How to store the result of an executed shell command in a variable in python?

Question

I need to store the result of a shell command that I executed in a variable, but I couldn\'t get it working. I tried like:

import os    

call = os.system(\"         


        

Answer 1

commands.getstatusoutput would work well for this situation. (Deprecated since Python 2.6)

import commands
print(commands.getstatusoutput("cat syscall_list.txt | grep f89e7000 | awk '{print $2}'"))

Answer 2

All the other answers here are fine answers. In many situations, you do need to run external commands.

This specific example has another option: you can read the file, process it line by line, and do something with the output.

While this answer doesn't work for the "more general question being asked", I think it should always be considered. It is not always the "right answer", even where possible. Remembering this (easier), and knowing when (not) to apply it (more difficult), will make you a better programmer.

Answer 3

In python 3 you can use

import subprocess as sp
output = sp.getoutput('whoami --version')
print (output)

``

Answer 4

Use the subprocess module instead:

import subprocess
output = subprocess.check_output("cat syscall_list.txt | grep f89e7000 | awk '{print $2}'", shell=True)

Edit: this is new in Python 2.7. In earlier versions this should work (with the command rewritten as shown below):

import subprocess
output = subprocess.Popen(['awk', '/f89e7000/ {print $2}', 'syscall_list.txt'], stdout=subprocess.PIPE).communicate()[0]

---

As a side note, you can rewrite

cat syscall_list.txt | grep f89e7000

To

grep f89e7000 syscall_list.txt

And you can even replace the entire statement with a single awk script:

awk '/f89e7000/ {print $2}' syscall_list.txt

Leading to:

import subprocess
output = subprocess.check_output(['awk', '/f89e7000/ {print $2}', 'syscall_list.txt'])

Answer 5

os.popen works for this. popen - opens a pipe to or from command. The return value is an open file object connected to the pipe, which can be read. split('\n') converts the output to list

import os
list_of_ls = os.popen("ls").read().split('\n')
print list_of_ls

import os
list_of_call = os.popen("cat syscall_list.txt | grep f89e7000 | awk '{print $2}'").read().split('\n')
print list_of_call