tutorial

windows版本的emacs

If you find a second file with C-x C-f, the first file remains
inside Emacs.  You can switch back to it by finding it again with
C-x C-f.  This way you can get quite a number of files inside Emacs.

>> Create a file named "foo" by typing  C-x C-f foo <Return>.
   Then insert some text, edit it, and save "foo" by typing  C-x C-s.
   Finally, type C-x C-f TUTORIAL <Return>
   to come back to the tutorial.

Emacs stores each file's text inside an object called a "buffer".
Finding a file makes a new buffer inside Emacs.  To see a list of the
buffers that currently exist in your Emacs job, type

	C-x C-b   List buffers

>> Try C-x C-b now.

See how each buffer has a name, and it may also have a file name for
the file whose contents it holds.  ANY text you see in an Emacs window
is always part of some buffer.

>> Type C-x 1 to get rid of the buffer list.

When you have several buffers, only one of them is "current" at any
time.  That buffer is the one you edit.  If you want to edit another
buffer, you need to "switch" to it.  If you want to switch to a buffer
that corresponds to a file, you can do it by visiting the file again
with C-x C-f.  But there is an easier way: use the C-x b command.
In that command, you have to type the buffer's name.

>> Type C-x b foo <Return> to go back to the buffer "foo" which holds
   the text of the file "foo".  Then type C-x b TUTORIAL <Return>
   to come back to this tutorial.

Most of the time, the buffer's name is the same as the file name
(without the file directory part).  However, this is not always true.
The buffer list you make with C-x C-b always shows you the name of
every buffer.

ANY text you see in an Emacs window is always part of some buffer.
Some buffers do not correspond to files.  For example, the buffer
named "*Buffer List*" does not have any file.  It is the buffer which
contains the buffer list that you made with C-x C-b.  The buffer named
"*Messages*" also does not correspond to any file; it contains the
messages that have appeared on the bottom line during your Emacs
session.

>> Type C-x b *Messages* <Return> to look at the buffer of messages.
   Then type C-b TUTORIAL <Return> to come back to this tutorial.

If you make changes to the text of one file, then find another file,
this does not save the first file.  Its changes remain inside Emacs,
in that file's buffer.  The creation or editing of the second file's
buffer has no effect on the first file's buffer.  This is very useful,
but it also means that you need a convenient way to save the first
file's buffer.  It would be a nuisance to have to switch back to
it with C-x C-f in order to save it with C-x C-s.  So we have

	C-x s     Save some buffers

C-x s asks you about each buffer which contains changes that you have
not saved.  It asks you, for each such buffer, whether to save the
buffer.

>> Insert a line of text, then type C-x s.
   It should ask you whether to save the buffer named TUTORIAL.
   Answer yes to the question by typing "y".


* EXTENDING THE COMMAND SET
---------------------------

There are many, many more Emacs commands than could possibly be put
on all the control and meta characters.  Emacs gets around this with
the X (eXtend) command.  This comes in two flavors:

	C-x	Character eXtend.  Followed by one character.
	M-x	Named command eXtend.  Followed by a long name.

These are commands that are generally useful but used less than the
commands you have already learned about.  You have already seen two of
them: the file commands C-x C-f to Find and C-x C-s to Save.  Another
example is the command to end the Emacs session--this is the command
C-x C-c.  (Do not worry about losing changes you have made; C-x C-c
offers to save each changed file before it kills the Emacs.)

C-z is the command to exit Emacs *temporarily*--so that you can go
back to the same Emacs session afterward.

On systems which allow it, C-z "suspends" Emacs; that is, it returns
to the shell but does not destroy the Emacs.  In the most common
shells, you can resume Emacs with the `fg' command or with `%emacs'.

On systems which do not implement suspending, C-z creates a subshell
running under Emacs to give you the chance to run other programs and
return to Emacs afterward; it does not truly "exit" from Emacs.  In
this case, the shell command `exit' is the usual way to get back to
Emacs from the subshell.

The time to use C-x C-c is when you are about to log out.  It's also
the right thing to use to exit an Emacs invoked under mail handling
programs and other miscellaneous utilities, since they may not know
how to cope with suspension of Emacs.  In ordinary circumstances,
though, if you are not about to log out, it is better to suspend Emacs
with C-z instead of exiting Emacs.

There are many C-x commands.  Here is a list of the ones you have learned:

	C-x C-f		Find file.
	C-x C-s		Save file.
	C-x C-b		List buffers.
	C-x C-c		Quit Emacs.
	C-x 1		Delete all but one window.
	C-x u		Undo.

Named eXtended commands are commands which are used even less
frequently, or commands which are used only in certain modes.  An
example is the command replace-string, which globally replaces one
string with another.  When you type M-x, Emacs prompts you at the
bottom of the screen with M-x and you should type the name of the
command; in this case, "replace-string".  Just type "repl s<TAB>" and
Emacs will complete the name.  (<TAB> is the Tab key, usually found
above the CapsLock or Shift key near the left edge of the keyboard.)
End the command name with <Return>.

The replace-string command requires two arguments--the string to be
replaced, and the string to replace it with.  You must end each
argument with <Return>.

>> Move the cursor to the blank line two lines below this one.
   Then type M-x repl s<Return>changed<Return>altered<Return>.

   Notice how this line has changed: you've replaced
   the word c-h-a-n-g-e-d with "altered" wherever it occurred,
   after the initial position of the cursor.


* AUTO SAVE
-----------

When you have made changes in a file, but you have not saved them yet,
they could be lost if your computer crashes.  To protect you from
this, Emacs periodically writes an "auto save" file for each file that
you are editing.  The auto save file name has a # at the beginning and
the end; for example, if your file is named "hello.c", its auto save
file's name is "#hello.c#".  When you save the file in the normal way,
Emacs deletes its auto save file.

If the computer crashes, you can recover your auto-saved editing by
finding the file normally (the file you were editing, not the auto
save file) and then typing M-x recover file<Return>.  When it asks for
confirmation, type yes<Return> to go ahead and recover the auto-save
data.


* ECHO AREA
-----------

If Emacs sees that you are typing multicharacter commands slowly, it
shows them to you at the bottom of the screen in an area called the
"echo area".  The echo area contains the bottom line of the screen.


* MODE LINE
-----------

The line immediately above the echo area is called the "mode line".
The mode line says something like this:

--:**  TUTORIAL          (Fundamental)--L670--58%----------------

This line gives useful information about the status of Emacs and
the text you are editing.

You already know what the filename means--it is the file you have
found.  -NN%-- indicates your current position in the text; it means
that NN percent of the text is above the top of the screen.  If the
top of the file is on the screen, it will say --Top-- instead of
--00%--.  If the bottom of the text is on the screen, it will say
--Bot--.  If you are looking at text so small that all of it fits on
the screen, the mode line says --All--.

The L and digits indicate position in another way: they give the
current line number of point.

The stars near the front mean that you have made changes to the text.
Right after you visit or save a file, that part of the mode line shows
no stars, just dashes.

The part of the mode line inside the parentheses is to tell you what
editing modes you are in.  The default mode is Fundamental which is
what you are using now.  It is an example of a "major mode".  

Emacs has many different major modes.  Some of them are meant for
editing different languages and/or kinds of text, such as Lisp mode,
Text mode, etc.  At any time one and only one major mode is active,
and its name can always be found in the mode line just where
"Fundamental" is now.

Each major mode makes a few commands behave differently.  For example,
there are commands for creating comments in a program, and since each
programming language has a different idea of what a comment should
look like, each major mode has to insert comments differently.  Each
major mode is the name of an extended command, which is how you can
switch to that mode.  For example, M-x fundamental-mode is a command to
switch to Fundamental mode.

If you are going to be editing human-language text, such as this file, you
should probably use Text Mode.
>> Type M-x text mode<Return>.

Don't worry, none of the  Emacs commands you have learned changes in
any great way.  But you can observe that M-f and M-b now treat
apostrophes as part of words.  Previously, in Fundamental mode,
M-f and M-b treated apostrophes as word-separators.

Major modes usually make subtle changes like that one: most commands
do "the same job" in each major mode, but they work a little bit
differently.

To view documentation on your current major mode, type C-h m.

>> Use C-u C-v once or more to bring this line near the top of screen.
>> Type C-h m, to see how Text mode differs from Fundamental mode.
>> Type C-x 1 to remove the documentation from the screen.

Major modes are called major because there are also minor modes.
Minor modes are not alternatives to the major modes, just minor
modifications of them.  Each minor mode can be turned on or off by
itself, independent of all other minor modes, and independent of your
major mode.  So you can use no minor modes, or one minor mode, or any
combination of several minor modes.

One minor mode which is very useful, especially for editing
human-language text, is Auto Fill mode.  When this mode is on, Emacs
breaks the line in between words automatically whenever you insert
text and make a line that is too wide.

You can turn Auto Fill mode on by doing M-x auto fill mode<Return>.
When the mode is on, you can turn it off again by doing M-x
auto fill mode<Return>.  If the mode is off, this command turns it on,
and if the mode is on, this command turns it off.  We say that the
command "toggles the mode".

>> Type M-x auto fill mode<Return> now.  Then insert a line of "asdf "
   over again until you see it divide into two lines.  You must put in
   spaces between them because Auto Fill breaks lines only at spaces.

The margin is usually set at 70 characters, but you can change it
with the C-x f command.  You should give the margin setting you want
as a numeric argument.

>> Type C-x f with an argument of 20.  (C-u 2 0 C-x f).
   Then type in some text and see Emacs fill lines of 20
   characters with it.  Then set the margin back to 70 using
   C-x f again.

If you make changes in the middle of a paragraph, Auto Fill mode
does not re-fill it for you.
To re-fill the paragraph, type M-q (META-q) with the cursor inside
that paragraph.

>> Move the cursor into the previous paragraph and type M-q.


* SEARCHING
-----------

Emacs can do searches for strings (these are groups of contiguous
characters or words) either forward through the text or backward
through it.  Searching for a string is a cursor motion command;
it moves the cursor to the next place where that string appears.

The Emacs search command is different from the search commands
of most editors, in that it is "incremental".  This means that the
search happens while you type in the string to search for.

The command to initiate a search is C-s for forward search, and C-r
for reverse search.  BUT WAIT!  Don't try them now.