emacs 進階：瞭解命令

時間 2019-12-05

標籤 emacs 進階瞭解命令简体版

原文原文鏈接

命令組成

因爲emacs自己就是emacs lisp編寫的，因此在emacs中一個命令其實就是一個函數。html

(defun helm-M-x (_arg &optional command-name)
"Preconfigured `helm' for Emacs commands.
It is `helm' replacement of regular `M-x' `execute-extended-command'.
Unlike regular `M-x' emacs vanilla `execute-extended-command' command,
the prefix args if needed, can be passed AFTER starting `helm-M-x'.
When a prefix arg is passed BEFORE starting `helm-M-x', the first `C-u'
while in `helm-M-x' session will disable it.

You can get help on each command by persistent action."

快捷鍵	命令	說明
M-!	`shell-command`	使用系統shell 運行命令並輸出到`buffer` "Shell Command Output"
M-	`shell-command-on-region`	運行Shell命令並輸出到編輯區域
M-x	`helm-M-x`	運行emacs命令
-	`term`	打開`buffer`"terminal",運行終端
-	`eshell`	建立一個交互式的Elisp shell。

能夠經過設置shell-file-name變量的值來改變默認shellnode

(setq shell-file-name "/bin/bash")

eshell的用法shell

elisp

快速入門bash

掌握基本語法規則後就應該多看人家寫的代碼！
利用edebug更好更快地理解代碼
假如想要知道打開文件是怎麼操做的。session

首先定位函數的代碼。函數

已知快捷鍵C-x C-f。依次鍵入C-h k C-x C-f。
而後就會顯示函數的信息，點擊helm-files.el就能看到代碼。工具
若是不知道快捷鍵，則鍵入C-h a ，利用命令的名稱來搜索可能的選項。debug

(defun helm-find-files (arg)
  "Preconfigured `helm' for helm implementation of `find-file'.
Called with a prefix arg show history if some.
Don't call it from programs, use `helm-find-files-1' instead.
This is the starting point for nearly all actions you can do on files."
  (interactive "P")
  (let* ((hist            (and arg helm-ff-history (helm-find-files-history)))
         (smart-input     (or hist (helm-find-files-initial-input)))
         (default-input   (expand-file-name (helm-current-directory)))
         (input           (cond (helm-find-file-ignore-thing-at-point
                                 default-input)
                                ((and (eq major-mode 'org-agenda-mode)
                                      org-directory
                                      (not smart-input))
                                 (expand-file-name org-directory))
                                ((and (eq major-mode 'dired-mode) smart-input)
                                 (file-name-directory smart-input))
                                ((and (not (string= smart-input ""))
                                      smart-input))
                                (t default-input)))
         (input-as-presel (null (nth 0 (file-attributes input))))
         (presel          (helm-aif (or hist
                                        (and input-as-presel input)
                                        (buffer-file-name (current-buffer))
                                        (and (eq major-mode 'dired-mode)
                                             smart-input))
                              (if helm-ff-transformer-show-only-basename
                                  (helm-basename it) it))))
    (set-text-properties 0 (length input) nil input)
    (helm-find-files-1 input (and presel (null helm-ff-no-preselect)
                                  (concat "^" (regexp-quote presel))))))