1 \input texinfo.tex @c -*-texinfo-*-
2 @c We must \input texinfo.tex instead of texinfo, otherwise make
3 @c distcheck in the Texinfo distribution fails, because the texinfo Info
4 @c file is made first, and texi2dvi must include . first in the path.
5 @comment %**start of header
11 @documentencoding UTF-8
12 @comment %**end of header
15 This file describes how to use Info, the on-line, menu-driven GNU
18 Copyright @copyright{} 1989, 1992, 1996--2014 Free Software Foundation, Inc.
21 Permission is granted to copy, distribute and/or modify this document
22 under the terms of the GNU Free Documentation License, Version 1.3 or
23 any later version published by the Free Software Foundation; with no
24 Invariant Sections, with the Front-Cover texts being ``A GNU Manual,''
25 and with the Back-Cover Texts as in (a) below. A copy of the license
26 is included in the section entitled ``GNU Free Documentation License''.
28 (a) The FSF's Back-Cover Text is: ``You have the freedom to copy and
29 modify this GNU manual.''
33 @dircategory Texinfo documentation system
35 * Info: (info). How to use the documentation browsing system.
40 @subtitle The online, hyper-text GNU documentation system
42 @author and the GNU Texinfo community
44 @vskip 0pt plus 1filll
52 @top Info: An Introduction
54 The GNU Project distributes most of its on-line manuals in the
55 @dfn{Info format}, which you read using an @dfn{Info reader}. You are
56 probably using an Info reader to read this now.
58 There are two primary Info readers: @code{info}, a stand-alone program
59 designed just to read Info files (@pxref{Top,,What is Info?,
60 info-stnd, GNU Info}), and the @code{info} package in GNU Emacs, a
61 general-purpose editor. At present, only the Emacs reader supports
65 If you are new to the Info reader and want to learn how to use it,
66 type the command @kbd{h} now. It brings you to a programmed
69 To read about advanced Info commands, type @kbd{n} twice. This
70 brings you to @cite{Advanced Info Commands}, skipping over the `Getting
78 * Getting Started:: Getting started using an Info reader.
79 * Advanced:: Advanced Info commands.
80 * Expert Info:: Info commands for experts.
81 * GNU Free Documentation License:: The license for this documentation.
82 * Index:: An index of topics, commands, and variables.
85 @node Getting Started, Advanced, Top, Top
86 @comment node-name, next, previous, up
87 @chapter Getting Started
89 This first part of this Info manual describes how to get around inside
90 of Info. The second part of the manual describes various advanced
91 Info commands. The third part briefly explains how to generate Info
92 files from Texinfo files, and describes how to write an Info file
96 This manual is primarily designed for browsing with an Info reader
97 program on a computer, so that you can try Info commands while reading
98 about them. Reading it on paper or with an HTML browser is less
99 effective, since you must take it on faith that the commands described
100 really do what the manual says. By all means go through this manual
101 now that you have it; but please try going through the on-line version
104 @cindex Info reader, how to invoke
105 @cindex entering Info
106 There are two ways of looking at the online version of this manual:
110 Type @code{info} at your shell's command line. This approach uses a
111 stand-alone program designed just to read Info files.
114 Type @code{emacs} at the command line; then type @kbd{C-h i}
115 (@kbd{Control-h}, followed by @kbd{i}). This approach uses the Info
116 mode of the Emacs editor.
119 In either case, then type @kbd{mInfo} (just the letters), followed by
120 @key{RET}---the ``Return'' or ``Enter'' key. At this point, you should
121 be ready to follow the instructions in this manual as you read them on
123 @c FIXME! (pesch@cygnus.com, 14 dec 1992)
124 @c Is it worth worrying about what-if the beginner goes to somebody
125 @c else's Emacs session, which already has an Info running in the middle
126 @c of something---in which case these simple instructions won't work?
130 * Help-Small-Screen:: Starting Info on a Small Screen.
131 * Help:: How to use Info.
132 * Help-P:: Returning to the Previous node.
133 * Help-^L:: The Space, DEL, B and ^L commands.
134 * Help-Inv:: Invisible text in Emacs Info.
136 * Help-Xref:: Following cross-references.
137 * Help-Int:: Some intermediate Info commands.
138 * Help-Q:: Quitting Info.
141 @node Help-Small-Screen
142 @section Starting Info on a Small Screen
145 (In Info, you only see this section if your terminal has a small
146 number of lines; most readers pass by it without seeing it.)
149 @cindex small screen, moving around
150 Since your terminal has a relatively small number of lines on its
151 screen, it is necessary to give you special advice at the beginning.
153 If the entire text you are looking at fits on the screen, the text
154 @samp{All} will be displayed at the bottom of the screen. In the
155 stand-alone Info reader, it is displayed at the bottom right corner of
156 the screen; in Emacs, it is displayed on the modeline. If you see the
157 text @samp{Top} instead, it means that there is more text below that
158 does not fit. To move forward through the text and see another screen
159 full, press @key{SPC}, the Space bar. To move back up, press the key
160 labeled @samp{Backspace} or @samp{DEL} (on some keyboards, this key
161 might be labeled @samp{Delete}), or @key{S-SPC}.
164 Here are 40 lines of junk, so you can try @key{SPC} and @key{DEL} (or
165 @key{S-SPC}) and see what they do. At the end are instructions of
166 what you should do next.
211 If you have managed to get here, go back to the beginning with
212 @kbd{DEL} (or @key{S-SPC}), and come back here again, then you
213 understand the about the @samp{Space} and @samp{Backspace} keys. So
214 now type an @kbd{n}---just one character; don't type the quotes and
215 don't type the Return key afterward---to get to the normal start of
219 @node Help, Help-P, Help-Small-Screen, Getting Started
220 @comment node-name, next, previous, up
221 @section How to use Info
223 You are talking to the program Info, for reading documentation.
225 There are two ways to use Info: from within Emacs or as a
226 stand-alone reader that you can invoke from a shell using the command
229 @cindex node, in Info documents
230 Right now you are looking at one @dfn{Node} of Information.
231 A node contains text describing a specific topic at a specific
232 level of detail. This node's topic is ``how to use Info''. The mode
233 line says that this is node @samp{Help} in the file @file{info}.
235 @cindex header of Info node
236 The top line of a node is its @dfn{header}. This node's header
237 (look at it now) says that the @samp{Next} node after this one is the
238 node called @samp{Help-P}. An advanced Info command lets you go to
239 any node whose name you know. In the stand-alone Info reader program,
240 the header line shows the names of this node and the Info file as
241 well. In Emacs, the header line is displayed with a special typeface,
242 and remains at the top of the window all the time even if you scroll
245 Besides a @samp{Next}, a node can have a @samp{Previous} link, or an
246 @samp{Up} link, or both. As you can see, this node has all of these
249 @kindex n @r{(Info mode)}
250 Now it is time to move on to the @samp{Next} node, named @samp{Help-P}.
253 >> Type @kbd{n} to move there. Type just one character;
254 do not type the quotes and do not type a @key{RET} afterward.
258 @samp{>>} in the margin means it is really time to try a command.
261 >> If you are in Emacs and have a mouse, and if you already practiced
262 typing @kbd{n} to get to the next node, click now with the left
263 mouse button on the @samp{Next} link to do the same ``the mouse way''.
266 @node Help-P, Help-^L, Help, Getting Started
267 @comment node-name, next, previous, up
268 @section Returning to the Previous node
270 @kindex p @r{(Info mode)}
271 This node is called @samp{Help-P}. The @samp{Previous} node, as you see,
272 is @samp{Help}, which is the one you just came from using the @kbd{n}
273 command. Another @kbd{n} command now would take you to the next
274 node, @samp{Help-^L}.
277 >> But do not type @kbd{n} yet. First, try the @kbd{p} command, or
278 (in Emacs) click on the @samp{Prev} link. That takes you to
279 the @samp{Previous} node. Then use @kbd{n} to return here.
282 If you read this in Emacs, you will see an @samp{Info} item in the
283 menu bar, close to its right edge. Clicking the mouse on the
284 @samp{Info} menu-bar item opens a menu of commands which include
285 @samp{Next} and @samp{Previous} (and also some others which you didn't yet
288 This all probably seems insultingly simple so far, but @emph{please
289 don't} start skimming. Things will get complicated soon enough!
290 Also, please do not try a new command until you are told it is time
291 to. You could make Info skip past an important warning that was
295 >> Now do an @kbd{n}, or (in Emacs) click the middle mouse button on
296 the @samp{Next} link, to get to the node @samp{Help-^L} and learn more.
299 @node Help-^L, Help-Inv, Help-P, Getting Started
300 @comment node-name, next, previous, up
301 @section The Space, DEL, B and ^L commands
303 This node's mode line tells you that you are now at node
304 @samp{Help-^L}, and the header line tells you that @kbd{p} would get
305 you back to @samp{Help-P}. The node's title is highlighted and may be
306 underlined as well; it says what the node is about.
308 This is a big node and it does not all fit on your display screen.
309 You can tell that there is more that is not visible because you
310 can see the text @samp{Top} rather than @samp{All} near the bottom of
313 @kindex SPC @r{(Info mode)}
314 @kindex DEL @r{(Info mode)}
315 @kindex BACKSPACE @r{(Info mode)}
316 @findex Info-scroll-up
317 @findex Info-scroll-down
318 The @key{SPC}, @key{BACKSPACE} (or @key{DEL})@footnote{The key which
319 we call ``Backspace or DEL'' in this manual is labeled differently on
320 different keyboards. Look for a key which is a little ways above the
321 @key{ENTER} or @key{RET} key and which you normally use outside Emacs
322 to erase the character before the cursor, i.e., the character you
323 typed last. It might be labeled @samp{Backspace} or @samp{<-} or
324 @samp{DEL}, or sometimes @samp{Delete}.} and @kbd{b} commands exist to
325 allow you to ``move around'' in a node that does not all fit on the
326 screen at once. @key{SPC} moves forward, to show what was below the
327 bottom of the screen. @key{DEL} or @key{BACKSPACE} moves backward, to
328 show what was above the top of the screen (there is not anything above
329 the top until you have typed some spaces).
332 >> Now try typing a @key{SPC} (afterward, type a @key{BACKSPACE} to
336 When you type the @key{SPC}, the two lines that were at the bottom of
337 the screen appear at the top, followed by more lines. @key{DEL} or
338 @key{BACKSPACE} takes the two lines from the top and moves them to the
339 bottom, @emph{usually}, but if there are not a full screen's worth of
340 lines above them they may not make it all the way to the bottom.
342 If you are reading this in Emacs, note that the header line is
343 always visible, never scrolling off the display. That way, you can
344 always see the @samp{Next}, @samp{Prev}, and @samp{Up} links, and you
345 can conveniently go to one of these links at any time by
346 clicking the middle mouse button on the link.
348 @cindex reading Info documents top to bottom
349 @cindex Info documents as tutorials
350 @key{SPC} and @key{DEL} not only move forward and backward through
351 the current node. They also move between nodes. @key{SPC} at the end
352 of a node moves to the next node; @key{DEL} (or @key{BACKSPACE}) at
353 the beginning of a node moves to the previous node. In effect, these
354 commands scroll through all the nodes in an Info file as a single
355 logical sequence. You can read an entire manual top to bottom by just
356 typing @key{SPC}, and move backward through the entire manual from
357 bottom to top by typing @key{DEL} (or @key{BACKSPACE}).
359 In this sequence, a node's subnodes appear following their parent.
360 If a node has a menu, @key{SPC} takes you into the subnodes listed in
361 the menu, one by one. Once you reach the end of a node, and have seen
362 all of its subnodes, @key{SPC} takes you to the next node or to the
365 @kindex PAGEUP @r{(Info mode)}
366 @kindex PAGEDOWN @r{(Info mode)}
367 Many keyboards nowadays have two scroll keys labeled @samp{PageUp}
368 and @samp{PageDown} (or maybe @samp{Prior} and @samp{Next}). If your
369 keyboard has these keys, you can use them to move forward and backward
370 through the text of one node, like @key{SPC} and @key{BACKSPACE} (or
371 @key{DEL}). However, @key{PAGEUP} and @key{PAGEDOWN} keys never
372 scroll beyond the beginning or the end of the current node.
374 @kindex C-l @r{(Info mode)}
375 If your screen is ever garbaged, you can tell Info to display it
376 again by typing @kbd{C-l} (@kbd{Control-L}---that is, hold down
377 @key{CTRL} and type @kbd{L} or @kbd{l}).
380 >> Type @kbd{C-l} now.
383 @kindex b @r{(Info mode)}
384 To move back to the beginning of the node you are on, you can type
385 the @key{BACKSPACE} key (or @key{DEL}) many times. You can also type
386 @kbd{b} just once. @kbd{b} stands for ``beginning.''
389 >> Try that now. (We have put in enough verbiage to push this past
390 the first screenful, but screens are so big nowadays that perhaps it
391 isn't enough. You may need to shrink your Emacs or Info window.)
392 Then come back, by typing @key{SPC} one or more times.
395 @kindex ? @r{(Info mode)}
397 You have just learned a considerable number of commands. If you
398 want to use one but have trouble remembering which, you should type
399 @kbd{?}, which displays a brief list of commands. When you are
400 finished looking at the list, make it go away by typing @key{SPC}
404 >> Type a @key{?} now. Press @key{SPC} to see consecutive screenfuls of
405 the list until finished. Then type @key{SPC} several times. If
406 you are using Emacs, the help will then go away automatically.
409 (If you are using the stand-alone Info reader, type @kbd{C-x 0} to
410 return here, that is---press and hold @key{CTRL}, type an @kbd{x},
411 then release @key{CTRL} and @kbd{x}, and press @kbd{0}; that's a zero,
412 not the letter ``o''.)
414 From now on, you will encounter large nodes without warning, and
415 will be expected to know how to use @key{SPC} and @key{BACKSPACE} to
416 move around in them without being told. Since not all terminals have
417 the same size screen, it would be impossible to warn you anyway.
420 >> Now type @kbd{n}, or click the middle mouse button on the @samp{Next} link,
421 to visit the next node.
424 @node Help-Inv, Help-M, Help-^L, Getting Started
425 @comment node-name, next, previous, up
426 @section Invisible text in Emacs Info
428 Before discussing menus, we need to make some remarks that are only
429 relevant to users reading Info using Emacs. Users of the stand-alone
430 version can skip this node by typing @kbd{]} now.
432 @cindex invisible text in Emacs
433 In Emacs, certain text that appears in the stand-alone version is
434 normally hidden, technically because it has the @samp{invisibility}
435 property. Invisible text is really a part of the text. It becomes
436 visible (by default) after killing and yanking, it appears in printed
437 output, it gets saved to file just like any other text, and so on.
438 Thus it is useful to know it is there.
441 You can make invisible text visible by using the command @kbd{M-x
442 visible-mode}. Visible mode is a minor mode, so using the command a
443 second time will make the text invisible again. Watch the effects of
444 the command on the ``menu'' below and the top line of this node.
446 If you prefer to @emph{always} see the invisible text, you can set
447 @code{Info-hide-note-references} to @code{nil}. Enabling Visible mode
448 permanently is not a real alternative, because Emacs Info also uses
449 (although less extensively) another text property that can change the
450 text being displayed, the @samp{display} property. Only the
451 invisibility property is affected by Visible mode. When, in this
452 tutorial, we refer to the @samp{Emacs} behavior, we mean the
453 @emph{default} Emacs behavior.
455 Now type @kbd{]}, to learn about the @kbd{]} and @kbd{[} commands.
458 * ]: Help-]. Node telling about ].
459 * stuff: Help-]. Same node.
460 * Help-]:: Yet again, same node.
463 @node Help-], , , Help-Inv
464 @subsection The @kbd{]} and @kbd{[} commands
466 If you type @kbd{n} now, you get an error message saying that this
467 node has no next node. Similarly, if you type @kbd{p}, the error
468 message tells you that there is no previous node. (The exact message
469 depends on the Info reader you use.) This is because @kbd{n} and
470 @kbd{p} carry you to the next and previous node @emph{at the same
471 level}. The present node is contained in a menu (see next) of the
472 node you came from, and hence is considered to be at a lower level.
473 It is the only node in the previous node's menu (even though it was
474 listed three times). Hence it has no next or previous node that
475 @kbd{n} or @kbd{p} could move to.
477 If you systematically move through a manual by typing @kbd{n}, you run
478 the risk of skipping many nodes. You do not run this risk if you
479 systematically use @kbd{@key{SPC}}, because, when you scroll to the
480 bottom of a node and type another @kbd{@key{SPC}}, then this carries
481 you to the following node in the manual @emph{regardless of level}.
482 If you immediately want to go to that node, without having to scroll
483 to the bottom of the screen first, you can type @kbd{]}.
485 Similarly, @kbd{@key{BACKSPACE}} (or @kbd{@key{S-SPC}}) carries you to
486 the preceding node regardless of level, after you scrolled to the
487 beginning of the present node. If you want to go to the preceding
488 node immediately, you can type @kbd{[}.
490 For instance, typing this sequence will come back here in three steps:
491 @kbd{[ n [}. To do the same backward, type @kbd{] p ]}.
493 Now type @kbd{]} to go to the next node and learn about menus.
495 @node Help-M, Help-Xref, Help-Inv, Getting Started
496 @comment node-name, next, previous, up
497 @section Menus and the @kbd{m} command
499 @cindex menus in an Info document
501 With only the @kbd{n} (next), @kbd{p} (previous), @kbd{@key{SPC}},
502 @kbd{@key{BACKSPACE}}, @kbd{]} and @kbd{[} commands for moving between
503 nodes, nodes are restricted to a linear sequence. Menus allow a
504 branching structure. A menu is a list of other nodes you can move to.
505 It is actually just part of the text of the node formatted specially
506 so that Info can interpret it. The beginning of a menu is always
507 identified by a line which starts with @w{@samp{* Menu:}}. A node
508 contains a menu if and only if it has a line in it which starts that
509 way. The only menu you can use at any moment is the one in the node
510 you are in. To use a menu in any other node, you must move to that
513 After the start of the menu, each line that starts with a @samp{*}
514 identifies one subtopic. The line usually contains a brief name for
515 the subtopic (followed by a @samp{:}, normally hidden in Emacs), the
516 name of the node that talks about that subtopic (again, normally
517 hidden in Emacs), and optionally some further description of the
518 subtopic. Lines in the menu that do not start with a @samp{*} have no
519 special meaning---they are only for the human reader's benefit and do
520 not define additional subtopics. Here is an example:
523 * Foo: Node about FOO. This tells about FOO.
526 The subtopic name is Foo, and the node describing it is @samp{Node
527 about FOO}. The rest of the line is just for the reader's
528 Information. [[ But this line is not a real menu item, simply because
529 there is no line above it which starts with @w{@samp{* Menu:}}. Also,
530 in a real menu item, the @samp{*} would appear at the very start of
531 the line. This is why the ``normally hidden'' text in Emacs, namely
532 @samp{: Node about FOO.}, is actually visible in this example, even
533 when Visible mode is off.]]
535 When you use a menu to go to another node (in a way that will be
536 described soon), what you specify is the subtopic name, the first
537 thing in the menu line. Info uses it to find the menu line, extracts
538 the node name from it, and goes to that node. The reason that there
539 is both a subtopic name and a node name is that the node name must be
540 meaningful to the computer and may therefore have to be ugly looking.
541 The subtopic name can be chosen just to be convenient for the user to
542 specify. Often the node name is convenient for the user to specify
543 and so both it and the subtopic name are the same. There is an
544 abbreviation for this:
547 * Foo:: This tells about FOO.
551 This means that the subtopic name and node name are the same; they are
552 both @samp{Foo}. (The @samp{::} is normally hidden in Emacs.)
555 >> Now use @key{SPC} to find the menu in this node, then come back to
556 the front with a @kbd{b} and some @key{SPC}s. As you see, a menu is
557 actually visible in its node. If you cannot find a menu in a node
558 by looking at it, then the node does not have a menu and the
559 @kbd{m} command is not available.
562 If you keep typing @key{SPC} once the menu appears on the screen, it
563 will move to another node (the first one in the menu). If that
564 happens, type @key{BACKSPACE} to come back.
566 @kindex m @r{(Info mode)}
567 The command to go to one of the subnodes is @kbd{m}. This is very
568 different from the commands you have used: it is a command that
569 prompts you for more input.
571 The Info commands you know do not need additional input; when you
572 type one of them, Info processes it instantly and then is ready for
573 another command. The @kbd{m} command is different: it needs to know
574 the @dfn{name of the subtopic}. Once you have typed @kbd{m}, Info
575 tries to read the subtopic name.
577 Now, in the stand-alone Info, look for the line containing many
578 dashes near the bottom of the screen. (This is the stand-alone
579 equivalent for the mode line in Emacs.) There is one more line
580 beneath that one, but usually it is blank. (In Emacs, this is the
581 echo area.) When it is blank, Info is ready for a command, such as
582 @kbd{n} or @kbd{b} or @key{SPC} or @kbd{m}. If that line contains
583 text ending in a colon, it means Info is reading more input for the
584 last command. You can't type an Info command then, because Info is
585 trying to read input, not commands. You must either give the input
586 and finish the command you started, or type @kbd{Control-g} to cancel
587 the command. When you have done one of those things, the input entry
588 line becomes blank again. Then you can type Info commands again.
591 The command to go to a subnode via a menu is @kbd{m}. After you type
592 the @kbd{m}, the line at the bottom of the screen says @samp{Menu item: }.
593 You must then type the name of the subtopic you want, and end it with
596 @cindex abbreviating Info subnodes
597 You can abbreviate the subtopic name. If the abbreviation is not
598 unique, the first matching subtopic is chosen. Some menus put
599 the shortest possible abbreviation for each subtopic name in capital
600 letters, so you can see how much you need to type. It does not
601 matter whether you use upper case or lower case when you type the
602 subtopic. You should not put any spaces at the end, or inside of the
603 item name, except for one space where a space appears in the item in
606 @cindex completion of Info node names
607 You can also use the @dfn{completion} feature to help enter the
608 subtopic name. If you type the @key{TAB} key after entering part of a
609 name, it will fill in more of the name---as much as Info can deduce
610 from the part you have entered.
612 If you move the cursor to one of the menu subtopic lines, then you do
613 not need to type the argument: you just type a @key{RET}, and it
614 stands for the subtopic of the line you are on. You can also click
615 the middle mouse button directly on the subtopic line to go there.
617 Here is a menu to give you a chance to practice. This menu gives you
618 three ways of going to one place, Help-FOO:
621 * Foo: Help-FOO. A node you can visit for fun.
622 * Bar: Help-FOO. We have made two ways to get to the same place.
623 * Help-FOO:: And yet another!
626 (Turn Visible mode on if you are using Emacs.)
629 >> Now type just an @kbd{m} and see what happens:
632 Now you are ``inside'' an @kbd{m} command. Commands cannot be used
633 now; the next thing you will type must be the name of a subtopic.
635 You can change your mind about doing the @kbd{m} by typing
639 >> Try that now; notice the bottom line clear.
643 >> Then type another @kbd{m}.
647 >> Now type @kbd{BAR}, the item name. Do not type @key{RET} yet.
650 While you are typing the item name, you can use the @key{DEL} (or
651 @key{BACKSPACE}) key to cancel one character at a time if you make a
655 >> Press @key{DEL} to cancel the @samp{R}. You could type another @kbd{R}
656 to replace it. But you do not have to, since @samp{BA} is a valid
661 >> Now you are ready to go. Type a @key{RET}.
664 After visiting @samp{Help-FOO}, you should return here.
666 Another way to move to the menu subtopic lines and between them is
667 to type @key{TAB}. Each time you type a @key{TAB}, you move to the
668 next subtopic line. To move to a previous subtopic line in the
669 stand-alone reader, type @kbd{M-@key{TAB}}---that is, press and hold
670 the @key{META} key and then press @key{TAB}. (On some keyboards, the
671 @key{META} key might be labeled @samp{Alt}.) In Emacs Info, type
672 @kbd{S-@key{TAB}} to move to a previous subtopic line (press and hold
673 the @key{Shift} key and then press @key{TAB}).
675 Once you move cursor to a subtopic line, press @key{RET} to go to
676 that subtopic's node.
678 @cindex mouse support in Info mode
679 @kindex Mouse-2 @r{(Info mode)}
680 If your terminal supports a mouse, you have yet another way of going
681 to a subtopic. Move your mouse pointer to the subtopic line,
682 somewhere between the beginning @samp{*} and the colon @samp{:} which
683 ends the subtopic's brief name. You will see the subtopic's name
684 change its appearance (usually, its background color will change), and
685 the shape of the mouse pointer will change if your platform supports
686 that. After a while, if you leave the mouse on that spot, a small
687 window will pop up, saying ``Mouse-2: go to that node,'' or the same
688 message may appear at the bottom of the screen.
690 @kbd{Mouse-2} is the second button of your mouse counting from the
691 left---the middle button on a 3-button mouse. (On a 2-button mouse,
692 you may have to press both buttons together to ``press the middle
693 button''.) The message tells you pressing @kbd{Mouse-2} with the
694 current position of the mouse pointer (on subtopic in the menu) will
697 @findex Info-mouse-follow-nearest-node
698 More generally, @kbd{Mouse-2} in an Info buffer finds the nearest
699 link to another node and goes there. For example, near a cross
700 reference it acts like @kbd{f}, in a menu it acts like @kbd{m}, on the
701 node's header line it acts like @kbd{n}, @kbd{p}, or @kbd{u}, etc. At
702 end of the node's text @kbd{Mouse-2} moves to the next node, or up if
703 there's no next node.
706 >> Type @kbd{n} to see more commands.
709 @node Help-FOO, , , Help-M
710 @subsection The @kbd{u} command
712 Congratulations! This is the node @samp{Help-FOO}. It has an @samp{Up}
713 pointer @samp{Help-M}, the node you just came from via the @kbd{m}
714 command. This is the usual convention---the nodes you reach from a menu
715 have @samp{Up} nodes that lead back to the menu. Menus move Down in the
716 tree, and @samp{Up} moves Up. @samp{Previous}, on the other hand, is
717 usually used to ``stay on the same level but go backwards''.
719 @kindex u @r{(Info mode)}
721 You can go back to the node @samp{Help-M} by typing the command
722 @kbd{u} for ``Up''. This puts you at the menu subtopic line pointing
723 to the subnode that the @kbd{u} command brought you from. (Some Info
724 readers may put you at the @emph{front} of the node instead---to get
725 back to where you were reading, you have to type some @key{SPC}s.)
727 Another way to go Up is to click @kbd{Mouse-2} on the @samp{Up}
728 pointer shown in the header line (provided that you have a mouse).
731 >> Now type @kbd{u} to move back up to @samp{Help-M}.
734 @node Help-Xref, Help-Int, Help-M, Getting Started
735 @comment node-name, next, previous, up
736 @section Following Cross-References
738 @cindex cross references in Info documents
739 In Info documentation, you will see many @dfn{cross references}.
740 Cross references look like this: @xref{Help-Cross, Cross}. That text
741 is a real, live cross reference, whose name is @samp{Cross} and which
742 points to the node named @samp{Help-Cross}. (The node name is hidden
743 in Emacs. Do @kbd{M-x visible-mode} to show or hide it.)
745 @kindex f @r{(Info mode)}
746 @findex Info-follow-reference
747 You can follow a cross reference by moving the cursor to it and
748 press @key{RET}, just as in a menu. In Emacs, you can also click
749 @kbd{Mouse-1} on a cross reference to follow it; you can see that the
750 cross reference is mouse-sensitive by moving the mouse pointer to the
751 reference and watching how the underlying text and the mouse pointer
754 Another way to follow a cross reference is to type @kbd{f} and then
755 specify the name of the cross reference (in this case, @samp{Cross})
756 as an argument. For this command, it does not matter where the cursor
757 was. If the cursor is on or near a cross reference, @kbd{f} suggests
758 that reference name in parentheses as the default; typing @key{RET}
759 will follow that reference. However, if you type a different
760 reference name, @kbd{f} will follow the other reference which has that
764 >> Type @kbd{f}, followed by @kbd{Cross}, and then @key{RET}.
767 As you enter the reference name, you can use the @key{DEL} (or
768 @key{BACKSPACE}) key to edit your input. If you change your mind
769 about following any reference, you can use @kbd{Control-g} to cancel
770 the command. Completion is available in the @kbd{f} command; you can
771 complete among all the cross reference names in the current node by
774 To get a list of all the cross references in the current node, you
775 can type @kbd{?} after an @kbd{f}. The @kbd{f} continues to await a
776 cross reference name even after displaying the list, so if you don't
777 actually want to follow a reference, you should type a @kbd{Control-g}
778 to cancel the @kbd{f}.
781 >> Type @kbd{f?} to get a list of the cross references in this node. Then
782 type a @kbd{Control-g} and see how the @samp{f} gives up.
785 The @key{TAB}, @kbd{M-@key{TAB}} and @kbd{S-@key{TAB}} keys,
786 which move between menu items in a menu, also move between cross
787 references outside of menus.
789 Sometimes a cross reference (or a node) can lead to another file (in
790 other words another ``manual''), or, on occasion, even a file on a
791 remote machine (although Info files distributed with Emacs or the
792 stand-alone Info avoid using remote links). Such a cross reference
793 looks like this: @xref{Top,, Overview of Texinfo, texinfo, Texinfo:
794 The GNU Documentation Format}. (After following this link, type
795 @kbd{l} to get back to this node.) Here the name @samp{texinfo}
796 between parentheses refers to the file name. This file name appears
797 in cross references and node names if it differs from the current
798 file, so you can always know that you are going to be switching to
799 another manual and which one.
801 However, Emacs normally hides some other text in cross-references.
802 If you put your mouse over the cross reference, then the information
803 appearing in a separate box (tool tip) or in the echo area will show
804 the full cross-reference including the file name and the node name of
805 the cross reference. If you have a mouse, just leave it over the
806 cross reference @xref{Top,, Overview of Texinfo, texinfo, Texinfo:
807 The GNU Documentation Format}, and watch what happens. If you
808 always like to have that information visible without having to move
809 your mouse over the cross reference, use @kbd{M-x visible-mode}, or
810 set @code{Info-hide-note-references} to a value other than @code{t}
811 (@pxref{Emacs Info Variables}).
814 >> Now type @kbd{n} to learn more commands.
817 @node Help-Int, Help-Q, Help-Xref, Getting Started
818 @comment node-name, next, previous, up
819 @section Some intermediate Info commands
821 The introductory course is almost over; please continue
822 a little longer to learn some intermediate-level commands.
824 Most Info files have an index, which is actually a large node
825 containing little but a menu. The menu has one menu item for each
826 topic listed in the index. (As a special feature, menus for indices
827 may also include the line number within the node of the index entry.
828 This allows Info readers to go to the exact line of an entry, not just
829 the start of the containing node.)
831 You can get to the index from the main menu of the file with the
832 @kbd{m} command and the name of the index node; then you can use the
833 @kbd{m} command again in the index node to go to the node that
834 describes the topic you want.
836 There is also a short-cut Info command, @kbd{i}, which does all of
837 that for you. It searches the index for a given topic (a string) and
838 goes to the node which is listed in the index for that topic.
839 @xref{Search Index}, for a full explanation.
841 @kindex l @r{(Info mode)}
842 @findex Info-history-back
843 @cindex going back in Info history
844 If you have been moving around to different nodes and wish to
845 retrace your steps, the @kbd{l} command (@kbd{l} for @dfn{last}) will
846 do that, one node-step at a time. As you move from node to node, Info
847 records the nodes where you have been in a special history list. The
848 @kbd{l} command revisits nodes in the history list; each successive
849 @kbd{l} command moves one step back through the history.
852 >> Try typing @kbd{p p n} and then three @kbd{l}'s, pausing in between
853 to see what each @kbd{l} does. You should wind up right back here.
856 Note the difference between @kbd{l} and @kbd{p}: @kbd{l} moves to
857 where @emph{you} last were, whereas @kbd{p} always moves to the node
858 which the header says is the @samp{Previous} node (from this node, the
859 @samp{Prev} link leads to @samp{Help-Xref}).
861 @kindex r @r{(Info mode)}
862 @findex Info-history-forward
863 @cindex going forward in Info history
864 You can use the @kbd{r} command (@code{Info-history-forward} in Emacs)
865 to revisit nodes in the history list in the forward direction, so that
866 @kbd{r} will return you to the node you came from by typing @kbd{l}.
868 @kindex L @r{(Info mode)}
870 @cindex history list of visited nodes
871 The @kbd{L} command (@code{Info-history} in Emacs) creates a virtual
872 node that contains a list of all nodes you visited. You can select
873 a previously visited node from this menu to revisit it.
875 @kindex d @r{(Info mode)}
876 @findex Info-directory
877 @cindex go to Directory node
878 The @kbd{d} command (@code{Info-directory} in Emacs) gets you
879 instantly to the Directory node. This node, which is the first one
880 you saw when you entered Info, has a menu which leads (directly or
881 indirectly, through other menus), to all the nodes that exist. The
882 Directory node lists all the manuals and other Info documents that
883 are, or could be, installed on your system.
886 >> Try doing a @kbd{d}, then do an @kbd{l} to return here (yes,
890 @kindex t @r{(Info mode)}
891 @findex Info-top-node
892 @cindex go to Top node
893 The @kbd{t} command moves to the @samp{Top} node of the manual.
894 This is useful if you want to browse the manual's main menu, or select
895 some specific top-level menu item. The Emacs command run by @kbd{t}
896 is @code{Info-top-node}.
899 >> Now type @kbd{n} to see the last node of the course.
902 @xref{Advanced}, for more advanced Info features.
904 @c If a menu appears at the end of this node, remove it.
905 @c It is an accident of the menu updating command.
907 @node Help-Q, , Help-Int, Getting Started
908 @comment node-name, next, previous, up
909 @section Quitting Info
911 @kindex q @r{(Info mode)}
913 @cindex quitting Info mode
914 To get out of Info, back to what you were doing before, type @kbd{q}
915 for @dfn{Quit}. This runs @code{Info-exit} in Emacs.
917 This is the end of the basic course on using Info. You have learned
918 how to move in an Info document, and how to follow menus and cross
919 references. This makes you ready for reading manuals top to bottom,
920 as new users should do when they learn a new package.
922 Another set of Info commands is useful when you need to find
923 something quickly in a manual---that is, when you need to use a manual
924 as a reference rather than as a tutorial. We urge you to learn
925 these search commands as well. If you want to do that now, follow this
926 cross reference to @ref{Advanced}.
928 Yet another set of commands are meant for experienced users; you can
929 find them by looking in the Directory node for documentation on Info.
930 Finding them will be a good exercise in using Info in the usual
934 >> Type @kbd{d} to go to the Info directory node; then type
935 @kbd{mInfo} and Return, to get to the node about Info and
936 see what other help is available.
941 @chapter Advanced Info Commands
943 This chapter describes various advanced Info commands. (If you
944 are using a stand-alone Info reader, there are additional commands
945 specific to it, which are documented in several chapters of @ref{Top,,
946 GNU Info, info-stnd, GNU Info}.)
948 @kindex C-q @r{(Info mode)}
949 One advanced command useful with most of the others described here
950 is @kbd{C-q}, which ``quotes'' the next character so that it is
951 entered literally (@pxref{Inserting Text,,,emacs,The GNU Emacs
952 Manual}). For example, pressing @kbd{?} ordinarily brings up a list
953 of completion possibilities. If you want to (for example) search for
954 an actual @samp{?} character, the simplest way is to insert it using
955 @kbd{C-q ?}. This works the same in Emacs and stand-alone Info.
958 * Search Text:: How to search Info documents.
959 * Search Index:: How to search the indices for specific subjects.
960 * Go to node:: How to go to a node by name.
961 * Choose menu subtopic:: How to choose a menu subtopic by its number.
962 * Create Info buffer:: How to create a new Info buffer in Emacs.
963 * Emacs Info Variables:: Variables modifying the behavior of Emacs Info.
967 @node Search Text, Search Index, , Advanced
968 @comment node-name, next, previous, up
969 @section @kbd{s} searches Info documents
971 @cindex searching Info documents
972 @cindex Info document as a reference
973 The commands which move between and inside nodes allow you to read
974 the entire manual or its large portions. But what if you need to find
975 some information in the manual as fast as you can, and you don't know
976 or don't remember in what node to look for it? This need arises when
977 you use a manual as a @dfn{reference}, or when it is impractical to
978 read the entire manual before you start using the programs it
981 Info has powerful searching facilities that let you find things
982 quickly. You can search either the manual text or its indices.
984 @kindex s @r{(Info mode)}
986 The @kbd{s} command allows you to search a whole Info file for a string.
987 It switches to the next node if and when that is necessary. You
988 type @kbd{s} followed by the string to search for, terminated by
989 @key{RET}. To search for the same string again, just @kbd{s} followed
990 by @key{RET} will do. The file's nodes are scanned in the order
991 they are in the file, which has no necessary relationship to the
992 order that they may be in the tree structure of menus and @samp{next}
993 pointers. But normally the two orders are not very different. In any
994 case, you can always look at the mode line to find out what node you have
995 reached, if the header is not visible (this can happen, because @kbd{s}
996 puts your cursor at the occurrence of the string, not at the beginning
999 @kindex C-s @r{(Info mode)}
1000 @kindex C-r @r{(Info mode)}
1002 Instead of using @kbd{s} in Emacs Info and in the stand-alone Info,
1003 you can use an incremental search started with @kbd{C-s} or @kbd{C-r}.
1004 It can search through multiple Info nodes. @xref{Incremental Search,,,
1005 emacs, The GNU Emacs Manual}. In Emacs, you can disable this behavior
1006 by setting the variable @code{Info-isearch-search} to @code{nil}
1007 (@pxref{Emacs Info Variables}).
1009 @node Search Index, Go to node, Search Text, Advanced
1010 @comment node-name, next, previous, up
1011 @section @kbd{i} searches the indices for specific subjects
1013 @cindex searching Info indices
1014 @kindex i @r{(Info mode)}
1016 Since most topics in the manual should be indexed, you should try
1017 the index search first before the text search. The @kbd{i} command
1018 prompts you for a subject and then looks up that subject in the
1019 indices. If it finds an index entry with the subject you typed, it
1020 goes to the node to which that index entry points. You should browse
1021 through that node to see whether the issue you are looking for is
1022 described there. If it isn't, type @kbd{,} one or more times to go
1023 through additional index entries which match your subject.
1025 The @kbd{i} command and subsequent @kbd{,} commands find all index
1026 entries which include the string you typed @emph{as a substring}.
1027 For each match, Info shows in the echo area the full index entry it
1028 found. Often, the text of the full index entry already gives you
1029 enough information to decide whether it is relevant to what you are
1030 looking for, so we recommend that you read what Info shows in the echo
1031 area before looking at the node it displays.
1033 Since @kbd{i} looks for a substring, you can search for subjects even
1034 if you are not sure how they are spelled in the index. For example,
1035 suppose you want to find something that is pertinent to commands which
1036 complete partial input (e.g., when you type @key{TAB}). If you want
1037 to catch index entries that refer to ``complete,'' ``completion,'' and
1038 ``completing,'' you could type @kbd{icomplet@key{RET}}.
1040 Info documents which describe programs should index the commands,
1041 options, and key sequences that the program provides. If you are
1042 looking for a description of a command, an option, or a key, just type
1043 their names when @kbd{i} prompts you for a topic. For example, if you
1044 want to read the description of what the @kbd{C-l} key does, type
1045 @kbd{iC-l@key{RET}} literally.
1047 @findex Info-virtual-index
1048 @kindex I @r{(Info mode)}
1049 Emacs provides the command @code{Info-virtual-index}, bound to the
1050 @kbd{I} key. This behaves like @kbd{i}, but constructs a virtual
1051 info node displaying the results of an index search, making it easier
1052 to select the one you want.
1054 @findex info-apropos
1055 @findex index-apropos
1056 If you aren't sure which manual documents the topic you are looking
1057 for, try the @kbd{M-x info-apropos} command in Emacs, or the @kbd{M-x
1058 index-apropos} command in the stand-alone reader. It prompts for
1059 a string and then looks up that string in all the indices of all the
1060 Info documents installed on your system.
1062 @node Go to node, Choose menu subtopic, Search Index, Advanced
1063 @comment node-name, next, previous, up
1064 @section @kbd{g} goes to a node by name
1066 @kindex g @r{(Info mode)}
1067 @findex Info-goto-node
1068 @cindex go to a node by name
1069 If you know a node's name, you can go there by typing @kbd{g}, the
1070 name, and @key{RET}. Thus, @kbd{gTop@key{RET}} would go to the node
1071 called @samp{Top} in this file. (This is equivalent to @kbd{t}, see
1072 @ref{Help-Int}.) @kbd{gGo to node@key{RET}} would come back here.
1074 Unlike @kbd{m}, @kbd{g} does not allow the use of abbreviations.
1075 But it does allow completion, so you can type @key{TAB} to complete a
1078 @cindex go to another Info file
1079 To go to a node in another file, you can include the file name in the
1080 node name by putting it at the front, in parentheses. Thus,
1081 @kbd{g(dir)Top@key{RET}} would go to the Info Directory node, which is
1082 the node @samp{Top} in the Info file @file{dir}. Likewise,
1083 @kbd{g(emacs)Top@key{RET}} (or just @kbd{g(emacs)@key{RET}}) goes to the
1084 top node of the Emacs manual.
1086 The node name @samp{*} specifies the whole file. So you can look at
1087 all of the current file by typing @kbd{g*@key{RET}} or all of any
1088 other file with @kbd{g(@var{filename})*@key{RET}}.
1090 @node Choose menu subtopic, Create Info buffer, Go to node, Advanced
1091 @comment node-name, next, previous, up
1092 @section @kbd{1}--@kbd{9} choose a menu subtopic by its number
1094 @kindex 1 @r{through} 9 @r{(Info mode)}
1095 @findex Info-nth-menu-item
1096 @cindex select @var{n}'th menu item
1097 If you begrudge each character of type-in which your system requires,
1098 you might like to use the commands @kbd{1}, @kbd{2}, @kbd{3}, @kbd{4},
1099 @dots{}, @kbd{9}. They are short for the @kbd{m} command together
1100 with a name of a menu subtopic. @kbd{1} goes through the first item
1101 in the current node's menu; @kbd{2} goes through the second item, etc.
1102 In the stand-alone reader, @kbd{0} goes through the last menu item;
1103 this is so you need not count how many entries are there.
1105 If your display supports multiple fonts, colors or underlining, and
1106 you are using Emacs's Info mode to read Info files, the third, sixth
1107 and ninth menu items have a @samp{*} that stands out, either in color
1108 or in some other attribute, such as underline; this makes it easy to
1109 see at a glance which number to use for an item.
1111 Some terminals don't support either multiple fonts, colors or
1112 underlining. If you need to actually count items, it is better to use
1113 @kbd{m} instead, and specify the name, or use @key{TAB} to quickly
1114 move between menu items.
1116 @node Create Info buffer, Emacs Info Variables, Choose menu subtopic, Advanced
1117 @comment node-name, next, previous, up
1118 @section @kbd{M-n} creates a new independent Info buffer in Emacs
1120 @kindex M-n @r{(Info mode)}
1121 @findex clone-buffer
1122 @cindex multiple Info buffers
1123 If you are reading Info in Emacs, you can select a new independent
1124 Info buffer in a new Emacs window by typing @kbd{M-n}. The new buffer
1125 starts out as an exact copy of the old one, but you will be able to
1126 move independently between nodes in the two buffers. (In Info mode,
1127 @kbd{M-n} runs the Emacs command @code{clone-buffer}.)
1129 In Emacs Info, you can also produce new Info buffers by giving a
1130 numeric prefix argument to the @kbd{m} and @kbd{g} commands. @kbd{C-u
1131 m} and @kbd{C-u g} go to a new node in exactly the same way that
1132 @kbd{m} and @kbd{g} do, but they do so in a new Info buffer which they
1133 select in another window.
1135 Another way to produce new Info buffers in Emacs is to use a numeric
1136 prefix argument for the @kbd{C-h i} command (@code{info}) which
1137 switches to the Info buffer with that number. Thus, @kbd{C-u 2 C-h i}
1138 switches to the buffer @samp{*info*<2>}, creating it if necessary.
1140 @findex info-display-manual
1141 If you have created many Info buffers in Emacs, you might find it
1142 difficult to remember which buffer is showing which manual. You can
1143 use the command @kbd{M-x info-display-manual} to show an Info manual
1144 by name, reusing an existing buffer if there is one.
1146 @node Emacs Info Variables, , Create Info buffer, Advanced
1147 @comment node-name, next, previous, up
1148 @section Emacs Info-mode Variables
1150 The following variables may modify the behavior of Info-mode in Emacs;
1151 you may wish to set one or several of these variables interactively,
1152 or in your init file. @xref{Examining, Examining and Setting
1153 Variables, Examining and Setting Variables, emacs, The GNU Emacs
1154 Manual}. The stand-alone Info reader program has its own set of
1155 variables, described in @ref{Variables,, Manipulating Variables,
1156 info-stnd, GNU Info}.
1159 @item Info-directory-list
1160 The list of directories to search for Info files. Each element is a
1161 string (directory name) or @code{nil} (try default directory). If not
1162 initialized Info uses the environment variable @env{INFOPATH} to
1163 initialize it, or @code{Info-default-directory-list} if there is no
1164 @env{INFOPATH} variable in the environment.
1166 If you wish to customize the Info directory search list for both Emacs
1167 Info and stand-alone Info, it is best to set the @env{INFOPATH}
1168 environment variable, since that applies to both programs.
1170 @item Info-additional-directory-list
1171 A list of additional directories to search for Info documentation files.
1172 These directories are not searched for merging the @file{dir} file.
1174 @item Info-mode-hook
1175 Hooks run when @code{Info-mode} is called. By default, it contains
1176 the hook @code{turn-on-font-lock} which enables highlighting of Info
1177 files. You can change how the highlighting looks by customizing the
1178 faces @code{info-node}, @code{info-xref}, @code{info-xref-visited},
1179 @code{info-header-xref}, @code{info-header-node}, @code{info-menu-header},
1180 @code{info-menu-star}, and @code{info-title-@var{n}} (where @var{n}
1181 is the level of the section, a number between 1 and 4). To customize
1182 a face, type @kbd{M-x customize-face @key{RET} @var{face} @key{RET}},
1183 where @var{face} is one of the face names listed here.
1185 @item Info-fontify-maximum-menu-size
1186 Maximum size of menu to fontify if @code{font-lock-mode} is non-@code{nil}.
1188 @item Info-fontify-visited-nodes
1189 If non-@code{nil}, menu items and cross-references pointing to visited
1190 nodes are displayed in the @code{info-xref-visited} face.
1192 @item Info-use-header-line
1193 If non-@code{nil}, Emacs puts in the Info buffer a header line showing
1194 the @samp{Next}, @samp{Prev}, and @samp{Up} links. A header line does
1195 not scroll with the rest of the buffer, making these links always
1198 @item Info-hide-note-references
1199 As explained in earlier nodes, the Emacs version of Info normally
1200 hides some text in menus and cross-references. You can completely
1201 disable this feature, by setting this option to @code{nil}. Setting
1202 it to a value that is neither @code{nil} nor @code{t} produces an
1203 intermediate behavior, hiding a limited amount of text, but showing
1204 all text that could potentially be useful.
1206 @item Info-scroll-prefer-subnodes
1207 If set to a non-@code{nil} value, @key{SPC} and @key{BACKSPACE} (or
1208 @key{DEL}, or @key{S-SPC}) keys in a menu visit subnodes of the
1209 current node before scrolling to its end or beginning, respectively.
1210 For example, if the node's menu appears on the screen, the next
1211 @key{SPC} moves to a subnode indicated by the following menu item.
1212 Setting this option to @code{nil} results in behavior similar to the
1213 stand-alone Info reader program, which visits the first subnode from
1214 the menu only when you hit the end of the current node. The default
1217 @item Info-isearch-search
1218 If non-@code{nil}, isearch in Info searches through multiple nodes.
1220 @item Info-enable-active-nodes
1221 When set to a non-@code{nil} value, allows Info to execute Lisp code
1222 associated with nodes. The Lisp code is executed when the node is
1223 selected. The Lisp code to be executed should follow the node
1224 delimiter (the @samp{DEL} character) and an @samp{execute: } tag, like
1228 ^_execute: (message "This is an active node!")
1234 @chapter Info for Experts
1237 This chapter explains how to write an Info file by hand. However,
1238 in most cases, writing a Texinfo file is better, since you can use it
1239 to make a printed manual or produce other formats, such as HTML and
1240 DocBook, as well as for generating Info files.
1242 The @code{makeinfo} command converts a Texinfo file into an Info file;
1243 @code{texinfo-format-region} and @code{texinfo-format-buffer} are GNU
1244 Emacs functions that do the same.
1246 @xref{Top,, Overview of Texinfo, texinfo, Texinfo: The GNU
1247 Documentation Format}, for how to write a Texinfo file.
1249 @xref{Creating an Info File,,, texinfo, Texinfo: The GNU Documentation
1250 Format}, for how to create an Info file from a Texinfo file.
1252 @xref{Installing an Info File,,, texinfo, Texinfo: The GNU
1253 Documentation Format}, for how to install an Info file after you
1256 However, if you want to edit an Info file manually and install it manually,
1260 * Add:: Describes how to add new nodes to the hierarchy.
1261 Also tells what nodes look like.
1262 * Menus:: How to add to or create menus in Info nodes.
1263 * Cross-refs:: How to add cross-references to Info nodes.
1264 * Tags:: How to make tags tables for Info files.
1265 * Checking:: Checking an Info File.
1268 @node Add, Menus, , Expert Info
1269 @comment node-name, next, previous, up
1270 @section Adding a new node to Info
1272 To add a new topic to the list in the Info directory, you must:
1276 Create some nodes, in some file, to document that topic.
1278 Put that topic in the menu in the directory. @xref{Menus, Menu}.
1281 @cindex node delimiters
1282 The new node can live in an existing documentation file, or in a new
1283 one. It must have a @samp{^_} character before it (invisible to the
1284 user; this node has one but you cannot see it), and it ends with either
1285 a @samp{^_}, a @samp{^L} (``formfeed''), or the end of file.@footnote{If
1286 you put in a @samp{^L} to end a new node, be sure that there is a
1287 @samp{^_} after it to start the next one, since @samp{^L} cannot
1288 @emph{start} a node. Also, a nicer way to make a node boundary be a
1289 page boundary as well is to put a @samp{^L} @emph{right after} the
1292 The @samp{^_} starting a node must be followed by a newline or a
1293 @samp{^L} newline, after which comes the node's header line. The
1294 header line must give the node's name (by which Info finds it), and
1295 state the names of the @samp{Next}, @samp{Previous}, and @samp{Up}
1296 nodes (if there are any). As you can see, this node's @samp{Up} node
1297 is the node @samp{Expert Info}. The @samp{Next} node is @samp{Menus}.
1299 @cindex node header line format
1300 @cindex format of node headers
1301 The keywords @dfn{Node}, @dfn{Next}, @dfn{Previous}, and @dfn{Up}
1302 may appear in any order, anywhere in the header line, but the
1303 recommended order is the one in this sentence. Each keyword must be
1304 followed by a colon, spaces and tabs, and then the appropriate name.
1305 The name may be terminated with a tab, a comma, or a newline. A space
1306 does not end it; node names may contain spaces. The case of letters
1307 in the names is insignificant.
1309 @cindex node name format
1310 @cindex Directory node
1311 A node name has two forms. A node in the current file is named by
1312 what appears after the @samp{Node: } in that node's first line. For
1313 example, this node's name is @samp{Add}. A node in another file is
1314 named by @samp{(@var{filename})@var{node-within-file}}, as in
1315 @samp{(info)Add} for this node. If the file name starts with @samp{./},
1316 then it is relative to the current directory; otherwise, it is
1317 relative starting from the standard directory for Info files of your
1318 site. The name @samp{(@var{filename})Top} can be abbreviated to just
1319 @samp{(@var{filename})}. By convention, the name @samp{Top} is used
1320 for the ``highest'' node in any single file---the node whose @samp{Up}
1321 points out of the file. The @samp{Directory} node is @file{(dir)}, it
1322 points to a file @file{dir} which holds a large menu listing all the
1323 Info documents installed on your site. The @samp{Top} node of a
1324 document file listed in the @samp{Directory} should have an @samp{Up:
1327 @cindex unstructured documents
1328 The node name @kbd{*} is special: it refers to the entire file.
1329 Thus, @kbd{g*} shows you the whole current file. The use of the
1330 node @kbd{*} is to make it possible to make old-fashioned,
1331 unstructured files into nodes of the tree.
1333 The @samp{Node:} name, in which a node states its own name, must not
1334 contain a file name, since when Info searches for a node, it does not
1335 expect a file name to be there. The @samp{Next}, @samp{Previous} and
1336 @samp{Up} names may contain them. In this node, since the @samp{Up}
1337 node is in the same file, it was not necessary to use one.
1339 Note that the nodes in this file have a file name in the header
1340 line. The file names are ignored by Info, but they serve as comments
1341 to help identify the node for the user.
1343 @node Menus, Cross-refs, Add, Expert Info
1344 @comment node-name, next, previous, up
1345 @section How to Create Menus
1347 Any node in the Info hierarchy may have a @dfn{menu}---a list of subnodes.
1348 The @kbd{m} command searches the current node's menu for the topic which it
1349 reads from the terminal.
1351 @cindex menu and menu entry format
1352 A menu begins with a line starting with @w{@samp{* Menu:}}. The
1353 rest of the line is a comment. After the starting line, every line
1354 that begins with a @samp{* } lists a single topic. The name of the
1355 topic---what the user must type at the @kbd{m}'s command prompt to
1356 select this topic---comes right after the star and space, and is
1357 followed by a colon, spaces and tabs, and the name of the node which
1358 discusses that topic. The node name, like node names following
1359 @samp{Next}, @samp{Previous} and @samp{Up}, may be terminated with a
1360 tab, comma, or newline; it may also be terminated with a period.
1362 If the node name and topic name are the same, then rather than
1363 giving the name twice, the abbreviation @samp{* @var{name}::} may be
1364 used (and should be used, whenever possible, as it reduces the visual
1365 clutter in the menu).
1367 It is considerate to choose the topic names so that they differ
1368 from each other very near the beginning---this allows the user to type
1369 short abbreviations. In a long menu, it is a good idea to capitalize
1370 the beginning of each item name which is the minimum acceptable
1371 abbreviation for it (a long menu is more than 5 or so entries).
1373 The nodes listed in a node's menu are called its ``subnodes,'' and it
1374 is their ``superior''. They should each have an @samp{Up:} pointing at
1375 the superior. It is often useful to arrange all or most of the subnodes
1376 in a sequence of @samp{Next} and @samp{Previous} pointers so that
1377 someone who wants to see them all need not keep revisiting the Menu.
1379 The Info Directory is simply the menu of the node @samp{(dir)Top}---that
1380 is, node @samp{Top} in file @file{.../info/dir}. You can put new entries
1381 in that menu just like any other menu. The Info Directory is @emph{not} the
1382 same as the file directory called @file{info}. It happens that many of
1383 Info's files live in that file directory, but they do not have to; and
1384 files in that directory are not automatically listed in the Info
1387 Also, although the Info node graph is claimed to be a ``hierarchy,''
1388 in fact it can be @emph{any} directed graph. Shared structures and
1389 pointer cycles are perfectly possible, and can be used if they are
1390 appropriate to the meaning to be expressed. There is no need for all
1391 the nodes in a file to form a connected structure. In fact, this file
1392 has two connected components. You are in one of them, which is under
1393 the node @samp{Top}; the other contains the node @samp{Help} which the
1394 @kbd{h} command goes to. In fact, since there is no garbage
1395 collector on the node graph, nothing terrible happens if a substructure
1396 is not pointed to, but such a substructure is rather useless since nobody
1397 can ever find out that it exists.
1399 @node Cross-refs, Tags, Menus, Expert Info
1400 @comment node-name, next, previous, up
1401 @section Creating Cross References
1403 @cindex cross reference format
1404 A cross reference can be placed anywhere in the text, unlike a menu
1405 item which must go at the front of a line. A cross reference looks
1406 like a menu item except that it has @samp{*note} instead of @samp{*}.
1407 It @emph{cannot} be terminated by a @samp{)}, because @samp{)}'s are
1408 so often part of node names. If you wish to enclose a cross reference
1409 in parentheses, terminate it with a period first. Here are two
1410 examples of cross references pointers:
1413 *Note details: commands. (See *note 3: Full Proof.)
1417 @emph{These are just examples.} The places they ``lead to'' do not
1421 * Help-Cross:: Target of a cross-reference.
1425 @node Help-Cross, , , Cross-refs
1426 @subsection The node reached by the cross reference in Info
1428 This is the node reached by the cross reference named @samp{Cross}.
1430 While this node is specifically intended to be reached by a cross
1431 reference, most cross references lead to nodes that ``belong''
1432 someplace else far away in the structure of an Info document. So you
1433 cannot expect this node to have a @samp{Next}, @samp{Previous} or
1434 @samp{Up} links pointing back to where you came from. In general, the
1435 @kbd{l} (el) command is the only way to get back there.
1438 >> Type @kbd{l} to return to the node where the cross reference was.
1441 @node Tags, Checking, Cross-refs, Expert Info
1442 @comment node-name, next, previous, up
1443 @section Tags Tables for Info Files
1445 @cindex tags tables in Info files
1446 You can speed up the access to nodes of a large Info file by giving
1447 it a tags table. Unlike the tags table for a program, the tags table for
1448 an Info file lives inside the file itself and is used
1449 automatically whenever Info reads in the file.
1452 To make a tags table, go to a node in the file using Emacs Info mode and type
1453 @kbd{M-x Info-tagify}. Then you must use @kbd{C-x C-s} to save the
1454 file. Info files produced by the @code{makeinfo} command that is part
1455 of the Texinfo package always have tags tables to begin with.
1457 @cindex stale tags tables
1458 @cindex update Info tags table
1459 Once the Info file has a tags table, you must make certain it is up
1460 to date. If you edit an Info file directly (as opposed to editing its
1461 Texinfo source), and, as a result of deletion of text, any node moves back
1462 more than a thousand characters in the file from the position
1463 recorded in the tags table, Info will no longer be able to find that
1464 node. To update the tags table, use the @code{Info-tagify} command
1467 An Info file tags table appears at the end of the file and looks like
1473 File: info, Node: Cross-refs^?21419
1474 File: info, Node: Tags^?22145
1480 Note that it contains one line per node, and this line contains
1481 the beginning of the node's header (ending just after the node name),
1482 a @samp{DEL} character, and the character position in the file of the
1483 beginning of the node.
1485 @node Checking, , Tags, Expert Info
1486 @section Checking an Info File
1488 When creating an Info file, it is easy to forget the name of a node when
1489 you are making a pointer to it from another node. If you put in the
1490 wrong name for a node, this is not detected until someone tries to go
1491 through the pointer using Info. Verification of the Info file is an
1492 automatic process which checks all pointers to nodes and reports any
1493 pointers which are invalid. Every @samp{Next}, @samp{Previous}, and
1494 @samp{Up} is checked, as is every menu item and every cross reference. In
1495 addition, any @samp{Next} which does not have a @samp{Previous} pointing
1496 back is reported. Only pointers within the file are checked, because
1497 checking pointers to other files would be terribly slow. But those are
1500 @findex Info-validate
1501 To check an Info file, do @kbd{M-x Info-validate} while looking at any
1502 node of the file with Emacs Info mode.
1504 @node GNU Free Documentation License
1505 @appendix GNU Free Documentation License
1506 @include doclicense.texi
1511 This is an alphabetical listing of all the commands, variables, and
1512 topics discussed in this document.