@c This is part of the Emacs manual.
@c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2000, 2001,
-@c 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+@c 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
@c See file emacs.texi for copying conditions.
@node Basic, Minibuffer, Exiting, Top
@chapter Basic Editing Commands
* Moving Point:: How to move the cursor to the place where you want to
change something.
* Erasing:: Deleting and killing text.
-* Undo:: Undoing recent changes in the text.
+* Basic Undo:: Undoing recent changes in the text.
* Files: Basic Files. Visiting, creating, and saving files.
* Help: Basic Help. Asking what a character does.
* Blank Lines:: Commands to make or delete blank lines.
@key{ENTER} key doesn't delete backwards, you need to do this.
@xref{DEL Does Not Delete}, for an explanation of how.
- Most PC keyboards have both a @key{BACKSPACE} key a short ways above
+ Most PC keyboards have both a @key{BACKSPACE} key not far above
@key{RET} or @key{ENTER}, and a @key{DELETE} key elsewhere. On these
keyboards, Emacs supports when possible the usual convention that the
@key{BACKSPACE} key deletes backwards (it is @key{DEL}), while the
Emacs can split lines automatically when they become too long, if you
turn on a special minor mode called @dfn{Auto Fill} mode.
-@xref{Filling}, for how to use Auto Fill mode.
+@xref{Filling}, for how to use Auto Fill mode and other modes for
+@dfn{filling} text.
If you prefer to have text characters replace (overwrite) existing
text rather than shove it to the right, you can enable Overwrite mode,
clicking the left mouse button where you want to move to.
There are also control and meta characters for cursor motion. Some
-are equivalent to the arrow keys (these date back to the days before
-terminals had arrow keys, and are usable on terminals which don't have
-them). Others do more sophisticated things.
+are equivalent to the arrow keys (it is faster to use these control
+keys than move your hand over to the arrow keys). Others do more
+sophisticated things.
@kindex C-a
@kindex C-e
@item @key{DELETE}
@itemx @key{BACKSPACE}
One of these keys, whichever is the large key above the @key{RET} or
-@key{ENTER} key, deletes the character before point, like @key{DEL}.
-If that is @key{BACKSPACE}, and your keyboard also has @key{DELETE},
+@key{ENTER} key, deletes the character before point---it is @key{DEL}.
+If @key{BACKSPACE} is @key{DEL}, and your keyboard also has @key{DELETE},
then @key{DELETE} deletes forwards, like @kbd{C-d}.
@item C-k
Kill to the end of the line (@code{kill-line}).
@xref{Killing}, for more flexible ways of killing text.
-@node Undo
+@node Basic Undo
@section Undoing Changes
-@cindex undo
-@cindex changes, undoing
- You can undo all the recent changes in the buffer text, up to a
-certain point. Each buffer records changes individually, and the undo
-command always applies to the current buffer. Usually each editing
-command makes a separate entry in the undo records, but some commands
-such as @code{query-replace} make many entries, and very simple commands
-such as self-inserting characters are often grouped to make undoing less
-tedious.
+ Emacs records a list of changes made in the buffer text, so you can
+you can undo all the recent changes, as far as the records go.
+Usually each editing command makes a separate entry in the undo
+records, but sometimes an entry covers just part of a command, and
+very simple commands may be grouped.
@table @kbd
@item C-x u
-Undo one batch of changes---usually, one command worth (@code{undo}).
+Undo one entry of the undo records---usually, one command worth
+(@code{undo}).
@item C-_
@itemx C-/
The same.
-@item C-u C-x u
-Undo one batch of changes in the region.
@end table
-@kindex C-x u
-@kindex C-_
-@kindex C-/
-@findex undo
The command @kbd{C-x u} (or @kbd{C-_} or @kbd{C-/}) is how you undo.
The first time you give this command, it undoes the last change.
Point moves back to where it was before the command that made the
change.
- Consecutive repetitions of @kbd{C-_} or @kbd{C-x u} undo earlier and
-earlier changes, back to the limit of the undo information available.
-If all recorded changes have already been undone, the undo command
-displays an error message and does nothing.
-
-@findex undo-only
- Any command other than an undo command breaks the sequence of undo
-commands. Starting from that moment, the previous undo commands become
-ordinary changes that you can undo. Thus, to redo changes you have
-undone, type @kbd{C-f} or any other command that will harmlessly break
-the sequence of undoing, then type more undo commands. On the other
-hand, if you want to ignore previous undo commands, use @kbd{M-x
-undo-only}. This is like @code{undo}, but will not redo changes
-you have just undone.
-
-@cindex selective undo
-@kindex C-u C-x u
- Ordinary undo applies to all changes made in the current buffer. You
-can also perform @dfn{selective undo}, limited to the current region
-(@pxref{Mark}).
-To do this, specify the region you want, then run the @code{undo}
-command with a prefix argument (the value does not matter): @kbd{C-u C-x
-u} or @kbd{C-u C-_}. This undoes the most recent change in the region.
-To undo further changes in the same region, repeat the @code{undo}
-command (no prefix argument is needed). In Transient Mark mode
-(@pxref{Transient Mark}), any use of @code{undo} when there is an
-active region performs selective undo; you do not need a prefix
-argument.
-
- If you notice that a buffer has been modified accidentally, the
-easiest way to recover is to type @kbd{C-_} repeatedly until the stars
-disappear from the front of the mode line. At this time, all the
-modifications you made have been canceled. Whenever an undo command
-makes the stars disappear from the mode line, it means that the buffer
-contents are the same as they were when the file was last read in or
-saved.
-
- If you do not remember whether you changed the buffer deliberately,
-type @kbd{C-_} once. When you see the last change you made undone, you
-will see whether it was an intentional change. If it was an accident,
-leave it undone. If it was deliberate, redo the change as described
-above.
-
- Not all buffers record undo information. Buffers whose names start with
-spaces don't; these buffers are used internally by Emacs and its extensions
-to hold text that users don't normally look at or edit.
-
- You cannot undo mere cursor motion; only changes in the buffer
-contents save undo information. However, some cursor motion commands
-set the mark, so if you use these commands from time to time, you can
-move back to the neighborhoods you have moved through by popping the
-mark ring (@pxref{Mark Ring}).
-
-@vindex undo-limit
-@vindex undo-strong-limit
-@vindex undo-outer-limit
-@cindex undo limit
- When the undo information for a buffer becomes too large, Emacs
-discards the oldest undo information from time to time (during garbage
-collection). You can specify how much undo information to keep by
-setting three variables: @code{undo-limit}, @code{undo-strong-limit},
-and @code{undo-outer-limit}. Their values are expressed in units of
-bytes of space.
-
- The variable @code{undo-limit} sets a soft limit: Emacs keeps undo
-data for enough commands to reach this size, and perhaps exceed it,
-but does not keep data for any earlier commands beyond that. Its
-default value is 20000. The variable @code{undo-strong-limit} sets a
-stricter limit: a previous command (not the most recent one) which
-pushes the size past this amount is itself forgotten. The default
-value of @code{undo-strong-limit} is 30000.
-
- Regardless of the values of those variables, the most recent change
-is never discarded unless it gets bigger than @code{undo-outer-limit}
-(normally 3,000,000). At that point, Emacs discards the undo data and
-warns you about it. This is the only situation in which you cannot
-undo the last command. If this happens, you can increase the value of
-@code{undo-outer-limit} to make it even less likely to happen in the
-future. But if you didn't expect the command to create such large
-undo data, then it is probably a bug and you should report it.
-@xref{Bugs,, Reporting Bugs}.
-
- The reason the @code{undo} command has three key bindings, @kbd{C-x
-u}, @kbd{C-_} and @kbd{C-/}, is that it is worthy of a
-single-character key, but @kbd{C-x u} is more straightforward for
-beginners to type.
+ Consecutive repetitions of @kbd{C-x u} (or its aliases) undo earlier
+and earlier changes, back to the limit of the undo information
+available. If all recorded changes have already been undone, the undo
+command displays an error message and does nothing.
+
+ The undo command applies only to changes in the buffer; you can't
+use it to undo mere cursor motion. However, some cursor motion
+commands set the mark, so if you use these commands from time to time,
+you can move back to the neighborhoods you have moved through by
+popping the mark ring (@pxref{Mark Ring}).
@node Basic Files
@section Files
The commands described above are sufficient for creating and altering
text in an Emacs buffer; the more advanced Emacs commands just make
-things easier. But to keep any text permanently you must put it in a
+things easier. However, to keep any text permanently you must put it in a
@dfn{file}. Files are named units of text which are stored by the
operating system for you to retrieve later by name. To look at or use
the contents of a file in any way, including editing the file with
Emacs, you must specify the file name.
- Consider a file named @file{/usr/rms/foo.c}. In Emacs, to begin editing
-this file, type
+ Consider a file named @file{test.emacs}. (We can assume it is in
+your home directory.) In Emacs, to begin editing this file, type
@example
-C-x C-f /usr/rms/foo.c @key{RET}
+C-x C-f test.emacs @key{RET}
@end example
@noindent
the buffer for you to edit. If you alter the text, you can @dfn{save}
the new text in the file by typing @kbd{C-x C-s} (@code{save-buffer}).
This makes the changes permanent by copying the altered buffer contents
-back into the file @file{/usr/rms/foo.c}. Until you save, the changes
-exist only inside Emacs, and the file @file{foo.c} is unaltered.
+back into the file @file{test.emacs}. Until you save, the changes
+exist only inside Emacs, and the file @file{test.emacs} is unaltered.
To create a file, just visit the file with @kbd{C-x C-f} as if it
already existed. This creates an empty buffer in which you can insert
characters in the ``empty'' columns, just before the @samp{\}
character that indicates continuation.
- Sometimes it is nice to have Emacs insert newlines automatically when
-a line gets too long. Continuation on the screen does not do that. Use
-Auto Fill mode (@pxref{Filling}) if that's what you want.
+ Continued lines can be rather difficult to read, since each line is
+typically broken in the middle of a word. You can have Emacs insert a
+newline automatically when a line gets too long, by using Auto Fill
+mode. Another approach, intermediate between continued lines and Auto
+Fill mode, is Long Lines mode, which ensures that wrapping only occurs
+in the spaces between words. @xref{Filling}.
@cindex truncation
@cindex line truncation, and fringes
- As an alternative to continuation, Emacs can display long lines by
-@dfn{truncation}. This means that all the characters that do not fit
-in the width of the screen or window do not appear at all. @samp{$}
-in the last column or a small straight arrow in the fringe to the
-right of the window indicates a truncated line.
+ Emacs can also display long lines by @dfn{truncation}. This means
+that all the characters that do not fit in the width of the screen or
+window do not appear at all. @samp{$} in the last column or a small
+straight arrow in the fringe to the right of the window indicates a
+truncated line.
@xref{Display Custom}, for more information about line truncation,
and other variables that affect how text is displayed.
that looks like this:
@smallexample
-Char: c (0143, 99, 0x63) point=21044 of 26883(78%) column 53
+Char: c (99, #o143, #x63) point=28062 of 36168 (78%) column=53
@end smallexample
-@noindent
-(In fact, this is the output produced when point is before the
-@samp{column} in the example.)
-
The four values after @samp{Char:} describe the character that follows
point, first by showing it and then by giving its character code in
-octal, decimal and hex. For a non-@acronym{ASCII} multibyte character, these are
+decimal, octal and hex. For a non-@acronym{ASCII} multibyte character, these are
followed by @samp{file} and the character's representation, in hex, in
the buffer's coding system, if that coding system encodes the character
safely and with a single byte (@pxref{Coding Systems}). If the
character's encoding is longer than one byte, Emacs shows @samp{file ...}.
However, if the character displayed is in the range 0200 through
-0377 octal, there's a case that it actually represents an invalid
-UTF-8 byte. Emacs represents such a byte in a buffer by a sequence of
-8-bit characters, but displays only the original invalid byte in octal
-form. In such a case, Emacs shows @samp{part of display ...} instead
-of @samp{file}.
+0377 octal, it may actually stand for an invalid UTF-8 byte read from
+a file. In Emacs, that byte is represented as a sequence of 8-bit
+characters, but all of them together display as the original invalid
+byte, in octal code. In this case, @kbd{C-x =} shows @samp{part of
+display ...} instead of @samp{file}.
@samp{point=} is followed by the position of point expressed as a character
count. The front of the buffer counts as position 1, one character later
in the buffer. Afterward in parentheses comes the position expressed as a
percentage of the total size.
- @samp{column} is followed by the horizontal position of point, in
+ @samp{column=} is followed by the horizontal position of point, in
columns from the left edge of the window.
If the buffer has been narrowed, making some of the text at the
might display this:
@smallexample
-Char: C (0103, 67, 0x43) point=252 of 889(28%) <231 - 599> column 0
+Char: C (67, #o103, #x43) point=252 of 889 (28%) <231-599> column=0
@end smallexample
@noindent
point. The output might look like this:
@smallexample
-point=26957 of 26956(100%) column 0
+point=36169 of 36168 (EOB) column=0
@end smallexample
@cindex character set of character at point
(if it supports the character).
@item
-If you are running Emacs on a window system, the font name and glyph
-code for the character. If you are running Emacs on a terminal, the
-code(s) sent to the terminal.
+If you are running Emacs on a graphical display, the font name and
+glyph code for the character. If you are running Emacs on a text-only
+terminal, the code(s) sent to the terminal.
@item
The character's text properties (@pxref{Text Properties,,,
(@pxref{Font Lock}) enabled:
@smallexample
- character: @`A (04300, 2240, 0x8c0, U+00C0)
+ character: @`A (2240, #o4300, #x8c0, U+00C0)
charset: latin-iso8859-1
(Right-Hand Part of Latin Alphabet 1@dots{}
- code point: 64
+ code point: #x40
syntax: w which means: word
category: l:Latin
- to input: type "`A"
-buffer code: 0x81 0xC0
- file code: ESC 2C 41 40 (encoded by coding system iso-2022-7bit)
- display: terminal code 0xC0
+ to input: type "`A" with latin-1-prefix
+buffer code: #x81 #xC0
+ file code: #xC0 (encoded by coding system iso-latin-1)
+ display: terminal code #xC0
There are text properties here:
fontified t
negative argument, type a minus sign after @kbd{C-u}. Just a minus sign
without digits normally means @minus{}1.
- @kbd{C-u} followed by a character which is neither a digit nor a minus
-sign has the special meaning of ``multiply by four.'' It multiplies the
-argument for the next command by four. @kbd{C-u} twice multiplies it by
-sixteen. Thus, @kbd{C-u C-u C-f} moves forward sixteen characters. This
-is a good way to move forward ``fast,'' since it moves about 1/5 of a line
-in the usual size screen. Other useful combinations are @kbd{C-u C-n},
-@kbd{C-u C-u C-n} (move down a good fraction of a screen), @kbd{C-u C-u
-C-o} (make ``a lot'' of blank lines), and @kbd{C-u C-k} (kill four
-lines).@refill
+ @kbd{C-u} without digits or minus sign has the special meaning of
+``four times'': it multiplies the argument for the next command by
+four. @kbd{C-u C-u} multiplies it by sixteen. Thus, @kbd{C-u C-u
+C-f} moves forward sixteen characters. This is a good way to move
+forward ``fast,'' since it moves about 1/5 of a line in the usual size
+screen. Other useful combinations are @kbd{C-u C-n}, @kbd{C-u C-u
+C-n} (move down a good fraction of a screen), @kbd{C-u C-u C-o} (make
+``a lot'' of blank lines), and @kbd{C-u C-k} (kill four lines).@refill
Some commands care only about whether there is an argument, and not about
its value. For example, the command @kbd{M-q} (@code{fill-paragraph}) with