Thank you for kind reply. I appreciate it.

2018. 1. 19. 오전 2:54에 "Glenn Morris" <rgm@gnu.org>님이 작성:
Glenn Morris wrote:

> Eshell makes process-environment buffer-local.

If you repeat your experiment with

emacs -Q --eval '(setq eshell-modify-global-environment t)' -f eshell

it works as you wanted.