Passing Variables to Subprocess.Popen

Why does passing variables to subprocess.Popen not work despite passing a list of arguments?

Drop shell=True. The arguments to Popen() are treated differently on Unix if shell=True:

import sys
from subprocess import Popen, PIPE

# populate list of arguments
args = ["mytool.py"]
for opt, optname in zip("-a -x -p".split(), "address port pass".split()):
    args.extend([opt, str(servers[server][optname])])
args.extend("some additional command".split())

# run script
p = Popen([sys.executable or 'python'] + args, stdout=PIPE)
# use p.stdout here...
p.stdout.close()
p.wait()

Note that passing shell=True for commands with external input is a security hazard, as described by a warning in the docs.

Using a variable in a subprocess.Popen command

You need shell=True because otherwise it'll look for an executable with that name. shell=True tells the method to use the shell to execute the command so > and friends become what you originally intended them to be (redirection).

The following code you posted:

from subprocess import Popen, PIPE, STDOUT 
files = raw_input('File Name: ')                                                                                                 
p = subprocess.Popen(['hexdump files > hexdump.dat' ], stdout=PIPE, stderr=STDOUT)                                         
out,err = p.communicate(input=files)  

will not work because you're just passing files to hexdump, and if a file with the name files doesn't exist you'll get an error (and if it does exist, it's still probably not what you wanted.)

What you want is to build the string you're executing:

file = "input.dat"
p = subprocess.Popen("hexdump " + file + " > hexdump.dat", shell=True)

Pass variable to subprocess

Something like

with open('iplist', 'r', encoding="utf-8") as ip_file:
    for ip in ip_file:
      cmd = ['./mmdbinspect', '--db', '/usr/local/var/GeoIP/GeoLite2-City.mmdb', ip.strip()]
      result = subprocess.run(cmd, stdout=subprocess.PIPE)
      print(result.stdout)

passing $_POST variable with subprocess.Popen

You should use popen in Python and $argv[] in PHP

Python Script

import os

value1 = 'test'
value2 = 'test2'
cmd = rf'php /mypath/myphp.php {value1} {value2}'
os.popen(cmd)

PHP Script

<?php

var_dump($argv); //['myphp.php', 'test', 'test2']
echo "Value1: ".$argv[1];
echo "Value2: ".$argv[2];

?>

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