Python Subprocess not working on Windows 7 - python

Can anyone explain what's happening here? Even built in cmd.exe commands aren't working:
Python 3.4.0 (v3.4.0:04f714765c13, Mar 16 2014, 19:25:23) [MSC v.1600 64 bit (AM
D64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import subprocess
>>> subprocess.call('dir')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "D:\Python34\lib\subprocess.py", line 535, in call
with Popen(*popenargs, **kwargs) as p:
File "D:\Python34\lib\subprocess.py", line 848, in __init__
restore_signals, start_new_session)
File "D:\Python34\lib\subprocess.py", line 1104, in _execute_child
startupinfo)
FileNotFoundError: [WinError 2] The system cannot find the file specified
>>>

To use 'dir', you have to pass shell=True:
>>> import subprocess
>>> subprocess.call('dir', shell=True)
You have to do this because dir is built into the shell itself, it's not a standalone console application. This is also mentioned in the subprocess.Popen documentation:
On Windows with shell=True, the COMSPEC environment variable specifies
the default shell. The only time you need to specify shell=True on
Windows is when the command you wish to execute is built into the
shell (e.g. dir or copy). You do not need shell=True to run a batch
file or console-based executable.

Related

"subprocess.call" doesn't work. error message: "[WinError 193] %1 is not a valid Win32 application" [duplicate]

This question already has answers here:
OSError: [WinError 193] %1 is not a valid Win32 application
(14 answers)
Closed 2 years ago.
my script has to open different kind of scripts (.exe, .py, .c, etc..) and to reach this goal I use these two instructions:
os.chdir(FOLDER_PATH)
os.system("start "+SCRIPT_NAME)
the code works, but it shows the console window whenever os.system("start "+SCRIPT_NAME) is used. to hide it, I read on internet that I have to use the subprocess module. I tried to use these commands but they don't work:
C:\test
λ ls -l
total 16
-rw-r--r-- 1 Admin 197121 13721 Oct 19 00:44 test.py
C:\test
λ python
Python 3.8.3 (tags/v3.8.3:6f8c832, May 13 2020, 22:20:19) [MSC v.1925 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>
>>> import subprocess
>>> from subprocess import CREATE_NO_WINDOW
>>>
>>> subprocess.call("test.py", creationflags=CREATE_NO_WINDOW)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Users\Admin\AppData\Local\Programs\Python\Python38-32\lib\subprocess.py", line 340, in call
with Popen(*popenargs, **kwargs) as p:
File "C:\Users\Admin\AppData\Local\Programs\Python\Python38-32\lib\subprocess.py", line 854, in __init__
self._execute_child(args, executable, preexec_fn, close_fds,
File "C:\Users\Admin\AppData\Local\Programs\Python\Python38-32\lib\subprocess.py", line 1307, in _execute_child
hp, ht, pid, tid = _winapi.CreateProcess(executable, args,
OSError: [WinError 193] %1 is not a valid Win32 application
>>>
how can I solve the issue?
You can use call(), but run() is supposed to be a newer version, and more robust. https://docs.python.org/3/library/subprocess.html Use whichever flavor you like, as long as it achieves your goals.
#! /usr/bin/env python3
import subprocess as sp
cmd = ['echo', 'hi'] ## separate args in list. safer this way
response = sp .run( cmd, stdout=sp.PIPE, stderr=sp.PIPE, encoding='utf-8', creationflags=sp.CREATE_NO_WINDOW)
print( response.stderr, response.stdout )
cmd = 'echo hi' ## alternate string method
response = sp .run( cmd, stdout=sp.PIPE, stderr=sp.PIPE, shell=True, encoding='utf-8', creationflags=sp.CREATE_NO_WINDOW)
print( response.stderr, response.stdout )
If you don't specify encoding, then it returns b'binary encoded strings'

Python subprocess.call fails on windows without shell=True

I am using Python 2.7.14 on windows 10 64bit. I need to use
subprocess.call
but it is failing everytime if I will not pass shell=True. As per the python doc, shell=True should not be used. Also I want to know why it is failing.
python
ActivePython 2.7.14.2717 (ActiveState Software Inc.) based on
Python 2.7.14 (default, Dec 15 2017, 16:31:45) [MSC v.1500 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import subprocess
>>> subprocess.call(['date'])
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Python27\lib\subprocess.py", line 168, in call
return Popen(*popenargs, **kwargs).wait()
File "C:\Python27\lib\subprocess.py", line 390, in __init__
errread, errwrite)
File "C:\Python27\lib\subprocess.py", line 640, in _execute_child
startupinfo)
WindowsError: [Error 2] The system cannot find the file specified
But when run with shell=True, it is running fine
>>> subprocess.call(['date'],shell=True)
The current date is: Wed 12/04/2019
Enter the new date: (mm-dd-yy)
I tried on mac too and subprocess.call is running fine without shell=True
Please help.
date is not an executable, but a builtin function of cmd.exe. You cannot use it outside the shell.

Can't install pygame_sdl2

I'm creating a tower defense game using python and pygame. I would like to add this one on the Google Play Store, but I need to create an apk file.
I'm following a tutorial on GitHub:
https://github.com/renpytom/rapt-pygame-example.
I follow all the instructions but can't install pygame_sdl2.
I use the command prompt, and use $ python setup.py install in the appropriate directory.
But it gave me this error :
C:\Users\gomes\Downloads\pygame_sdl2-master>python setup.py install
Traceback (most recent call last):
File "setup.py", line 59, in <module>
parse_cflags([ "sh", "-c", "sdl2-config --cflags" ])
File "C:\Users\gomes\Downloads\pygame_sdl2-master\setuplib.py", line 93, in parse_cflags
output = subprocess.check_output(command, universal_newlines=True)
File "C:\Python27\lib\subprocess.py", line 212, in check_output
process = Popen(stdout=PIPE, *popenargs, **kwargs)
File "C:\Python27\lib\subprocess.py", line 390, in __init__
errread, errwrite)
File "C:\Python27\lib\subprocess.py", line 640, in _execute_child
startupinfo)
WindowsError: [Error 2] Le fichier spÚcifiÚ est introuvable
I tried to reinstall pygame_sdl2-master, but gave me the same result.
You need the appropriate Windows dependencies and cython. I did some researching and testing and found this solution:
Install cython, type this in a terminal:
$ pip install cython
Go to your pygame_sdl2 directory and download the Windows dependencies by typing:
$ git clone https://github.com/renpy/pygame_sdl2_windeps
If it's not in the pygame_sdl2 directory, just move pygame_sdl2_windeps there manually.
Start building the library:
$ python setup.py install
I directly download pygame_sdl2_windeps on github. I have copied this one one the pygame_sdl2 directory and use the "python setup.py install" command in the command prompt, and IT WORKS !!!
C:\PGS4A\pygame_sdl2>python
Python 2.7.13 (v2.7.13:a06454b1afa1, Dec 17 2016, 20:42:59) [MSC v.1500 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import pygame_sdl2
>>>
Thank you for your help !!!

Raspberry Pi Radio Transmitter Error

I have read that the Raspberry Pi is capable of transmitting FM.
I have downloaded the script and put on the directory "/home/pi/".
Then I have executed following commands in the terminal over putty:
pi#raspberrypi ~ $ sudo python
Python 2.7.3 (default, Mar 18 2014, 05:13:23)
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import PiFm
>>> PiFm.play_sound("left_right.wav")
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "PiFm.py", line 7, in play_sound
call(["./pifm", filename])
File "/usr/lib/python2.7/subprocess.py", line 493, in call
return Popen(*popenargs, **kwargs).wait()
File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
errread, errwrite)
File "/usr/lib/python2.7/subprocess.py", line 1259, in _execute_child
raise child_exception
OSError: [Errno 13] Permission denied
I have ensured that the soundfile "left_right.wav" is in the same directory.
I don't know why this error is throwed.
I use Raspbian as OS, if this is revelant...
EDIT: The files used are in this download: http://cdn.makezine.com/make/pifm/PiRadio.zip

Cannot use python-nmap

I have multiple times installed python-nmap following the instructions on their site, but it just doesn't work. Every time I try to test it by doing:
>>> import nmap
>>> nm = nmap.PortScanner()
I get the following error:
Python 2.7.4 (default, Apr 19 2013, 18:28:01)
[GCC 4.7.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import nmap
>>> nm = nmap.PortScanner()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "nmap/nmap.py", line 118, in __init__
p = subprocess.Popen(['nmap', '-V'], bufsize=10000, stdout=subprocess.PIPE)
File "/usr/lib/python2.7/subprocess.py", line 711, in __init__
errread, errwrite)
File "/usr/lib/python2.7/subprocess.py", line 1308, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory
All help is greatly appreciated. Thanks in advance.
This error is fixed if you install a later version of nmap for python 2.*
Follow the link here: http://nmap.org/book/inst-macosx.html
You need to install nmap by the looks of it

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