Some information about Emacs

Online auxiliary description of Emacs

Emacs is an integrated work environment. People who use Emacs for the first time or are not familiar with Emacs are often overwhelmed. Therefore, emacs provides a very convenient and powerful online help instruction to help you use Emacs.

Basic Emacs knowledge

Before discussing e-mapreduce's online auxiliary instructions, let's talk about how to start e-mapreduce. The method for starting Emacs is very simple. You only need to enter ''emacs ''at the screen prompt. If you leave Emacs, you only need to enter ''ctrl-x Ctrl-C' to exit Emacs. Press ''ctrl-x Ctrl-C' to press ''x' on the keyboard. Press the ctrl key on the keyboard and then press 'C' in English text. Of course, there are many ways to enter and exit Emacs. Here we only introduce one method, so that users can quickly use the online auxiliary instructions of Emacs, other methods will be mentioned in the following sections.

In addition to the method for entering and leaving Emacs, there is also a command that is very useful, that is, ''ctrl-g ''. ''Ctrl-g'' can be used to cancel the entered command. If you do not want to execute the entered command, you can cancel it at any time.

Emacs can be used to type commands in two ways:

CTRL
Meta key
All Emacs commands can be expressed by the meta key.
The meta key can be replaced by the ESC key. Common Emacs commands
There will be a hotkey link. The hotkey is usually composed of CTRL
The type at the beginning. For example, ''ctrl-x Ctrl-C' represents the hotkey
''Save-Buffers-kill-Emacs ''of the Emacs command ''. To use the meta key
To express the same effect as Ctrl-x Ctrl-C, you must type

''Esc-x save-Buffers-kill-Emacs ''.

You can use the Emacs completion function by using the meta key. Because Completion allows the user to enter the minimum number of words, the system can invoke the Command executed by the worker. The following describes the Emacs completion.

Emacs completion means that, as long as you type the part of the string, emacs will automatically enter the remaining part in the corresponding position. If the given string is insufficient to determine the remaining parts, emacs will list all possible results for the user to decide the desired string name. The scope of completion is as follows:

Command
Files under a specific directory
Buffer Zone
Emacs variable
To what is the file, buffer, and Emacs variable in a specific directory?
Later chapters will be discussed one after another. Here we will discuss completion, just
Online auxiliary instructions for using completion to Emacs.

There are three methods to use Emacs completion:

Tab should fill up the remaining strings as much as possible.
Space fills up the characters before the puncutation character. The filled characters do not exceed one word.
? List all possible completions options.
To use completion, type some strings, and then press tab,
Space or? You can. For example, if you type ''m-x au tab '',
The ''type tab appears below, and the screen appears in another window:

Possible completions are:
Auto-fill-mode auto-lower-Mode
Auto-raise-mode auto-save-Mode

If you type ''m-x au space '', ''m-x auto-'' is displayed at the bottom of the screen -''.
If you type space, the following command is displayed in another window:

Possible completions are:
Auto-fill-mode auto-lower-Mode
Auto-raise-mode auto-save-Mode

This seems to mean that tabs and spaces have the same functions. Actually, they are different.
We can see from the next example. Type ''m-x auto-F tab ''.
''M-x auto-fill-mode''; however, if you type ''m-x auto-f space '', you can only obtain
''M-x auto-fill-''. To get ''m-x auto-fill-mode'', you must type it again.
Space. This is the aforementioned ''space ''. Only one ''puncutation'' is entered at a time''
The meaning of a previous word, while the tab is as much as possible to determine all
The length of the displayed string is not limited to ''puncutation.
Type? Is to display all possible strings in another Emacs window,
In this case, you can enter the appropriate command based on the message in the window. For example, type ''m-x au? '',
Another window on the screen displays the following information:

Possible completions are:
Auto-fill-mode auto-lower-Mode
Auto-raise-mode auto-save-Mode

Type ''m-x au? '', Then the completion action is not executed,
This is? It is the largest difference from tab and space.

If the content of a window is too large to be exhausted at a time, you must scroll the window. Scroll window
You can use the ''ctrl-v'' and ''meta-v'' commands to move windows up and down.

Emacs Teaching Materials

For more information about Emacs, see tutorial ). You can simply enter ''ctrl-H t'' (Help-with-tutorial) to enter the Emacs self-learning status.

The teaching materials of Emacs can be divided into the following parts:

This section describes how to type Emacs commands, that is, CTRL and meta keys.
Viewing screenfuls
Basic cursor control
CTRL-G usage
Emacs windows and multiple windows
Inserting and deleting
Undo
Emacs file processing
Buffers of Emacs
Extending the command set
Introduction to Emacs mode line and echo area
Searching
Recursive editing levels
Getting more help
Leaving Emacs
Copyright questions about Emacs
The teaching materials of Emacs are mainly about editing functions. Although Emacs Functions
More than that, but editing is the most basic function of Emacs.
Of course, we need to start with it. Therefore, emacs's self-taught teaching materials are also edited for introduction.
As for other Emacs artifacts, you cannot learn from this tutorial.
Therefore, this article will introduce the working environment of Emacs in Chapter 3.

CTRL-H usage

In addition to teaching materials for reference, emacs also provides other online auxiliary instruction functions, allowing users to view required information at any time. The online auxiliary description of Emacs is started with ''ctrl-h'', which has the following two types:

CTRL-H
CTRL-H Ctrl-H

Press ctrl-H (Help-command) to display the following message at the bottom of the screen: C-H (type? For further options)-at this time, ''ctrl-h'' is only used as a prefix key, which is used to wait for the user to enter other commands. If you enter ''? '', All available options are displayed at the bottom of the screen. You can select the appropriate options as needed. If you type ''ctrl-h'' Ctrl-H (FELP-for-help) twice, the following displays: type one of the options listed or space to scroll at this time, emacs will open another window, list all the options for help and give a brief description, to scroll this window, type space. This newly opened window has a total of 21 options, including: a B c f c-f I k c-k l m N P S T V W C-c-d c-N C-P C-W. the method for using these 21 Options is very simple, as long as you enter any choice after ''ctrl-h. For example, to select ''a', run ''ctrl-H.

Now we will explain the commonly used online auxiliary instructions in Emacs. Common online assistance instructions for Emacs include:

CTRL-H C
CTRL-H K
CTRL-H W
CTRL-H
CTRL-H v
CTRL-H I
''Ctrl-H C' and ''ctrl-H k'' have similar functions.
Related information. The only difference between the two lies in the detailed explanation of the commands.
''Ctrl-H C' is a brief description of the commands connected to the hotkey, while ''ctrl-H k'' describes the links.
Hotkey command. Both have a predicate, that is, the crowdsourced security testing.
What is the hotkey, and want to know the name of the command used by this hotkey. Today
''Ctrl-x Ctrl-C' example to illustrate the difference between the two.

Type ''ctrl-h c ret ''(Ret, that is, enter on the keyboard. When any command is input, an enter must be followed. This function is used to inform the system that the command input is complete and relevant actions can be started .) Then, describe key briefly:-On the back of '':'', type ''ctrl-x Ctrl-C'. Then, describe key briefly: -C-X c-c runs the command save-Buffers-kill-Emacs ''is displayed, and ''ctrl-h k ret'' is typed '', describe key:-on the lower side of '':'', type ''ctrl-x Ctrl-C '', emacs will display the following message in another window: Save-Buffers-kill-Emacs: offer to save each buffer, then kill this Emacs process. with prefix Arg, silently save all file-Visiting buffers, then Kill. The first line of this message is the full name of the commands linked to hotkey, and the subsequent lines are detailed descriptions of this command. ''Ctrl-H w'' W (where-Is) is the opposite of ''ctrl-H c'' and ''ctrl-H k. ''Ctrl-H w'' is used when you know the Emacs command and want to know whether there is a corresponding hotkey. For example, if you type ''ctrl-H w '',

Where is command:

After '':'', type ''save-Buffers-kill-Emacs ''.

Save-Buffers-kill-Emacs is on C-X c-c. You can check whether the command has a corresponding hotkey. ''Ctrl-H w'' can use Emacs completion, but the biggest inconvenience is the first character that must be given to the command. For example, ''save-Buffers-kill-Emacs ''must begin with a substring starting with" S "to gradually use the completion of Emacs. If you do not enter a substring starting with "S" and enter any strings after "S", the corresponding command cannot be found, therefore, to use ''ctrl-H w'', you must remember the first word of the command. In addition, the online auxiliary description of Emacs provides another help, allowing users to type any sub-string and find corresponding commands, that is, ''ctrl-H ''. If you type ''ctrl-H A', command-Apropos (Regexp) is displayed at the bottom of the screen ): in this case, you only need to give any sub-string or ''regular expression'' 6.3 related to the command to discuss what regular expression is.) Press RET and Emacs will open another window, list all the commands that contain this substring or regular expression. The maximum difference between this command and ''ctrl-H w'' is as follows:

Use the substring ''ctrl-H A', which is not limited to the first character of the command, ''ctrl-H w'' must start with the first word of the command. You can use ''ctrl-H a' to give the sub-string at any position in the command.
　
''Ctrl-H a' cannot use completion, while ''ctrl-H w'' can use completion.
　
''Ctrl-H a' mainly aims to prevent the user from correctly typing the first element of the command, you can list all the commands that contain some sub-strings that the user remembers.
In addition to the commonly used online auxiliary instructions, emacs also has a very practical data query center, that is, ''ctrl-H I ''. ''Ctrl-H I '': Run ''info program''. It is mainly used to create a file with a tree structure. Currently, all file files related to Emacs can be viewed through info. In the end, all file files related to GNU will be able to see the full picture of their file files.
The info mode method is simple. You only need to type ''ctrl-H I 'to view all the files related to Emacs. After entering info, how can I use it effectively? It will be discussed in detail in the next section.
The above is a frequently used online help description. If the online help message is displayed in another window, the message cannot be displayed. To reference other materials, you must scroll the window. For Windows scrolling commands, refer to the following methods:
CTRL-x 1 (delete-other-Windows)
(All the commands corresponding to hotkey in this article are placed in brackets. Keep the window where the cursor is located, and close other windows.
CTRL-x O (Other-window)
The cursor can be switched between different windows. In other words, if the cursor is in the working window, you can use this command to remove the cursor from the window that displays the online auxiliary instructions, and vice versa.
CTRL-V (scroll-up)
Roll the screen to the upper part of the screen so that you can see the information at the bottom of the screen.
Meta-V (scroll-down)
Scroll down the screen, so you can repeat the materials you have read.

EMACS Info usage instructions

I have previously omitted the usage of info, and I will go further into details. In the online auxiliary description function of Emacs, the info content is the most abundant. Because any online auxiliary instruction files can be found in info mode. Because, info is used to place the entire Emacs manual.

Info takes the tree structure for Emacs files, so it is based on root. Info: Execute info program. There are two methods to use info program:
CTRL-H I
ESC-x info
Info is used to process all related files in hypertext mode. After you type ''ctrl-H I 'or ''esc-x info'', the system enters the top of the info tree structure. The following figure shows the first screen when you enter info:-*-text-*-this is the file... /INFO/Dir, which contains the topmost node of the info hierarchy. the first time you invoke info you start off looking at that node, which is (DIR) top .? File: Dir node: Top this is the top of the info tree this (the directory node) gives a menu of major topics. typing "D" returns here, "Q" exits ,"? "Lists all info commands," H "gives a primer for first-timers," mtexinfo "visits texinfo topic, etc. --- please add documentation to this tree. (See info topic first .) --- * menu: the list of major topics begins on the next line. * info: (Info ). documentation Browsing System. * Emacs: (Emacs ). the extensible self-documenting text editor. * VIP: (VIP ). A vi-emulation for Emacs. * texinfo: (texi. INF O ). with one source file, make either a printed manual (through Tex) or an info file (through texinfo ). full documentation in this menu item. * termcap: (termcap ). the termcap library, which enables application programs to handle all types of character-display terminals. * RegEx: (RegEx ). the GNU Regular Expression Library. * CPP: (cpp.info ). c pre-processor. * GCC: (gcc.info ). gnu c compiler --- An ansi c compiler developed by FSF. * gzip: (gzip.info ). GNU zip program --- An compress package developed by FSF. * ispell: (ispell.info ). A spelling checker. * libg ++: (libg ++. info ). g ++ libraries. * gmake: (make.info ). A make Utility developed by FSF. * bison: (bison.info ). gnu yacc. * gawk: (gawk.info ). GNU awk --- pattern scanning and processing language. * GDB: (gdb.info ). GNU Debugger. * I Nfo-stnd: (info-stnd.info ). stand along GNU info. * makeinfo: (makeinfo.info ). program for producing *. info file from *. texi file. * graphics: (graphics.info ). A set programs for producing plot files and display them on Tektronix 4010, postscript, and X Window System compatible output devices. * M4: (m4.info ). m4 is macro processor, in the sense that it copies its input to the output, expending Ma CROs as it goes. GNU M4 is mostly compatible with system v, Release 3 version. * hyperbole: (hypb.info ). GNU Emacs-based everyday information management system. use {c-h d} for a demo. include smart key context-sensitive mouse or keyboard key support, a powerful Rolodex, and extensible hypertext facilities including hyper-links in mail and news messages. * standards coding style :( standards. INF O). GNU coding style. At this time, the first column on the screen is the header, which contains the basic information of this node. The header provides a maximum of five messages:
File)
Node)
Next node of this node)
The previous node of this node (prev)
The upper node of this node (up)

At this time, the screen only shows two things, because the screen is the top of the info tree structure.

Information under the header is used to tell how to use info. It provides five things.

H
If you do not know how to use the info mode, you can use the info online help description after entering the info mode. To use the online help description of info, you only need to enter 'h'' after entering info mode. This is not just an online help instruction, but also a teaching guide. Following its instructions, we can understand how to use the info mode.
D
The ''ctrl-H I 'command first enters the root of the info tree structure. In any case, type ''d' to return to this root.
?
For all info-related commands, just type ''? ''To get a full picture of all commands.
Q
To leave info, just type ''q'' to exit info and return to the previous buffer zone.
M texinfo <return>
This command is used to use the menu item of info. The method is as follows:
Type ''m ''.
Enter the name of the file referenced by the plugin, or use the completion function to simplify the input.
Type ret.

What is menu item.

Under these five commands, the menu item that can be used by this node. You can enter ''ret ''directly under the menu to be referenced ''. In this case, info displays the related files of this menu on the screen. In addition to the preceding commands, you can use the info command to obtain the required commands. The following is an introduction:
N
Move the node to the next node connected to the node.
P
Move the node to the previous node connected to the node.
U
Move the node to the node on the previous layer.
M
Commands for moving between the above nodes must be connected between the nodes. If you want to move across, these commands cannot be done. In this case, you must use the menu to read the files of the kuyue node. There are two ways to use menu:
''Mtexinfo''
This menu method can be seen on the first screen of info. This method consists of three things:
M is the command to use menu.
When you type M in texinfo, minibuffer displays
Menu item: enter the name of the file to be reviewed. Therefore, texinfo indicates the name of the file. In this case, you can enter a name starting with '*' on the screen. If you have just entered info, you can use the following texinfo names: info, emacs, VIP, forms, gnus, Cl, GCC, CPP, makeinfo, info-stnd, Texi, hyperbole, and Ave ave.
RET
After the file name is entered, press ret to inform the system that the file name has been entered. You can start the operation.
Type ''ret ''directly''
If a text prefixed with ''' * menu: ''appears in the file when reading a knot, it indicates that the following columns start, it is a usable menu item. In this case, you can directly type ''ret ''to refer to the file of another node.

Some conditions for using menu are the menu to be used, which must be listed in the file of this node. To use the menu of another node, you must first go to the node where you want to use the menu to use its menu. Menu has a certain structure. The first column of all menus starts with ''menu. * Menu: the list of major topics begins on the next line. all columns after this column, as long as the column starts with '*', indicates an item that can be used. The syntax of menu item is as follows: * info: (Info). Documentation browsing system. It is mainly composed of four parts:

*
Each menu item starts.
Subtopic:
''' * ''' Is the name of the subtopic, followed by '':''. Info is the name of the subtopic. The subtopic name in this example is ''info ''. If you want to use the command ''m'', the name of the texinfo to be given by the menu item is the name of the subtopic.
Node name
Subtopic: the end name used. Generally, the same subtopic and node name are used as much as possible for ease of use. If the two names are the same, the names after the subtopic are omitted and expressed in two. For example, ''' * info ::''.
Node description
The content behind the node is selective. It is mainly used to roughly describe the node.
L
If you want to return to the node referenced by the previous (last), you can use the instruction l To Go Back step by step.
B
Command B can move the cursor to the front of the file.
SPC
If the file is too long, type A blank key (SPC) to scroll the screen.
CTRL-G
To cancel the entered command at any time, type ctrl-G