Accessing shell variables in Python

Question

Running echo $HISTFILE in bash gives me /home/myname/.bash_history.

Now I'm trying to use Python to access this HISTFILE shell variable by doing the following:

import subprocess
x = subprocess.check_output('echo $HISTFILE', shell=True)
print(x)

However, this gives me a blank output.

If subprocess.check_output along with shell=True executes the command in a shell, why doesn't it have a HISTFILE variable that I can access?
How can I work my way around this?

Note that for HISTFILE to show up in the environment (os.environ), it must first be exported: unix.stackexchange.com/questions/295555 I think it isn't by default. — Wander Nauta
– Wander Nauta, Commented Aug 20, 2020 at 19:13
$HISTFILE looks like any other environment variable but in reality it's a shell variable and you've to export it in order to access it using os.environ or child processes. — Oli
– Oli, Commented Aug 20, 2020 at 19:34

Armin Primadi · Accepted Answer · 2020-08-20 19:10:20Z

0

Using subprocess seems to be overkill for the task, you can use os.environ to access environment variables.

import os
os.environ['HISTFILE']

answered Aug 20, 2020 at 19:10

Armin Primadi

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1 Comment

That gives me a KeyError.