With-Editor

This library makes it possible to reliably use the Emacsclient as the $EDITOR of child processes. It makes sure that they know how to call home. For remote processes a substitute is provided, which communicates with Emacs on standard output/input instead of using a socket as the Emacsclient does.

It provides the commands with-editor-async-shell-command and with-editor-shell-command, which are intended as replacements for async-shell-command and shell-command. They automatically export $EDITOR making sure the executed command uses the current Emacs instance as “the editor”. With a prefix argument these commands prompt for an alternative environment variable such as $GIT_EDITOR. To always use these variants add this to your init file:

(define-key (current-global-map)
  [remap async-shell-command] 'with-editor-async-shell-command)
(define-key (current-global-map)
  [remap shell-command] 'with-editor-shell-command)

Alternatively use the global shell-command-with-editor-mode, which always sets $EDITOR for all Emacs commands which ultimately use shell-command to asynchronously run some shell command.

The command with-editor-export-editor exports $EDITOR or another such environment variable in shell-mode, eshell-mode, term-mode and vterm-mode buffers. Use this Emacs command before executing a shell command which needs the editor set, or always arrange for the current Emacs instance to be used as editor by adding it to the appropriate mode hooks:

(add-hook 'shell-mode-hook  'with-editor-export-editor)
(add-hook 'eshell-mode-hook 'with-editor-export-editor)
(add-hook 'term-exec-hook   'with-editor-export-editor)
(add-hook 'vterm-mode-hook  'with-editor-export-editor)

Some variants of this function exist, these two forms are equivalent:

(add-hook 'shell-mode-hook
	    (apply-partially 'with-editor-export-editor "GIT_EDITOR"))
(add-hook 'shell-mode-hook 'with-editor-export-git-editor)

This library can also be used by other packages which need to use the current Emacs instance as editor. In fact this library was written for Magit and its git-commit-mode and git-rebase-mode. Consult git-rebase.el and the related code in magit-sequence.el for a simple example.