I read this somewhere a while ago but cant seem to find it. I am trying to find a command that will execute commands in the terminal and then output the result.

For example: the script will be:

command 'ls -l'

It will out the result of running that command in the terminal

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11 Answers

There are several ways to do this:

A simple way is using the os module:

import os os.system("ls -l")

More complex things can be achieved with the subprocess module: for example:

import subprocess test = subprocess.Popen(["ping","-W","2","-c", "1", "192.168.1.70"], stdout=subprocess.PIPE) output = test.communicate()[0]
4

I prefer usage of subprocess module:

from subprocess import call call(["ls", "-l"])

Reason is that if you want to pass some variable in the script this gives very easy way for example take the following part of the code

abc = a.c call(["vim", abc])
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In fact any question on subprocess will be a good read

import os os.system("echo 'hello world'")

This should work. I do not know how to print the output into the python Shell.

You should also look into commands.getstatusoutput

This returns a tuple of length 2.. The first is the return integer (0 - when the commands is successful) second is the whole output as will be shown in the terminal.

For ls

import commands s = commands.getstatusoutput('ls') print s >> (0, 'file_1\nfile_2\nfile_3') s[1].split("\n") >> ['file_1', 'file_2', 'file_3']

for python3 use subprocess

import subprocess s = subprocess.getstatusoutput(f'ps -ef | grep python3') print(s)

You can also check for errors:

import subprocess s = subprocess.getstatusoutput('ls') if s[0] == 0: print(s[1]) else: print('Custom Error {}'.format(s[1])) # >>> Applications # >>> Desktop # >>> Documents # >>> Downloads # >>> Library # >>> Movies # >>> Music # >>> Pictures 
import subprocess s = subprocess.getstatusoutput('lr') if s[0] == 0: print(s[1]) else: print('Custom Error: {}'.format(s[1])) # >>> Custom Error: /bin/sh: lr: command not found

In python3 the standard way is to use subprocess.run

res = subprocess.run(['ls', '-l'], capture_output=True) print(res.stdout)

The os.popen() is pretty simply to use, but it has been deprecated since Python 2.6. You should use the subprocess module instead.

Read here: reading a os.popen(command) into a string

Jupyter

In a jupyter notebook you can use the magic function ! 

!echo "execute a command" files = !ls -a /data/dir/ #get the output into a variable

ipython

To execute this as a .py script you would need to use ipython 

files = get_ipython().getoutput('ls -a /data/dir/')

execute script 

$ ipython my_script.py

You could import the 'os' module and use it like this : 

import os os.system('#DesiredAction')
  • Running: subprocess.run
  • Output: subprocess.PIPE
  • Error: raise RuntimeError
#! /usr/bin/env python3 import subprocess def runCommand (command): output=subprocess.run( command, stdout=subprocess.PIPE, stderr=subprocess.PIPE) if output.returncode != 0: raise RuntimeError( output.stderr.decode("utf-8")) return output output = runCommand ([command, arguments]) print (output.stdout.decode("utf-8"))