Making eshell your own

emacs

I have written utilities for choosing what information, icons, and faces your eshell prompt presents.

Example eshell prompts:

/img/esh-ex.png /img/esh-me.png

Eshell prompt customization takes place in eshell-prompt-function and eshell-prompt-regexp. The former determines the content of your prompt while the latter distinguishes your commands.

I define a macro esh-section taking a name, an icon, a form or variable to be evaluated, and optionally face properties. They create anonymous functions which will be evaluated and concatenated at prompt-time. 

(require 'dash)
(require 's)

(defmacro with-face (STR &rest PROPS)
  "Return STR propertized with PROPS."
  `(propertize ,STR 'face (list ,@PROPS)))

(defmacro esh-section (NAME ICON FORM &rest PROPS)
  "Build eshell section NAME with ICON prepended to evaled FORM with PROPS."
  `(setq ,NAME
         (lambda () (when ,FORM
                      (-> ,ICON
                          (concat esh-section-delim ,FORM)
                          (with-face ,@PROPS))))))

(defun esh-acc (acc x)
  "Accumulator for evaluating and concatenating esh-sections."
  (--if-let (funcall x)
      (if (s-blank? acc)
          it
        (concat acc esh-sep it))
    acc))

(defun esh-prompt-func ()
  "Build `eshell-prompt-function'"
  (concat esh-header
          (-reduce-from 'esh-acc "" eshell-funcs)
          "\n"
          eshell-prompt-string))

Now lets define the needed configuration. 

;; Separator between esh-sections
(setq esh-sep "  ")  ; or " | "

;; Separator between an esh-section icon and form
(setq esh-section-delim " ")

;; Eshell prompt header
(setq esh-header "\n ")  ; or "\n┌─"

;; Eshell prompt regexp and string. Unless you are varying the prompt by eg.
;; your login, these can be the same.
(setq eshell-prompt-regexp " ")   ; or "└─> "
(setq eshell-prompt-string " ")   ; or "└─> "

Now we are set to build some sections. A note, if a section's form returns nil, then it will be skipped, so the effect of eg. python virtual environments will only appear when you have an active venv. 

(esh-section esh-dir
             "\xf07c"  ;  (faicon folder)
             (abbreviate-file-name (eshell/pwd))
             '(:foreground "gold" :bold ultra-bold :underline t))

(esh-section esh-git
             "\xe907"  ;  (git icon)
             (magit-get-current-branch)
             '(:foreground "pink"))

(esh-section esh-python
             "\xe928"  ;  (python icon)
             pyvenv-virtual-env-name)

(esh-section esh-clock
             "\xf017"  ;  (clock icon)
             (format-time-string "%H:%M" (current-time))
             '(:foreground "forest green"))

;; Below I implement a "prompt number" section
(setq esh-prompt-num 0)
(add-hook 'eshell-exit-hook (lambda () (setq esh-prompt-num 0)))
(advice-add 'eshell-send-input :before
            (lambda (&rest args) (setq esh-prompt-num (incf esh-prompt-num))))

(esh-section esh-num
             "\xf0c9"  ;  (list icon)
             (number-to-string esh-prompt-num)
             '(:foreground "brown"))

;; Choose which eshell-funcs to enable
(setq eshell-funcs (list esh-dir esh-git esh-python esh-clock esh-num))

;; Enable the new eshell prompt
(setq eshell-prompt-function 'esh-prompt-func)

Further extensions to explore are predicate-based face application for eg. distinguishing master and other branches and modeline-like foreground separation.

I've hosted the code altogether at this gist.

display/shell in my config will host the most recent iteration and all my other emacs tweaks.

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