How to Hide the Console When I Use Os.System() or Subprocess.Call()

How do I hide the console when I use os.system() or subprocess.call()?

The process STARTUPINFO can hide the console window:

si = subprocess.STARTUPINFO()
si.dwFlags |= subprocess.STARTF_USESHOWWINDOW
#si.wShowWindow = subprocess.SW_HIDE # default
subprocess.call('taskkill /F /IM exename.exe', startupinfo=si)

Or set the creation flags to disable creating the window:

CREATE_NO_WINDOW = 0x08000000
subprocess.call('taskkill /F /IM exename.exe', creationflags=CREATE_NO_WINDOW)

The above is still a console process with valid handles for console I/O (verified by calling GetFileType on the handles returned by GetStdHandle). It just has no window and doesn't inherit the parent's console, if any.

You can go a step farther by forcing the child to have no console at all:

DETACHED_PROCESS = 0x00000008
subprocess.call('taskkill /F /IM exename.exe', creationflags=DETACHED_PROCESS)

In this case the child's standard handles (i.e. GetStdHandle) are 0, but you can set them to an open disk file or pipe such as subprocess.DEVNULL (3.3) or subprocess.PIPE.

How to hide output of subprocess

For python >= 3.3, Redirect the output to DEVNULL:

import os
import subprocess

retcode = subprocess.call(['echo', 'foo'], 
    stdout=subprocess.DEVNULL,
    stderr=subprocess.STDOUT)

For python <3.3, including 2.7 use:

FNULL = open(os.devnull, 'w')
retcode = subprocess.call(['echo', 'foo'], 
    stdout=FNULL, 
    stderr=subprocess.STDOUT)

It is effectively the same as running this shell command:

retcode = os.system("echo 'foo' &> /dev/null")

Running a process in pythonw with Popen without a console

From here:

import subprocess

def launchWithoutConsole(command, args):
    """Launches 'command' windowless and waits until finished"""
    startupinfo = subprocess.STARTUPINFO()
    startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW
    return subprocess.Popen([command] + args, startupinfo=startupinfo).wait()

if __name__ == "__main__":
    # test with "pythonw.exe"
    launchWithoutConsole("d:\\bin\\gzip.exe", ["-d", "myfile.gz"])

Note that sometimes suppressing the console makes subprocess calls fail with "Error 6: invalid handle". A quick fix is to redirect stdin, as explained here: Python running as Windows Service: OSError: [WinError 6] The handle is invalid

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