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(Screen): Copyedit. Define "buffer" and "current buffer" early on.

Browse source 
(Point): Copyedit.  Relegate historical trivia to a footnote.
(Mode Line): Explain mode-line format more consistently.
(Menu Bar): Copyedit.
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@ -7,52 +7,50 @@
@cindex screen
@cindex parts of the screen
On a text-only terminal, the Emacs display occupies the whole
screen. On a graphical display, such as on GNU/Linux using the X
Window System, Emacs creates its own windows to use. We use the term
@dfn{frame} to mean the entire text-only screen or an entire
system-level window used by Emacs. Emacs uses both kinds of frames,
in the same way, to display your editing. Emacs normally starts out
with just one frame, but you can create additional frames if you wish.
@xref{Frames}.
On a text-only terminal, the Emacs display occupies the entire
terminal screen. On a graphical display, such as on GNU/Linux using
the X Window System, Emacs creates its own windows to use. We use the
term @dfn{frame} to mean the entire terminal screen or graphical
window used by Emacs. Emacs uses both kinds of frames, in the same
way, to display your editing. Emacs normally starts out with just one
frame, but you can create additional frames if you wish
(@pxref{Frames}).
When you start Emacs, the main central area of the frame, all except
for the top and bottom and sides, displays the text you are editing.
This area is called @dfn{the window}. At the top there is normally a
@dfn{menu bar} where you can access a series of menus; then there may
be a @dfn{tool bar}, a row of icons that perform editing commands if
you click on them. Below this, the window begins, often with a
@dfn{scroll bar} on one side. Below the window comes the last line of
the frame, a special @dfn{echo area} or @dfn{minibuffer window}, where
prompts appear and you enter information when Emacs asks for it. See
following sections for more information about these special lines.
The frame consists of several distinct regions. At the top of the
frame is a @dfn{menu bar}, which allows you to access commands via a
series of menus. On a graphical display, directly below the menu bar
is a @dfn{tool bar}, a row of icons that perform editing commands if
you click on them. At the very bottom of the frame is a special
@dfn{echo area}, where short informative messages are displayed and
where you enter information when Emacs asks for it.
You can subdivide the window horizontally or vertically to make
multiple text windows, each of which can independently display some
file or text (@pxref{Windows}). In this manual, the word ``window''
refers to the initial large window if not subdivided, or any one of
the multiple windows you have subdivided it into.
The main area of the frame, below the tool bar (if one exists) and
above the echo area, is called @dfn{the window}. This is where Emacs
displays the @dfn{buffer}: the text that you are editing. On a
graphical display, the window possesses a @dfn{scroll bar} on one
side, which you can use to display different parts of the buffer in
the window. The last line of the window is a @dfn{mode line}. This
displays various information about what is going on in the buffer,
such as whether there are unsaved changes, the editing modes that are
in use, the current line number, and so forth.
When you start Emacs, there is normally only one window in the
frame. However, you can subdivide this window horizontally or
vertically to create multiple windows, each of which can independently
display a buffer (@pxref{Windows}). In this manual, the word
``window'' refers to the initial large window if not subdivided, or
any one of the multiple windows you have subdivided it into.
At any time, one window is the @dfn{selected window}. On graphical
displays, the selected window normally shows a more prominent cursor
(usually solid and blinking) while other windows show a weaker cursor
(such as a hollow box). Text terminals have just one cursor, so it
always appears in the selected window.
Most Emacs commands implicitly apply to the text in the selected
window; the text in unselected windows is mostly visible for
reference. However, mouse commands generally operate on whatever
window you click them in, whether selected or not. If you use
multiple frames on a graphical display, then giving the input focus to
a particular frame selects a window in that frame.
Each window's last line is a @dfn{mode line}, which describes what
is going on in that window. It appears in different color and/or a ``3D''
box if the terminal supports them; its contents normally begin with
@w{@samp{--:-- @ *scratch*}} when Emacs starts. The mode line
displays status information such as what buffer is being displayed
above it in the window, what major and minor modes are in use, and
whether the buffer contains unsaved changes.
(such as a hollow box). Text terminals have just one cursor, so it
always appears in the selected window. The buffer displayed in the
selected window is called the @dfn{current buffer}, and it is where
editing happens. Most Emacs commands implicitly apply to the current
buffer; the text displayed in unselected windows is mostly visible for
reference. If you use multiple frames on a graphical display,
selecting a particular frame selects a window in that frame.
@menu
* Point:: The place in the text where editing commands operate.
@ -66,11 +64,14 @@ whether the buffer contains unsaved changes.
@cindex point
@cindex cursor
Within Emacs, the active cursor shows the location at which
editing commands will take effect. This location is called @dfn{point}.
Many Emacs commands move point through the text, so that you can edit at
different places in it. You can also place point by clicking mouse
button 1 (normally the left button).
The active cursor shows the location at which editing commands will
take effect, which is called @dfn{point}@footnote{The term ``point''
comes from the character @samp{.}, which was the command in TECO (the
language in which the original Emacs was written) for accessing the
value now called ``point.''}. Many Emacs commands move point to
different places in the buffer; for example, you can place point by
clicking mouse button 1 (normally the left button) at the desired
location.
While the cursor appears to be @emph{on} a character, you should
think of point as @emph{between} two characters; it points @emph{before}
@ -89,141 +90,147 @@ each buffer has its own point location. A buffer that is not
currently displayed remembers its point location in case you display
it again later. When Emacs displays multiple windows, each window has
its own point location. If the same buffer appears in more than one
window, each window has its own point position in that buffer, and (when
possible) its own cursor.
window, each window has its own point position in that buffer.
A text-only terminal has just one cursor, in the selected window.
The other windows do not show a cursor, even though they do have their
own position of point. When Emacs updates the screen on a text-only
terminal, it has to put the cursor temporarily at the place the output
goes. This doesn't mean point is there, though. Once display
updating finishes, Emacs puts the cursor where point is.
On graphical displays, Emacs shows a cursor in each window; the
On a graphical display, Emacs shows a cursor in each window; the
selected window's cursor is solid and blinking, and the other cursors
are just hollow. Thus, the most prominent cursor always shows you the
selected window, on all kinds of terminals.
@xref{Cursor Display}, for customizable variables that control display
of the cursor or cursors.
The term ``point'' comes from the character @samp{.}, which was the
command in TECO (the language in which the original Emacs was written)
for accessing the value now called ``point.''
are hollow. On a text-only terminal, there is just one cursor, in the
selected window; even though the unselected windows have their own
point positions, they do not display a cursor. @xref{Cursor Display},
for customizable variables that control cursor display.
@node Echo Area
@section The Echo Area
@cindex echo area
The line at the bottom of the frame (below the mode line) is the
@dfn{echo area}. It is used to display small amounts of text for
various purposes.
The line at the very bottom of the frame is the @dfn{echo area}. It
is used to display small amounts of text for various purposes.
@dfn{Echoing} means displaying the characters that you type. At the
command line, the operating system normally echoes all your input.
Emacs handles echoing differently.
Single-character commands do not echo in Emacs, and multi-character
commands echo only if you pause while typing them. As soon as you pause
for more than a second in the middle of a command, Emacs echoes all the
characters of the command so far. This is to @dfn{prompt} you for the
rest of the command. Once echoing has started, the rest of the command
echoes immediately as you type it. This behavior is designed to give
confident users fast response, while giving hesitant users maximum
feedback. You can change this behavior by setting a variable
(@pxref{Display Custom}).
@dfn{Echoing} means displaying the characters that you type.
Single-character commands, including most simple editing operations,
are not echoed. Multi-character commands are echoed if you pause
while typing them: if you pause for more than a second in the middle
of a command, Emacs echoes all the characters of the command so far,
to prompt you for the rest of the command. The echoed characters are
displayed in the echo area. Once echoing has started, the rest of the
command echoes immediately as you type it. This behavior is designed
to give confident users fast response, while giving hesitant users
maximum feedback. @xref{Display Custom}.
@cindex error message in the echo area
If a command cannot do its job, it may display an @dfn{error
message} in the echo area. Error messages are accompanied by beeping
or by flashing the screen. The error also discards any input you have
typed ahead.
message}. Error messages are also displayed in the echo area. They
may be accompanied by beeping or by flashing the screen.
Some commands display informative messages in the echo area. These
messages look much like error messages, but they are not announced
with a beep and do not throw away input. Sometimes the message tells
you what the command has done, when this is not obvious from looking
at the text being edited. Sometimes the sole purpose of a command is
to show you a message giving you specific information---for example,
@kbd{C-x =} (hold down @key{CTRL} and type @kbd{x}, then let go of
@key{CTRL} and type @kbd{=}) displays a message describing the
character position of point in the text and its current column in the
window. Commands that take a long time often display messages ending
in @samp{...} while they are working, and add @samp{done} at the end
when they are finished. They may also indicate progress with
percentages.
Some commands display informative messages in the echo area. Unlike
error messages, these messages are not announced with a beep or flash.
Sometimes the message tells you what the command has done, when this
is not obvious from looking at the text being edited. Other times,
the sole purpose of a command is to show you a message giving you
specific information. For example, @kbd{C-x =} (hold down @key{CTRL}
and type @kbd{x}, then let go of @key{CTRL} and type @kbd{=}) displays
a message describing the character position of point in the text and
its current column in the window. Commands that take a long time
often display messages ending in @samp{...} while they are working,
and add @samp{done} at the end when they are finished. They may also
indicate progress with percentages.
@cindex @samp{*Messages*} buffer
@cindex saved echo area messages
@cindex messages saved from echo area
Echo-area informative messages are saved in an editor buffer named
@samp{*Messages*}. (We have not explained buffers yet; see
@ref{Buffers}, for more information about them.) If you miss a message
that appears briefly on the screen, you can switch to the
@samp{*Messages*} buffer to see it again. (Successive progress messages
are often collapsed into one in that buffer.)
@vindex message-log-max
The size of @samp{*Messages*} is limited to a certain number of
lines. The variable @code{message-log-max} specifies how many lines.
Once the buffer has that many lines, adding lines at the end deletes lines
from the beginning, to keep the size constant. @xref{Variables}, for
how to set variables such as @code{message-log-max}.
Informative echo-area messages are saved in a special buffer named
@samp{*Messages*}. (We have not explained buffers yet; see
@ref{Buffers}, for more information about them.) If you miss a
message that appeared briefly on the screen, you can switch to the
@samp{*Messages*} buffer to see it again. The @samp{*Messages*}
buffer is limited to a certain number of lines, specified by the
variable @code{message-log-max}. (We have not explained variables
either; see @ref{Variables}, for more information about them.) Beyond
this limit, one line is deleted from the beginning whenever a new
message line is added at the end.
The echo area is also used to display the @dfn{minibuffer}, a window
where you can input arguments to commands, such as the name of a file
to be edited. When the minibuffer is in use, the echo area begins
with a prompt string that usually ends with a colon; also, the cursor
appears in that line because it is the selected window. You can
always get out of the minibuffer by typing @kbd{C-g}.
@cindex minibuffer
The echo area is also used to display the @dfn{minibuffer}, a
special window where you can input arguments to commands, such as the
name of a file to be edited. When the minibuffer is in use, the text
displayed in the echo area begins with a @dfn{prompt string} (usually
ending with a colon); also, the active cursor appears within the
minibuffer, which is temporarily considered the selected window. You
can always get out of the minibuffer by typing @kbd{C-g}.
@xref{Minibuffer}.
@node Mode Line
@section The Mode Line
@cindex mode line
@cindex top level
@c
Each text window's last line is a @dfn{mode line}, which describes
what is going on in that window. The mode line starts and ends with
dashes. When there is only one text window, the mode line appears
right above the echo area; it is the next-to-last line in the frame.
On a text-only terminal, the mode line is in inverse video if the
terminal supports that; on a graphics display, the mode line has a 3D
box appearance to help it stand out. The mode line of the selected
window is highlighted if possible; see @ref{Optional Mode Line}, for
more information.
At the bottom of each window is a @dfn{mode line}, which describes
what is going on in the current buffer. When there is only one
window, the mode line appears right above the echo area; it is the
next-to-last line in the frame. On a graphical display, the mode line
is drawn with a 3D box appearance, and the mode line of the selected
window has a brighter color than that of unselected windows to make it
stand out. On a text-only terminal, the mode line is usually drawn in
inverse video.
Normally, the mode line looks like this:
The text displayed in the mode line has the following format:
@example
-@var{cs}:@var{ch}@var{R}-@var{fr} @var{buf} @var{pos} @var{line} (@var{major} @var{minor})------
-@var{cs}:@var{ch}-@var{fr} @var{buf} @var{pos} @var{line} (@var{major} @var{minor})------
@end example
@noindent
This gives information about the window and the buffer it displays: the
buffer's name, what major and minor modes are in use, whether the
buffer's text has been changed, and how far down the buffer you are
currently looking.
The @var{cs} string and the colon character after it describe the
character set and newline convention used for the current buffer.
Normally, Emacs handles these settings intelligently, but it is
sometimes useful to have this information.
@var{ch} contains two stars @samp{**} if the text in the buffer has
been edited (the buffer is ``modified''), or @samp{--} if the buffer has
not been edited. For a read-only buffer, it is @samp{%*} if the buffer
is modified, and @samp{%%} otherwise.
@var{cs} describes the character set of the buffer (@pxref{Coding
Systems}). If it is a dash (@samp{-}), that indicates the default
state of affairs: no special character set handling, except for the
end-of-line translations described in the next paragraph. @samp{=}
means no conversion whatsoever. Letters represent various nontrivial
@dfn{coding systems}---for example, @samp{1} represents ISO Latin-1.
On a text-only terminal, @var{cs} is preceded by two additional
characters that describe the coding system for keyboard input and the
coding system for terminal output. Furthermore, if you are using an
input method, @var{cs} is preceded by a string that identifies the
input method, which takes the form @samp{@var{i}>}, @samp{@var{i}+},
or @samp{@var{i}@@} (@pxref{Input Methods}).
@var{R} is @samp{@@} if the default-directory for the current buffer
is on a remote machine, or a hyphen otherwise.
@cindex end-of-line conversion, mode-line indication
The character after @var{cs} is usually a colon. However, under
some circumstances a different string is displayed, which indicates a
nontrivial end-of-line convention. Usually, lines of text are
separated by @dfn{newline characters}, but two other conventions are
sometimes used. The MS-DOS convention is to use a ``carriage-return''
character followed by a ``linefeed'' character; when editing such
files, the colon changes to either a backslash (@samp{\}) or
@samp{(DOS)}, depending on the operating system. The Macintosh
end-of-line convention is to use a ``carriage-return'' character
instead of a newline; when editing such files, the colon indicator
changes to either a forward slash (@samp{/}) or @samp{(Mac)}. On some
systems, Emacs displays @samp{(Unix)} instead of the colon for files
that use newline as the line separator.
The next element on the mode line is the string indicated by
@var{ch}. This shows two dashes (@samp{--}) if the buffer displayed
in the window has the same contents as the corresponding file on the
disk; i.e., if the buffer is ``unmodified''. If the buffer is
modified, it shows two stars (@samp{**}). For a read-only buffer, it
shows @samp{%*} if the buffer is modified, and @samp{%%} otherwise.
The character after @var{ch} is normally a dash (@samp{-}).
However, if the default-directory for the current buffer is on a
remote machine, @samp{@@} is displayed instead (@pxref{File Names}).
@var{fr} gives the selected frame name (@pxref{Frames}). It appears
only on text-only terminals. The initial frame's name is @samp{F1}.
@var{buf} is the name of the window's @dfn{buffer}. Usually this is
the same as the name of a file you are editing. @xref{Buffers}.
The buffer displayed in the selected window (the window with the
cursor) is the @dfn{current buffer}, where editing happens. When a
command's effect applies to ``the buffer,'' we mean it does those
things to the current buffer.
@var{buf} is the name of the buffer displayed in the window.
Usually, this is the same as the name of a file you are editing.
@xref{Buffers}.
@var{pos} tells you whether there is additional text above the top of
the window, or below the bottom. If your buffer is small and it is all
@ -234,34 +241,29 @@ if you are looking at the end of the buffer, or @samp{@var{nn}%}, where
With Size Indication mode, you can display the size of the buffer as
well. @xref{Optional Mode Line}.
@var{line} is @samp{L} followed by the current line number of point.
This is present when Line Number mode is enabled (it normally is).
You can display the current column number too, by turning on Column
Number mode. It is not enabled by default because it is somewhat
slower. @xref{Optional Mode Line}.
@var{line} is the character @samp{L} followed by the line number at
point. (You can display the current column number too, by turning on
Column Number mode. @xref{Optional Mode Line}.)
@var{major} is the name of the @dfn{major mode} in effect in the
buffer. A buffer can only be in one major mode at a time. The major
modes available include Fundamental mode (the least specialized), Text
mode, Lisp mode, C mode, Texinfo mode, and many others. @xref{Major
Modes}, for details of how the modes differ and how to select
them.
@var{major} is the name of the @dfn{major mode} used in the buffer.
A major mode is a principal editing mode for the buffer, such as Text
mode, Lisp mode, C mode, and so forth. @xref{Major Modes}.
Some major modes display additional information after the major mode
name. For example, Rmail buffers display the current message number and
the total number of messages. Compilation buffers and Shell buffers
display the status of the subprocess.
@var{minor} is a list of some of the @dfn{minor modes} that are
turned on at the moment in the window's chosen buffer. For example,
@samp{Fill} means that Auto Fill mode is on. @samp{Abbrev} means that
Word Abbrev mode is on. @samp{Ovwrt} means that Overwrite mode is on.
@xref{Minor Modes}, for more information.
@var{minor} is a list of some of the @dfn{minor modes} turned on in
the buffer. Minor modes are optional editing modes that provide
additional features on top of the major mode. @xref{Minor Modes}.
@samp{Narrow} means that the buffer being displayed has editing
restricted to only a portion of its text. (This is not really a minor
mode, but is like one.) @xref{Narrowing}. @samp{Def} means that a
keyboard macro is being defined. @xref{Keyboard Macros}.
Some features are listed together with the minor modes whenever they
are turned on, even through they are not really minor modes.
@samp{Narrow} means that the buffer being displayed has editing
restricted to only a portion of its text (@pxref{Narrowing}).
@samp{Def} means that a keyboard macro is currently being defined
(@pxref{Keyboard Macros}).
In addition, if Emacs is inside a recursive editing level, square
brackets (@samp{[@dots{}]}) appear around the parentheses that
@ -271,46 +273,10 @@ editing levels affect Emacs globally, not just one buffer, the square
brackets appear in every window's mode line or not in any of them.
@xref{Recursive Edit}.@refill
@var{cs} states the coding system used for the file you are editing.
A dash indicates the default state of affairs: no code conversion,
except for end-of-line translation if the file contents call for that.
@samp{=} means no conversion whatsoever. Nontrivial code conversions
are represented by various letters---for example, @samp{1} refers to ISO
Latin-1. @xref{Coding Systems}, for more information.
On a text-only terminal, @var{cs} includes two additional characters
which describe the coding system for keyboard input and the coding
system for terminal output. They come right before the coding system
used for the file you are editing.
If you are using an input method, a string of the form
@samp{@var{i}>} is added to the beginning of @var{cs}; @var{i}
identifies the input method. (Some input methods show @samp{+} or
@samp{@@} instead of @samp{>}.) @xref{Input Methods}.
When multibyte characters are not enabled, @var{cs} does not appear at
all. @xref{Enabling Multibyte}.
@cindex end-of-line conversion, mode-line indication
The colon after @var{cs} changes to another string in some cases.
Emacs uses newline characters to separate lines in the buffer. Some
files use different conventions for separating lines: either
carriage-return linefeed (the MS-DOS convention) or just
carriage-return (the Macintosh convention). If the buffer's file uses
carriage-return linefeed, the colon changes to either a backslash
(@samp{\}) or @samp{(DOS)}, depending on the operating system. If the
file uses just carriage-return, the colon indicator changes to either
a forward slash (@samp{/}) or @samp{(Mac)}. On some systems, Emacs
displays @samp{(Unix)} instead of the colon for files that use newline
as the line separator.
@xref{Optional Mode Line}, to add other handy information to the
mode line, such as the size of the buffer, the current column number
of point, and whether new mail for you has arrived.
The mode line is mouse-sensitive; when you move the mouse across
various parts of it, Emacs displays help text to say what a click in
that place will do. @xref{Mode Line Mouse}.
You can change the appearance of the mode line as well as the format
of its contents. @xref{Optional Mode Line}. In addition, the mode
line is mouse-sensitive; clicking on different parts of the mode line
performs various commands. @xref{Mode Line Mouse}.
@node Menu Bar
@section The Menu Bar
@ -325,19 +291,22 @@ here, as you can more easily see them yourself.
@findex tmm-menubar
@findex menu-bar-open
On a graphical display, you can use the mouse to choose a command
from the menu bar. A right-arrow at the end of the menu item means it
leads to a subsidiary menu; @samp{...} at the end means that the
command invoked will read arguments (further input from you) before it
actually does anything.
from the menu bar. A right-arrow at the end of a menu item means it
leads to a subsidiary menu, or @dfn{submenu}. A @samp{...} at the end
of a menu item means that the command invoked will prompt you for
further input before it actually does anything.
You can also invoke the first menu bar item by pressing @key{F10} (to run
the command @code{menu-bar-open}). You can then navigate the menus with
the arrow keys. You select an item by pressing @key{RET} and cancel menu
navigation with @key{ESC}.
Some of the commands in the menu bar have ordinary key bindings as
well; if so, a key binding is shown in parentheses after the item
itself. To view the full command name and documentation for a menu
item, type @kbd{C-h k}, and then select the menu bar with the mouse in
the usual way (@pxref{Key Help}).
To view the full command name and documentation for a menu item, type
@kbd{C-h k}, and then select the menu bar with the mouse in the usual
way (@pxref{Key Help}).
Instead of using the mouse, you can also invoke the first menu bar
item by pressing @key{F10} (to run the command @code{menu-bar-open}).
You can then navigate the menus with the arrow keys. To activate a
selected menu item, press @key{RET}; to cancel menu navigation, press
@key{ESC}.
On text-only terminals with no mouse, you can use the menu bar by
typing @kbd{M-`} or @key{F10} (these run the command
@ -351,9 +320,6 @@ that item; it is usually the initial of some word in the item's name.
This letter or digit is separated from the item name by @samp{=>}. You
can type the item's letter or digit to select the item.
Some of the commands in the menu bar have ordinary key bindings as
well; one such binding is shown in parentheses after the item itself.
@ignore
arch-tag: 104ba40e-d972-4866-a542-a98be94bdf2f
@end ignore