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1 \input texinfo @c -*-texinfo-*-
2 @comment %**start of header
3 @setfilename info.info
4 @settitle Info
5 @syncodeindex fn cp
6 @syncodeindex vr cp
7 @syncodeindex ky cp
8 @comment %**end of header
9 @comment $Id: info.texi,v 1.21 2002/04/23 18:36:05 rms Exp $
10
11 @dircategory Texinfo documentation system
12 @direntry
13 * Info: (info). How to use the documentation browsing system.
14 @end direntry
15
16 @ifinfo
17 This file describes how to use Info, the on-line, menu-driven GNU
18 documentation system.
19
20 Copyright (C) 1989, 92, 96, 97, 98, 99, 2000, 2001, 2002
21 Free Software Foundation, Inc.
22
23
24 Permission is granted to copy, distribute and/or modify this document
25 under the terms of the GNU Free Documentation License, Version 1.1 or
26 any later version published by the Free Software Foundation; with no
27 Invariant Sections, with the Front-Cover texts being ``A GNU
28 Manual'', and with the Back-Cover Texts as in (a) below. A copy of the
29 license is included in the section entitled ``GNU Free Documentation
30 License'' in the Emacs manual.
31
32 (a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify
33 this GNU Manual, like GNU software. Copies published by the Free
34 Software Foundation raise funds for GNU development.''
35
36 This document is part of a collection distributed under the GNU Free
37 Documentation License. If you want to distribute this document
38 separately from the collection, you can do so by adding a copy of the
39 license to the document, as described in section 6 of the license.
40 @end ifinfo
41
42 @titlepage
43 @title Info
44 @subtitle The online, hyper-text GNU documentation system
45 @author Brian Fox
46 @author and the GNU Texinfo community
47 @page
48 @vskip 0pt plus 1filll
49 Copyright @copyright{} 1989, 92, 93, 96, 97, 98, 99, 2000, 2001
50 Free Software Foundation, Inc.
51 @sp 2
52 Published by the Free Software Foundation @*
53 59 Temple Place - Suite 330 @*
54 Boston, MA 02111-1307, USA.
55
56 Permission is granted to copy, distribute and/or modify this document
57 under the terms of the GNU Free Documentation License, Version 1.1 or
58 any later version published by the Free Software Foundation; with no
59 Invariant Sections, with the Front-Cover texts being ``A GNU
60 Manual'', and with the Back-Cover Texts as in (a) below. A copy of the
61 license is included in the section entitled ``GNU Free Documentation
62 License'' in the Emacs manual.
63
64 (a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify
65 this GNU Manual, like GNU software. Copies published by the Free
66 Software Foundation raise funds for GNU development.''
67
68 This document is part of a collection distributed under the GNU Free
69 Documentation License. If you want to distribute this document
70 separately from the collection, you can do so by adding a copy of the
71 license to the document, as described in section 6 of the license.
72 @end titlepage
73
74 @ifnottex
75 @node Top
76 @top Info: An Introduction
77
78 Info is a program, which you are using now, for reading documentation of
79 computer programs. The GNU Project distributes most of its on-line
80 manuals in the Info format, so you need a program called @dfn{Info
81 reader} to read the manuals. One of such programs you are using now.
82
83 @ifinfo
84 If you are new to Info and want to learn how to use it, type the
85 command @kbd{h} now. It brings you to a programmed instruction
86 sequence.
87
88 To learn expert-level Info commands, type @kbd{n} twice. This brings you to
89 @cite{Info for Experts}, skipping over the `Getting Started' chapter.
90 @end ifinfo
91 @end ifnottex
92
93 @menu
94 * Getting Started:: Getting started using an Info reader.
95 * Expert Info:: Info commands for experts.
96 * Creating an Info File:: How to make your own Info file.
97 * Index:: An index of topics, commands, and variables.
98 @end menu
99
100 @node Getting Started, Expert Info, Top, Top
101 @comment node-name, next, previous, up
102 @chapter Getting Started
103
104 This first part of the Info manual describes how to get around inside
105 of Info. The second part of the manual describes various advanced
106 Info commands, and how to write an Info as distinct from a Texinfo
107 file. The third part briefly explains how to generate Info files from
108 Texinfo files.
109
110 @ifnotinfo
111 This manual is primarily designed for browsing with an Info reader
112 program on a computer, so that you can try Info commands while reading
113 about them. Reading it on paper or with an HTML browser is less
114 effective, since you must take it on faith that the commands described
115 really do what the manual says. By all means go through this manual
116 now that you have it; but please try going through the on-line version
117 as well.
118
119 @cindex Info reader, how to invoke
120 @cindex entering Info
121 There are two ways of looking at the online version of this manual:
122
123 @enumerate
124 @item
125 Type @code{info} at your shell's command line. This approach uses a
126 stand-alone program designed just to read Info files.
127
128 @item
129 Type @code{emacs} at the command line; then type @kbd{C-h i}
130 (@kbd{Control-h}, followed by @kbd{i}). This approach uses the Info
131 mode of the Emacs program, an editor with many other capabilities.
132 @end enumerate
133
134 In either case, then type @kbd{mInfo} (just the letters), followed by
135 @key{RET}---the ``Return'' or ``Enter'' key. At this point, you should
136 be ready to follow the instructions in this manual as you read them on
137 the screen.
138 @c FIXME! (pesch@cygnus.com, 14 dec 1992)
139 @c Is it worth worrying about what-if the beginner goes to somebody
140 @c else's Emacs session, which already has an Info running in the middle
141 @c of something---in which case these simple instructions won't work?
142 @end ifnotinfo
143
144 @menu
145 * Help-Small-Screen:: Starting Info on a Small Screen
146 * Help:: How to use Info
147 * Help-P:: Returning to the Previous node
148 * Help-^L:: The Space, DEL, B and ^L commands.
149 * Help-M:: Menus
150 * Help-Xref:: Following cross-references
151 * Help-Int:: Some intermediate Info commands
152 * Help-Q:: Quitting Info
153 @end menu
154
155 @node Help-Small-Screen
156 @section Starting Info on a Small Screen
157
158 @ifnotinfo
159 (In Info, you only see this section if your terminal has a small
160 number of lines; most readers pass by it without seeing it.)
161 @end ifnotinfo
162
163 @cindex small screen, moving around
164 Since your terminal has a relatively small number of lines on its
165 screen, it is necessary to give you special advice at the beginning.
166
167 If you see the text @samp{--All----} near the bottom right corner
168 of the screen, it means the entire text you are looking at fits on the
169 screen. If you see @samp{--Top----} instead, it means that there is
170 more text below that does not fit. To move forward through the text
171 and see another screen full, press @key{SPC}, the Space bar. To move
172 back up, press the key labeled @samp{Backspace} or @samp{DEL} (on some
173 keyboards, this key might be labeled @samp{Delete}).
174
175 @ifinfo
176 Here are 40 lines of junk, so you can try @key{SPC} and @key{DEL} and
177 see what they do. At the end are instructions of what you should do
178 next.
179
180 @format
181 This is line 20
182 This is line 21
183 This is line 22
184 This is line 23
185 This is line 24
186 This is line 25
187 This is line 26
188 This is line 27
189 This is line 28
190 This is line 29
191 This is line 30
192 This is line 31
193 This is line 32
194 This is line 33
195 This is line 34
196 This is line 35
197 This is line 36
198 This is line 37
199 This is line 38
200 This is line 39
201 This is line 40
202 This is line 41
203 This is line 42
204 This is line 43
205 This is line 44
206 This is line 45
207 This is line 46
208 This is line 47
209 This is line 48
210 This is line 49
211 This is line 50
212 This is line 51
213 This is line 52
214 This is line 53
215 This is line 54
216 This is line 55
217 This is line 56
218 This is line 57
219 This is line 58
220 This is line 59
221 @end format
222
223 If you have managed to get here, go back to the beginning with
224 @kbd{DEL} (or @key{BACKSPACE}), and come back here again, then you
225 understand the about the @samp{Space} and @samp{Backspace} keys. So
226 now type an @kbd{n} ---just one character; don't type the quotes and
227 don't type the Return key afterward--- to get to the normal start of
228 the course.
229 @end ifinfo
230
231 @node Help, Help-P, Help-Small-Screen, Getting Started
232 @comment node-name, next, previous, up
233 @section How to use Info
234
235 You are talking to the program Info, for reading documentation.
236
237 @cindex node, in Info documents
238 Right now you are looking at one @dfn{Node} of Information.
239 A node contains text describing a specific topic at a specific
240 level of detail. This node's topic is ``how to use Info''. The mode
241 line says that this is node @samp{Help} in the file @file{info}.
242
243 @cindex header of Info node
244 The top line of a node is its @dfn{header}. This node's header (look at
245 it now) says that the @samp{Next} node after this one is the node
246 called @samp{Help-P}. An advanced Info command lets you go to any node
247 whose name you know. In the stand-alone Info reader program, the
248 header line shows the names of this node and the info file as well.
249 In Emacs, the header line is displayed in a special typeface, and it
250 doesn't scroll off the screen when you scroll the display. The names
251 of this node and of its Info file are omitted by Emacs from the header
252 line.
253
254 Besides a @samp{Next}, a node can have a @samp{Previous} or an
255 @samp{Up} links, or both. As you can see, this node has all of these
256 links.
257
258 @kindex n @r{(Info mode)}
259 Now it is time to move on to the @samp{Next} node, named @samp{Help-P}.
260
261 @format
262 >> Type @kbd{n} to move there. Type just one character;
263 do not type the quotes and do not type a @key{RET} afterward.
264 @end format
265
266 @noindent
267 @samp{>>} in the margin means it is really time to try a command.
268
269 @format
270 >> If you have a mouse, and if you already practiced typing @kbd{n}
271 to get to the next node, click now with the right mouse button on
272 the @samp{Next} link to do the same ``the mouse way''.
273 @end format
274
275 @node Help-P, Help-^L, Help, Getting Started
276 @comment node-name, next, previous, up
277 @section Returning to the Previous node
278
279 @kindex p @r{(Info mode)}
280 This node is called @samp{Help-P}. The @samp{Previous} node, as you see,
281 is @samp{Help}, which is the one you just came from using the @kbd{n}
282 command. Another @kbd{n} command now would take you to the next
283 node, @samp{Help-^L}. In Emacs, @kbd{n} runs the Emacs command
284 @code{Info-next}, and @kbd{p} runs @code{Info-prev}.
285
286 @format
287 >> But do not type @kbd{n} yet. First, try the @kbd{p} command,
288 or click the mouse on the @samp{Prev} link, which takes you to the
289 @samp{Previous} node. When you get there, you can do an @kbd{n}
290 again to return here.
291 @end format
292
293 If you read this in Emacs, you will see an @samp{Info} item in the
294 menu bar, close to its right edge. Clicking your mouse on the
295 @samp{Info} menu-bar item opens a menu of commands which include
296 @samp{Next} and @samp{Prev} (and also some others which you didn't yet
297 learn about).
298
299 This all probably seems insultingly simple so far, but @emph{do not} be
300 led into skimming. Things will get more complicated soon. Also,
301 do not try a new command until you are told it is time to. Otherwise,
302 you may make Info skip past an important warning that was coming up.
303
304 @format
305 >> Now do an @kbd{n}, or click the mouse on the @samp{Next} link, to
306 get to the node @samp{Help-^L} and learn more.
307 @end format
308
309 @node Help-^L, Help-M, Help-P, Getting Started
310 @comment node-name, next, previous, up
311 @section The Space, DEL, B and ^L commands.
312
313 This node's mode line tells you that you are now at node
314 @samp{Help-^L}, and the header line tells you that @kbd{p} would get
315 you back to @samp{Help-P}. The node's title is highlighted and may be
316 underlined as well; it says what the node is about.
317
318 This is a big node and it does not all fit on your display screen.
319 You can tell that there is more that is not visible because you
320 can see the string @samp{--Top-----} rather than @samp{--All----} near
321 the bottom right corner of the screen.
322
323 @kindex SPC @r{(Info mode)}
324 @kindex DEL @r{(Info mode)}
325 @kindex BACKSPACE @r{(Info mode)}
326 @findex Info-scroll-up
327 @findex Info-scroll-down
328 The @key{SPC}, @key{BACKSPACE} (or @key{DEL})@footnote{The key which
329 we call ``Backspace or DEL'' in this manual is labeled differently on
330 different keyboards. Look for a key which is a little ways above the
331 @key{ENTER} or @key{RET} key and which you normally use outside Emacs
332 to erase the character before the cursor, i.e.@: the character you
333 typed last. It might be labeled @samp{Backspace} or @samp{<-} or
334 @samp{DEL}, or sometimes @samp{Delete}.} and @kbd{b} commands exist to
335 allow you to ``move around'' in a node that does not all fit on the
336 screen at once. @key{SPC} moves forward, to show what was below the
337 bottom of the screen. @key{DEL} or @key{BACKSPACE} moves backward, to
338 show what was above the top of the screen (there is not anything above
339 the top until you have typed some spaces). In Emacs, @key{SPC} runs
340 the command @code{Info-scroll-up}, while @key{BACKSPACE} runs
341 @code{Info-scroll-down}.
342
343 @format
344 >> Now try typing a @key{SPC} (afterward, type a @key{BACKSPACE} to
345 return here).
346 @end format
347
348 When you type the @key{SPC}, the two lines that were at the bottom of
349 the screen appear at the top, followed by more lines. @key{DEL} or
350 @key{BACKSPACE} takes the two lines from the top and moves them to the
351 bottom, @emph{usually}, but if there are not a full screen's worth of
352 lines above them they may not make it all the way to the bottom.
353
354 If you are reading this in Emacs, note that the header line is
355 always visible, never scrolling off the display. That way, you can
356 always see the @samp{Next}, @samp{Prev}, and @samp{Up} links, and you
357 can conveniently go to one of these links from anywhere in the node by
358 clicking the mouse on one of these links.
359
360 @cindex reading Info documents top to bottom
361 @cindex Info documents as tutorials
362 @key{SPC} and @key{DEL} not only move forward and backward through
363 the current node. When these keys hit the beginning or the end of the
364 current node, they move to preceding or subsequent nodes.
365 Specifically, they scroll through all the nodes in an Info file as a
366 single logical sequence. In this sequence, a node's subnodes appear
367 following their parent. If a node has a menu, @key{SPC} takes you
368 into the subnodes listed in the menu, one by one. Once you reach the
369 end of a node, and have seen all of its subnodes, @key{SPC} takes you
370 to the next node or to the parent's next node. This is so you could
371 read the entire manual top to bottom by just typing @key{SPC}.
372
373 @kindex PAGEUP @r{(Info mode)}
374 @kindex PAGEDOWN @r{(Info mode)}
375 Many keyboards nowadays have two scroll keys labeled @samp{PageUp}
376 and @samp{PageDown} (or maybe @samp{Prior} and @samp{Next}). If your
377 keyboard has these keys, you can use them to move forward and backward
378 through the text, like with @key{SPC} and @key{BACKSPACE}. However,
379 unlike @key{SPC} and @key{BACKSPACE}, @key{PAGEUP} and @key{PAGEDOWN}
380 keys will never scroll beyond the beginning or the end of the current
381 node.
382
383 @kindex C-l @r{(Info mode)}
384 If your screen is ever garbaged, you can tell Info to display it
385 again by typing @kbd{C-l} (@kbd{Control-L}, that is---hold down
386 @key{CTRL} and type @kbd{L} or @kbd{l}).
387
388 @format
389 >> Type @kbd{C-l} now.
390 @end format
391
392 @kindex b @r{(Info mode)}
393 To move back to the beginning of the node you are on, you can type
394 a lot of @key{BACKSPACE} keys. You can also type simply @kbd{b} for
395 beginning.
396
397 @format
398 >> Try that now. (We have put in enough verbiage to push this past
399 the first screenful, but screens are so big nowadays that perhaps it
400 isn't enough. You may need to shrink your Emacs or Info window.)
401 Then come back, by typing @key{SPC} one or more times.
402 @end format
403
404 If your screen is very tall, all of this node might fit at once.
405 In that case, @kbd{b} won't do anything. Sorry; what can we do?
406
407 @kindex ? @r{(Info mode)}
408 @findex Info-summary
409 You have just learned a considerable number of commands. If you
410 want to use one but have trouble remembering which, you should type
411 a @kbd{?} (in Emacs it runs the @code{Info-summary} command) which
412 displays a brief list of commands. When you are finished looking at
413 the list, make it go away by typing a @key{SPC} repeatedly.
414
415 @format
416 >> Type a @key{?} now. Press @key{SPC} to see consecutive screenfuls of
417 the list until finished. Then type @key{SPC} several times, until
418 it goes away.
419 @end format
420
421 (If you are using the stand-alone Info reader, type @kbd{C-x 0} to
422 return here, that is---press and hold @key{CTRL}, type an @kbd{x},
423 then release @key{CTRL} and @kbd{x}, and press @kbd{0}---a zero, not
424 the letter ``o''.)
425
426 From now on, you will encounter large nodes without warning, and
427 will be expected to know how to use @key{SPC} and @key{BACKSPACE} to
428 move around in them without being told. Since not all terminals have
429 the same size screen, it would be impossible to warn you anyway.
430
431 @format
432 >> Now type @kbd{n}, or click the mouse on the @samp{Next} link, to
433 see the description of the @kbd{m} command.
434 @end format
435
436 @node Help-M, Help-Xref, Help-^L, Getting Started
437 @comment node-name, next, previous, up
438 @section Menus and the @kbd{m} command
439
440 @cindex menus in an Info document
441 @cindex Info menus
442 With only the @kbd{n} (next) and @kbd{p} (previous) commands for
443 moving between nodes, nodes are restricted to a linear sequence.
444 Menus allow a branching structure. A menu is a list of other nodes
445 you can move to. It is actually just part of the text of the node
446 formatted specially so that Info can interpret it. The beginning of a
447 menu is always identified by a line which starts with @samp{* Menu:}.
448 A node contains a menu if and only if it has a line in it which starts
449 that way. The only menu you can use at any moment is the one in the
450 node you are in. To use a menu in any other node, you must move to
451 that node first.
452
453 After the start of the menu, each line that starts with a @samp{*}
454 identifies one subtopic. The line usually contains a brief name
455 for the subtopic (followed by a @samp{:}), the name of the node that talks
456 about that subtopic, and optionally some further description of the
457 subtopic. Lines in the menu that do not start with a @samp{*} have no
458 special meaning---they are only for the human reader's benefit and do
459 not define additional subtopics. Here is an example:
460
461 @example
462 * Foo: Node about FOO. This tells about FOO.
463 @end example
464
465 The subtopic name is Foo, and the node describing it is @samp{Node
466 about FOO}. The rest of the line is just for the reader's
467 Information. [[ But this line is not a real menu item, simply because
468 there is no line above it which starts with @samp{* Menu:}.]]
469
470 When you use a menu to go to another node (in a way that will be
471 described soon), what you specify is the subtopic name, the first
472 thing in the menu line. Info uses it to find the menu line, extracts
473 the node name from it, and goes to that node. The reason that there
474 is both a subtopic name and a node name is that the node name must be
475 meaningful to the computer and may therefore have to be ugly looking.
476 The subtopic name can be chosen just to be convenient for the user to
477 specify. Often the node name is convenient for the user to specify
478 and so both it and the subtopic name are the same. There is an
479 abbreviation for this:
480
481 @example
482 * Foo:: This tells about FOO.
483 @end example
484
485 @noindent
486 This means that the subtopic name and node name are the same; they are
487 both @samp{Foo}.
488
489 @format
490 >> Now use @key{SPC} to find the menu in this node, then come back to
491 the front with a @kbd{b} and some @key{SPC}s. As you see, a menu is
492 actually visible in its node. If you cannot find a menu in a node
493 by looking at it, then the node does not have a menu and the
494 @kbd{m} command is not available.
495 @end format
496
497 @kindex m @r{(Info mode)}
498 The command to go to one of the subnodes is @kbd{m}---but @emph{do
499 not do it yet!} Before you use @kbd{m}, you need to learn about
500 commands which prompt you for more input. So far, you have learned
501 several commands that do not need additional input; when you typed
502 one, Info processed it and was instantly ready for another command.
503 The @kbd{m} command is different: it is incomplete without the
504 @dfn{name of the subtopic}. Once you have typed @kbd{m}, Info tries
505 to read the subtopic name.
506
507 Now look for the line containing many dashes near the bottom of the
508 screen. There is one more line beneath that one, but usually it is
509 blank. If it is empty, Info is ready for a command, such as @kbd{n}
510 or @kbd{b} or @key{SPC} or @kbd{m}. If that line contains text ending
511 in a colon, it means Info is trying to read more input for the last
512 command. At such times, commands do not work, because Info tries to
513 use them as the input it needs. You must either type your response and
514 finish the command you started, or type @kbd{Control-g} to cancel the
515 command. When you have done one of those things, the line becomes
516 blank again.
517
518 @findex Info-menu
519 The command to go to a subnode via a menu is @kbd{m}. After you type
520 the @kbd{m}, the line at the bottom of the screen says @samp{Menu item: }.
521 You must then type the name of the subtopic you want, and end it with
522 a @key{RET}. In Emacs, @kbd{m} runs the command @code{Info-menu}.
523
524 @cindex abbreviating Info subnodes
525 You can abbreviate the subtopic name. If the abbreviation is not
526 unique, the first matching subtopic is chosen. Some menus put
527 the shortest possible abbreviation for each subtopic name in capital
528 letters, so you can see how much you need to type. It does not
529 matter whether you use upper case or lower case when you type the
530 subtopic. You should not put any spaces at the end, or inside of the
531 item name, except for one space where a space appears in the item in
532 the menu.
533
534 @cindex completion of Info node names
535 You can also use the @dfn{completion} feature to help enter the subtopic
536 name. If you type the @key{TAB} key after entering part of a name, it will
537 magically fill in more of the name---as much as follows uniquely from
538 what you have entered.
539
540 If you move the cursor to one of the menu subtopic lines, then you do
541 not need to type the argument: you just type a @key{RET}, and it
542 stands for the subtopic of the line you are on.
543
544 Here is a menu to give you a chance to practice. This menu gives you
545 three ways of going to one place, Help-FOO:
546
547 @menu
548 * Foo: Help-FOO. A node you can visit for fun.
549 * Bar: Help-FOO. Strange! two ways to get to the same place.
550 * Help-FOO:: And yet another!
551 @end menu
552
553 @format
554 >> Now type just an @kbd{m} and see what happens:
555 @end format
556
557 Now you are ``inside'' an @kbd{m} command. Commands cannot be used
558 now; the next thing you will type must be the name of a subtopic.
559
560 You can change your mind about doing the @kbd{m} by typing
561 @kbd{Control-g}.
562
563 @format
564 >> Try that now; notice the bottom line clear.
565 @end format
566
567 @format
568 >> Then type another @kbd{m}.
569 @end format
570
571 @format
572 >> Now type @kbd{BAR}, the item name. Do not type @key{RET} yet.
573 @end format
574
575 While you are typing the item name, you can use the @key{DEL} (or
576 @key{BACKSPACE}) key to cancel one character at a time if you make a
577 mistake.
578
579 @format
580 >> Press @key{DEL} to cancel the @samp{R}. You could type another @kbd{R}
581 to replace it. But you do not have to, since @samp{BA} is a valid
582 abbreviation.
583 @end format
584
585 @format
586 >> Now you are ready to go. Type a @key{RET}.
587 @end format
588
589 After visiting @samp{Help-FOO}, you should return here.
590
591 Another way to move to the menu subtopic lines and between them is
592 to type @key{TAB}. Each time you type a @key{TAB}, you move to the
593 next subtopic line. To move to a previous subtopic line, type
594 @kbd{M-@key{TAB}}---that is, press and hold the @key{META} key and then
595 press @key{TAB}. (On some keyboards, the @key{META} key might be labeled
596 @samp{Alt}.)
597
598 Once you move cursor to a subtopic line, press @key{RET} to go to
599 that subtopic's node.
600
601 @cindex mouse support in Info mode
602 @kindex Mouse-2 @r{(Info mode)}
603 If your terminal supports a mouse, you have yet another way of going
604 to a subtopic. Move your mouse pointer to the subtopic line,
605 somewhere between the beginning @samp{*} and the colon @samp{:} which
606 ends the subtopic's brief name. You will see the subtopic's name
607 change its appearance (usually, its background color will change), and
608 the shape of the mouse pointer will change if your platform supports
609 that. After a while, if you leave the mouse on that spot, a tooltip
610 will pop up saying ``Mouse-2: go to that node''. (If the tooltips are
611 turned off or unavailable, this message is displayed in the @dfn{echo
612 area}, the bottom screen line where you typed the menu subtopics in
613 response to the prompt.) @kbd{Mouse-2} is the second button of your
614 mouse counting from the left---the rightmost button for two-button
615 mice, the middle button for 3-button mice. So pressing @kbd{Mouse-2}
616 while the mouse pointer is on a menu subtopic goes to that subtopic.
617
618 @findex Info-mouse-follow-nearest-node
619 More generally, @kbd{Mouse-2} in an Info buffer runs the Emacs
620 command @code{Info-mouse-follow-nearest-node}, which finds the nearest
621 link to another node and goes there. For example, near a cross
622 reference it acts like @kbd{f}, in a menu it acts like @kbd{m}, on the
623 node's header line it acts like @kbd{n}, @kbd{p}, or @kbd{u}, etc. At
624 end of the node's text @kbd{Mouse-2} moves to the next node, or up if
625 there's no next node.
626
627 Here is another way to get to Help-FOO, a menu. You can ignore this
628 if you want, or else try it by typing @key{TAB} and then @key{RET}, or
629 clicking @kbd{Mouse-2} on it (but then please come back to here).
630
631 @menu
632 * Help-FOO::
633 @end menu
634
635 @format
636 >> Type @kbd{n} to see more commands.
637 @end format
638
639 @node Help-FOO, , , Help-M
640 @subsection The @kbd{u} command
641
642 Congratulations! This is the node @samp{Help-FOO}. It has an @samp{Up}
643 pointer @samp{Help-M}, the node you just came from via the @kbd{m}
644 command. This is the usual convention---the nodes you reach from a menu
645 have @samp{Up} nodes that lead back to the menu. Menus move Down in the
646 tree, and @samp{Up} moves Up. @samp{Previous}, on the other hand, is
647 usually used to ``stay on the same level but go backwards''.
648
649 @kindex u @r{(Info mode)}
650 @findex Info-up
651 You can go back to the node @samp{Help-M} by typing the command
652 @kbd{u} for ``Up'' (the Emacs command run by @kbd{u} is
653 @code{Info-up}). That puts you at the @emph{front} of the node---to
654 get back to where you were reading you have to type some @key{SPC}s.
655 (Some Info readers, such as the one built into Emacs, put you at the
656 same place where you were reading in @samp{Help-M}.)
657
658 Another way to go Up is to click on the @samp{Up} pointer shown in
659 the header line (provided that you have a mouse).
660
661 @format
662 >> Now type @kbd{u} to move back up to @samp{Help-M}.
663 @end format
664
665 @node Help-Xref, Help-Int, Help-M, Getting Started
666 @comment node-name, next, previous, up
667 @section Following Cross-References
668
669 @cindex cross references in Info documents
670 In Info documentation, you will see many @dfn{cross references}.
671 Cross references look like this: @xref{Help-Cross, Cross}. That text
672 is a real, live cross reference, whose name is @samp{Cross} and which
673 points to the node named @samp{Help-Cross}.
674
675 @kindex f @r{(Info mode)}
676 @findex Info-follow-reference
677 There are two ways to follow a cross reference. You can move the
678 cursor to it and press @key{RET}, just as in a menu. @key{RET}
679 follows the cross reference that the cursor is on. Or you can type
680 @kbd{f} and then specify the name of the cross reference (in this
681 case, @samp{Cross}) as an argument. In Emacs Info, @kbd{f} runs
682 @code{Info-follow-reference},
683
684 In the @kbd{f} command, you select the cross reference with its
685 name, so it does not matter where the cursor was. If the cursor is on
686 or near a cross reference, @kbd{f} suggests that reference name in
687 parentheses as the default; typing @key{RET} will follow that
688 reference. However, if you type a different reference name, @kbd{f}
689 will follow the other reference which has that name.
690
691 @format
692 >> Type @kbd{f}, followed by @kbd{Cross}, and then @key{RET}.
693 @end format
694
695 As you enter the reference name, you can use the @key{DEL} (or
696 @key{BACKSPACE}) key to edit your input. If you change your mind
697 about following any reference, you can use @kbd{Control-g} to cancel
698 the command. Completion is available in the @kbd{f} command; you can
699 complete among all the cross reference names in the current node by
700 typing a @key{TAB}.
701
702 To get a list of all the cross references in the current node, you
703 can type @kbd{?} after an @kbd{f}. The @kbd{f} continues to await a
704 cross reference name even after displaying the list, so if you don't
705 actually want to follow a reference, you should type a @kbd{Control-g}
706 to cancel the @kbd{f}.
707
708 @format
709 >> Type @kbd{f?} to get a list of the cross references in this node. Then
710 type a @kbd{Control-g} and see how the @samp{f} gives up.
711 @end format
712
713 The @key{TAB} and @kbd{M-@key{TAB}} key, which move between menu
714 items in a menu, also move between cross references outside of menus.
715
716 @node Help-Int, Help-Q, Help-Xref, Getting Started
717 @comment node-name, next, previous, up
718 @section Some intermediate Info commands
719
720 The introductory course is almost over; please continue
721 a little longer to learn some intermediate-level commands.
722
723 Most Info files have an index, which is actually a large node that
724 contains nothing but a menu. The menu has one menu item for each
725 topic listed in the index. You can find the index node from the main
726 menu of the file, with the @kbd{m} command; then you can use the
727 @kbd{m} command again in the index node to go to the node that
728 describes the topic.
729
730 There is also a short-cut Info command, @kbd{i}, which does all of
731 that for you. It searches the index for a given topic (a string) and
732 goes to the node which is listed in the index for that topic.
733 @xref{Info Search}, for a full explanation.
734
735 @kindex l @r{(Info mode)}
736 @findex Info-last
737 @cindex going back in Info mode
738 If you have been moving around to different nodes and wish to
739 retrace your steps, the @kbd{l} command (@kbd{l} for @dfn{last}) will
740 do that, one node-step at a time. As you move from node to node, Info
741 records the nodes where you have been in a special history list. The
742 @kbd{l} command revisits nodes in the history list; each successive
743 @kbd{l} command moves one step back through the history.
744
745 If you have been following directions, an @kbd{l} command now will get
746 you back to @samp{Help-M}. Another @kbd{l} command would undo the
747 @kbd{u} and get you back to @samp{Help-FOO}. Another @kbd{l} would undo
748 the @kbd{m} and get you back to @samp{Help-M}.
749
750 In Emacs, @kbd{l} runs the command @code{Info-last}.
751
752 @format
753 >> Try typing three @kbd{l}'s, pausing in between to see what each
754 @kbd{l} does. Then follow directions again and you will end up
755 back here.
756 @end format
757
758 Note the difference between @kbd{l} and @kbd{p}: @kbd{l} moves to
759 where @emph{you} last were, whereas @kbd{p} always moves to the node
760 which the header says is the @samp{Previous} node (from this node, the
761 @samp{Prev} link leads to @samp{Help-M}).
762
763 @kindex d @r{(Info mode)}
764 @findex Info-directory
765 @cindex go to Directory node
766 The @kbd{d} command (@code{Info-directory} in Emacs) gets you
767 instantly to the Directory node. This node, which is the first one
768 you saw when you entered Info, has a menu which leads (directly or
769 indirectly, through other menus), to all the nodes that exist. The
770 Directory node lists all the manuals and other Info documents that
771 are, or could be, installed on your system.
772
773 @format
774 >> Try doing a @kbd{d}, then do an @kbd{l} to return here (yes,
775 @emph{do} return).
776 @end format
777
778 @kindex t @r{(Info mode)}
779 @findex Info-top-node
780 @cindex go to Top node
781 The @kbd{t} command moves to the @samp{Top} node of the manual.
782 This is useful if you want to browse the manual's main menu, or select
783 some specific top-level menu item. The Emacs command run by @kbd{t}
784 is @code{Info-top-node}.
785
786 Clicking @kbd{Mouse-2} on or near a cross reference also follows the
787 reference. You can see that the cross reference is mouse-sensitive by
788 moving the mouse pointer to the reference and watching how the
789 underlying text and the mouse pointer change in response.
790
791 @format
792 >> Now type @kbd{n} to see the last node of the course.
793 @end format
794
795 @xref{Expert Info}, for more advanced Info features.
796
797 @c If a menu appears at the end of this node, remove it.
798 @c It is an accident of the menu updating command.
799
800 @node Expert Info
801 @chapter Info for Experts
802
803 This chapter describes various Info commands for experts. (If you
804 are using a stand-alone Info reader, there are additional commands
805 specific to it, which are documented in several chapters of @ref{Top,,
806 GNU Info, info-stnd, GNU Info}.)
807
808 This chapter also explains how to write an Info as distinct from a
809 Texinfo file. (However, in most cases, writing a Texinfo file is
810 better, since you can use it to make a printed manual or an HTML file
811 as well as for generating Info files.) @xref{Top,, Overview of
812 Texinfo, texinfo, Texinfo: The GNU Documentation Format}.)
813
814 @menu
815 * Advanced:: Advanced Info commands: g, s, e, and 1 - 5.
816 * Info Search:: How to search Info documents for specific subjects.
817 * Add:: Describes how to add new nodes to the hierarchy.
818 Also tells what nodes look like.
819 * Menus:: How to add to or create menus in Info nodes.
820 * Cross-refs:: How to add cross-references to Info nodes.
821 * Tags:: How to make tags tables for Info files.
822 * Checking:: Checking an Info File
823 * Emacs Info Variables:: Variables modifying the behavior of Emacs Info.
824 @end menu
825
826 @node Advanced, Info Search, , Expert Info
827 @comment node-name, next, previous, up
828 @section Advanced Info Commands
829
830 Here are some more Info commands that make it easier to move around.
831
832 @unnumberedsubsec @kbd{g} goes to a node by name
833
834 @kindex g @r{(Info mode)}
835 @findex Info-goto-node
836 @cindex go to a node by name
837 If you know a node's name, you can go there by typing @kbd{g}, the
838 name, and @key{RET}. Thus, @kbd{gTop@key{RET}} would go to the node
839 called @samp{Top} in this file. (This is equivalent to @kbd{t}, see
840 @ref{Help-Int}.) @kbd{gAdvanced@key{RET}} would come back here.
841 @kbd{g} in Emacs runs the command @code{Info-goto-node}.
842
843 Unlike @kbd{m}, @kbd{g} does not allow the use of abbreviations.
844 But it does allow completion, so you can type @key{TAB} to complete a
845 partial node name.
846
847 @cindex go to another Info file
848 To go to a node in another file, you can include the file name in the
849 node name by putting it at the front, in parentheses. Thus,
850 @kbd{g(dir)Top@key{RET}} would go to the Info Directory node, which is
851 the node @samp{Top} in the Info file @file{dir}. Likewise,
852 @kbd{g(emacs)Top@key{RET}} goes to the top node of the Emacs manual.
853
854 The node name @samp{*} specifies the whole file. So you can look at
855 all of the current file by typing @kbd{g*@key{RET}} or all of any
856 other file with @kbd{g(@var{filename})@key{RET}}.
857
858 @unnumberedsubsec @kbd{1} -- @kbd{9} choose a menu subtopic by its number
859
860 @kindex 1 @r{through} 9 @r{(Info mode)}
861 @findex Info-nth-menu-item
862 @cindex select @var{n}'th menu item
863 If you begrudge each character of type-in which your system requires,
864 you might like to use the commands @kbd{1}, @kbd{2}, @kbd{3}, @kbd{4},
865 @dots{}, @kbd{9}. They are short for the @kbd{m} command together
866 with a name of a menu subtopic. @kbd{1} goes through the first item
867 in the current node's menu; @kbd{2} goes through the second item, etc.
868 In the stand-alone reader, @kbd{0} goes through the last menu item;
869 this is so you need not count how many entries are there. In Emacs,
870 the digit keys run the command @code{Info-nth-menu-item}.
871
872 If your display supports multiple fonts, and you are using Emacs'
873 Info mode to read Info files, the @samp{*} for the fifth menu item
874 stands out, either in color or in some other attribute, such as
875 underline, and so is the @samp{*} for the ninth item; this makes it
876 easy to see at a glance which number to use for an item.
877
878 Some terminals don't support colors or underlining. If you need to
879 actually count items, it is better to use @kbd{m} instead, and specify
880 the name, or use @key{TAB} to quickly move between menu items.
881
882 @unnumberedsubsec @kbd{e} makes Info document editable
883
884 @kindex e @r{(Info mode)}
885 @findex Info-edit
886 @cindex edit Info document
887 The Info command @kbd{e} changes from Info mode to an ordinary
888 Emacs editing mode, so that you can edit the text of the current node.
889 Type @kbd{C-c C-c} to switch back to Info. The @kbd{e} command is allowed
890 only if the variable @code{Info-enable-edit} is non-@code{nil}.
891
892 The @kbd{e} command only works in Emacs, where it runs the command
893 @code{Info-edit}. The stand-alone Info reader doesn't allow you to
894 edit the Info file, so typing @kbd{e} there goes to the end of the
895 current node.
896
897 @node Info Search, Add, Advanced, Expert Info
898 @comment node-name, next, previous, up
899 @section How to search Info documents for specific subjects
900
901 @cindex searching Info documents
902 @cindex Info document as a reference
903 The commands which move between and inside nodes allow you to read
904 the entire manual or its large portions. But what if you need to find
905 some information in the manual as fast as you can, and you don't know
906 or don't remember in what node to look for it? This need arises when
907 you use a manual as a @dfn{reference}, or when it is impractical to
908 read the entire manual before you start using the programs it
909 describes.
910
911 Info has powerful searching facilities that let you find things
912 quickly. You can search either the manual indices or its text.
913
914 @kindex i @r{(Info mode)}
915 @findex Info-index
916 Since most subjects related to what the manual describes should be
917 indexed, you should try the index search first. The @kbd{i} command
918 prompts you for a subject and then looks up that subject in the
919 indices. If it finds an index entry with the subject you typed, it
920 goes to the node to which that index entry points. You should browse
921 through that node to see whether the issue you are looking for is
922 described there. If it isn't, type @kbd{,} one or more times to go
923 through additional index entries which match your subject.
924
925 The @kbd{i} command finds all index entries which include the string
926 you typed @emph{as a substring}. For each match, Info shows in the
927 echo area the full index entry it found. Often, the text of the full
928 index entry already gives you enough information to decide whether it
929 is relevant to what you are looking for, so we recommend that you read
930 what Emacs shows in the echo are before looking at the node it
931 displays.
932
933 Since @kbd{i} looks for a substring, you can search for subjects even
934 if you are not sure how they are spelled in the index. For example,
935 suppose you want to find something that is pertinent to commands which
936 complete partial input (e.g., when you type @key{TAB}). If you want
937 to catch index entries that refer to ``complete'', ``completion'', and
938 ``completing'', you could type @kbd{icomplet@key{RET}}.
939
940 Info documents which describe programs should index the commands,
941 options, and key sequences that the program provides. If you are
942 looking for a description of a command, an option, or a key, just type
943 their names when @kbd{i} prompts you for a topic. For example, if you
944 want to read the description of what the @kbd{C-f} key does, type
945 @kbd{iC-f@key{RET}}. Here @kbd{C-f} are 3 literal characters
946 @samp{C}, @samp{-}, and @samp{f}, not the ``Control-f'' command key
947 you type inside Emacs to run the command bound to @kbd{C-f}.
948
949 In Emacs, @kbd{i} runs the command @code{Info-index}.
950
951 @kindex s @r{(Info mode)}
952 @findex Info-search
953 The @kbd{s} command allows you to search a whole file for a string.
954 It switches to the next node if and when that is necessary. You
955 type @kbd{s} followed by the string to search for, terminated by
956 @key{RET}. To search for the same string again, just @kbd{s} followed
957 by @key{RET} will do. The file's nodes are scanned in the order
958 they are in in the file, which has no necessary relationship to the
959 order that they may be in the tree structure of menus and @samp{next}
960 pointers. But normally the two orders are not very different. In any
961 case, you can always do a @kbd{b} to find out what node you have
962 reached, if the header is not visible (this can happen, because @kbd{s}
963 puts your cursor at the occurrence of the string, not at the beginning
964 of the node).
965
966 @kindex M-s @r{(Info mode)}
967 In Emacs, @kbd{Meta-s} is equivalent to @kbd{s}. That is for
968 compatibility with other GNU packages that use @kbd{M-s} for a similar
969 kind of search command. Both @kbd{s} and @kbd{M-s} run in Emacs the
970 command @code{Info-search}.
971
972
973 @node Add, Menus, Info Search, Expert Info
974 @comment node-name, next, previous, up
975 @section Adding a new node to Info
976
977 To add a new topic to the list in the Info directory, you must:
978
979 @enumerate
980 @item
981 Create some nodes, in some file, to document that topic.
982 @item
983 Put that topic in the menu in the directory. @xref{Menus, Menu}.
984 @end enumerate
985
986 Usually, the way to create the nodes is with Texinfo (@pxref{Top,,
987 Overview of Texinfo, texinfo, Texinfo: The GNU Documentation Format});
988 this has the advantage that you can also make a printed manual or HTML
989 from them. You would use the @samp{@@dircategory} and
990 @samp{@@direntry} commands to put the manual into the Info directory.
991 However, if you want to edit an Info file manually and install it
992 manually, here is how.
993
994 @cindex node delimiters
995 The new node can live in an existing documentation file, or in a new
996 one. It must have a @samp{^_} character before it (invisible to the
997 user; this node has one but you cannot see it), and it ends with either
998 a @samp{^_}, a @samp{^L} (``formfeed''), or the end of file.@footnote{If
999 you put in a @samp{^L} to end a new node, be sure that there is a
1000 @samp{^_} after it to start the next one, since @samp{^L} cannot
1001 @emph{start} a node. Also, a nicer way to make a node boundary be a
1002 page boundary as well is to put a @samp{^L} @emph{right after} the
1003 @samp{^_}.}
1004
1005 The @samp{^_} starting a node must be followed by a newline or a
1006 @samp{^L} newline, after which comes the node's header line. The
1007 header line must give the node's name (by which Info finds it), and
1008 state the names of the @samp{Next}, @samp{Previous}, and @samp{Up}
1009 nodes (if there are any). As you can see, this node's @samp{Up} node
1010 is the node @samp{Expert Info}. The @samp{Next} node is @samp{Menus}.
1011
1012 @cindex node header line format
1013 @cindex format of node headers
1014 The keywords @dfn{Node}, @dfn{Next}, @dfn{Previous}, and @dfn{Up}
1015 may appear in any order, anywhere in the header line, but the
1016 recommended order is the one in this sentence. Each keyword must be
1017 followed by a colon, spaces and tabs, and then the appropriate name.
1018 The name may be terminated with a tab, a comma, or a newline. A space
1019 does not end it; node names may contain spaces. The case of letters
1020 in the names is insignificant.
1021
1022 @cindex node name format
1023 @cindex Directory node
1024 A node name has two forms. A node in the current file is named by
1025 what appears after the @samp{Node: } in that node's first line. For
1026 example, this node's name is @samp{Add}. A node in another file is
1027 named by @samp{(@var{filename})@var{node-within-file}}, as in
1028 @samp{(info)Add} for this node. If the file name starts with ``./'',
1029 then it is relative to the current directory; otherwise, it is
1030 relative starting from the standard directory for Info files of your
1031 site. The name @samp{(@var{filename})Top} can be abbreviated to just
1032 @samp{(@var{filename})}. By convention, the name @samp{Top} is used
1033 for the ``highest'' node in any single file---the node whose @samp{Up}
1034 points out of the file. The @samp{Directory} node is @file{(dir)}, it
1035 points to a file @file{dir} which holds a large menu listing all the
1036 Info documents installed on your site. The @samp{Top} node of a
1037 document file listed in the @samp{Directory} should have an @samp{Up:
1038 (dir)} in it.
1039
1040 @cindex unstructured documents
1041 The node name @kbd{*} is special: it refers to the entire file.
1042 Thus, @kbd{g*} shows you the whole current file. The use of the
1043 node @kbd{*} is to make it possible to make old-fashioned,
1044 unstructured files into nodes of the tree.
1045
1046 The @samp{Node:} name, in which a node states its own name, must not
1047 contain a file name, since when Info searches for a node, it does not
1048 expect a file name to be there. The @samp{Next}, @samp{Previous} and
1049 @samp{Up} names may contain them. In this node, since the @samp{Up}
1050 node is in the same file, it was not necessary to use one.
1051
1052 Note that the nodes in this file have a file name in the header
1053 line. The file names are ignored by Info, but they serve as comments
1054 to help identify the node for the user.
1055
1056 @node Menus, Cross-refs, Add, Expert Info
1057 @comment node-name, next, previous, up
1058 @section How to Create Menus
1059
1060 Any node in the Info hierarchy may have a @dfn{menu}---a list of subnodes.
1061 The @kbd{m} command searches the current node's menu for the topic which it
1062 reads from the terminal.
1063
1064 @cindex menu and menu entry format
1065 A menu begins with a line starting with @samp{* Menu:}. The rest of the
1066 line is a comment. After the starting line, every line that begins
1067 with a @samp{* } lists a single topic. The name of the topic--what
1068 the user must type at the @kbd{m}'s command prompt to select this
1069 topic---comes right after the star and space, and is followed by a
1070 colon, spaces and tabs, and the name of the node which discusses that
1071 topic. The node name, like node names following @samp{Next}, @samp{Previous}
1072 and @samp{Up}, may be terminated with a tab, comma, or newline; it may also
1073 be terminated with a period.
1074
1075 If the node name and topic name are the same, then rather than
1076 giving the name twice, the abbreviation @samp{* @var{name}::} may be
1077 used (and should be used, whenever possible, as it reduces the visual
1078 clutter in the menu).
1079
1080 It is considerate to choose the topic names so that they differ
1081 from each other very near the beginning---this allows the user to type
1082 short abbreviations. In a long menu, it is a good idea to capitalize
1083 the beginning of each item name which is the minimum acceptable
1084 abbreviation for it (a long menu is more than 5 or so entries).
1085
1086 The nodes listed in a node's menu are called its ``subnodes'', and it
1087 is their ``superior''. They should each have an @samp{Up:} pointing at
1088 the superior. It is often useful to arrange all or most of the subnodes
1089 in a sequence of @samp{Next} and @samp{Previous} pointers so that
1090 someone who wants to see them all need not keep revisiting the Menu.
1091
1092 The Info Directory is simply the menu of the node @samp{(dir)Top}---that
1093 is, node @samp{Top} in file @file{.../info/dir}. You can put new entries
1094 in that menu just like any other menu. The Info Directory is @emph{not} the
1095 same as the file directory called @file{info}. It happens that many of
1096 Info's files live in that file directory, but they do not have to; and
1097 files in that directory are not automatically listed in the Info
1098 Directory node.
1099
1100 Also, although the Info node graph is claimed to be a ``hierarchy'',
1101 in fact it can be @emph{any} directed graph. Shared structures and
1102 pointer cycles are perfectly possible, and can be used if they are
1103 appropriate to the meaning to be expressed. There is no need for all
1104 the nodes in a file to form a connected structure. In fact, this file
1105 has two connected components. You are in one of them, which is under
1106 the node @samp{Top}; the other contains the node @samp{Help} which the
1107 @kbd{h} command goes to. In fact, since there is no garbage
1108 collector, nothing terrible happens if a substructure is not pointed
1109 to, but such a substructure is rather useless since nobody can
1110 ever find out that it exists.
1111
1112 @node Cross-refs, Tags, Menus, Expert Info
1113 @comment node-name, next, previous, up
1114 @section Creating Cross References
1115
1116 @cindex cross reference format
1117 A cross reference can be placed anywhere in the text, unlike a menu
1118 item which must go at the front of a line. A cross reference looks
1119 like a menu item except that it has @samp{*note} instead of @samp{*}.
1120 It @emph{cannot} be terminated by a @samp{)}, because @samp{)}'s are
1121 so often part of node names. If you wish to enclose a cross reference
1122 in parentheses, terminate it with a period first. Here are two
1123 examples of cross references pointers:
1124
1125 @example
1126 *Note details: commands. (See *note 3: Full Proof.)
1127 @end example
1128
1129 @noindent
1130 @emph{These are just examples.} The places they ``lead to'' do not
1131 really exist!
1132
1133 @menu
1134 * Help-Cross:: Target of a cross-reference.
1135 @end menu
1136
1137
1138 @node Help-Cross, , , Cross-refs
1139 @subsection The node reached by the cross reference in Info
1140
1141 This is the node reached by the cross reference named @samp{Cross}.
1142
1143 While this node is specifically intended to be reached by a cross
1144 reference, most cross references lead to nodes that ``belong''
1145 someplace else far away in the structure of an Info document. So you
1146 cannot expect this node to have a @samp{Next}, @samp{Previous} or
1147 @samp{Up} links pointing back to where you came from. In general, the
1148 @kbd{l} (el) command is the only way to get back there.
1149
1150 @format
1151 >> Type @kbd{l} to return to the node where the cross reference was.
1152 @end format
1153
1154 @node Help-Q, , Help-Int, Getting Started
1155 @comment node-name, next, previous, up
1156 @section Quitting Info
1157
1158 @kindex q @r{(Info mode)}
1159 @findex Info-exit
1160 @cindex quitting Info mode
1161 To get out of Info, back to what you were doing before, type @kbd{q}
1162 for @dfn{Quit}. This runs @code{Info-exit} in Emacs.
1163
1164 This is the end of the basic course on using Info. You have learned
1165 how to move in an Info document, and how to follow menus and cross
1166 references. This makes you ready for reading manuals top to bottom,
1167 as new users should do when they learn a new package.
1168
1169 Another set of Info commands is useful when you need to find
1170 something quickly in a manual---that is, when you need to use a manual
1171 as a reference rather than as a tutorial. We urge you to learn
1172 these search commands as well. If you want to do that now, follow this
1173 cross reference to @ref{Info Search}.
1174
1175 Yet another set of commands are meant for experienced users; you can
1176 find them by looking in the Directory node for documentation on Info.
1177 Finding them will be a good exercise in using Info in the usual
1178 manner.
1179
1180 @format
1181 >> Type @kbd{d} to go to the Info directory node; then type
1182 @kbd{mInfo} and Return, to get to the node about Info and
1183 see what other help is available.
1184 @end format
1185
1186
1187 @node Tags, Checking, Cross-refs, Expert Info
1188 @comment node-name, next, previous, up
1189 @section Tags Tables for Info Files
1190
1191 @cindex tags tables in info files
1192 You can speed up the access to nodes of a large Info file by giving
1193 it a tags table. Unlike the tags table for a program, the tags table for
1194 an Info file lives inside the file itself and is used
1195 automatically whenever Info reads in the file.
1196
1197 @findex Info-tagify
1198 To make a tags table, go to a node in the file using Emacs Info mode and type
1199 @kbd{M-x Info-tagify}. Then you must use @kbd{C-x C-s} to save the
1200 file. Info files produced by the @code{makeinfo} command that is part
1201 of the Texinfo package always have tags tables to begin with.
1202
1203 @cindex stale tags tables
1204 @cindex update Info tags table
1205 Once the Info file has a tags table, you must make certain it is up
1206 to date. If you edit an Info file directly (as opposed to editing its
1207 Texinfo source), and, as a result of deletion of text, any node moves back
1208 more than a thousand characters in the file from the position
1209 recorded in the tags table, Info will no longer be able to find that
1210 node. To update the tags table, use the @code{Info-tagify} command
1211 again.
1212
1213 An Info file tags table appears at the end of the file and looks like
1214 this:
1215
1216 @example
1217 ^_^L
1218 Tag Table:
1219 File: info, Node: Cross-refs^?21419
1220 File: info, Node: Tags^?22145
1221 ^_
1222 End Tag Table
1223 @end example
1224
1225 @noindent
1226 Note that it contains one line per node, and this line contains
1227 the beginning of the node's header (ending just after the node name),
1228 a @samp{DEL} character, and the character position in the file of the
1229 beginning of the node.
1230
1231
1232 @node Checking, Emacs Info Variables, Tags, Expert Info
1233 @section Checking an Info File
1234
1235 When creating an Info file, it is easy to forget the name of a node when
1236 you are making a pointer to it from another node. If you put in the
1237 wrong name for a node, this is not detected until someone tries to go
1238 through the pointer using Info. Verification of the Info file is an
1239 automatic process which checks all pointers to nodes and reports any
1240 pointers which are invalid. Every @samp{Next}, @samp{Previous}, and
1241 @samp{Up} is checked, as is every menu item and every cross reference. In
1242 addition, any @samp{Next} which does not have a @samp{Previous} pointing
1243 back is reported. Only pointers within the file are checked, because
1244 checking pointers to other files would be terribly slow. But those are
1245 usually few.
1246
1247 @findex Info-validate
1248 To check an Info file, do @kbd{M-x Info-validate} while looking at any
1249 node of the file with Emacs Info mode.
1250
1251 @node Emacs Info Variables, , Checking, Expert Info
1252 @section Emacs Info-mode Variables
1253
1254 The following variables may modify the behavior of Info-mode in Emacs;
1255 you may wish to set one or several of these variables interactively, or
1256 in your @file{~/.emacs} init file. @xref{Examining, Examining and Setting
1257 Variables, Examining and Setting Variables, emacs, The GNU Emacs
1258 Manual}. The stand-alone Info reader program has its own set of
1259 variables, described in @ref{Variables,, Manipulating Variables,
1260 info-stnd, GNU Info}.
1261
1262 @vtable @code
1263 @item Info-directory-list
1264 The list of directories to search for Info files. Each element is a
1265 string (directory name) or @code{nil} (try default directory). If not
1266 initialized Info uses the environment variable @env{INFOPATH} to
1267 initialize it, or @code{Info-default-directory-list} if there is no
1268 @env{INFOPATH} variable in the environment.
1269
1270 If you wish to customize the Info directory search list for both Emacs
1271 info and stand-alone Info, it is best to set the @env{INFOPATH}
1272 environment variable, since that applies to both programs.
1273
1274 @item Info-additional-directory-list
1275 A list of additional directories to search for Info documentation files.
1276 These directories are not searched for merging the @file{dir} file.
1277
1278 @item Info-fontify
1279 When set to a non-@code{nil} value, enables highlighting of Info
1280 files. The default is @code{t}. You can change how the highlighting
1281 looks by customizing the faces @code{info-node}, @code{info-menu-5},
1282 @code{info-xref}, @code{info-header-xref}, @code{info-header-node},
1283 @code{info-title-@var{n}-face} (where @var{n} is the level of the
1284 section, a number between 1 and 4), and @code{info-menu-header}. To
1285 customize a face, type @kbd{M-x customize-face @key{RET} @var{face}
1286 @key{RET}}, where @var{face} is one of the face names listed here.
1287
1288 @item Info-use-header-line
1289 If non-@code{nil}, Emacs puts in the Info buffer a header line showing
1290 the @samp{Next}, @samp{Prev}, and @samp{Up} links. A header line does
1291 not scroll with the rest of the buffer, making these links always
1292 visible.
1293
1294 @item Info-scroll-prefer-subnodes
1295 If set to a non-@code{nil} value, @key{SPC} and @key{BACKSPACE} (or
1296 @key{DEL}) keys in a menu visit subnodes of the current node before
1297 scrolling to its end or beginning, respectively. For example, if the
1298 node's menu appears on the screen, the next @key{SPC} moves to a
1299 subnode indicated by the following menu item. Setting this option to
1300 @code{nil} results in behavior similar to the stand-alone Info reader
1301 program, which visits the first subnode from the menu only when you
1302 hit the end of the current node. The default is @code{t}.
1303
1304 @item Info-enable-active-nodes
1305 When set to a non-@code{nil} value, allows Info to execute Lisp code
1306 associated with nodes. The Lisp code is executed when the node is
1307 selected. The Lisp code to be executed should follow the node
1308 delimiter (the @samp{DEL} character) and an @samp{execute: } tag, like
1309 this:
1310
1311 @example
1312 ^_execute: (message "This is an active node!")
1313 @end example
1314
1315 @item Info-enable-edit
1316 Set to @code{nil}, disables the @samp{e} (@code{Info-edit}) command. A
1317 non-@code{nil} value enables it. @xref{Add, Edit}.
1318 @end vtable
1319
1320
1321 @node Creating an Info File
1322 @chapter Creating an Info File from a Texinfo File
1323
1324 @code{makeinfo} is a utility that converts a Texinfo file into an Info
1325 file; @code{texinfo-format-region} and @code{texinfo-format-buffer} are
1326 GNU Emacs functions that do the same.
1327
1328 @xref{Top,, Overview of Texinfo, texinfo, Texinfo: The GNU
1329 Documentation Format}, to learn how to write a Texinfo file.
1330
1331 @xref{Creating an Info File,,, texinfo, Texinfo: The GNU Documentation
1332 Format}, to learn how to create an Info file from a Texinfo file.
1333
1334 @xref{Installing an Info File,,, texinfo, Texinfo: The GNU
1335 Documentation Format}, to learn how to install an Info file after you
1336 have created one.
1337
1338 @node Index
1339 @unnumbered Index
1340
1341 This is an alphabetical listing of all the commands, variables, and
1342 topics discussed in this document.
1343
1344 @printindex cp
1345
1346 @bye