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* C-d to close eshell :eshell:emacs:elisp:config:
One of the "tricks" that I have learned to use when working with
terminals is using ~C-d~ to close them, or when working on a TTY
logout. It somehow grew to the extent that if I can't use it, I get
annoyed, like with ~eshell~.
I have customized ~ansi-term~ to immediately close its buffer after the
shell quits. This makes it very easy to start an ~ansi-term~, which I've
bound to ~C-c t~, run a quick command (perhaps ~make~, or similar), ~C-d~,
and I'm out. I want that for my ~eshell~ too.
There are a few conditions that I want met before the buffer is
killed, though.
1. Since ~eshell~ is an Emacs mode like any other, ~C-d~ is usually used
to forward-kill characters, I don't want to lose this.
2. I only want it to quit when the line of input is empty.
The following piece of code make sure these conditions are met.
1. It interactively calls =delete-char=, which keeps keybindings like
~C-4 C-d~ to delete 4 characters working.
2. It catches the error condition which is signaled whenever
=delete-char= can't do it's job (like when there's nothing left to
delete in the buffer).
3. It checks to make sure that the signaled error is the =end-of-buffer=
error. I don't want to kill the buffer if I try to delete more
characters than are in the buffer because I feel that could cause
irritating surprises.
4. It checks of the cursor is at the ~eshell~ prompt. This, combined
with only responding to the =end-of-buffer= error, makes sure we're
on an empty line and not just at the end of the input. Sometimes
keys are pressed at the wrong time and I don't want to have to
re-type a command just because I was being an idiot.
5. If the right conditions aren't met, signal the error again so I can
see what's going on.
#+BEGIN_SRC emacs-lisp
(defun eshell-C-d ()
"Either call `delete-char' interactively or quit."
(interactive)
(condition-case err
(call-interactively #'delete-char)
(error (if (and (eq (car err) 'end-of-buffer)
(looking-back eshell-prompt-regexp))
(kill-buffer)
(signal (car err) (cdr err))))))
#+END_SRC
I then bind this to =C-d= in eshell.
#+BEGIN_SRC emacs-lisp
(add-hook 'eshell-mode-hook
(lambda () (local-set-key (kbd "C-d") #'eshell-C-d)))
#+END_SRC
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