Python subprocess output format?

Question

I wanted to print the OS system information for a Pi in python. The OS command "cat /etc/os-release" works fine in the Terminal with nice row formatting.

In Python I used :

import subprocess

output = subprocess.check_output("cat /etc/os-release", shell=True)
print("Version info: ",output)

That works, but I do not get any newlines:

Version info:  b'PRETTY_NAME="Raspbian GNU/Linux 9 (stretch)"\nNAME="Raspbian GNU/Linux"\nVERSION_ID="9"\nVERSION="9 (stretch)"\nID=raspbian\nID_LIKE=debian\nHOME_URL="http://www.raspbian.org/"\nSUPPORT_URL="http://www.raspbian.org/RaspbianForums"\nBUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"\n'

How can I format the output to add newlines?

Possible duplicate of Convert bytes to a string?

Open AI - Opting Out
– Open AI - Opting Out

2018-12-18 23:49:29 +00:00
Commented Dec 18, 2018 at 23:49 — Open AI - Opting Out
– Open AI - Opting Out, Commented Dec 18, 2018 at 23:49
'str(output)' would work

jath03
– jath03

2018-12-18 23:54:09 +00:00
Commented Dec 18, 2018 at 23:54 — jath03
– jath03, Commented Dec 18, 2018 at 23:54

Sébastien Lavoie · Accepted Answer · 2018-12-19 00:45:14Z

19

The problem is that your string is a bytestring, as denoted in the output with the letter b as a prefix to the string: Version info: b'PRETTY_NAME="Raspbian GNU/Linux...

A simple fix would be to decode the string as follows:

import subprocess

output = subprocess.check_output("cat /etc/os-release", shell=True)
output = output.decode("utf-8")
print("Version info: ",output)

And the result will be printed correctly. You can verify that this is a different object if you print its type before and after decoding:

import subprocess

output = subprocess.check_output("cat /etc/os-release", shell=True)
print(type(output))
output = output.decode("utf-8")
print(type(output))

This will result in the following output:

<class 'bytes'>
<class 'str'>

answered Dec 19, 2018 at 0:45

Sébastien Lavoie

9821 gold badge11 silver badges19 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

user3005949 Over a year ago

That did it !Nice clean solution !

Collectives™ on Stack Overflow

Python subprocess output format?

1 Answer 1

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related