Emacs快速入门

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Emacs快速入门

Ubuntu初安装时，其时是有emacs图形界面和emacs终端界面两个快捷方式的。你只需要用鼠标点击就可以进入相应的模式。

不过如果你真心开始想用emacs，相信会有更便捷的方式，比如在终端输入emacs -nw，我们可以查emacs的帮助文档来看一眼这个-nw参数是什么意思（--no-window-system, -nw），如下

打开emacs的帮助文档：emacs --help

另外对于emacs，我想说的是，其实常用的命令并不多，花几小时就能熟悉，熟练掌握也不难，但需要经常使用，不然肯定会忘记掉。

emacs --help
Usage: emacs [OPTION-OR-FILENAME]...

Run Emacs, the extensible, customizable, self-documenting real-time
display editor.  The recommended way to start Emacs for normal editing
is with no options at all.

Run M-x info RET m emacs RET m emacs invocation RET inside Emacs to
read the main documentation for these command-line arguments.

Initialization options:

--batch                     do not do interactive display; implies -q
--chdir DIR                 change to directory DIR
--daemon                    start a server in the background
--debug-init                enable Emacs Lisp debugger for init file
--display, -d DISPLAY       use X server DISPLAY
--no-desktop                do not load a saved desktop
--no-init-file, -q          load neither ~/.emacs nor default.el
--no-loadup, -nl            do not load loadup.el into bare Emacs
--no-site-file              do not load site-start.el
--no-x-resources            do not load X resources
--no-site-lisp, -nsl        do not add site-lisp directories to load-path
--no-splash                 do not display a splash screen on startup
--no-window-system, -nw     do not communicate with X, ignoring $DISPLAY
--quick, -Q                 equivalent to:
                              -q --no-site-file --no-site-lisp --no-splash
                              --no-x-resources
--script FILE               run FILE as an Emacs Lisp script
--terminal, -t DEVICE       use DEVICE for terminal I/O
--user, -u USER             load ~USER/.emacs instead of your own

Action options:

FILE                    visit FILE using find-file
+LINE                   go to line LINE in next FILE
+LINE:COLUMN            go to line LINE, column COLUMN, in next FILE
--directory, -L DIR     prepend DIR to load-path (with :DIR, append DIR)
--eval EXPR             evaluate Emacs Lisp expression EXPR
--execute EXPR          evaluate Emacs Lisp expression EXPR
--file FILE             visit FILE using find-file
--find-file FILE        visit FILE using find-file
--funcall, -f FUNC      call Emacs Lisp function FUNC with no arguments
--insert FILE           insert contents of FILE into current buffer
--kill                  exit without asking for confirmation
--load, -l FILE         load Emacs Lisp FILE using the load function
--visit FILE            visit FILE using find-file

Display options:

--background-color, -bg COLOR   window background color
--basic-display, -D             disable many display features;
                                  used for debugging Emacs
--border-color, -bd COLOR       main border color
--border-width, -bw WIDTH       width of main border
--color, --color=MODE           override color mode for character terminals;
                                  MODE defaults to `auto', and
                                  can also be `never', `always',
                                  or a mode name like `ansi8'
--cursor-color, -cr COLOR       color of the Emacs cursor indicating point
--font, -fn FONT                default font; must be fixed-width
--foreground-color, -fg COLOR   window foreground color
--fullheight, -fh               make the first frame high as the screen
--fullscreen, -fs               make the first frame fullscreen
--fullwidth, -fw                make the first frame wide as the screen
--maximized, -mm                make the first frame maximized
--geometry, -g GEOMETRY         window geometry
--no-bitmap-icon, -nbi          do not use picture of gnu for Emacs icon
--iconic                        start Emacs in iconified state
--internal-border, -ib WIDTH    width between text and main border
--line-spacing, -lsp PIXELS     additional space to put between lines
--mouse-color, -ms COLOR        mouse cursor color in Emacs window
--name NAME                     title for initial Emacs frame
--no-blinking-cursor, -nbc      disable blinking cursor
--reverse-video, -r, -rv        switch foreground and background
--title, -T TITLE               title for initial Emacs frame
--vertical-scroll-bars, -vb     enable vertical scroll bars
--xrm XRESOURCES                set additional X resources
--parent-id XID                 set parent window
--help                          display this help and exit
--version                       output version information and exit

You can generally also specify long option names with a single -; for
example, -batch as well as --batch.  You can use any unambiguous
abbreviation for a --option.

Various environment variables and window system resources also affect
the operation of Emacs.  See the main documentation.

Report bugs to bug-gnu-emacs@gnu.org.  First, please see the Bugs
section of the Emacs manual or the file BUGS.

Emacs命令的格式

通常你可以找到一些emacs的cheat sheet，这里面会有大量的命令描述，所以弄清楚这些命令代表哪些按键是最基本的要求，最常用的组合通常有下面这些，

C-n ：最常用的命令格式（n为任意字符）
ESC n ：次常用的命令格式（n为任意字符）
C-x something ：（通常为文件操作类）
C-c something ：（通常与某些特殊的编辑模式有关）

按键含义
C-g 表示Ctrl+g组合键，即C代表Crtl
RETURN 回车键，即enter
META ESC(或Alt)键
ESC x 先按下ESC，再按下x键，注意先后顺序
S-right 按下shift键，同时按下按下鼠标右键
C-S-right 按下shift键，同时按下ctrl键和鼠标右键

注：

每个emacs都有完整的名字，如：forward-word命令即按下ESC f
当发现一个命令有全名，却没有对应的按键时，可以先输入ESC x，再输入相应的全名，回车后即执行。
META键很特殊，在sun工作站上空格两边即为此按键，但是在大多数键盘上这个按键并不存在，其功能基本上与ESC等价，在某些键盘上与Alt通用。
META与ESC的区别在于：
- META的组合命令在按键的同时输入，同时放开键
- ESC的组合命令先按ESC，松开后输入其余内容。

Emacs打开方式

（图形界面）在终端界面输入：

$ emacs hello.c   或   $ emacs

如果你想要在终端使用字符界面，如前所述，在终端界面输入：

$ emacs -nw hello.c

即可。

常用的命令

常用的命令这里只列一下，其实你只要在网上搜索emacs cheatsheet就可以找到这些ＰＤＦ文件，当然也有emacs cheatsheet的墙纸。下面这个链接就提供了不少漂亮的墙纸，你可以根据你的电脑显示器的尺寸去下载，做桌面也是挺不错的，

https://www.emacswiki.org/emacs/EmacsWallpaper
(资料：https://www.emacswiki.org/emacs/CategoryReferenceSheet)

顺便说一下，emacswiki（https://www.emacswiki.org/emacs）是个非常不错的中文学习网站。

M-x cd：切换当前工作目录(这个命令cheatsheet里居然没有，特别列出来)

一般情况下，当使用‘C-x C-f’命令时，你看到的是 home directory，如果要切换目录，请使用“M-x cd”命令

如果你要设定emacs的启动目录，可以使用command-line-default-directory，我的`.emacs`配置文件看起就是这样的

(custom-set-variables
 ;; the below lines are for color theme setting
 '(ansi-color-faces-vector
   [default default default italic underline success warning error])
 '(ansi-color-names-vector
   ["#2e3436" "#a40000" "#4e9a06" "#c4a000" "#204a87" "#5c3566" "#729fcf" "#eeeeec"])
 '(custom-enabled-themes (quote (wheatgrass))))

(custom-set-faces)

(setq command-line-default-directory "~/devc/emacsdir" )

下面我象征性地列一下各个命令，这些命令的原文的地址在：https://www.ast.cam.ac.uk/~vasily/idl/emacs_commands_list.html

C = Control
M = Meta = Alt|Esc

Basics
C-x C-f "find" file i.e. open/create a file in buffer
C-x C-s save the file
C-x C-w write the text to an alternate name
C-x C-v find alternate file
C-x i insert file at cursor position
C-x b create/switch buffers
C-x C-b show buffer list
C-x k kill buffer
C-z suspend emacs 
C-X C-c close down emacs

Basic movement
C-f forward char
C-b backward char
C-p previous line
C-n next line
M-f forward one word
M-b backward one word
C-a beginning of line
C-e end of line
C-v one page up
M-v scroll down one page
M-< beginning of text
M-> end of text

Editing
M-n repeat the following command n times
C-u repeat the following command 4 times
C-u n repeat n times
C-d delete a char
M-d delete word
M-Del delete word backwards
C-k kill line

C-Space Set beginning mark (for region marking for example)
C-W "kill" (delete) the marked region region
M-W copy the marked region
C-y "yank" (paste) the copied/killed region/line
M-y yank earlier text (cycle through kill buffer)
C-x C-x exchange cursor and mark

C-t transpose two chars
M-t transpose two words
C-x C-t transpose lines
M-u make letters uppercase in word from cursor position to end
M-c simply make first letter in word uppercase
M-l opposite to M-u

Important
C-g quit the running/entered command
C-x u undo previous action
M-x revert-buffer RETURN (insert like this) undo all changes since last save
M-x recover-file RETURN Recover text from an autosave-file
M-x recover-session RETURN if you edited several files

Online-Help
C-h c which command does this keystroke invoke
C-h k which command does this keystroke invoke and what does it do?
C-h l what were my last 100 typed keys
C-h w what key-combo does this command have?
C-h f what does this function do
C-h v what's this variable and what is it's value
C-h b show all keycommands for this buffer
C-h t start the emacs tutorial
C-h i start the info reader
C-h C-k start up info reader and go to a certain key-combo point
C-h F show the emacs FAQ
C-h p show infos about the Elisp package on this machine

Search/Replace
C-s Search forward
C-r search backward
C-g return to where search started (if you are still in search mode)
M-% query replace
Space or y replace this occurence
Del or n don't replace
. only replace this and exit (replace)
, replace and pause (resume with Space or y)
! replace all following occurences
^ back to previous match
RETURN or q quit replace


Search/Replace with regular expressions
Characters to use in regular expressions:
^ beginning of line
$ end of line
. single char
.* group or null of chars
\< beginning of a word
\> end of a word
[] every char inside the backets (for example [a-z] means every small letter)

M C-s RETURN search for regular expression forward
M C-r RETURN search for regular expression backward
M C-s incremental search
C-s repeat incremental search
M C-r incremental search backwards
C-r repeat backwards
M-x query-replace-regexp search and replace

Window-Commands
C-x 2 split window vertically
C-x o change to other window
C-x 0 delete window
C-x 1 close all windows except the one the cursors in
C-x ^ enlarge window
M-x shrink-window command says it ;-)
M C-v scroll other window
C-x 4 f find file in other window
C-x 4 o change to other window
C-x 4 0 kill buffer and window
C-x 5 2 make new frame
C-x 5 f find file in other frame
C-x 5 o change to other frame
C-x 5 0 close this frame

Bookmark commands
C-x r m set a bookmark at current cursor pos
C-x r b jump to bookmark
M-x bookmark-rename says it
M-x bookmark-delete "
M-x bookmark-save "
C-x r l list bookmarks
d mark bookmark for deletion
r rename bookmark
s save all listed bookmarks
f show bookmark the cursor is over
m mark bookmarks to be shown in multiple window
v show marked bookmarks (or the one the cursor is over)
t toggle listing of the corresponding paths
w " path to this file
x delete marked bookmarks
Del ?
q quit bookmark list


M-x bookmark-write write all bookmarks in given file
M-x bookmark-load load bookmark from given file

Shell
M-x shell starts shell modus
C-c C-c same as C-c under unix (stop running job)
C-d delete char forward
C-c C-d Send EOF
C-c C-z suspend job (C-z under unix)
M-p show previous commands

DIRectory EDitor (dired)
C-x d start up dired
C (large C) copy 
d mark for erase
D delete right away
e or f open file or directory
g reread directory structure from file
G change group permissions (chgrp)
k delete line from listing on screen (don't actually delete)
m mark with *
n move to next line
o open file in other window and go there
C-o open file in other window but don't change there
P print file
q quit dired
Q do query-replace in marked files
R rename file
u remove mark
v view file content
x delete files marked with D
z compress file
M-Del remove all marks (whatever kind)
~ mark backup files (name~ files) for deletion
# mark auto-save files (#name#) for deletion
*/ mark directory with * (C-u * removes that mark again)
= compare this file with marked file
M-= compare this file with it's backup file
! apply shell command to this file
M-} change to the next file marked with * od D
M-{ " previous "
% d mark files described through regular expression for deletion
% m " (with *)
+ create directory
> changed to next dir
< change to previous dir
s toggle between sorting by name or date

Maybe into this category also fits this command:
M-x speedbar starts up a separate window with a directory view

Telnet
M-x telnet starts up telnet-modus
C-d either delete char or send EOF
C-c C-c stop running job (similar to C-c under unix)
C-c C-d send EOF
C-c C-o clear output of last command
C-c C-z suspend execution of command
C-c C-u kill line backwards
M-p recall previous command

Text
Works only in text mode 
M-s center line
M-S center paragraph
M-x center-region name says 

Macro-commands
C-x ( start macro definition
C-x ) end of macro definition
C-x e execute last definied macro
M-n C-x e execute last defined macro n times
M-x name-last-kbd-macro give name to macro (for saving)
M-x insert-keyboard-macro save named macro into file
M-x load-file load macro
M-x macroname execute macroname

Programming
M C-\ indent region between cursor and mark
M-m move to first (non-space) char in this line
M-^ attach this line to previous
M-; formatize and indent comment
C, C++ and Java Modes
M-a beginning of statement
M-e end of statement
M C-a beginning of function
M C-e end of function
C-c RETURN Set cursor to beginning of function and mark at the end
C-c C-q indent the whole function according to indention style
C-c C-a toggle modus in which after electric signs (like {}:';./*) emacs does the indention
C-c C-d toggle auto hungry mode in which emacs deletes groups of spaces with one del-press
C-c C-u go to beginning of this preprocessor statement
C-c C-c comment out marked area
More general (I guess)
M-x outline-minor-mode collapses function definitions in a file to a mere {...} 
M-x show-subtree If you are in one of the collapsed functions, this un-collapses it 
In order to achive some of the feats coming up now you have to run etags *.c *.h *.cpp (or what ever ending you source files have) in the source directory
M-. (Thats Meta dot) If you are in a function call, this will take you to it's definition 
M-x tags-search ENTER Searches through all you etaged 
M-, (Meta comma) jumps to the next occurence for tags-search 
M-x tags-query-replace yum. This lets you replace some text in all the tagged files 


GDB (Debugger)
M-x gdb starts up gdm in an extra window

Version Control
C-x v d show all registered files in this dir
C-x v = show diff between versions
C-x v u remove all changes since last checkin
C-x v ~ show certain version in different window
C-x v l print log
C-x v i mark file for version control add
C-x v h insert version control header into file
C-x v r check out named snapshot
C-x v s create named snapshot
C-x v a create changelog file in gnu-style