:bind (:map eshell-hist-mode-map
     ("<down>" . 'next-line)
     ("<up>" . 'previous-line)
     ([remap eshell-previous-matching-input-from-input] . helm-eshell-history)
     ([remap eshell-list-history] . helm-eshell-history)
     ))

  (use-package eshell
     :config
     (require 'em-hist)      
     (use-package eshell-git-prompt
       :config
       ;; the powerline prompt is best but I've no idea how to shorten it to the last directory.
       (eshell-git-prompt-use-theme 'powerline)
       (define-advice eshell-git-prompt-powerline-dir (:override () short)
   "Show only last directory."
   (file-name-nondirectory (directory-file-name default-directory))))
     :bind (:map eshell-hist-mode-map
     ("<down>" . 'next-line)
     ("<up>" . 'previous-line)
     ([remap eshell-previous-matching-input-from-input] . helm-eshell-history)
     ([remap eshell-list-history] . helm-eshell-history)
     ))

(cl-defun fish-prompt (&optional (filename default-directory))
  "A simple prompt with a fish-like abbreviation of `$PWD'."
  (let ((cwd (or (file-remote-p filename 'localname) filename)))
    (concat
     "\f\n"
     (file-remote-p cwd)
     (replace-regexp-in-string
      "[^./][^/]*/"
      (lambda (match) (string (aref match 0) ?/))
      (substring (abbreviate-file-name cwd) 0 -1))
     ;; Add slash if it was the only character in the filename.
     (when (file-equal-p "/" cwd) "/")
     (if (zerop (user-uid)) " # " " $ "))))