Saving the output of a process run by python

Question

I have the following code:

import os

commands = [r"cd c:\bugs\*722857\*722857 && chrome.exe --no-sandbox --single-process ..\..\cr-1195650-cve-2021-30588-stepped.html",
            r"cd c:\bugs\*722857\*722857 && chrome.exe --no-sandbox --single-process --js-flags=-expose-gc ..\..\cr-1057593-cve-2020-6428-stepped.html",
            r"cd c:\bugs\*722857\*722857 && chrome.exe --no-sandbox --single-process ..\..\cr-1032000-stepped.html",            
            ]

for i in commands:
    os.system(i)

I would like to save the output of each command, either as a string or list of strings. Any advice?

score 0 · Answer 1 · answered Mar 20 '22 at 07:19

0

You need to have a look at subprocess module. Either subprocess.getstatusoutput or subprocess.getoutput is matching your requirement. If you just want to save the output, the return value from subprocess.getoutput is enough.

answered Mar 20 '22 at 07:19

Ji Bin

491
3
9

When running with subprocesses, either with check_output or popen, I get a file not found error, so I was hoping to use os if possible – NetMax Mar 20 '22 at 07:28
If you are creating Popen object by subprocess.Popen, please note, the argument `shell` need to set True, as your input are some commands. like proc = subprocess.Popen('cd c:\somelocation\ && ...', shell=True, ...) – Ji Bin Mar 20 '22 at 07:34
when using something like: for i in commands: out = subprocess.Popen(i, shell=True) it only runs one command – NetMax Mar 20 '22 at 08:15
Based on your code, does chrome.exe is your %PATH% envirement? if not, I think it will raise 'FileNotFound'. – Ji Bin Mar 21 '22 at 02:31

score 0 · Answer 2 · answered Mar 20 '22 at 07:22

0

Replace os.system(i) with output = os.popen(i).read(), as the first one only passes command to the system, while the second creates a pipe to communicate with whatever is executed.

answered Mar 20 '22 at 07:22

vladko312

99
6

I'm trying to use .upper() on the output, but it doesn't seem to be working, any recommendations? – NetMax Mar 20 '22 at 08:19
How are you doing it? – vladko312 Mar 20 '22 at 22:29
output = os.popen(i).read() then output = output.upper(), then print (output) – NetMax Mar 21 '22 at 06:55
@NetMax And how exactly is it not working? It works for me on python 3.10 and should work. – vladko312 Mar 24 '22 at 01:58

Saving the output of a process run by python

2 Answers2