Getting the current shell type from python script

Question

My script sets some environment varrible, to be used by the Makefiles, so since every shell, bash(export to set varriable) and tcsh(setenv), I need to get the correct shell type, from where we have run the python, I have tried using $SHELL varrriable, but it always given me sh as my shell.

Is there a way, I can get the right shell type from a python script or will it always output "SH" as the $SHELL variable.

Why do you need the shell for this? subprocess.* functions have arguments for environment variables! — ThiefMaster
– ThiefMaster, Commented Jan 20, 2014 at 7:43
$SHELL gives you the login shell, not the current shell. Why not specify a specific shell in the Makefile, or use #!? — cdarke
– cdarke, Commented Jan 20, 2014 at 9:20
I need this, because different users can have different shell preference, and the scripts should detect from which shell, the user have invoked it, and then based on that, it should output the correct data varriables (setenv/export) for it. — Viks
– Viks, Commented Jan 20, 2014 at 18:52

DevOops · Accepted Answer · 2016-02-26 21:54:07Z

11

Sorry to bring this back from the dead but I just did this myself. The following should give you the path to your current shell:

from os import environ
print(environ['SHELL'])

You should be able to replace shell with any environment variable you're looking for.

answered Feb 26, 2016 at 21:54

DevOops

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4 Comments

Jens Timmerman Over a year ago

doesn't work: my shell is set to fish, when I start bash in fish SHELL is still set to fish, it never changes to bash, not exec bash, not bash -c "env | grep SHELL" or anything other I can think of

DevOops Over a year ago

your configured shell is still fish though. The environment variable approach this is using wouldn't detect that you dropped into a Bash process to exec python, that's not it's design. If you want a parent proc, I should think you can do that with subprocess somehow. What's the use case herein though? It seems like a manufactured issue.

Jens Timmerman Over a year ago

There are plenty of reasons why you would like to know what shell called the python script. e.g. when you have written a python script that outputs shell commands for the current shell as in the question. It doesn't matter what the configured shell is when I need to generate output that is meant for the current shell that is calling python.

Cnoobplusplus Over a year ago

One could have different environment variables, aliases, etc. in .bashrc than in config.fish or .cshrc. Also you could run different script in background simple by starting a different shell. For example when using default system shell: running python use the system python (2.6 in my case) whereas changing shell running python will run the latest python (3.7) with access to non-default libraries, etc.

Alirezaarabi · Accepted Answer · 2023-02-13 11:11:39Z

2

use shellingham like below

import shellingham

try:
    shell = shellingham.detect_shell()
except shellingham.ShellDetectionFailure:
    shell = provide_default()

the shell will return you a tuple with two params and you can read your shell name with shell[0]

answered Feb 13, 2023 at 11:11

Alirezaarabi

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Comments

Near Privman · Accepted Answer · 2022-08-21 22:06:38Z

1

For the case that a user has launched a shell of a different type from their login shell, and then invoked your Python script in that shell, you need to look at the executable used to run your script's parent process:

import os
os.path.realpath(f'/proc/{os.getppid()}/exe')

answered Aug 21, 2022 at 22:06

Near Privman

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