Why does passing variables to subprocess.Popen not work despite passing a list of arguments?
python, subprocess
Solution
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.
Problem
I have a script which calls another Python script by `subprocess.Popen`. But since I have arguments stored in variable(s) ``` servers[server]['address'] servers[server]['port'] servers[server]['pass'] ``` I am unable to perform the command ``` p = subprocess.Popen( ["python mytool.py -a ", servers[server]['address'], "-x", servers[server]['port'], "-p", servers[server]['pass'], "some additional command"], shell=True, stdout=subprocess.PIPE ) ```