help.texi 26.5 KB
Newer Older
Dave Love's avatar
#  
Dave Love committed
1
@c This is part of the Emacs manual.
2 3
@c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2000, 2001,
@c   2002, 2003, 2004, 2005 Free Software Foundation, Inc.
Dave Love's avatar
#  
Dave Love committed
4 5 6 7 8 9 10 11 12 13 14
@c See file emacs.texi for copying conditions.
@node Help, Mark, M-x, Top
@chapter Help
@kindex Help
@cindex help
@cindex self-documentation
@findex help-command
@kindex C-h
@kindex F1

  Emacs provides extensive help features accessible through a single
Eli Zaretskii's avatar
Eli Zaretskii committed
15
character, @kbd{C-h}.  @kbd{C-h} is a prefix key that is used for
16
commands that display documentation.  The characters that you can type after
Dave Love's avatar
#  
Dave Love committed
17 18 19 20 21 22 23 24 25 26 27
@kbd{C-h} are called @dfn{help options}.  One help option is @kbd{C-h};
that is how you ask for help about using @kbd{C-h}.  To cancel, type
@kbd{C-g}.  The function key @key{F1} is equivalent to @kbd{C-h}.

@kindex C-h C-h
@findex help-for-help
  @kbd{C-h C-h} (@code{help-for-help}) displays a list of the possible
help options, each with a brief description.  Before you type a help
option, you can use @key{SPC} or @key{DEL} to scroll through the list.

  @kbd{C-h} or @key{F1} means ``help'' in various other contexts as
28 29 30 31
well.  After a prefix key, it displays a list of the alternatives that
can follow the prefix key.  (A few prefix keys don't support
@kbd{C-h}, because they define other meanings for it, but they all
support @key{F1}.)
Dave Love's avatar
#  
Dave Love committed
32 33

  Most help buffers use a special major mode, Help mode, which lets you
Dave Love's avatar
Dave Love committed
34
scroll conveniently with @key{SPC} and @key{DEL}.  It also offers
35 36
hyperlinks to URLs and further help regarding cross-referenced names, Info
nodes, customization buffers and the like.  @xref{Help Mode}.
Dave Love's avatar
#  
Dave Love committed
37

38 39
@cindex searching documentation efficiently
@cindex looking for a subject in documentation
40
  If you are looking for a certain feature, but don't know where
Richard M. Stallman's avatar
Richard M. Stallman committed
41
exactly it is documented, and aren't sure of the name of a
42
related command or variable, we recommend trying these methods.  Usually
43 44
it is best to start with an apropos command, then try searching the
manual index, then finally look in the FAQ and the package keywords.
45 46 47

@table @kbd
@item C-h a @var{topic} @key{RET}
48
This searches for commands whose names match @var{topic}, which should
Richard M. Stallman's avatar
Richard M. Stallman committed
49 50
be a regular expression (@pxref{Regexps}).  Browse the buffer that this
command displays to find what you are looking for.  @xref{Apropos}.
51

52
@item M-x apropos @key{RET} @var{topic} @key{RET}
53 54
This works like @kbd{C-h a}, but it also searches for noninteractive
functions and for variables.  @xref{Apropos}.
55

56
@item M-x apropos-documentation @key{RET} @var{topic} @key{RET}
Dave Love's avatar
Dave Love committed
57 58 59 60
This searches the @emph{documentation strings} (the built-in short
descriptions) of all variables and functions (not their names) for a
match for @var{topic}, a regular expression.  @xref{Apropos}.

61
@item C-h i d m emacs @key{RET} i @var{topic} @key{RET}
62
This looks up @var{topic} in the indices of the Emacs on-line manual.
Eli Zaretskii's avatar
Eli Zaretskii committed
63
If there are several matches, Emacs displays the first one.  You can then
Luc Teirlinck's avatar
Luc Teirlinck committed
64
press @kbd{,} to move to other matches, until you find what you are
65 66
looking for.

67
@item C-h i d m emacs @key{RET} s @var{topic} @key{RET}
68 69 70 71
Similar, but searches for @var{topic} (which can be a regular
expression) in the @emph{text} of the manual rather than in its
indices.

Juri Linkov's avatar
Juri Linkov committed
72
@item C-h C-f
73 74
This brings up the Emacs FAQ.  You can use the Info commands
to browse it.
75

76
@item C-h p
77
Finally, you can try looking up a suitable package using keywords
78
pertinent to the feature you need.  @xref{Library Keywords}.
79 80
@end table

81
  To find the documentation of a key sequence or a menu item, type
82
@kbd{C-h K} and then type that key sequence or select the menu
83 84
item.  This looks up the description of the command invoked by the key
or the menu in the appropriate manual (not necessarily the Emacs
85
manual).  Likewise, use @kbd{C-h F} for reading documentation of a
86 87
command.

Dave Love's avatar
#  
Dave Love committed
88 89 90 91 92 93 94 95 96
@menu
* Help Summary::	Brief list of all Help commands.
* Key Help::		Asking what a key does in Emacs.
* Name Help::		Asking about a command, variable or function name.
* Apropos::		Asking what pertains to a given topic.
* Library Keywords::	Finding Lisp libraries by keywords (topics).
* Language Help::       Help relating to international language support.
* Help Mode::           Special features of Help mode and Help buffers.
* Misc Help::		Other help commands.
97
* Help Files::          Commands to display pre-written help files.
Dave Love's avatar
Dave Love committed
98
* Help Echo::           Help on active text and tooltips (`balloon help')
Dave Love's avatar
#  
Dave Love committed
99 100 101 102 103
@end menu

@iftex
@node Help Summary
@end iftex
Karl Berry's avatar
Karl Berry committed
104
@ifnottex
Dave Love's avatar
#  
Dave Love committed
105 106
@node Help Summary
@section Help Summary
Karl Berry's avatar
Karl Berry committed
107
@end ifnottex
Dave Love's avatar
#  
Dave Love committed
108

109 110 111
  Here is a summary of the Emacs interactive help commands.
@xref{Help Files}, for other help commands that just display a
pre-written file of information.
Dave Love's avatar
#  
Dave Love committed
112 113 114 115 116 117 118 119 120 121

@table @kbd
@item C-h a @var{regexp} @key{RET}
Display a list of commands whose names match @var{regexp}
(@code{apropos-command}).
@item C-h b
Display a table of all key bindings in effect now, in this order: minor
mode bindings, major mode bindings, and global bindings
(@code{describe-bindings}).
@item C-h c @var{key}
Eli Zaretskii's avatar
Eli Zaretskii committed
122
Show the name of the command that @var{key} runs
Richard M. Stallman's avatar
Richard M. Stallman committed
123 124
(@code{describe-key-briefly}).  Here @kbd{c} stands for ``character.''
For more extensive information on @var{key}, use @kbd{C-h k}.
Dave Love's avatar
#  
Dave Love committed
125 126 127 128 129
@item C-h f @var{function} @key{RET}
Display documentation on the Lisp function named @var{function}
(@code{describe-function}).  Since commands are Lisp functions,
a command name may be used.
@item C-h h
130
Display the @file{HELLO} file, which shows examples of various character
Dave Love's avatar
#  
Dave Love committed
131 132 133 134 135 136 137 138 139 140 141 142 143 144 145
sets.
@item C-h i
Run Info, the program for browsing documentation files (@code{info}).
The complete Emacs manual is available on-line in Info.
@item C-h k @var{key}
Display the name and documentation of the command that @var{key} runs
(@code{describe-key}).
@item C-h l
Display a description of the last 100 characters you typed
(@code{view-lossage}).
@item C-h m
Display documentation of the current major mode (@code{describe-mode}).
@item C-h p
Find packages by topic keyword (@code{finder-by-keyword}).
@item C-h s
146
Display the current contents of the syntax table, plus an explanation of
Dave Love's avatar
#  
Dave Love committed
147 148 149 150
what they mean (@code{describe-syntax}).  @xref{Syntax}.
@item C-h t
Enter the Emacs interactive tutorial (@code{help-with-tutorial}).
@item C-h v @var{var} @key{RET}
Eli Zaretskii's avatar
Eli Zaretskii committed
151
Display the documentation of the Lisp variable @var{var}
Dave Love's avatar
#  
Dave Love committed
152 153
(@code{describe-variable}).
@item C-h w @var{command} @key{RET}
Eli Zaretskii's avatar
Eli Zaretskii committed
154
Show which keys run the command named @var{command} (@code{where-is}).
Dave Love's avatar
#  
Dave Love committed
155
@item C-h C @var{coding} @key{RET}
Eli Zaretskii's avatar
Eli Zaretskii committed
156
Describe coding system @var{coding}
Dave Love's avatar
#  
Dave Love committed
157 158 159 160 161 162
(@code{describe-coding-system}).
@item C-h C @key{RET}
Describe the coding systems currently in use.
@item C-h I @var{method} @key{RET}
Describe an input method (@code{describe-input-method}).
@item C-h L @var{language-env} @key{RET}
Richard M. Stallman's avatar
Richard M. Stallman committed
163
Display information on the character sets, coding systems, and input
Eli Zaretskii's avatar
Eli Zaretskii committed
164
methods used for language environment @var{language-env}
Dave Love's avatar
#  
Dave Love committed
165
(@code{describe-language-environment}).
166
@item C-h F @var{function} @key{RET}
Dave Love's avatar
#  
Dave Love committed
167 168
Enter Info and go to the node documenting the Emacs function @var{function}
(@code{Info-goto-emacs-command-node}).
169
@item C-h K @var{key}
Dave Love's avatar
#  
Dave Love committed
170 171
Enter Info and go to the node where the key sequence @var{key} is
documented (@code{Info-goto-emacs-key-command-node}).
172
@item C-h S @var{symbol} @key{RET}
Dave Love's avatar
#  
Dave Love committed
173 174
Display the Info documentation on symbol @var{symbol} according to the
programming language you are editing (@code{info-lookup-symbol}).
175 176
@item C-h .
Display a help message associated with special text areas, such as
177
links in @samp{*Help*} buffers (@code{display-local-help}).
Dave Love's avatar
#  
Dave Love committed
178 179 180 181 182 183 184 185 186
@end table

@node Key Help
@section Documentation for a Key

@kindex C-h c
@findex describe-key-briefly
  The most basic @kbd{C-h} options are @kbd{C-h c}
(@code{describe-key-briefly}) and @w{@kbd{C-h k}} (@code{describe-key}).
187 188
@kbd{C-h c @var{key}} displays in the echo area the name of the command
that @var{key} is bound to.  For example, @kbd{C-h c C-f} displays
Dave Love's avatar
#  
Dave Love committed
189 190 191 192 193 194 195 196 197 198 199 200 201
@samp{forward-char}.  Since command names are chosen to describe what
the commands do, this is a good way to get a very brief description of
what @var{key} does.

@kindex C-h k
@findex describe-key
  @kbd{C-h k @var{key}} is similar but gives more information: it
displays the documentation string of the command as well as its name.
This is too big for the echo area, so a window is used for the display.

  @kbd{C-h c} and @kbd{C-h k} work for any sort of key sequences,
including function keys and mouse events.

202 203 204 205 206 207 208
@kindex C-h w
@findex where-is
  @kbd{C-h w @var{command} @key{RET}} tells you what keys are bound to
@var{command}.  It displays a list of the keys in the echo area.  If it
says the command is not on any key, you must use @kbd{M-x} to run it.
@kbd{C-h w} runs the command @code{where-is}.

Dave Love's avatar
#  
Dave Love committed
209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227
@node Name Help
@section Help by Command or Variable Name

@kindex C-h f
@findex describe-function
  @kbd{C-h f} (@code{describe-function}) reads the name of a Lisp function
using the minibuffer, then displays that function's documentation string
in a window.  Since commands are Lisp functions, you can use this to get
the documentation of a command that you know by name.  For example,

@example
C-h f auto-fill-mode @key{RET}
@end example

@noindent
displays the documentation of @code{auto-fill-mode}.  This is the only
way to get the documentation of a command that is not bound to any key
(one which you would normally run using @kbd{M-x}).

228 229 230 231 232 233 234 235 236
  @kbd{C-h f} is also useful for Lisp functions that you are planning
to use in a Lisp program.  For example, if you have just written the
expression @code{(make-vector len)} and want to check that you are
using @code{make-vector} properly, type @kbd{C-h f make-vector
@key{RET}}.  Because @kbd{C-h f} allows all function names, not just
command names, you may find that some of your favorite completion
abbreviations that work in @kbd{M-x} don't work in @kbd{C-h f}.  An
abbreviation may be unique among command names, yet fail to be unique
when other function names are allowed.
Dave Love's avatar
#  
Dave Love committed
237

Eli Zaretskii's avatar
Eli Zaretskii committed
238 239 240 241 242 243 244
  The default function name for @kbd{C-h f} to describe, if you type
just @key{RET}, is the name of the function called by the innermost Lisp
expression in the buffer around point, @emph{provided} that is a valid,
defined Lisp function name.  For example, if point is located following
the text @samp{(make-vector (car x)}, the innermost list containing
point is the one that starts with @samp{(make-vector}, so the default is
to describe the function @code{make-vector}.
Dave Love's avatar
#  
Dave Love committed
245 246 247 248 249 250 251 252 253 254

  @kbd{C-h f} is often useful just to verify that you have the right
spelling for the function name.  If @kbd{C-h f} mentions a name from the
buffer as the default, that name must be defined as a Lisp function.  If
that is all you want to know, just type @kbd{C-g} to cancel the @kbd{C-h
f} command, then go on editing.

  @kbd{C-h v} (@code{describe-variable}) is like @kbd{C-h f} but describes
Lisp variables instead of Lisp functions.  Its default is the Lisp symbol
around or before point, but only if that is the name of a known Lisp
255 256 257 258 259 260 261 262 263
variable.  @xref{Variables}.

  Help buffers describing Emacs variables and functions normally have
hyperlinks to the definition, if you have the source files installed.
(@xref{Hyperlinking}.)  If you know Lisp (or C), this provides the
ultimate documentation.  If you don't know Lisp, you should learn it.
If you are just @emph{using} Emacs, treating Emacs as an object
(file), then you don't really love it.  For true intimacy with your
editor, you need to read the source code.
264

Dave Love's avatar
#  
Dave Love committed
265 266 267 268 269 270 271 272 273 274 275 276 277
@node Apropos
@section Apropos

@kindex C-h a
@findex apropos-command
@cindex apropos
  A more sophisticated sort of question to ask is, ``What are the
commands for working with files?''  To ask this question, type @kbd{C-h
a file @key{RET}}, which displays a list of all command names that
contain @samp{file}, including @code{copy-file}, @code{find-file}, and
so on.  With each command name appears a brief description of how to use
the command, and what keys you can currently invoke it with.  For
example, it would say that you can invoke @code{find-file} by typing
Richard M. Stallman's avatar
Richard M. Stallman committed
278
@kbd{C-x C-f}.  The @kbd{a} in @kbd{C-h a} stands for ``Apropos'';
Dave Love's avatar
#  
Dave Love committed
279 280 281 282
@kbd{C-h a} runs the command @code{apropos-command}.  This command
normally checks only commands (interactive functions); if you specify a
prefix argument, it checks noninteractive functions as well.

283 284 285 286 287 288 289 290
  Because @kbd{C-h a} looks only for commands matching the string you
specify, you may not find what you want on the first try.  In that
case, don't just give up.  You can give Apropos a list of words to
search for.  When more than one word is specified, at least two of
those words must be present for an item to match.  If you are looking
for commands to kill a chunk of text before point, try @kbd{C-h a kill
back behind before @key{RET}}.  For even greater flexibility, you can
also supply a regular expression to Apropos (@pxref{Regexps}).
Dave Love's avatar
#  
Dave Love committed
291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307

  Here is a set of arguments to give to @kbd{C-h a} that covers many
classes of Emacs commands, since there are strong conventions for naming
the standard Emacs commands.  By giving you a feel for the naming
conventions, this set should also serve to aid you in developing a
technique for picking @code{apropos} strings.

@quotation
char, line, word, sentence, paragraph, region, page, sexp, list, defun,
rect, buffer, frame, window, face, file, dir, register, mode, beginning, end,
forward, backward, next, previous, up, down, search, goto, kill, delete,
mark, insert, yank, fill, indent, case, change, set, what, list, find,
view, describe, default.
@end quotation

@findex apropos-variable
  To list all user variables that match a regexp, use the command
308 309 310
@kbd{M-x apropos-variable}.  By default, this command shows only
variables meant for user customization; if you specify a prefix
argument, it checks all variables.
Dave Love's avatar
#  
Dave Love committed
311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333

@findex apropos
  To list all Lisp symbols that contain a match for a regexp, not just
the ones that are defined as commands, use the command @kbd{M-x apropos}
instead of @kbd{C-h a}.  This command does not check key bindings by
default; specify a numeric argument if you want it to check them.

@findex apropos-documentation
  The @code{apropos-documentation} command is like @code{apropos} except
that it searches documentation strings as well as symbol names for
matches for the specified regular expression.

@findex apropos-value
  The @code{apropos-value} command is like @code{apropos} except that it
searches symbols' values for matches for the specified regular
expression.  This command does not check function definitions or
property lists by default; specify a numeric argument if you want it to
check them.

@vindex apropos-do-all
  If the variable @code{apropos-do-all} is non-@code{nil}, the commands
above all behave as if they had been given a prefix argument.

334
@vindex apropos-sort-by-scores
335
@cindex apropos search results, order by score
336 337 338 339 340
  By default, Apropos lists the search results in alphabetical order.
If the variable @code{apropos-sort-by-scores} is non-@code{nil},
Apropos tries to guess the relevance of each result, and displays the
most relevant ones first.

Dave Love's avatar
#  
Dave Love committed
341 342
  If you want more information about a function definition, variable or
symbol property listed in the Apropos buffer, you can click on it with
343
@kbd{Mouse-1} or @kbd{Mouse-2}, or move there and type @key{RET}.
Dave Love's avatar
#  
Dave Love committed
344 345 346 347 348 349 350 351 352 353

@node Library Keywords
@section Keyword Search for Lisp Libraries

@kindex C-h p
@findex finder-by-keyword
The @kbd{C-h p} command lets you search the standard Emacs Lisp
libraries by topic keywords.  Here is a partial list of keywords you can
use:

354 355
@multitable {emulations} {aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa}
@item abbrev@tab abbreviation handling, typing shortcuts, macros.
Juri Linkov's avatar
Juri Linkov committed
356 357
@item bib@tab code related to the @code{bib} bibliography processor.
@item c@tab support for the C language and related languages.
358 359
@item calendar@tab calendar and time management support.
@item comm@tab communications, networking, remote access to files.
Juri Linkov's avatar
Juri Linkov committed
360
@item convenience@tab convenience features for faster editing.
361 362 363 364
@item data@tab support for editing files of data.
@item docs@tab support for Emacs documentation.
@item emulations@tab emulations of other editors.
@item extensions@tab Emacs Lisp language extensions.
Juri Linkov's avatar
Juri Linkov committed
365 366
@item faces@tab support for multiple fonts.
@item files@tab support for editing and manipulating files.
367 368 369 370
@item frames@tab support for Emacs frames and window systems.
@item games@tab games, jokes and amusements.
@item hardware@tab support for interfacing with exotic hardware.
@item help@tab support for on-line help systems.
Juri Linkov's avatar
Juri Linkov committed
371
@item hypermedia@tab support for links between text or other media types.
372 373 374
@item i18n@tab internationalization and alternate character-set support.
@item internal@tab code for Emacs internals, build process, defaults.
@item languages@tab specialized modes for editing programming languages.
Juri Linkov's avatar
Juri Linkov committed
375 376
@item lisp@tab Lisp support, including Emacs Lisp.
@item local@tab code local to your site.
377 378
@item maint@tab maintenance aids for the Emacs development group.
@item mail@tab modes for electronic-mail handling.
Juri Linkov's avatar
Juri Linkov committed
379 380 381
@item matching@tab various sorts of searching and matching.
@item mouse@tab mouse support.
@item multimedia@tab images and sound support.
382 383
@item news@tab support for netnews reading and posting.
@item oop@tab support for object-oriented programming.
Juri Linkov's avatar
Juri Linkov committed
384
@item outlines@tab support for hierarchical outlining.
385 386
@item processes@tab process, subshell, compilation, and job control support.
@item terminals@tab support for terminal types.
Juri Linkov's avatar
Juri Linkov committed
387
@item tex@tab supporting code for the @TeX{} formatter.
388
@item tools@tab programming tools.
Juri Linkov's avatar
Juri Linkov committed
389
@item unix@tab front-ends/assistants for, or emulators of, UNIX-like features.
390 391
@item wp@tab word processing.
@end multitable
Dave Love's avatar
#  
Dave Love committed
392 393 394 395 396

@node Language Help
@section Help for International Language Support

  You can use the command @kbd{C-h L}
397 398 399 400 401 402
(@code{describe-language-environment}) to find out information about
the support for a specific language environment.  @xref{Language
Environments}.  This tells you which languages this language
environment is useful for, and lists the character sets, coding
systems, and input methods that go with it.  It also shows some sample
text to illustrate scripts.
Dave Love's avatar
#  
Dave Love committed
403 404 405 406 407 408 409 410 411 412 413 414 415 416 417

  The command @kbd{C-h h} (@code{view-hello-file}) displays the file
@file{etc/HELLO}, which shows how to say ``hello'' in many languages.

  The command @kbd{C-h I} (@code{describe-input-method}) describes
information about input methods---either a specified input method, or by
default the input method in use.  @xref{Input Methods}.

  The command @kbd{C-h C} (@code{describe-coding-system}) describes
information about coding systems---either a specified coding system, or
the ones currently in use.  @xref{Coding Systems}.

@node Help Mode
@section Help Mode Commands

Eli Zaretskii's avatar
Eli Zaretskii committed
418 419
  Help buffers provide the same commands as View mode (@pxref{Misc File
Ops}), plus a few special commands of their own.
Dave Love's avatar
#  
Dave Love committed
420 421 422 423 424

@table @kbd
@item @key{SPC}
Scroll forward.
@item @key{DEL}
425 426 427
@itemx @key{BS}
Scroll backward.  On some keyboards, this key is known as @key{BS} or
@key{backspace}.
Dave Love's avatar
#  
Dave Love committed
428 429 430 431 432 433
@item @key{RET}
Follow a cross reference at point.
@item @key{TAB}
Move point forward to the next cross reference.
@item S-@key{TAB}
Move point back to the previous cross reference.
434 435
@item Mouse-1
@itemx Mouse-2
Dave Love's avatar
#  
Dave Love committed
436 437 438
Follow a cross reference that you click on.
@end table

439
  When a function name (@pxref{M-x,, Running Commands by Name}) or
Dave Love's avatar
#  
Dave Love committed
440
variable name (@pxref{Variables}) appears in the documentation, it
441 442 443 444
normally appears inside paired single-quotes.  You can click on the
name with @kbd{Mouse-1} or @kbd{Mouse-2}, or move point there and type
@key{RET}, to view the documentation of that command or variable.  Use
@kbd{C-c C-b} to retrace your steps.
Dave Love's avatar
#  
Dave Love committed
445

446 447 448 449 450
@cindex URL, viewing in help
@cindex help, viewing web pages
@cindex viewing web pages in help
@cindex web pages, viewing in help
@findex browse-url
Bill Wohler's avatar
Bill Wohler committed
451
  You can follow cross references to URLs (web pages) as well.  When
452 453 454 455
you follow a cross reference that is a URL, the @code{browse-url}
command is used to view the web page in a browser of your choosing.
@xref{Browse-URL}.

Dave Love's avatar
#  
Dave Love committed
456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474
@kindex @key{TAB} @r{(Help mode)}
@findex help-next-ref
@kindex S-@key{TAB} @r{(Help mode)}
@findex help-previous-ref
  There are convenient commands for moving point to cross references in
the help text.  @key{TAB} (@code{help-next-ref}) moves point down to the
next cross reference.  Use @kbd{S-@key{TAB}} to move point up to the
previous cross reference (@code{help-previous-ref}).

@node Misc Help
@section Other Help Commands

@kindex C-h i
@findex info
@cindex Info
@cindex manuals, on-line
@cindex on-line manuals
  @kbd{C-h i} (@code{info}) runs the Info program, which is used for
browsing through structured documentation files.  The entire Emacs manual
Eli Zaretskii's avatar
Eli Zaretskii committed
475
is available within Info.  Eventually all the documentation of the GNU
Dave Love's avatar
#  
Dave Love committed
476 477 478
system will be available.  Type @kbd{h} after entering Info to run
a tutorial on using Info.

479
@cindex find Info manual by its file name
480 481 482 483 484 485
  With a numeric argument, @kbd{C-h i} selects an Info buffer with the
number appended to the default @samp{*info*} buffer name
(e.g. @samp{*info*<2>}).  This is useful if you want to browse
multiple Info manuals simultaneously.  If you specify just @kbd{C-u}
as the prefix argument, @kbd{C-h i} prompts for the name of a
documentation file.  This way, you can browse a file which doesn't
Dave Love's avatar
#  
Dave Love committed
486
have an entry in the top-level Info menu.  It is also handy when you
487 488
need to get to the documentation quickly, and you know the exact name
of the file.
Dave Love's avatar
#  
Dave Love committed
489

490 491
@kindex C-h F
@kindex C-h K
Dave Love's avatar
#  
Dave Love committed
492 493
@findex Info-goto-emacs-key-command-node
@findex Info-goto-emacs-command-node
494 495 496 497 498 499 500
  There are two special help commands for accessing Emacs
documentation through Info.  @kbd{C-h F @var{function} @key{RET}}
enters Info and goes straight to the documentation of the Emacs
function @var{function}.  @kbd{C-h K @var{key}} enters Info and goes
straight to the documentation of the key @var{key}.  These two keys
run the commands @code{Info-goto-emacs-command-node} and
@code{Info-goto-emacs-key-command-node}.  You can use @kbd{C-h K} to
501
find the documentation of a menu item: just select that menu item when
502
@kbd{C-h K} prompts for a key.
503

504 505 506 507
  @kbd{C-h F} and @kbd{C-h K} know about commands and keys described
in manuals other than the Emacs manual.  Thus, they make it easier to
find the documentation of commands and keys when you are not sure
which manual describes them, like when using some specialized mode.
Dave Love's avatar
#  
Dave Love committed
508

509 510 511 512 513 514 515
@kindex C-h S
@findex info-lookup-symbol
  When editing a program, if you have an Info version of the manual
for the programming language, you can use the command @kbd{C-h S}
(@code{info-lookup-symbol}) to refer to the manual documentation for a
symbol (keyword, function or variable).  The details of how this
command works depend on the major mode.
Dave Love's avatar
#  
Dave Love committed
516 517 518 519

@kindex C-h l
@findex view-lossage
  If something surprising happens, and you are not sure what commands you
520
typed, use @kbd{C-h l} (@code{view-lossage}).  @kbd{C-h l} displays the last
Dave Love's avatar
#  
Dave Love committed
521 522 523
100 command characters you typed in.  If you see commands that you don't
know, you can use @kbd{C-h c} to find out what they do.

524 525 526 527 528 529
@kindex C-h e
@findex view-echo-area-messages
  To review messages that recently appeared in the echo area, use
@kbd{C-h e} (@code{view-echo-area-messages}).  This displays the
buffer @code{*Messages*}, where those messages are kept.

Dave Love's avatar
#  
Dave Love committed
530 531 532 533
@kindex C-h m
@findex describe-mode
  Emacs has numerous major modes, each of which redefines a few keys and
makes a few other changes in how editing works.  @kbd{C-h m}
534
(@code{describe-mode}) displays documentation on the current major mode,
Dave Love's avatar
#  
Dave Love committed
535 536 537 538 539 540 541 542
which normally describes all the commands that are changed in this
mode.

@kindex C-h b
@findex describe-bindings
  @kbd{C-h b} (@code{describe-bindings}) and @kbd{C-h s}
(@code{describe-syntax}) present other information about the current
Emacs mode.  @kbd{C-h b} displays a list of all the key bindings now in
543
effect, showing the local bindings defined by the current minor modes first,
Dave Love's avatar
#  
Dave Love committed
544 545 546 547 548 549 550 551 552 553 554
then the local bindings defined by the current major mode, and finally
the global bindings (@pxref{Key Bindings}).  @kbd{C-h s} displays the
contents of the syntax table, with explanations of each character's
syntax (@pxref{Syntax}).

  You can get a similar list for a particular prefix key by typing
@kbd{C-h} after the prefix key.  (There are a few prefix keys for which
this does not work---those that provide their own bindings for
@kbd{C-h}.  One of these is @key{ESC}, because @kbd{@key{ESC} C-h} is
actually @kbd{C-M-h}, which marks a defun.)

555 556 557 558 559 560 561 562
@node Help Files
@section Help Files

  The Emacs help commands described above display the state of data
bases within Emacs.  Emacs has a few other help commands that display
pre-written help files.  These commands all have the form @kbd{C-h
C-@var{char}}; that is, @kbd{C-h} followed by a control character.

Dave Love's avatar
#  
Dave Love committed
563 564 565 566
@kindex C-h C-c
@findex describe-copying
@kindex C-h C-d
@findex describe-distribution
567 568 569 570 571 572
@kindex C-h C-e
@findex view-emacs-problems
@kindex C-h C-f
@findex view-emacs-FAQ
@kindex C-h C-n
@findex view-emacs-news
Dave Love's avatar
#  
Dave Love committed
573 574
@kindex C-h C-p
@findex describe-project
575 576 577 578
@kindex C-h C-t
@findex view-emacs-todo
@kindex C-h C-w
@findex describe-no-warranty
579
  The other @kbd{C-h} options display various files containing useful
580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605
information.

@table @kbd
@item C-h C-c
Displays the Emacs copying conditions (@code{describe-copying}).
These are the rules under which you can copy and redistribute Emacs.
@item C-h C-d
Displays information on how to download or order the latest version of
Emacs and other GNU software (@code{describe-distribution}).
@item C-h C-e
Displays the list of known Emacs problems, sometimes with suggested
workarounds (@code{view-emacs-problems}).
@item C-h C-f
Displays the Emacs frequently-answered-questions list (@code{view-emacs-FAQ}).
@item C-h C-n
Displays the Emacs ``news'' file, which lists new Emacs features, most
recent first (@code{view-emacs-news}).
@item C-h C-p
Displays general information about the GNU Project
(@code{describe-project}).
@item C-h C-t
Displays the Emacs to-do list (@code{view-todo}).
@item C-h C-w
Displays the full details on the complete absence of warranty for GNU
Emacs (@code{describe-no-warranty}).
@end table
Dave Love's avatar
Dave Love committed
606 607 608 609 610

@node Help Echo
@section Help on Active Text and Tooltips

@cindex tooltips
611
@cindex balloon help
Richard M. Stallman's avatar
Richard M. Stallman committed
612
  When a region of text is ``active,'' so that you can select it with
Richard M. Stallman's avatar
Richard M. Stallman committed
613
the mouse or a key like @kbd{RET}, it often has associated help text.
614 615
Areas of the mode line are examples.  On most window systems, the help
text is displayed as a ``tooltip'' (sometimes known as ``balloon
616 617 618 619
help''), when you move the mouse over the active text.  @xref{Tooltips}.
On some systems, it is shown in the echo area.  On text-only
terminals, Emacs may not be able to follow the mouse and hence will
not show the help text on mouse-over.
620 621 622 623 624 625 626 627 628 629

@kindex C-h .
@findex display-local-help
@vindex help-at-pt-display-when-idle
  You can also access text region help info using the keyboard.  The
command @kbd{C-h .} (@code{display-local-help}) displays any help text
associated with the text at point, using the echo area.  If you want
help text to be displayed automatically whenever it is available at
point, set the variable @code{help-at-pt-display-when-idle} to
@code{t}.
Miles Bader's avatar
Miles Bader committed
630 631 632 633

@ignore
   arch-tag: 6f33ab62-bc75-4367-8057-fd67cc15c3a1
@end ignore