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6bf7aab6 | 1 | @c This is part of the Emacs manual. |
739a80b3 | 2 | @c Copyright (C) 1985,86,87,93,94,95,1997,2001 Free Software Foundation, Inc. |
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3 | @c See file emacs.texi for copying conditions. |
4 | @node Screen, User Input, Acknowledgments, Top | |
5 | @chapter The Organization of the Screen | |
6 | @cindex screen | |
7 | @cindex parts of the screen | |
8 | @c | |
9 | ||
10 | On a text-only terminal, the Emacs display occupies the whole screen. | |
11 | On the X Window System, Emacs creates its own X windows to use. We use | |
12 | the term @dfn{frame} to mean an entire text-only screen or an entire X | |
13 | window used by Emacs. Emacs uses both kinds of frames in the same way | |
14 | to display your editing. Emacs normally starts out with just one frame, | |
15 | but you can create additional frames if you wish. @xref{Frames}. | |
16 | ||
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17 | When you start Emacs, the entire frame except for the top and bottom |
18 | is devoted to the text you are editing. This area is called the | |
19 | @dfn{window}. At the top there is normally a @dfn{menu bar} where you | |
20 | can access a series of menus; then there may be a @dfn{tool bar}, a | |
21 | row of icons that perform editing commands if you click on them. | |
22 | Below this, the window begins. The last line is a special @dfn{echo | |
23 | area} or @dfn{minibuffer window}, where prompts appear and where you | |
24 | can enter information when Emacs asks for it. See below for more | |
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25 | information about these special lines. |
26 | ||
27 | You can subdivide the large text window horizontally or vertically | |
28 | into multiple text windows, each of which can be used for a different | |
29 | file (@pxref{Windows}). In this manual, the word ``window'' always | |
30 | refers to the subdivisions of a frame within Emacs. | |
31 | ||
32 | The window that the cursor is in is the @dfn{selected window}, in | |
33 | which editing takes place. Most Emacs commands implicitly apply to the | |
34 | text in the selected window (though mouse commands generally operate on | |
35 | whatever window you click them in, whether selected or not). The other | |
36 | windows display text for reference only, unless/until you select them. | |
37 | If you use multiple frames under the X Window System, then giving the | |
38 | input focus to a particular frame selects a window in that frame. | |
39 | ||
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40 | Each window's last line is a @dfn{mode line}, which describes what |
41 | is going on in that window. It appears in inverse video, if the | |
42 | terminal supports that; its contents normally begin with | |
43 | @w{@samp{--:-- @ *scratch*}} when Emacs starts. The mode line | |
44 | displays status information such as what buffer is being displayed | |
45 | above it in the window, what major and minor modes are in use, and | |
46 | whether the buffer contains unsaved changes. | |
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47 | |
48 | @menu | |
49 | * Point:: The place in the text where editing commands operate. | |
50 | * Echo Area:: Short messages appear at the bottom of the screen. | |
51 | * Mode Line:: Interpreting the mode line. | |
52 | * Menu Bar:: How to use the menu bar. | |
53 | @end menu | |
54 | ||
55 | @node Point | |
56 | @section Point | |
57 | @cindex point | |
58 | @cindex cursor | |
59 | ||
60 | Within Emacs, the terminal's cursor shows the location at which | |
61 | editing commands will take effect. This location is called @dfn{point}. | |
62 | Many Emacs commands move point through the text, so that you can edit at | |
63 | different places in it. You can also place point by clicking mouse | |
64 | button 1. | |
65 | ||
66 | While the cursor appears to point @emph{at} a character, you should | |
67 | think of point as @emph{between} two characters; it points @emph{before} | |
68 | the character that appears under the cursor. For example, if your text | |
69 | looks like @samp{frob} with the cursor over the @samp{b}, then point is | |
70 | between the @samp{o} and the @samp{b}. If you insert the character | |
71 | @samp{!} at that position, the result is @samp{fro!b}, with point | |
72 | between the @samp{!} and the @samp{b}. Thus, the cursor remains over | |
73 | the @samp{b}, as before. | |
74 | ||
75 | Sometimes people speak of ``the cursor'' when they mean ``point,'' or | |
76 | speak of commands that move point as ``cursor motion'' commands. | |
77 | ||
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78 | Text-only terminals have only one cursor, and when output is in |
79 | progress it must appear where the output is being displayed. This | |
80 | does not mean that point is moving. It is only that Emacs has no way | |
81 | to show you the location of point except when the terminal is idle. | |
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82 | |
83 | If you are editing several files in Emacs, each in its own buffer, | |
84 | each buffer has its own point location. A buffer that is not currently | |
85 | displayed remembers where point is in case you display it again later. | |
86 | ||
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87 | When Emacs displays multiple windows, each window has its own point |
88 | location. On text-only terminals, the cursor shows the location of | |
89 | point in the selected window. On graphical terminals, Emacs shows a | |
90 | cursor in each window; the selected window's cursor is solid, and the | |
91 | other cursors are hollow. Either way, the cursor or cursors tell you | |
92 | which window is selected. If the same buffer appears in more than one | |
93 | window, each window has its own position for point in that buffer, and | |
94 | (when possible) its own cursor. | |
95 | ||
96 | @xref{Cursor Display}, for customization options that control display | |
97 | of the cursor or cursors. | |
6bf7aab6 | 98 | |
2684ed46 | 99 | The term ``point'' comes from the character @samp{.}, which was the |
6bf7aab6 | 100 | command in TECO (the language in which the original Emacs was written) |
2684ed46 | 101 | for accessing the value now called ``point.'' |
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102 | |
103 | @node Echo Area | |
104 | @section The Echo Area | |
105 | @cindex echo area | |
106 | @c | |
107 | ||
108 | The line at the bottom of the frame (below the mode line) is the | |
109 | @dfn{echo area}. It is used to display small amounts of text for | |
110 | several purposes. | |
111 | ||
112 | @dfn{Echoing} means displaying the characters that you type. Outside | |
113 | Emacs, the operating system normally echoes all your input. Emacs | |
114 | handles echoing differently. | |
115 | ||
116 | Single-character commands do not echo in Emacs, and multi-character | |
117 | commands echo only if you pause while typing them. As soon as you pause | |
118 | for more than a second in the middle of a command, Emacs echoes all the | |
119 | characters of the command so far. This is to @dfn{prompt} you for the | |
120 | rest of the command. Once echoing has started, the rest of the command | |
121 | echoes immediately as you type it. This behavior is designed to give | |
122 | confident users fast response, while giving hesitant users maximum | |
123 | feedback. You can change this behavior by setting a variable | |
af6eba70 | 124 | (@pxref{Display Custom}). |
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125 | |
126 | @cindex error message in the echo area | |
1ba2ce68 | 127 | If a command cannot be executed, it may display an @dfn{error message} |
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128 | in the echo area. Error messages are accompanied by beeping or by |
129 | flashing the screen. The error also discards any input you have typed | |
130 | ahead. | |
6bf7aab6 | 131 | |
1ba2ce68 | 132 | Some commands display informative messages in the echo area. These |
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133 | messages look much like error messages, but they are not announced with |
134 | a beep and do not throw away input. Sometimes the message tells you | |
135 | what the command has done, when this is not obvious from looking at the | |
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136 | text being edited. Sometimes the sole purpose of a command is to show |
137 | you a message giving you specific information---for example, @kbd{C-x =} | |
138 | displays a message describing the character position of point in the text | |
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139 | and its current column in the window. Commands that take a long time |
140 | often display messages ending in @samp{...} while they are working, and | |
141 | add @samp{done} at the end when they are finished. | |
142 | ||
143 | @cindex @samp{*Messages*} buffer | |
144 | @cindex saved echo area messages | |
145 | @cindex messages saved from echo area | |
146 | Echo-area informative messages are saved in an editor buffer named | |
147 | @samp{*Messages*}. (We have not explained buffers yet; see | |
148 | @ref{Buffers}, for more information about them.) If you miss a message | |
149 | that appears briefly on the screen, you can switch to the | |
150 | @samp{*Messages*} buffer to see it again. (Successive progress messages | |
151 | are often collapsed into one in that buffer.) | |
152 | ||
153 | @vindex message-log-max | |
154 | The size of @samp{*Messages*} is limited to a certain number of lines. | |
155 | The variable @code{message-log-max} specifies how many lines. Once the | |
156 | buffer has that many lines, each line added at the end deletes one line | |
157 | from the beginning. @xref{Variables}, for how to set variables such as | |
158 | @code{message-log-max}. | |
159 | ||
160 | The echo area is also used to display the @dfn{minibuffer}, a window that | |
161 | is used for reading arguments to commands, such as the name of a file to be | |
162 | edited. When the minibuffer is in use, the echo area begins with a prompt | |
163 | string that usually ends with a colon; also, the cursor appears in that line | |
164 | because it is the selected window. You can always get out of the | |
165 | minibuffer by typing @kbd{C-g}. @xref{Minibuffer}. | |
166 | ||
167 | @node Mode Line | |
168 | @section The Mode Line | |
169 | @cindex mode line | |
170 | @cindex top level | |
171 | @c | |
172 | ||
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173 | Each text window's last line is a @dfn{mode line}, which describes |
174 | what is going on in that window. When there is only one text window, | |
175 | the mode line appears right above the echo area; it is the | |
8858fc50 | 176 | next-to-last line in the frame. The mode line starts and ends with |
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177 | dashes. On a text-mode display, the mode line is in inverse video if |
178 | the terminal supports that; on a graphics display, the mode line has a | |
10886485 | 179 | 3D box appearance to help it stand out. |
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180 | |
181 | Normally, the mode line looks like this: | |
182 | ||
183 | @example | |
184 | -@var{cs}:@var{ch} @var{buf} (@var{major} @var{minor})--@var{line}--@var{pos}------ | |
185 | @end example | |
186 | ||
187 | @noindent | |
188 | This gives information about the buffer being displayed in the window: the | |
189 | buffer's name, what major and minor modes are in use, whether the buffer's | |
190 | text has been changed, and how far down the buffer you are currently | |
191 | looking. | |
192 | ||
193 | @var{ch} contains two stars @samp{**} if the text in the buffer has | |
194 | been edited (the buffer is ``modified''), or @samp{--} if the buffer has | |
195 | not been edited. For a read-only buffer, it is @samp{%*} if the buffer | |
196 | is modified, and @samp{%%} otherwise. | |
197 | ||
198 | @var{buf} is the name of the window's @dfn{buffer}. In most cases | |
199 | this is the same as the name of a file you are editing. @xref{Buffers}. | |
200 | ||
201 | The buffer displayed in the selected window (the window that the | |
66e46e19 | 202 | cursor is in) is also Emacs's current buffer, the one that editing |
6bf7aab6 | 203 | takes place in. When we speak of what some command does to ``the |
66e46e19 | 204 | buffer,'' we are talking about the current buffer. |
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205 | |
206 | @var{line} is @samp{L} followed by the current line number of point. | |
207 | This is present when Line Number mode is enabled (which it normally is). | |
208 | You can optionally display the current column number too, by turning on | |
209 | Column Number mode (which is not enabled by default because it is | |
210 | somewhat slower). @xref{Optional Mode Line}. | |
211 | ||
212 | @var{pos} tells you whether there is additional text above the top of | |
213 | the window, or below the bottom. If your buffer is small and it is all | |
214 | visible in the window, @var{pos} is @samp{All}. Otherwise, it is | |
215 | @samp{Top} if you are looking at the beginning of the buffer, @samp{Bot} | |
216 | if you are looking at the end of the buffer, or @samp{@var{nn}%}, where | |
217 | @var{nn} is the percentage of the buffer above the top of the | |
218 | window.@refill | |
219 | ||
220 | @var{major} is the name of the @dfn{major mode} in effect in the | |
221 | buffer. At any time, each buffer is in one and only one of the possible | |
222 | major modes. The major modes available include Fundamental mode (the | |
223 | least specialized), Text mode, Lisp mode, C mode, Texinfo mode, and many | |
224 | others. @xref{Major Modes}, for details of how the modes differ and how | |
225 | to select one.@refill | |
226 | ||
227 | Some major modes display additional information after the major mode | |
228 | name. For example, Rmail buffers display the current message number and | |
229 | the total number of messages. Compilation buffers and Shell buffers | |
230 | display the status of the subprocess. | |
231 | ||
232 | @var{minor} is a list of some of the @dfn{minor modes} that are turned | |
233 | on at the moment in the window's chosen buffer. For example, | |
234 | @samp{Fill} means that Auto Fill mode is on. @samp{Abbrev} means that | |
235 | Word Abbrev mode is on. @samp{Ovwrt} means that Overwrite mode is on. | |
236 | @xref{Minor Modes}, for more information. @samp{Narrow} means that the | |
237 | buffer being displayed has editing restricted to only a portion of its | |
238 | text. This is not really a minor mode, but is like one. | |
239 | @xref{Narrowing}. @samp{Def} means that a keyboard macro is being | |
240 | defined. @xref{Keyboard Macros}. | |
241 | ||
242 | In addition, if Emacs is currently inside a recursive editing level, | |
243 | square brackets (@samp{[@dots{}]}) appear around the parentheses that | |
244 | surround the modes. If Emacs is in one recursive editing level within | |
245 | another, double square brackets appear, and so on. Since recursive | |
246 | editing levels affect Emacs globally, not just one buffer, the square | |
247 | brackets appear in every window's mode line or not in any of them. | |
248 | @xref{Recursive Edit}.@refill | |
249 | ||
250 | Non-windowing terminals can only show a single Emacs frame at a time | |
251 | (@pxref{Frames}). On such terminals, the mode line displays the name of | |
252 | the selected frame, after @var{ch}. The initial frame's name is | |
253 | @samp{F1}. | |
254 | ||
255 | @var{cs} states the coding system used for the file you are editing. | |
256 | A dash indicates the default state of affairs: no code conversion, | |
257 | except for end-of-line translation if the file contents call for that. | |
258 | @samp{=} means no conversion whatsoever. Nontrivial code conversions | |
259 | are represented by various letters---for example, @samp{1} refers to ISO | |
260 | Latin-1. @xref{Coding Systems}, for more information. If you are using | |
261 | an input method, a string of the form @samp{@var{i}>} is added to the | |
262 | beginning of @var{cs}; @var{i} identifies the input method. (Some input | |
263 | methods show @samp{+} or @samp{@@} instead of @samp{>}.) @xref{Input | |
264 | Methods}. | |
265 | ||
266 | When you are using a character-only terminal (not a window system), | |
267 | @var{cs} uses three characters to describe, respectively, the coding | |
268 | system for keyboard input, the coding system for terminal output, and | |
269 | the coding system used for the file you are editing. | |
270 | ||
271 | When multibyte characters are not enabled, @var{cs} does not appear at | |
272 | all. @xref{Enabling Multibyte}. | |
273 | ||
274 | @cindex end-of-line conversion, mode-line indication | |
275 | The colon after @var{cs} can change to another string in certain | |
ad4a78d6 | 276 | circumstances. Emacs uses newline characters to separate lines in the buffer. |
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277 | Some files use different conventions for separating lines: either |
278 | carriage-return linefeed (the MS-DOS convention) or just carriage-return | |
279 | (the Macintosh convention). If the buffer's file uses carriage-return | |
280 | linefeed, the colon changes to either a backslash (@samp{\}) or | |
281 | @samp{(DOS)}, depending on the operating system. If the file uses just | |
282 | carriage-return, the colon indicator changes to either a forward slash | |
283 | (@samp{/}) or @samp{(Mac)}. On some systems, Emacs displays | |
284 | @samp{(Unix)} instead of the colon even for files that use newline to | |
285 | separate lines. | |
286 | ||
287 | @vindex eol-mnemonic-unix | |
288 | @vindex eol-mnemonic-dos | |
289 | @vindex eol-mnemonic-mac | |
290 | @vindex eol-mnemonic-undecided | |
291 | You can customize the mode line display for each of the end-of-line | |
292 | formats by setting each of the variables @code{eol-mnemonic-unix}, | |
293 | @code{eol-mnemonic-dos}, @code{eol-mnemonic-mac}, and | |
294 | @code{eol-mnemonic-undecided} to any string you find appropriate. | |
4e3a22f8 | 295 | @xref{Variables}, for an explanation of how to set variables. |
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296 | |
297 | @xref{Optional Mode Line}, for features that add other handy | |
298 | information to the mode line, such as the current column number of | |
299 | point, the current time, and whether new mail for you has arrived. | |
300 | ||
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301 | The mode line is mouse-sensitive; when you move the mouse across |
302 | various parts of it, Emacs displays help text to say what a click in | |
303 | that place will do. @xref{Mode Line Mouse}. | |
ad4a78d6 | 304 | |
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305 | @node Menu Bar |
306 | @section The Menu Bar | |
307 | @cindex menu bar | |
308 | ||
309 | Each Emacs frame normally has a @dfn{menu bar} at the top which you | |
310 | can use to perform certain common operations. There's no need to list | |
311 | them here, as you can more easily see for yourself. | |
312 | ||
313 | @kindex M-` | |
314 | @kindex F10 | |
315 | @findex tmm-menubar | |
316 | When you are using a window system, you can use the mouse to choose a | |
317 | command from the menu bar. An arrow pointing right, after the menu | |
318 | item, indicates that the item leads to a subsidiary menu; @samp{...} at | |
319 | the end means that the command will read arguments from the keyboard | |
320 | before it actually does anything. | |
321 | ||
322 | To view the full command name and documentation for a menu item, type | |
323 | @kbd{C-h k}, and then select the menu bar with the mouse in the usual | |
324 | way (@pxref{Key Help}). | |
325 | ||
326 | On text-only terminals with no mouse, you can use the menu bar by | |
327 | typing @kbd{M-`} or @key{F10} (these run the command | |
328 | @code{tmm-menubar}). This command enters a mode in which you can select | |
329 | a menu item from the keyboard. A provisional choice appears in the echo | |
330 | area. You can use the left and right arrow keys to move through the | |
331 | menu to different choices. When you have found the choice you want, | |
332 | type @key{RET} to select it. | |
333 | ||
334 | Each menu item also has an assigned letter or digit which designates | |
335 | that item; it is usually the initial of some word in the item's name. | |
336 | This letter or digit is separated from the item name by @samp{=>}. You | |
337 | can type the item's letter or digit to select the item. | |
338 | ||
339 | Some of the commands in the menu bar have ordinary key bindings as | |
340 | well; if so, the menu lists one equivalent key binding in parentheses | |
341 | after the item itself. |