Executing linux command with "|" and "'\n'" in Python

Question

I try to execute linux command in Python, but I don't get any output and any error.

import subprocess, os
cmd = ["iwconfig", "wlan0", "|", "grep", "ESSID", "|", "awk", "-F:", "'{print $2}'", "|", "sed", "'s/\"//g'"]
proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
output, error = proc.communicate()
print(output.decode("ascii"))

The output should be the ESSID of connected Wi-Fi.

I am sorry, I read the other questions, but I can't get it.

score 2 · Answer 1 · answered Apr 13 '19 at 17:33

2

| is a shell feature. You need shell=True.

proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)

answered Apr 13 '19 at 17:33

Daniel Roseman

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It is weird, I get different output unlike with terminal. – John Doe Apr 13 '19 at 17:35
If you are using `shell=True`, you may want to join the elements of `cmd` into a single string again, rather than letting `Popen` join them. – chepner Apr 13 '19 at 17:38
I am sorry, I read the other questions, but I can't get it. – John Doe Apr 13 '19 at 17:50

Executing linux command with "|" and "'\n'" in Python

1 Answers1