Python execute windows cmd functions

dir is not a file, it is an internal command, so the shell keyword must be set to True.

subprocess.call(["dir"], shell=True)

Try this

import os

os.system("windows command")

ex: for date

os.system("date")

Almost everyone's answers are right but it seems I can do what I need using os.popen -- varStr = os.popen('dir /b *.py').read()

First of all, to get a directory listing, you should rather use os.listdir(). If you invoke dir instead, you'll have to parse its output to make any use of it, which is lots of unnecessary work and is error-prone.

Now,

dir is a cmd.exe built-in command, it's not a standalone executable. cmd.exe itself is the executable that implements it.

So, you have two options (use check_output instead of check_call if you need to get the output instead of just printing it):

• use cmd's /C switch (execute a command and quit):

  subprocess.check_call(['cmd','/c','dir','/s'])
  

• use shell=True Popen() option (execute command line through the system shell):

  subprocess.check_call('dir /s', shell=True)
  

The first way is the recommended one. That's because:

• In the 2nd case, cmd, will do any shell transformations that it normally would (e.g. splitting the line into arguments, unquoting, environment variable expansion etc). So, your arguments may suddenly become something else and potentially harmful. In particular, if they happen to contain any spaces and cmd special characters and/or keywords.
• shell=True uses the "default system shell" (pointed to via COMSPEC environment variable in the case of Windows), so if the user has redefined it, your program will behave unexpectedly.