Cannot find the file specified when using subprocess.call('dir', shell=True) in Python
I think you may have a problem with your COMSPEC
environment variable:
>>> import os
>>> os.environ['COMSPEC']
'C:\\Windows\\system32\\cmd.exe'
>>> import subprocess
>>> subprocess.call('dir', shell=True)
(normal output here)
>>> os.environ['COMSPEC'] = 'C:\\nonexistent.exe'
>>> subprocess.call('dir', shell=True)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "c:\Python27\lib\subprocess.py", line 493, in call
return Popen(*popenargs, **kwargs).wait()
File "c:\Python27\lib\subprocess.py", line 679, in __init__
errread, errwrite)
File "c:\Python27\lib\subprocess.py", line 896, in _execute_child
startupinfo)
WindowsError: [Error 2] The system cannot find the file specified
I discovered this potential issue by digging into subprocess.py
and looking in the _execute_child
function, as pointed-to by the traceback. There, you'll find a block starting with if shell:
that will search the environment for said variable and use it to create the arguments used to launch the process.
Before downvote, note that the question was edited after i posted this answer.
I think os.listdir
is more suitable for your case:
>>> import os
>>> os.listdir()
['1.txt', '2.txt', '3.txt', 'DLLs', 'Doc', 'e.txt', 'include', 'Lib', 'libs', 'LICENSE.txt', 'm.txt', 'msvcr100.dll', 'NEWS.txt', 'py.exe', 'python.exe', 'python33.dll', 'pythonw.exe', 'pyw.exe', 'README.txt', 'Scripts', 't.txt', 'tcl', 'Tools']
If you want to run it in the command line itself, and just feeling like to call it, you can use os.sytem
:
os.system('dir')
This will run the commmand, but it returns 0
and you can't store it.
In case anyone else besides me doesn't see this in the (3.4) docs right away:
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.
Note Read the Security Considerations section before using shell=True.