Subject: eshell: built-ins do not handle command substitution

From: Yegor Timoshenko <[email-masked]>
Date: Tue, 6 Mar 2018 04:34:33 +0000

In M-x eshell:

  $ which echo
  eshell/echo is a compiled Lisp function in `em-basic.el'.
  $ which *echo
  /run/current-system/sw/bin/echo
  $ echo ${mktemp -d}
  $ *echo ${mktemp -d}
  /tmp/tmp.UaiWQ0YPIX

GNU Emacs 27.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.26)
 of 2018-02-25