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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 1.13 2001/05/03 14:03:33 karl Exp $
10
11 @dircategory Texinfo documentation system
12 @direntry
13 * Info: (info). 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
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 for reading documentation, which you are using now.
79
80 @ifinfo
81 If you are new to Info and want to learn how to use it, type the
82 command @kbd{h} now. It brings you to a programmed instruction
83 sequence.
84
85 To learn advanced Info commands, type @kbd{n} twice. This brings you to
86 @cite{Info for Experts}, skipping over the `Getting Started' chapter.
87 @end ifinfo
88 @end ifnottex
89
90 @menu
91 * Getting Started:: Getting started using an Info reader.
92 * Advanced Info:: Advanced commands within Info.
93 * Creating an Info File:: How to make your own Info file.
94 * Index:: An index of topics, commands, and variables.
95 @end menu
96
97 @node Getting Started, Advanced Info, Top, Top
98 @comment node-name, next, previous, up
99 @chapter Getting Started
100
101 This first part of the Info manual describes how to get around inside
102 of Info. The second part of the manual describes various advanced
103 Info commands, and how to write an Info as distinct from a Texinfo
104 file. The third part briefly explains how to generate Info files from
105 Texinfo files.
106
107 @ifnotinfo
108 This manual is primarily designed for browsing with an Info reader
109 program on a computer, so that you can try Info commands while reading
110 about them. Reading it on paper or with an HTML browser is less
111 effective, since you must take it on faith that the commands described
112 really do what the manual says. By all means go through this manual
113 now that you have it; but please try going through the on-line version
114 as well.
115
116 @cindex Info reader, how to invoke
117 @cindex entering Info
118 There are two ways of looking at the online version of this manual:
119
120 @enumerate
121 @item
122 Type @code{info} at your shell's command line. This approach uses a
123 stand-alone program designed just to read Info files.
124
125 @item
126 Type @code{emacs} at the command line; then type @kbd{C-h i}
127 (@kbd{Control-h}, followed by @kbd{i}). This approach uses the Info
128 mode of the Emacs program, an editor with many other capabilities.
129 @end enumerate
130
131 In either case, then type @kbd{mInfo} (just the letters), followed by
132 @key{RET}---the ``Return'' or ``Enter'' key. At this point, you should
133 be ready to follow the instructions in this manual as you read them on
134 the screen.
135 @c FIXME! (pesch@cygnus.com, 14 dec 1992)
136 @c Is it worth worrying about what-if the beginner goes to somebody
137 @c else's Emacs session, which already has an Info running in the middle
138 @c of something---in which case these simple instructions won't work?
139 @end ifnotinfo
140
141 @menu
142 * Help-Small-Screen:: Starting Info on a Small Screen
143 * Help:: How to use Info
144 * Help-P:: Returning to the Previous node
145 * Help-^L:: The Space, Rubout, B and ^L commands.
146 * Help-M:: Menus
147 * Help-Int:: Some intermediate Info commands
148 * Help-Q:: Quitting Info
149 @end menu
150
151 @node Help-Small-Screen
152 @section Starting Info on a Small Screen
153
154 @ifnotinfo
155 (In Info, you only see this section if your terminal has a small
156 number of lines; most readers pass by it without seeing it.)
157 @end ifnotinfo
158
159 @cindex small screen, moving around
160 Since your terminal has a relatively small number of lines on its
161 screen, it is necessary to give you special advice at the beginning.
162
163 If you see the text @samp{--All----} near the bottom right corner
164 of the screen, it means the entire text you are looking at fits on the
165 screen. If you see @samp{--Top----} instead, it means that there is
166 more text below that does not fit. To move forward through the text
167 and see another screen full, press @key{SPC}, the Space bar. To move
168 back up, press the key labeled @samp{Backspace} or @samp{DEL} (on some
169 keyboards, this key might be labeled @samp{Delete}).
170
171 @ifinfo
172 Here are 40 lines of junk, so you can try @key{SPC} and @key{DEL} and
173 see what they do. At the end are instructions of what you should do
174 next.
175
176 @format
177 This is line 20
178 This is line 21
179 This is line 22
180 This is line 23
181 This is line 24
182 This is line 25
183 This is line 26
184 This is line 27
185 This is line 28
186 This is line 29
187 This is line 30
188 This is line 31
189 This is line 32
190 This is line 33
191 This is line 34
192 This is line 35
193 This is line 36
194 This is line 37
195 This is line 38
196 This is line 39
197 This is line 40
198 This is line 41
199 This is line 42
200 This is line 43
201 This is line 44
202 This is line 45
203 This is line 46
204 This is line 47
205 This is line 48
206 This is line 49
207 This is line 50
208 This is line 51
209 This is line 52
210 This is line 53
211 This is line 54
212 This is line 55
213 This is line 56
214 This is line 57
215 This is line 58
216 This is line 59
217 @end format
218
219 If you have managed to get here, go back to the beginning with
220 @kbd{DEL} (or @key{BACKSPACE}), and come back here again, then you
221 understand the about the @samp{Space} and @samp{Backspace} keys. So
222 now type an @kbd{n} ---just one character; don't type the quotes and
223 don't type the Return key afterward--- to get to the normal start of
224 the course.
225 @end ifinfo
226
227 @node Help, Help-P, Help-Small-Screen, Getting Started
228 @comment node-name, next, previous, up
229 @section How to use Info
230
231 You are talking to the program Info, for reading documentation.
232
233 @cindex node, in Info documents
234 Right now you are looking at one @dfn{Node} of Information.
235 A node contains text describing a specific topic at a specific
236 level of detail. This node's topic is ``how to use Info''. The mode
237 line says that this is node @samp{Help} in the file @file{info}.
238
239 @cindex header of Info node
240 The top line of a node is its @dfn{header}. This node's header (look at
241 it now) says that the @samp{Next} node after this one is the node
242 called @samp{Help-P}. An advanced Info command lets you go to any node
243 whose name you know. In the stand-alone Info reader program, the
244 header line shows the names of this node and the info file as well.
245 In Emacs, the header line is displayed in a special typeface, and it
246 doesn't scroll off the screen when you scroll the display. The names
247 of this node and of its Info file are omitted by Emacs from the header
248 line.
249
250 Besides a @samp{Next}, a node can have a @samp{Previous} or an
251 @samp{Up} links, or both. As you can see, this node has all of these
252 links.
253
254 @kindex n @r{(Info mode)}
255 Now it is time to move on to the @samp{Next} node, named @samp{Help-P}.
256
257 @format
258 >> Type @kbd{n} to move there. Type just one character;
259 do not type the quotes and do not type a @key{RET} afterward.
260 @end format
261
262 @noindent
263 @samp{>>} in the margin means it is really time to try a command.
264
265 @format
266 >> If you have a mouse, and if you already practiced typing @kbd{n}
267 to get to the next node, click now with the right mouse button on
268 the @samp{Next} link to do the same ``the mouse way''.
269 @end format
270
271 @node Help-P, Help-^L, Help, Getting Started
272 @comment node-name, next, previous, up
273 @section Returning to the Previous node
274
275 @kindex p @r{(Info mode)}
276 This node is called @samp{Help-P}. The @samp{Previous} node, as you see,
277 is @samp{Help}, which is the one you just came from using the @kbd{n}
278 command. Another @kbd{n} command now would take you to the next
279 node, @samp{Help-^L}. In Emacs, @kbd{n} runs the Emacs command
280 @code{Info-next}, and @kbd{p} runs @code{Info-prev}.
281
282 @format
283 >> But do not type @kbd{n} yet. First, try the @kbd{p} command,
284 or click the mouse on the @samp{Prev} link, which takes you to the
285 @samp{Previous} node. When you get there, you can do an @kbd{n}
286 again to return here.
287 @end format
288
289 If you read this in Emacs, you will see an @samp{Info} item in the
290 menu bar, close to its right edge. Clicking your mouse on the
291 @samp{Info} menu-bar item opens a menu of commands which include
292 @samp{Next} and @samp{Prev} (and also some others which you didn't yet
293 learn about).
294
295 This all probably seems insultingly simple so far, but @emph{do not} be
296 led into skimming. Things will get more complicated soon. Also,
297 do not try a new command until you are told it is time to. Otherwise,
298 you may make Info skip past an important warning that was coming up.
299
300 @format
301 >> Now do an @kbd{n}, or click the mouse on the @samp{Next} link, to
302 get to the node @samp{Help-^L} and learn more.
303 @end format
304
305 @node Help-^L, Help-M, Help-P, Getting Started
306 @comment node-name, next, previous, up
307 @section The Space, DEL, B and ^L commands.
308
309 This node's mode line tells you that you are now at node @samp{Help-^L},
310 and the header line tells you that @kbd{p} would get you back to
311 @samp{Help-P}. The node's title is underlined; it says what the node
312 is about (most nodes have titles).
313
314 This is a big node and it does not all fit on your display screen.
315 You can tell that there is more that is not visible because you
316 can see the string @samp{--Top-----} rather than @samp{--All----} near
317 the bottom right corner of the screen.
318
319 @kindex SPC @r{(Info mode)}
320 @kindex DEL @r{(Info mode)}
321 @kindex BACKSPACE @r{(Info mode)}
322 @findex Info-scroll-up
323 @findex Info-scroll-down
324 The @key{SPC}, @key{BACKSPACE} (or @key{DEL})@footnote{The key which
325 we call ``Backspace or DEL'' in this manual is labeled differently on
326 different keyboards. Look for a key which is a little ways above the
327 @key{ENTER} or @key{RET} key and which you normally use outside Emacs
328 to erase the character before the cursor, i.e.@: the character you
329 typed last. It might be labeled @samp{Backspace} or @samp{<-} or
330 @samp{DEL}, or sometimes @samp{Delete}.} and @kbd{b} commands exist to
331 allow you to ``move around'' in a node that does not all fit on the
332 screen at once. @key{SPC} moves forward, to show what was below the
333 bottom of the screen. @key{DEL} or @key{BACKSPACE} moves backward, to
334 show what was above the top of the screen (there is not anything above
335 the top until you have typed some spaces). In Emacs, @key{SPC} runs
336 the command @code{Info-scroll-up}, while @key{BACKSPACE} runs
337 @code{Info-scroll-down}.
338
339 @format
340 >> Now try typing a @key{SPC} (afterward, type a @key{BACKSPACE} to
341 return here).
342 @end format
343
344 When you type the @key{SPC}, the two lines that were at the bottom of
345 the screen appear at the top, followed by more lines. @key{DEL} or
346 @key{BACKSPACE} takes the two lines from the top and moves them to the
347 bottom, @emph{usually}, but if there are not a full screen's worth of
348 lines above them they may not make it all the way to the bottom.
349
350 If you are reading this in Emacs, note that the header line is
351 always visible, never scrolling off the display. That way, you can
352 always see the @samp{Next}, @samp{Prev}, and @samp{Up} links, and you
353 can conveniently go to one of these links from anywhere in the node by
354 clicking the mouse on one of these links.
355
356 @cindex reading Info documents top to bottom
357 @cindex Info documents as tutorials
358 @key{SPC} and @key{DEL} not only move forward and backward through
359 the current node. When these keys hit the beginning or the end of the
360 current node, they move to preceding or subsequent nodes.
361 Specifically, they scroll through all the nodes in an Info file as a
362 single logical sequence. In this sequence, a node's subnodes appear
363 following their parent. If a node has a menu, @key{SPC} takes you
364 into the subnodes listed in the menu, one by one. Once you reach the
365 end of a node, and have seen all of its subnodes, @key{SPC} takes you
366 to the next node or to the parent's next node. This is so you could
367 read the entire manual top to bottom by just typing @key{SPC}.
368
369 @kindex PAGEUP @r{(Info mode)}
370 @kindex PAGEDOWN @r{(Info mode)}
371 Many keyboards nowadays have two scroll keys labeled @samp{PageUp}
372 and @samp{PageDown} (or maybe @samp{Prior} and @samp{Next}). If your
373 keyboard has these keys, you can use them to move forward and backward
374 through the text, like with @key{SPC} and @key{BACKSPACE}. However,
375 unlike @key{SPC} and @key{BACKSPACE}, @key{PAGEUP} and @key{PAGEDOWN}
376 keys will never scroll beyond the beginning or the end of the current
377 node.
378
379 @kindex C-l @r{(Info mode)}
380 If your screen is ever garbaged, you can tell Info to print it out
381 again by typing @kbd{C-l} (@kbd{Control-L}, that is---hold down
382 @key{CTRL} and type @kbd{L} or @kbd{l}).
383
384 @format
385 >> Type @kbd{C-l} now.
386 @end format
387
388 @kindex b @r{(Info mode)}
389 To move back to the beginning of the node you are on, you can type
390 a lot of @key{BACKSPACE} keys. You can also type simply @kbd{b} for
391 beginning.
392
393 @format
394 >> Try that now. (We have put in enough verbiage to push this past
395 the first screenful, but screens are so big nowadays that perhaps it
396 isn't enough. You may need to shrink your Emacs or Info window.)
397 Then come back, with @key{SCS}s.
398 @end format
399
400 If your screen is very tall, all of this node might fit at once.
401 In that case, @kbd{b} won't do anything. Sorry; what can we do?
402
403 @kindex ? @r{(Info mode)}
404 @findex Info-summary
405 You have just learned a considerable number of commands. If you
406 want to use one but have trouble remembering which, you should type
407 a @kbd{?} (in Emacs it runs the @code{Info-summary} command) which
408 prints out a brief list of commands. When you are finished looking at
409 the list, make it go away by typing a @key{SPC} repeatedly.
410
411 @format
412 >> Type a @key{?} now. Press @key{SPC} to see consecutive screenfuls of
413 the list until finished. Then type @key{SPC} several times, until
414 it goes away.
415 @end format
416
417 (If you are using the stand-alone Info reader, type @kbd{C-x 0} to
418 return here, that is---press and hold @key{CTRL}, type an @kbd{x},
419 then release @key{CTRL} and @kbd{x}, and press @kbd{0}---a zero, not
420 the letter ``o''.)
421
422 From now on, you will encounter large nodes without warning, and
423 will be expected to know how to use @key{SPC} and @key{BACKSPACE} to
424 move around in them without being told. Since not all terminals have
425 the same size screen, it would be impossible to warn you anyway.
426
427 @format
428 >> Now type @kbd{n}, or click the mouse on the @samp{Next} link, to
429 see the description of the @kbd{m} command.
430 @end format
431
432 @node Help-M, Help-Int, Help-^L, Getting Started
433 @comment node-name, next, previous, up
434 @section Menus and the @kbd{m} command
435
436 @cindex menus in an Info document
437 @cindex Info menus
438 With only the @kbd{n} (next) and @kbd{p} (previous) commands for
439 moving between nodes, nodes are restricted to a linear sequence.
440 Menus allow a branching structure. A menu is a list of other nodes
441 you can move to. It is actually just part of the text of the node
442 formatted specially so that Info can interpret it. The beginning of a
443 menu is always identified by a line which starts with @samp{* Menu:}.
444 A node contains a menu if and only if it has a line in it which starts
445 that way. The only menu you can use at any moment is the one in the
446 node you are in. To use a menu in any other node, you must move to
447 that node first.
448
449 After the start of the menu, each line that starts with a @samp{*}
450 identifies one subtopic. The line usually contains a brief name
451 for the subtopic (followed by a @samp{:}), the name of the node that talks
452 about that subtopic, and optionally some further description of the
453 subtopic. Lines in the menu that do not start with a @samp{*} have no
454 special meaning---they are only for the human reader's benefit and do
455 not define additional subtopics. Here is an example:
456
457 @example
458 * Foo: Node about FOO This tells about FOO
459 @end example
460
461 The subtopic name is Foo, and the node describing it is @samp{Node
462 about FOO}. The rest of the line is just for the reader's
463 Information. [[ But this line is not a real menu item, simply because
464 there is no line above it which starts with @samp{* Menu:}.]]
465
466 When you use a menu to go to another node (in a way that will be
467 described soon), what you specify is the subtopic name, the first
468 thing in the menu line. Info uses it to find the menu line, extracts
469 the node name from it, and goes to that node. The reason that there
470 is both a subtopic name and a node name is that the node name must be
471 meaningful to the computer and may therefore have to be ugly looking.
472 The subtopic name can be chosen just to be convenient for the user to
473 specify. Often the node name is convenient for the user to specify
474 and so both it and the subtopic name are the same. There is an
475 abbreviation for this:
476
477 @example
478 * Foo:: This tells about FOO
479 @end example
480
481 @noindent
482 This means that the subtopic name and node name are the same; they are
483 both @samp{Foo}.
484
485 @format
486 >> Now use @key{SPC} to find the menu in this node, then come back to
487 the front with a @kbd{b} and some @key{SPC}s. As you see, a menu is
488 actually visible in its node. If you cannot find a menu in a node
489 by looking at it, then the node does not have a menu and the
490 @kbd{m} command is not available.
491 @end format
492
493 @kindex m @r{(Info mode)}
494 The command to go to one of the subnodes is @kbd{m}---but @emph{do
495 not do it yet!} Before you use @kbd{m}, you need to learn about
496 commands which prompt you for more input. So far, you have learned
497 several commands that do not need additional input; when you typed
498 one, Info processed it and was instantly ready for another command.
499 The @kbd{m} command is different: it is incomplete without the
500 @dfn{name of the subtopic}. Once you have typed @kbd{m}, Info tries
501 to read the subtopic name.
502
503 Now look for the line containing many dashes near the bottom of the
504 screen. There is one more line beneath that one, but usually it is
505 blank. If it is empty, Info is ready for a command, such as @kbd{n}
506 or @kbd{b} or @key{SPC} or @kbd{m}. If that line contains text ending
507 in a colon, it means Info is trying to read more input for the last
508 command. At such times, commands do not work, because Info tries to
509 use them as the input it needs. You must either type your response and
510 finish the command you started, or type @kbd{Control-g} to cancel the
511 command. When you have done one of those things, the line becomes
512 blank again.
513
514 @findex Info-menu
515 The command to go to a subnode via a menu is @kbd{m}. After you type
516 the @kbd{m}, the line at the bottom of the screen says @samp{Menu item: }.
517 You must then type the name of the subtopic you want, and end it with
518 a @key{RET}. In Emacs, @kbd{m} runs the command @code{Info-menu}.
519
520 @cindex abbreviating Info subnodes
521 You can abbreviate the subtopic name. If the abbreviation is not
522 unique, the first matching subtopic is chosen. Some menus put
523 the shortest possible abbreviation for each subtopic name in capital
524 letters, so you can see how much you need to type. It does not
525 matter whether you use upper case or lower case when you type the
526 subtopic. You should not put any spaces at the end, or inside of the
527 item name, except for one space where a space appears in the item in
528 the menu.
529
530 @cindex completion of Info node names
531 You can also use the @dfn{completion} feature to help enter the subtopic
532 name. If you type the @key{TAB} key after entering part of a name, it will
533 magically fill in more of the name---as much as follows uniquely from
534 what you have entered.
535
536 If you move the cursor to one of the menu subtopic lines, then you do
537 not need to type the argument: you just type a @key{RET}, and it
538 stands for the subtopic of the line you are on.
539
540 Here is a menu to give you a chance to practice. This menu gives you
541 three ways of going to one place, Help-FOO:
542
543 @menu
544 * Foo: Help-FOO. A node you can visit for fun.
545 * Bar: Help-FOO. Strange! two ways to get to the same place.
546 * Help-FOO:: And yet another!
547 @end menu
548
549 @format
550 >> Now type just an @kbd{m} and see what happens:
551 @end format
552
553 Now you are ``inside'' an @kbd{m} command. Commands cannot be used
554 now; the next thing you will type must be the name of a subtopic.
555
556 You can change your mind about doing the @kbd{m} by typing
557 @kbd{Control-g}.
558
559 @format
560 >> Try that now; notice the bottom line clear.
561 @end format
562
563 @format
564 >> Then type another @kbd{m}.
565 @end format
566
567 @format
568 >> Now type @kbd{BAR}, the item name. Do not type @key{RET} yet.
569 @end format
570
571 While you are typing the item name, you can use the @key{DEL} (or
572 @key{BACKSPACE}) key to cancel one character at a time if you make a
573 mistake.
574
575 @format
576 >> Press @key{DEL} to cancel the @samp{R}. You could type another @kbd{R}
577 to replace it. But you do not have to, since @samp{BA} is a valid
578 abbreviation.
579 @end format
580
581 @format
582 >> Now you are ready to go. Type a @key{RET}.
583 @end format
584
585 After visiting @samp{Help-FOO}, you should return here.
586
587 Another way to move to the menu subtopic lines and between them is
588 to type @key{TAB}. Each time you type a @key{TAB}, you move to the
589 next subtopic line. To move to a previous subtopic line, type
590 @kbd{M-@key{TAB}}---that is, press and hold the @key{META} key and then
591 press @key{TAB}. (On some keyboards, the @key{META} key might be labeled
592 @samp{Alt}.)
593
594 Once you move cursor to a subtopic line, press @key{RET} to go to
595 that subtopic's node.
596
597 @cindex mouse support in Info mode
598 @kindex Mouse-2 @r{(Info mode)}
599 If your terminal supports a mouse, you have yet another way of going
600 to a subtopic. Move your mouse pointer to the subtopic line,
601 somewhere between the beginning @samp{*} and the colon @samp{:} which
602 ends the subtopic's brief name. You will see the subtopic's name
603 change its appearance (usually, its background color will change), and
604 the shape of the mouse pointer will change if your platform supports
605 that. After a while, if you leave the mouse on that spot, a tooltip
606 will pop up saying ``Mouse-2: go to that node''. (If the tooltips are
607 turned off or unavailable, this message is printed in the @dfn{echo
608 area}, the bottom screen line where you typed the menu subtopics in
609 response to the prompt.) @kbd{Mouse-2} is the second button of your
610 mouse counting from the left---the rightmost button for two-button
611 mice, the middle button for 3-button mice. So pressing @kbd{Mouse-2}
612 while the mouse pointer is on a menu subtopic goes to that subtopic.
613
614 @findex Info-mouse-follow-nearest-node
615 More generally, @kbd{Mouse-2} in an Info buffer runs the Emacs
616 command @code{Info-mouse-follow-nearest-node}, which finds the nearest
617 link to another node and goes there. For example, near a cross
618 reference it acts like @kbd{f}, in a menu it acts like @kbd{m}, on the
619 node's header line it acts like @kbd{n}, @kbd{p}, or @kbd{u}, etc. At
620 end of the node's text @kbd{Mouse-2} moves to the next node, or up if
621 there's no next node.
622
623 Here is another way to get to Help-FOO, a menu. You can ignore this
624 if you want, or else try it by typing @key{TAB} and then @key{RET}, or
625 clicking @kbd{Mouse-2} on it (but then please come back to here).
626
627 @menu
628 * Help-FOO::
629 @end menu
630
631 @format
632 >> Type @kbd{n} to see more commands.
633 @end format
634
635 @node Help-FOO, , , Help-M
636 @subsection The @kbd{u} command
637
638 Congratulations! This is the node @samp{Help-FOO}. It has an @samp{Up}
639 pointer @samp{Help-M}, the node you just came from via the @kbd{m}
640 command. This is the usual convention---the nodes you reach from a menu
641 have @samp{Up} nodes that lead back to the menu. Menus move Down in the
642 tree, and @samp{Up} moves Up. @samp{Previous}, on the other hand, is
643 usually used to ``stay on the same level but go backwards''.
644
645 @kindex u @r{(Info mode)}
646 @findex Info-up
647 You can go back to the node @samp{Help-M} by typing the command
648 @kbd{u} for ``Up'' (the Emacs command run by @kbd{u} is
649 @code{Info-up}). That puts you at the @emph{front} of the node---to
650 get back to where you were reading you have to type some @key{SPC}s.
651 (Some Info readers, such as the one built into Emacs, put you at the
652 same place where you were reading in @samp{Help-M}.)
653
654 Another way to go Up is to click on the @samp{Up} pointer shown in
655 the header line (provided that you have a mouse).
656
657 @format
658 >> Now type @kbd{u} to move back up to @samp{Help-M}.
659 @end format
660
661 @node Help-Int, Help-Q, Help-M, Getting Started
662 @comment node-name, next, previous, up
663 @section Some intermediate Info commands
664
665 The introductory course is almost over; please continue
666 a little longer to learn some intermediate-level commands.
667
668 @kindex l @r{(Info mode)}
669 @findex Info-last
670 @cindex going back in Info mode
671 If you have been moving around to different nodes and wish to
672 retrace your steps, the @kbd{l} command (@kbd{l} for @dfn{last}) will
673 do that, one node-step at a time. As you move from node to node, Info
674 records the nodes where you have been in a special history list. The
675 @kbd{l} command revisits nodes in the history list; each successive
676 @kbd{l} command moves one step back through the history.
677
678 If you have been following directions, ad @kbd{l} command now will get
679 you back to @samp{Help-M}. Another @kbd{l} command would undo the
680 @kbd{u} and get you back to @samp{Help-FOO}. Another @kbd{l} would undo
681 the @kbd{m} and get you back to @samp{Help-M}.
682
683 In Emacs, @kbd{l} runs the command @code{Info-last}.
684
685 @format
686 >> Try typing three @kbd{l}'s, pausing in between to see what each
687 @kbd{l} does. Then follow directions again and you will end up
688 back here.
689 @end format
690
691 Note the difference between @kbd{l} and @kbd{p}: @kbd{l} moves to
692 where @emph{you} last were, whereas @kbd{p} always moves to the node
693 which the header says is the @samp{Previous} node (from this node, the
694 @samp{Prev} link leads to @samp{Help-M}).
695
696 @kindex d @r{(Info mode)}
697 @findex Info-directory
698 @cindex go to Directory node
699 The @kbd{d} command (@code{Info-directory} in Emacs) gets you
700 instantly to the Directory node. This node, which is the first one
701 you saw when you entered Info, has a menu which leads (directly or
702 indirectly, through other menus), to all the nodes that exist. The
703 Directory node lists all the manuals and other Info documents that
704 are, or could be, installed on your system.
705
706 @format
707 >> Try doing a @kbd{d}, then do an @kbd{l} to return here (yes,
708 @emph{do} return).
709 @end format
710
711 @kindex t @r{(Info mode)}
712 @findex Info-top-node
713 @cindex go to Top node
714 The @kbd{t} command moves to the @samp{Top} node of the manual.
715 This is useful if you want to browse the manual's main menu, or select
716 some specific top-level menu item. The Emacs command run by @kbd{t}
717 is @code{Info-top-node}.
718
719 Sometimes, in Info documentation, you will see a cross reference.
720 Cross references look like this: @xref{Help-Cross, Cross}. That is a
721 real, live cross reference which is named @samp{Cross} and points at
722 the node named @samp{Help-Cross}.
723
724 @kindex f @r{(Info mode)}
725 @findex Info-follow-reference
726 @cindex cross references in Info documents
727 If you wish to follow a cross reference, you must use the @kbd{f}
728 command. The @kbd{f} must be followed by the cross reference name
729 (in this case, @samp{Cross}). If the cursor is on or near the cross
730 reference, Info suggests the name if the nearest reference in
731 parentheses; typing @key{RET} will follow that reference. You can
732 also type a different name, if the default is not what you want.
733 While you enter the name, you can use the @key{DEL} (or
734 @key{BACKSPACE}) key to edit your input. If you change your mind
735 about following any reference, you can use @kbd{Control-g} to cancel
736 the command.
737
738 Completion is available in the @kbd{f} command; you can complete among
739 all the cross reference names in the current node by typing a @key{TAB}.
740
741 @kbd{f} runs @code{Info-follow-reference} in Emacs.
742
743 @format
744 >> Type @kbd{f}, followed by @kbd{Cross}, and a @key{RET}.
745 @end format
746
747 To get a list of all the cross references in the current node, you can
748 type @kbd{?} after an @kbd{f}. The @kbd{f} continues to await a
749 cross reference name even after printing the list, so if you don't
750 actually want to follow a reference, you should type a @kbd{Control-g}
751 to cancel the @kbd{f}.
752
753 @format
754 >> Type @kbd{f?} to get a list of the cross references in this node. Then
755 type a @kbd{Control-g} and see how the @samp{f} gives up.
756 @end format
757
758 The @key{TAB} and @kbd{M-@key{TAB}} key, which move between
759 subtopics in a menu can move between cross references as well. Once
760 the cursor is on a cross reference, you can press @key{RET} to follow
761 that reference, just like you do in a menu.
762
763 Clicking @kbd{Mouse-2} on or near a cross reference also follows the
764 reference. You can see that the cross reference is mouse-sensitive by
765 moving the mouse pointer to the reference and watching how the
766 underlying text and the mouse pointer change in response.
767
768 @format
769 >> Now type @kbd{n} to see the last node of the course.
770 @end format
771
772 @xref{Advanced Info}, for more advanced Info features.
773
774 @c If a menu appears at the end of this node, remove it.
775 @c It is an accident of the menu updating command.
776
777 @node Advanced Info
778 @chapter Info for Experts
779
780 This chapter describes various advanced Info commands. (If you are
781 using a stand-alone Info reader, there are additional commands
782 specific to it, which are documented in several chapters of @ref{Top,,
783 GNU Info, info-stnd, GNU Info}.)
784
785 This chapter also explains how to write an Info as distinct from a
786 Texinfo file. (However, in most cases, writing a Texinfo file is
787 better, since you can use it @emph{both} to generate an Info file and
788 to make a printed manual. @xref{Top,, Overview of Texinfo, texinfo,
789 Texinfo: The GNU Documentation Format}.)
790
791 @menu
792 * Expert:: Advanced Info commands: g, s, e, and 1 - 5.
793 * Info Search:: How to search Info documents for specific subjects.
794 * Add:: Describes how to add new nodes to the hierarchy.
795 Also tells what nodes look like.
796 * Menus:: How to add to or create menus in Info nodes.
797 * Cross-refs:: How to add cross-references to Info nodes.
798 * Tags:: How to make tags tables for Info files.
799 * Checking:: Checking an Info File
800 * Emacs Info Variables:: Variables modifying the behavior of Emacs Info.
801 @end menu
802
803 @node Expert, Info Search, , Advanced Info
804 @comment node-name, next, previous, up
805 @section Advanced Info Commands
806
807 Here are some more Info commands that make it easier to move around.
808
809 @unnumberedsubsec @kbd{g} goes to a node by name
810
811 @kindex g @r{(Info mode)}
812 @findex Info-goto-node
813 @cindex go to a node by name
814 If you know a node's name, you can go there by typing @kbd{g}, the
815 name, and @key{RET}. Thus, @kbd{gTop@key{RET}} would go to the node
816 called @samp{Top} in this file. (This is equivalent to @kbd{t}, see
817 @ref{Help-Int}.) @kbd{gExpert@key{RET}} would come back here.
818 @kbd{g} in Emacs runs the command @code{Info-goto-node}.
819
820 Unlike @kbd{m}, @kbd{g} does not allow the use of abbreviations.
821 But it does allow completion, so you can type @key{TAB} to complete a
822 partial node name.
823
824 @cindex go to another Info file
825 To go to a node in another file, you can include the file name in the
826 node name by putting it at the front, in parentheses. Thus,
827 @kbd{g(dir)Top@key{RET}} would go to the Info Directory node, which is
828 the node @samp{Top} in the Info file @file{dir}. Likewise,
829 @kbd{g(emacs)Top@key{RET}} goes to the top node of the Emacs manual.
830
831 The node name @samp{*} specifies the whole file. So you can look at
832 all of the current file by typing @kbd{g*@key{RET}} or all of any
833 other file with @kbd{g(@var{filename})@key{RET}}.
834
835 @unnumberedsubsec @kbd{1} -- @kbd{9} choose a menu subtopic by its number
836
837 @kindex 1 @r{through} 9 @r{(Info mode)}
838 @findex Info-nth-menu-item
839 @cindex select @var{n}'th menu item
840 If you begrudge each character of type-in which your system requires,
841 you might like to use the commands @kbd{1}, @kbd{2}, @kbd{3}, @kbd{4},
842 @dots{}, @kbd{9}. They are short for the @kbd{m} command together
843 with a name of a menu subtopic. @kbd{1} goes through the first item
844 in the current node's menu; @kbd{2} goes through the second item, etc.
845 In the stand-alone reader, @kbd{0} goes through the last menu item;
846 this is so you need not count how many entries are there. In Emacs,
847 the digit keys run the command @code{Info-nth-menu-item}.
848
849 If your display supports multiple fonts, and you are using Emacs'
850 Info mode to read Info files, the @samp{*} for the fifth menu item
851 stands out, either in color or in some other attribute, such as
852 underline, and so is the @samp{*} for the ninth item; this makes it
853 easy to see at a glance which number to use for an item.
854
855 Some terminals don't support colors or underlining. If you need to
856 actually count items, it is better to use @kbd{m} instead, and specify
857 the name, or use @key{TAB} to quickly move between menu items.
858
859 @unnumberedsubsec @kbd{e} makes Info document editable
860
861 @kindex e @r{(Info mode)}
862 @findex Info-edit
863 @cindex edit Info document
864 The Info command @kbd{e} changes from Info mode to an ordinary
865 Emacs editing mode, so that you can edit the text of the current node.
866 Type @kbd{C-c C-c} to switch back to Info. The @kbd{e} command is allowed
867 only if the variable @code{Info-enable-edit} is non-@code{nil}.
868
869 The @kbd{e} command only works in Emacs, where it runs the command
870 @code{Info-edit}. The stand-alone Info reader doesn't allow you to
871 edit the Info file, so typing @kbd{e} there goes to the end of the
872 current node.
873
874 @node Info Search, Add, Expert, Advanced Info
875 @comment node-name, next, previous, up
876 @section How to search Info documents for specific subjects
877
878 @cindex searching Info documents
879 @cindex Info document as a reference
880 The commands which move between and inside nodes allow you to read
881 the entire manual or its large portions. But what if you need to find
882 some information in the manual as fast as you can, and you don't know
883 or don't remember in what node to look for it? This need arises when
884 you use a manual as a @dfn{reference}, or when it is impractical to
885 read the entire manual before you start using the programs it
886 describes.
887
888 Info has powerful searching facilities that let you find things
889 quickly. You can search either the manual indices or its text.
890
891 @kindex i @r{(Info mode)}
892 @findex Info-index
893 Since most subjects related to what the manual describes should be
894 indexed, you should try the index search first. The @kbd{i} command
895 prompts you for a subject and then looks up that subject in the
896 indices. If it finds an index entry with the subject you typed, it
897 goes to the node to which that index entry points. You should browse
898 through that node to see whether the issue you are looking for is
899 described there. If it isn't, type @kbd{,} one or more times to go
900 through additional index entries which match your subject.
901
902 The @kbd{i} command finds all index entries which include the string
903 you typed @emph{as a substring}. For each match, Info shows in the
904 echo area the full index entry it found. Often, the text of the full
905 index entry already gives you enough information to decide whether it
906 is relevant to what you are looking for, so we recommend that you read
907 what Emacs shows in the echo are before looking at the node it
908 displays.
909
910 Since @kbd{i} looks for a substring, you can search for subjects even
911 if you are not sure how they are spelled in the index. For example,
912 suppose you want to find something that is pertinent to commands which
913 complete partial input (e.g., when you type @key{TAB}). If you want
914 to catch index entries that refer to ``complete'', ``completion'', and
915 ``completing'', you could type @kbd{icomplet@key{RET}}.
916
917 Info documents which describe programs should index the commands,
918 options, and key sequences that the program provides. If you are
919 looking for a description of a command, an option, or a key, just type
920 their names when @kbd{i} prompts you for a topic. For example, if you
921 want to read the description of what the @kbd{C-f} key does, type
922 @kbd{iC-f@key{RET}}. Here @kbd{C-f} are 3 literal characters
923 @samp{C}, @samp{-}, and @samp{f}, not the ``Control-f'' command key
924 you type inside Emacs to run the command bound to @kbd{C-f}.
925
926 In Emacs, @kbd{i} runs the command @code{Info-index}.
927
928 @kindex s @r{(Info mode)}
929 @findex Info-search
930 The @kbd{s} command allows you to search a whole file for a string.
931 It switches to the next node if and when that is necessary. You
932 type @kbd{s} followed by the string to search for, terminated by
933 @key{RET}. To search for the same string again, just @kbd{s} followed
934 by @key{RET} will do. The file's nodes are scanned in the order
935 they are in in the file, which has no necessary relationship to the
936 order that they may be in the tree structure of menus and @samp{next}
937 pointers. But normally the two orders are not very different. In any
938 case, you can always do a @kbd{b} to find out what node you have
939 reached, if the header is not visible (this can happen, because @kbd{s}
940 puts your cursor at the occurrence of the string, not at the beginning
941 of the node).
942
943 @kindex M-s @r{(Info mode)}
944 In Emacs, @kbd{Meta-s} is equivalent to @kbd{s}. That is for
945 compatibility with other GNU packages that use @kbd{M-s} for a similar
946 kind of search command. Both @kbd{s} and @kbd{M-s} run in Emacs the
947 command @code{Info-search}.
948
949
950 @node Add, Menus, Info Search, Advanced Info
951 @comment node-name, next, previous, up
952 @section Adding a new node to Info
953
954 To add a new topic to the list in the Info directory, you must:
955
956 @enumerate
957 @item
958 Create some nodes, in some file, to document that topic.
959 @item
960 Put that topic in the menu in the directory. @xref{Menus, Menu}.
961 @end enumerate
962
963 Usually, the way to create the nodes is with Texinfo (@pxref{Top,,
964 Overview of Texinfo, texinfo, Texinfo: The GNU Documentation Format});
965 this has the advantage that you can also make a printed manual from
966 them. However, if you want to edit an Info file, here is how.
967
968 @cindex node delimiters
969 The new node can live in an existing documentation file, or in a new
970 one. It must have a @samp{^_} character before it (invisible to the
971 user; this node has one but you cannot see it), and it ends with either
972 a @samp{^_}, a @samp{^L} (``formfeed''), or the end of file.@footnote{If
973 you put in a @samp{^L} to end a new node, be sure that there is a
974 @samp{^_} after it to start the next one, since @samp{^L} cannot
975 @emph{start} a node. Also, a nicer way to make a node boundary be a
976 page boundary as well is to put a @samp{^L} @emph{right after} the
977 @samp{^_}.}
978
979 The @samp{^_} starting a node must be followed by a newline or a
980 @samp{^L} newline, after which comes the node's header line. The header
981 line must give the node's name (by which Info finds it), and state the
982 names of the @samp{Next}, @samp{Previous}, and @samp{Up} nodes (if there
983 are any). As you can see, this node's @samp{Up} node is the node
984 @samp{Top}, which points at all the documentation for Info. The
985 @samp{Next} node is @samp{Menus}.
986
987 @cindex node header line format
988 @cindex format of node headers
989 The keywords @dfn{Node}, @dfn{Next}, @dfn{Previous}, and @dfn{Up}
990 may appear in any order, anywhere in the header line, but the
991 recommended order is the one in this sentence. Each keyword must be
992 followed by a colon, spaces and tabs, and then the appropriate name.
993 The name may be terminated with a tab, a comma, or a newline. A space
994 does not end it; node names may contain spaces. The case of letters
995 in the names is insignificant.
996
997 @cindex node name format
998 @cindex Directory node
999 A node name has two forms. A node in the current file is named by
1000 what appears after the @samp{Node: } in that node's first line. For
1001 example, this node's name is @samp{Add}. A node in another file is
1002 named by @samp{(@var{filename})@var{node-within-file}}, as in
1003 @samp{(info)Add} for this node. If the file name starts with ``./'',
1004 then it is relative to the current directory; otherwise, it is
1005 relative starting from the standard directory for Info files of your
1006 site. The name @samp{(@var{filename})Top} can be abbreviated to just
1007 @samp{(@var{filename})}. By convention, the name @samp{Top} is used
1008 for the ``highest'' node in any single file---the node whose @samp{Up}
1009 points out of the file. The @samp{Directory} node is @file{(dir)}, it
1010 points to a file @file{dir} which holds a large menu listing all the
1011 Info documents installed on your site. The @samp{Top} node of a
1012 document file listed in the @samp{Directory} should have an @samp{Up:
1013 (dir)} in it.
1014
1015 @cindex unstructured documents
1016 The node name @kbd{*} is special: it refers to the entire file.
1017 Thus, @kbd{g*} shows you the whole current file. The use of the
1018 node @kbd{*} is to make it possible to make old-fashioned,
1019 unstructured files into nodes of the tree.
1020
1021 The @samp{Node:} name, in which a node states its own name, must not
1022 contain a file name, since when Info searches for a node, it does not
1023 expect a file name to be there. The @samp{Next}, @samp{Previous} and
1024 @samp{Up} names may contain them. In this node, since the @samp{Up}
1025 node is in the same file, it was not necessary to use one.
1026
1027 Note that the nodes in this file have a file name in the header
1028 line. The file names are ignored by Info, but they serve as comments
1029 to help identify the node for the user.
1030
1031 @node Menus, Cross-refs, Add, Advanced Info
1032 @comment node-name, next, previous, up
1033 @section How to Create Menus
1034
1035 Any node in the Info hierarchy may have a @dfn{menu}---a list of subnodes.
1036 The @kbd{m} command searches the current node's menu for the topic which it
1037 reads from the terminal.
1038
1039 @cindex menu and menu entry format
1040 A menu begins with a line starting with @samp{* Menu:}. The rest of the
1041 line is a comment. After the starting line, every line that begins
1042 with a @samp{* } lists a single topic. The name of the topic--what
1043 the user must type at the @kbd{m}'s command prompt to select this
1044 topic---comes right after the star and space, and is followed by a
1045 colon, spaces and tabs, and the name of the node which discusses that
1046 topic. The node name, like node names following @samp{Next}, @samp{Previous}
1047 and @samp{Up}, may be terminated with a tab, comma, or newline; it may also
1048 be terminated with a period.
1049
1050 If the node name and topic name are the same, then rather than
1051 giving the name twice, the abbreviation @samp{* @var{name}::} may be
1052 used (and should be used, whenever possible, as it reduces the visual
1053 clutter in the menu).
1054
1055 It is considerate to choose the topic names so that they differ
1056 from each other very near the beginning---this allows the user to type
1057 short abbreviations. In a long menu, it is a good idea to capitalize
1058 the beginning of each item name which is the minimum acceptable
1059 abbreviation for it (a long menu is more than 5 or so entries).
1060
1061 The nodes listed in a node's menu are called its ``subnodes'', and it
1062 is their ``superior''. They should each have an @samp{Up:} pointing at
1063 the superior. It is often useful to arrange all or most of the subnodes
1064 in a sequence of @samp{Next} and @samp{Previous} pointers so that
1065 someone who wants to see them all need not keep revisiting the Menu.
1066
1067 The Info Directory is simply the menu of the node @samp{(dir)Top}---that
1068 is, node @samp{Top} in file @file{.../info/dir}. You can put new entries
1069 in that menu just like any other menu. The Info Directory is @emph{not} the
1070 same as the file directory called @file{info}. It happens that many of
1071 Info's files live in that file directory, but they do not have to; and
1072 files in that directory are not automatically listed in the Info
1073 Directory node.
1074
1075 Also, although the Info node graph is claimed to be a ``hierarchy'',
1076 in fact it can be @emph{any} directed graph. Shared structures and
1077 pointer cycles are perfectly possible, and can be used if they are
1078 appropriate to the meaning to be expressed. There is no need for all
1079 the nodes in a file to form a connected structure. In fact, this file
1080 has two connected components. You are in one of them, which is under
1081 the node @samp{Top}; the other contains the node @samp{Help} which the
1082 @kbd{h} command goes to. In fact, since there is no garbage
1083 collector, nothing terrible happens if a substructure is not pointed
1084 to, but such a substructure is rather useless since nobody can
1085 ever find out that it exists.
1086
1087 @node Cross-refs, Tags, Menus, Advanced Info
1088 @comment node-name, next, previous, up
1089 @section Creating Cross References
1090
1091 @cindex cross reference format
1092 A cross reference can be placed anywhere in the text, unlike a menu
1093 item which must go at the front of a line. A cross reference looks
1094 like a menu item except that it has @samp{*note} instead of @samp{*}.
1095 It @emph{cannot} be terminated by a @samp{)}, because @samp{)}'s are
1096 so often part of node names. If you wish to enclose a cross reference
1097 in parentheses, terminate it with a period first. Here are two
1098 examples of cross references pointers:
1099
1100 @example
1101 *Note details: commands. (See *note 3: Full Proof.)
1102 @end example
1103
1104 @noindent
1105 @emph{These are just examples.} The places they ``lead to'' do not
1106 really exist!
1107
1108 @menu
1109 * Help-Cross:: Target of a cross-reference.
1110 @end menu
1111
1112
1113 @node Help-Cross, , , Cross-refs
1114 @subsection The node reached by the cross reference in Info
1115
1116 This is the node reached by the cross reference named @samp{Cross}.
1117
1118 While this node is specifically intended to be reached by a cross
1119 reference, most cross references lead to nodes that ``belong''
1120 someplace else far away in the structure of an Info document. So you
1121 cannot expect this node to have a @samp{Next}, @samp{Previous} or
1122 @samp{Up} links pointing back to where you came from. In general, the
1123 @kbd{l} (el) command is the only way to get back there.
1124
1125 @format
1126 >> Type @kbd{l} to return to the node where the cross reference was.
1127 @end format
1128
1129 @node Help-Q, , Help-Int, Getting Started
1130 @comment node-name, next, previous, up
1131 @section Quitting Info
1132
1133 @kindex q @r{(Info mode)}
1134 @findex Info-exit
1135 @cindex quitting Info mode
1136 To get out of Info, back to what you were doing before, type @kbd{q}
1137 for @dfn{Quit}. This runs @code{Info-exit} in Emacs.
1138
1139 This is the end of the basic course on using Info. You have learned
1140 how to move in an Info document, and how to follow menus and cross
1141 references. This makes you ready for reading manuals top to bottom,
1142 as new users should do when they learn a new package.
1143
1144 Another set of Info commands is useful when you need to find
1145 something quickly in a manual---that is, when you need to use a manual
1146 as a reference rather than as a tutorial. We urge you to make learn
1147 these search commands as well. If you want to do that now, follow this
1148 cross reference to @ref{Info Search}.
1149
1150 Yet another set of commands are meant for experienced users; you can
1151 find them by looking in the Directory node for documentation on Info.
1152 Finding them will be a good exercise in using Info in the usual
1153 manner.
1154
1155 @format
1156 >> Type @kbd{d} to go to the Info directory node; then type
1157 @kbd{mInfo} and Return, to get to the node about Info and
1158 see what other help is available.
1159 @end format
1160
1161
1162 @node Tags, Checking, Cross-refs, Advanced Info
1163 @comment node-name, next, previous, up
1164 @section Tags Tables for Info Files
1165
1166 @cindex tags tables in info files
1167 You can speed up the access to nodes of a large Info file by giving
1168 it a tags table. Unlike the tags table for a program, the tags table for
1169 an Info file lives inside the file itself and is used
1170 automatically whenever Info reads in the file.
1171
1172 @findex Info-tagify
1173 To make a tags table, go to a node in the file using Emacs Info mode and type
1174 @kbd{M-x Info-tagify}. Then you must use @kbd{C-x C-s} to save the
1175 file. Info files produced by the @code{makeinfo} command that is part
1176 of the Texinfo package always have tags tables to begin with.
1177
1178 @cindex stale tags tables
1179 @cindex update Info tags table
1180 Once the Info file has a tags table, you must make certain it is up
1181 to date. If you edit an Info file directly (as opposed to editing its
1182 Texinfo source), and, as a result of deletion of text, any node moves back
1183 more than a thousand characters in the file from the position
1184 recorded in the tags table, Info will no longer be able to find that
1185 node. To update the tags table, use the @code{Info-tagify} command
1186 again.
1187
1188 An Info file tags table appears at the end of the file and looks like
1189 this:
1190
1191 @example
1192 ^_^L
1193 Tag Table:
1194 File: info, Node: Cross-refs^?21419
1195 File: info, Node: Tags^?22145
1196 ^_
1197 End Tag Table
1198 @end example
1199
1200 @noindent
1201 Note that it contains one line per node, and this line contains
1202 the beginning of the node's header (ending just after the node name),
1203 a @samp{DEL} character, and the character position in the file of the
1204 beginning of the node.
1205
1206
1207 @node Checking, Emacs Info Variables, Tags, Advanced Info
1208 @section Checking an Info File
1209
1210 When creating an Info file, it is easy to forget the name of a node when
1211 you are making a pointer to it from another node. If you put in the
1212 wrong name for a node, this is not detected until someone tries to go
1213 through the pointer using Info. Verification of the Info file is an
1214 automatic process which checks all pointers to nodes and reports any
1215 pointers which are invalid. Every @samp{Next}, @samp{Previous}, and
1216 @samp{Up} is checked, as is every menu item and every cross reference. In
1217 addition, any @samp{Next} which does not have a @samp{Previous} pointing
1218 back is reported. Only pointers within the file are checked, because
1219 checking pointers to other files would be terribly slow. But those are
1220 usually few.
1221
1222 @findex Info-validate
1223 To check an Info file, do @kbd{M-x Info-validate} while looking at any
1224 node of the file with Emacs Info mode.
1225
1226 @node Emacs Info Variables, , Checking, Advanced Info
1227 @section Emacs Info-mode Variables
1228
1229 The following variables may modify the behavior of Info-mode in Emacs;
1230 you may wish to set one or several of these variables interactively, or
1231 in your @file{~/.emacs} init file. @xref{Examining, Examining and Setting
1232 Variables, Examining and Setting Variables, emacs, The GNU Emacs
1233 Manual}. The stand-alone Info reader program has its own set of
1234 variables, described in @ref{Variables,, Manipulating Variables,
1235 info-stnd, GNU Info}.
1236
1237 @vtable @code
1238 @item Info-directory-list
1239 The list of directories to search for Info files. Each element is a
1240 string (directory name) or @code{nil} (try default directory). If not
1241 initialized Info uses the environment variable @env{INFOPATH} to
1242 initialize it, or @code{Info-default-directory-list} if there is no
1243 @env{INFOPATH} variable in the environment.
1244
1245 @item Info-additional-directory-list
1246 A list of additional directories to search for Info documentation files.
1247 These directories are not searched for merging the @file{dir} file.
1248
1249 @item Info-fontify
1250 When set to a non-@code{nil} value, enables highlighting of Info
1251 files. The default is @code{t}. You can change how the highlighting
1252 looks by customizing the faces @code{info-node}, @code{info-menu-5},
1253 @code{info-xref}, @code{info-header-xref}, @code{info-header-node},
1254 @code{info-title-@var{n}-face} (where @var{n} is the level of the
1255 section, a number between 1 and 4), and @code{info-menu-header}. To
1256 customize a face, type @kbd{M-x customize-face @key{RET} @var{face}
1257 @key{RET}}, where @var{face} is one of the face names listed here.
1258
1259 @item Info-use-header-line
1260 If non-@code{nil}, Emacs puts in the Info buffer a header line showing
1261 the @samp{Next}, @samp{Prev}, and @samp{Up} links. A header line does
1262 not scroll with the rest of the buffer, making these links always
1263 visible.
1264
1265 @item Info-scroll-prefer-subnodes
1266 If set to a non-@code{nil} value, @key{SPC} and @key{BACKSPACE} (or
1267 @key{DEL}) keys in a menu visit subnodes of the current node before
1268 scrolling to its end or beginning, respectively. For example, if the
1269 node's menu appears on the screen, the next @key{SPC} moves to a
1270 subnode indicated by the following menu item. Setting this option to
1271 @code{nil} results in behavior similar to the stand-alone Info reader
1272 program, which visits the first subnode from the menu only when you
1273 hit the end of the current node. The default is @code{t}.
1274
1275 @item Info-enable-active-nodes
1276 When set to a non-@code{nil} value, allows Info to execute Lisp code
1277 associated with nodes. The Lisp code is executed when the node is
1278 selected. The Lisp code to be executed should follow the node
1279 delimiter (the @samp{DEL} character) and an @samp{execute: } tag, like
1280 this:
1281
1282 @example
1283 ^_execute: (message "This is an active node!")
1284 @end example
1285
1286 @item Info-enable-edit
1287 Set to @code{nil}, disables the @samp{e} (@code{Info-edit}) command. A
1288 non-@code{nil} value enables it. @xref{Add, Edit}.
1289 @end vtable
1290
1291
1292 @node Creating an Info File
1293 @chapter Creating an Info File from a Texinfo File
1294
1295 @code{makeinfo} is a utility that converts a Texinfo file into an Info
1296 file; @code{texinfo-format-region} and @code{texinfo-format-buffer} are
1297 GNU Emacs functions that do the same.
1298
1299 @xref{Top,, Overview of Texinfo, texinfo, Texinfo: The GNU
1300 Documentation Format}, to learn how to write a Texinfo file.
1301
1302 @xref{Creating an Info File,,, texinfo, Texinfo: The GNU Documentation
1303 Format}, to learn how to create an Info file from a Texinfo file.
1304
1305 @xref{Installing an Info File,,, texinfo, Texinfo: The GNU
1306 Documentation Format}, to learn how to install an Info file after you
1307 have created one.
1308
1309 @node Index
1310 @unnumbered Index
1311
1312 This is an alphabetical listing of all the commands, variables, and
1313 topics discussed in this document.
1314
1315 @printindex cp
1316
1317 @bye