Env vars don't change within running program in various langs

env-load.go

package main

import (
	"fmt"
	"os"
)

func cwd() string {
	wd, _ := os.Getwd()
	return wd
}

func envPwd() string {
	return os.Getenv("PWD")
}

func main() {
	fmt.Println(cwd())
	os.Chdir("/")
	fmt.Println(cwd())

	os.Chdir(envPwd())
	fmt.Printf("pwdFromEnv: %s cwd: %s\n", envPwd(), cwd())
	os.Chdir("/")
	fmt.Printf("pwdFromEnv: %s cwd: %s\n", envPwd(), cwd())
}

env-load.js

function cwd() {
    return process.cwd();
}

function envPwd() {
    return process.env['PWD'] || '/';
}

console.log('cwd', cwd());
process.chdir('/');
console.log('new wd', cwd());

process.chdir(envPwd());
console.log('pwd %s cwd %s', envPwd(), cwd());
process.chdir('/');
console.log('pwd %s cwd %s', envPwd(), cwd());

env-load.py

#!/usr/bin/env python

import os

def cwd():
  return os.getcwd()

def envPwd():
  return os.environ.get('PWD')

def main():
  print('cwd', cwd());
  os.chdir('/');
  print('new wd', cwd());

  os.chdir(envPwd());
  print('pwd %s cwd %s'%(envPwd(), cwd()))
  os.chdir('/');
  print('pwd %s cwd %s'%(envPwd(), cwd()))

if __name__ == '__main__':
  main()

env-load.sh

#/bin/bash

function envPwd {
  echo $@ $PWD;
}

envPwd 'cwd '
cd '/'
envPwd 'new wd '

cd $OLDPWD
echo -e 
envPwd 'cwd '
cd '/'
envPwd 'new wd '