Using subprocess.call() to pass commands to execute by cmd

Question

I am trying to set my IP address to a specific one on a LAN Network.

To do this i have tried using the following:

import subprocess
command='netsh interface ipv4 set address name="Local Area Connection* 4" source=static address=192.168.173.234 mask=255.255.255.0 gateway=192.168.0.1'
subprocess.call(["cmd.exe", command])

The only thing this results in is the starting up of an empty cmd.exe that isn't doing anything.

Also, what for would the shell=True be used ? When I try to use it, python returns a SyntaxError

UPDATE: If I use:

command='netsh interface ipv4 set address name="Local Area Connection* 4" source=static address=192.168.173.222 mask=255.255.255.0 gateway=192.168.0.1'
subprocess.check_call(["netsh.exe", command])

Python Returns the error:

Traceback (most recent call last):
  File "D:file path", line 8, in <module>
    subprocess.check_call(["netsh.exe", netsh_cmd])
  File "C:\Python27\lib\subprocess.py", line 540, in check_call
    raise CalledProcessError(retcode, cmd)
CalledProcessError: Command '['netsh.exe', 'netsh interface ipv4 set address name="Local Area Connection* 4" source=static address=192.168.173.222 mask=255.255.255.0 gateway=192.168.0.1']' returned non-zero exit status 1

are you on Windows? Why do you use single quotes? Does it work if you copy-paste the command *as is* into Windows console that runs `cmd.exe` (not Powershell)? How is `netsh` implemented -- is where `netsh.exe`? or is it an internal cmd.exe command (unlikely)? — jfs, Feb 15 '15 at 22:09
@J.F. Sebastian, I'm on Windows 8.1, changed the single quotes(wasn't aware it didn't work in cmd that way). Yes it does work if i type exactly what I stated here into the cmd.exe(has to be run as admin)/Power Shell(also admin). netsh.exe is in C:/Windows/System32/. — Mario Geuenich, Feb 16 '15 at 10:35
have you tried to run the suggested Python code as admin (for debugging)? `call(command)` or `call(command, shell=True)` — jfs, Feb 16 '15 at 11:12
@J.F. Sebastian How do you run python code as admin ? With `'/user:Administrator'` — Mario Geuenich, Feb 16 '15 at 12:35
run it (for debugging) in exactly the same way as you run netsh command that succeeds (open admin console and run Python script there. If it works; you could look for a proper way to escalate privileges). About the last error: Do not split netsh from the rest of the command. Pass the command as a single string exactly as you see it on the command line as my answer suggests. — jfs, Feb 16 '15 at 12:52
@J.F. Sebastian, I popened admin cmd and ran the python script, this time with added print statements as a token. The output was just the print statements, but nothing else changed. — Mario Geuenich, Feb 16 '15 at 13:25
my answer shows `subprocess.check_call(command)`. Why do you use `subprocess.check_call(["netsh.exe", command])` instead? — jfs, Feb 17 '15 at 03:11

Padraic Cunningham · Answer 1 · 2015-02-15T18:10:18.607

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If you use a string of args you need shell=True:

import subprocess
command="netsh interface ipv4 set address name='Local Area Connection* 4' source=static address=192.168.173.234 mask=255.255.255.0 gateway=192.168.0.1"
subprocess.call(command,shell=True)

You can do it without shell=True which I would recommend by passing a list of args:

import subprocess
command = ['netsh', 'interface', 'ipv4', 'set', 'address', 'name=Local Area Connection* 4', 'source=static', 'address=192.168.173.234', 'mask=255.255.255.0', 'gateway=192.168.0.1']


subprocess.call( command)

Or let shlex.split split the args for you:

import shlex

subprocess.call(shlex.split(command))

using check_call in place of call may also be preferable as call will not raise an error if there is a non-zero exit status where check_call will.

edited Feb 15 '15 at 18:10

answered Feb 15 '15 at 18:05

Padraic Cunningham

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@Mario. So what exactly happens? – Padraic Cunningham Feb 15 '15 at 18:13
Now that i have tried using check_call python returns a CalledProcessError: Command '['netsh', ...]' returned non-zero exit status 1 – Mario Geuenich Feb 15 '15 at 18:17
Yes, it works fine, but only as long as there is another computer connected to the network I have created on the machine that is trying to set a specific IP. – Mario Geuenich Feb 15 '15 at 18:35
and you run it exactly as posted from the cmd prompt? – Padraic Cunningham Feb 15 '15 at 18:36
it seems OP is on Windows. Unless `netsh` is an internal cmd.exe command (unlikely); you don't need `shell=True`. [Single quotes are used by `cmd.exe` only in specific cases](http://stackoverflow.com/q/24173825/4279). It seems if they are not erronious here then they should be preserved and passed to `netsh` as is and therefore `shlex.split()` should not be used here. – jfs Feb 15 '15 at 22:15
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@J.F.Sebastian, I originally used the command as is, you can see it in the first example and the OP said it did not work . Would shell=True make it fail? – Padraic Cunningham Feb 15 '15 at 22:43
1

@PadraicCunningham: It shouldn't in this case unless there is some other conflicting `netsh` program ([different rules for searching the executable](http://stackoverflow.com/a/25167402/4279)). The escaping rules ([what is considered a metacharacter](http://stackoverflow.com/a/27867015/4279)) are also different but it shouldn't mattter for the given command. [The exit code](http://stackoverflow.com/q/27842166/4279) might be converted to its two's complement negative value. – jfs Feb 15 '15 at 23:18

score 0 · Answer 2 · edited May 23 '17 at 12:05

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If there is netsh.exe somewhere in the search path (assuming you are on Windows) then you could pass the command string as is:

import subprocess

subprocess.check_call(command)

edited May 23 '17 at 12:05

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answered Feb 15 '15 at 22:09

jfs

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Using subprocess.call() to pass commands to execute by cmd

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