile("~/Downloads/example.png")
startfile("http://example.com")
I was getting an error when calling my open file() function. I was following along with a guide but the guide was written in windows while I'm on Linux. So the os.statrfile method wasn't working for me. I was able to alleviate this problem by doing the following:
Import libraries
import sys, os, subprocess
import tkinter
import tkinter.filedioalog as fd
import tkinter.messagebox as mb
After the lib imports I then called the subprocess method for opening a file in unix based OS which is "xdg-open" and the file that will be opened.
def open_file():
file = fd.askopenfilename(title='Choose a file of any type', filetypes=[('All files', "*.*")])
subprocess.call(['xdg-open', file])

How to get output of OS command from Jupyter notebook?

I am running Jupyter notebook on a server (python 3).
Want to see output of OS command (any OS command - this is just example):
output = os.system("pwd")
When I do print of it:
print (output)
Response is 0.
How to get a simple output (like in CLI)?
Thanks.
Just found it on internet and wanted to post.
It needs to be:
print(os.popen('ls').read())
(or any other OS command).
This works fine.
import os
print(os.getcwd())
print(os.system("pwd"))
But this question is a duplicate:
how to show current directory in ipython promp
Note that os.system() calls are not the preferred way to run any commands and do not ensure capturing the output (see here for more on this).
The preferred and safer mechanism which will capture the output of commands is subprocess.run() which has a capture_output parameter and returns a CompletedProcess object that has members including stdout and stderr which, if capture_output=True contain the output stream contents.
It is worth mentioning that for portability it is usually better to use the methods from the os, shutil, path & glob libraries, etc. This is because calls such as ls, pwd, dir, etc., will work on some platforms but not others.
Example:
import subprocess
result = subprocess.run(['cwd',], capture_output=True)
# Returns the current directory as a string for processing in result.stdout on Mac/Linux but raises an exception on Windows
print(result.stdout)
result = subprocess.run(['ls', '*.docx'], capture_output=True)
# Returns the *.docx files in the current directory as a string for processing in result.stdout on Mac/Linux but raises an exception on Windows
print(result.stdout)
However:
import pathlib
cwd = pathlib.Path.cwd() # Returns the current directory as a Path object on any platform.
print(cwd)
docs = cwd.glob('*.docx') # Returns an generator giving path for to any docx files in cwd on any platform
print(', '.join(p.name for p in docs)) # Print comma seperated list of filenames
Note that for long running or very verbose calls it is often better to use the subprocess.POpen constructor and communicate or wait.
If you want to start an external process and not wait for it to finish then use the asynco create_subprocess_exec() call instead.

Python how to open any file without explicit application call [duplicate]

I need to be able to open a document using its default application in Windows and Mac OS. Basically, I want to do the same thing that happens when you double-click on the document icon in Explorer or Finder. What is the best way to do this in Python?
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:
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.
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 using subprocess?
Security: In theory, this is more secure, but in fact we're needing to execute a command line one way or the other; in either environment, we need the environment and services to interpret, get paths, and so forth. In neither case are we executing arbitrary text, so it doesn't have an inherent "but you can type 'filename ; rm -rf /'" problem, and if the file name can be corrupted, using subprocess.call gives us little additional protection.
Error handling: It doesn't actually give us any more error detection, we're still depending on the retcode in either case; but the behavior to explicitly raise an exception in the case of an error will certainly help you notice if there is a failure (though in some scenarios, a traceback might not at all be more helpful than simply ignoring the error).
Spawns a (non-blocking) subprocess: We don't need to wait for the child process, since we're by problem statement starting a separate process.
To the objection "But subprocess is preferred." However, os.system() is not deprecated, and it's in some sense the simplest tool for this particular job. Conclusion: using os.system() is therefore also a correct answer.
A marked disadvantage is that the Windows start command requires you to pass in shell=True which negates most of the benefits of using subprocess.
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.
Just for completeness (it wasn't in the question), xdg-open will do the same on Linux.
import os
import subprocess
def click_on_file(filename):
'''Open document with default application in Python.'''
try:
os.startfile(filename)
except AttributeError:
subprocess.call(['open', filename])
If you have to use an heuristic method, you may consider webbrowser.
It's standard library and despite of its name it would also try to open files:
Note that on some platforms, trying to open a filename using this
function, may work and start the operating system’s associated
program. However, this is neither supported nor portable.
(Reference)
I tried this code and it worked fine in Windows 7 and Ubuntu Natty:
import webbrowser
webbrowser.open("path_to_file")
This code also works fine in Windows XP Professional, using Internet Explorer 8.
If you want to go the subprocess.call() way, it should look like this on Windows:
import subprocess
subprocess.call(('cmd', '/C', 'start', '', FILE_NAME))
You can't just use:
subprocess.call(('start', FILE_NAME))
because start is not an executable but a command of the cmd.exe program. This works:
subprocess.call(('cmd', '/C', 'start', FILE_NAME))
but only if there are no spaces in the FILE_NAME.
While subprocess.call method enquotes the parameters properly, the start command has a rather strange syntax, where:
start notes.txt
does something else than:
start "notes.txt"
The first quoted string should set the title of the window. To make it work with spaces, we have to do:
start "" "my notes.txt"
which is what the code on top does.
Start does not support long path names and white spaces. You have to convert it to 8.3 compatible paths.
import subprocess
import win32api
filename = "C:\\Documents and Settings\\user\\Desktop\file.avi"
filename_short = win32api.GetShortPathName(filename)
subprocess.Popen('start ' + filename_short, shell=True )
The file has to exist in order to work with the API call.
os.startfile(path, 'open') under Windows is good because when spaces exist in the directory, os.system('start', path_name) can't open the app correctly and when the i18n exist in the directory, os.system needs to change the unicode to the codec of the console in Windows.
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.
Here is the answer from Nick, adjusted slightly for WSL:
import os
import sys
import logging
import subprocess
def get_platform():
if sys.platform == 'linux':
try:
proc_version = open('/proc/version').read()
if 'Microsoft' in proc_version:
return 'wsl'
except:
pass
return sys.platform
def open_with_default_app(filename):
platform = get_platform()
if platform == 'darwin':
subprocess.call(('open', filename))
elif platform in ['win64', 'win32']:
os.startfile(filename.replace('/','\\'))
elif platform == 'wsl':
subprocess.call('cmd.exe /C start'.split() + [filename])
else: # linux variants
subprocess.call(('xdg-open', filename))
If you want to specify the app to open the file with on Mac OS X, use this:
os.system("open -a [app name] [file name]")
On windows 8.1, below have worked while other given ways with subprocess.call fails with path has spaces in it.
subprocess.call('cmd /c start "" "any file path with spaces"')
By utilizing this and other's answers before, here's an inline code which works on multiple platforms.
import sys, os, subprocess
subprocess.call(('cmd /c start "" "'+ filepath +'"') if os.name is 'nt' else ('open' if sys.platform.startswith('darwin') else 'xdg-open', filepath))
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.
I think you might want to open file in editor.
For Windows
subprocess.Popen(["notepad", filename])
For Linux
subprocess.Popen(["text-editor", filename])
I built a small library combining the best answers here for cross-platform support:
$ pip install universal-startfile
then launch a file or URL:
from startfile import startfile
startfile("~/Downloads/example.png")
startfile("http://example.com")
I was getting an error when calling my open file() function. I was following along with a guide but the guide was written in windows while I'm on Linux. So the os.statrfile method wasn't working for me. I was able to alleviate this problem by doing the following:
Import libraries
import sys, os, subprocess
import tkinter
import tkinter.filedioalog as fd
import tkinter.messagebox as mb
After the lib imports I then called the subprocess method for opening a file in unix based OS which is "xdg-open" and the file that will be opened.
def open_file():
file = fd.askopenfilename(title='Choose a file of any type', filetypes=[('All files', "*.*")])
subprocess.call(['xdg-open', file])

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

I need to be able to open a document using its default application in Windows and Mac OS. Basically, I want to do the same thing that happens when you double-click on the document icon in Explorer or Finder. What is the best way to do this in Python?
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:
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.
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 using subprocess?
Security: In theory, this is more secure, but in fact we're needing to execute a command line one way or the other; in either environment, we need the environment and services to interpret, get paths, and so forth. In neither case are we executing arbitrary text, so it doesn't have an inherent "but you can type 'filename ; rm -rf /'" problem, and if the file name can be corrupted, using subprocess.call gives us little additional protection.
Error handling: It doesn't actually give us any more error detection, we're still depending on the retcode in either case; but the behavior to explicitly raise an exception in the case of an error will certainly help you notice if there is a failure (though in some scenarios, a traceback might not at all be more helpful than simply ignoring the error).
Spawns a (non-blocking) subprocess: We don't need to wait for the child process, since we're by problem statement starting a separate process.
To the objection "But subprocess is preferred." However, os.system() is not deprecated, and it's in some sense the simplest tool for this particular job. Conclusion: using os.system() is therefore also a correct answer.
A marked disadvantage is that the Windows start command requires you to pass in shell=True which negates most of the benefits of using subprocess.
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.
Just for completeness (it wasn't in the question), xdg-open will do the same on Linux.
import os
import subprocess
def click_on_file(filename):
'''Open document with default application in Python.'''
try:
os.startfile(filename)
except AttributeError:
subprocess.call(['open', filename])
If you have to use an heuristic method, you may consider webbrowser.
It's standard library and despite of its name it would also try to open files:
Note that on some platforms, trying to open a filename using this
function, may work and start the operating system’s associated
program. However, this is neither supported nor portable.
(Reference)
I tried this code and it worked fine in Windows 7 and Ubuntu Natty:
import webbrowser
webbrowser.open("path_to_file")
This code also works fine in Windows XP Professional, using Internet Explorer 8.
If you want to go the subprocess.call() way, it should look like this on Windows:
import subprocess
subprocess.call(('cmd', '/C', 'start', '', FILE_NAME))
You can't just use:
subprocess.call(('start', FILE_NAME))
because start is not an executable but a command of the cmd.exe program. This works:
subprocess.call(('cmd', '/C', 'start', FILE_NAME))
but only if there are no spaces in the FILE_NAME.
While subprocess.call method enquotes the parameters properly, the start command has a rather strange syntax, where:
start notes.txt
does something else than:
start "notes.txt"
The first quoted string should set the title of the window. To make it work with spaces, we have to do:
start "" "my notes.txt"
which is what the code on top does.
Start does not support long path names and white spaces. You have to convert it to 8.3 compatible paths.
import subprocess
import win32api
filename = "C:\\Documents and Settings\\user\\Desktop\file.avi"
filename_short = win32api.GetShortPathName(filename)
subprocess.Popen('start ' + filename_short, shell=True )
The file has to exist in order to work with the API call.
os.startfile(path, 'open') under Windows is good because when spaces exist in the directory, os.system('start', path_name) can't open the app correctly and when the i18n exist in the directory, os.system needs to change the unicode to the codec of the console in Windows.
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.
Here is the answer from Nick, adjusted slightly for WSL:
import os
import sys
import logging
import subprocess
def get_platform():
if sys.platform == 'linux':
try:
proc_version = open('/proc/version').read()
if 'Microsoft' in proc_version:
return 'wsl'
except:
pass
return sys.platform
def open_with_default_app(filename):
platform = get_platform()
if platform == 'darwin':
subprocess.call(('open', filename))
elif platform in ['win64', 'win32']:
os.startfile(filename.replace('/','\\'))
elif platform == 'wsl':
subprocess.call('cmd.exe /C start'.split() + [filename])
else: # linux variants
subprocess.call(('xdg-open', filename))
If you want to specify the app to open the file with on Mac OS X, use this:
os.system("open -a [app name] [file name]")
On windows 8.1, below have worked while other given ways with subprocess.call fails with path has spaces in it.
subprocess.call('cmd /c start "" "any file path with spaces"')
By utilizing this and other's answers before, here's an inline code which works on multiple platforms.
import sys, os, subprocess
subprocess.call(('cmd /c start "" "'+ filepath +'"') if os.name is 'nt' else ('open' if sys.platform.startswith('darwin') else 'xdg-open', filepath))
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.
I think you might want to open file in editor.
For Windows
subprocess.Popen(["notepad", filename])
For Linux
subprocess.Popen(["text-editor", filename])
I built a small library combining the best answers here for cross-platform support:
$ pip install universal-startfile
then launch a file or URL:
from startfile import startfile
startfile("~/Downloads/example.png")
startfile("http://example.com")
I was getting an error when calling my open file() function. I was following along with a guide but the guide was written in windows while I'm on Linux. So the os.statrfile method wasn't working for me. I was able to alleviate this problem by doing the following:
Import libraries
import sys, os, subprocess
import tkinter
import tkinter.filedioalog as fd
import tkinter.messagebox as mb
After the lib imports I then called the subprocess method for opening a file in unix based OS which is "xdg-open" and the file that will be opened.
def open_file():
file = fd.askopenfilename(title='Choose a file of any type', filetypes=[('All files', "*.*")])
subprocess.call(['xdg-open', file])

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