1 This is Info file ../../info/xemacs.info, produced by Makeinfo version
2 1.68 from the input file xemacs.texi.
4 INFO-DIR-SECTION XEmacs Editor
6 * XEmacs: (xemacs). XEmacs Editor.
9 This file documents the XEmacs editor.
11 Copyright (C) 1985, 1986, 1988 Richard M. Stallman. Copyright (C)
12 1991, 1992, 1993, 1994 Lucid, Inc. Copyright (C) 1993, 1994 Sun
13 Microsystems, Inc. Copyright (C) 1995 Amdahl Corporation.
15 Permission is granted to make and distribute verbatim copies of this
16 manual provided the copyright notice and this permission notice are
17 preserved on all copies.
19 Permission is granted to copy and distribute modified versions of
20 this manual under the conditions for verbatim copying, provided also
21 that the sections entitled "The GNU Manifesto", "Distribution" and "GNU
22 General Public License" are included exactly as in the original, and
23 provided that the entire resulting derived work is distributed under the
24 terms of a permission notice identical to this one.
26 Permission is granted to copy and distribute translations of this
27 manual into another language, under the above conditions for modified
28 versions, except that the sections entitled "The GNU Manifesto",
29 "Distribution" and "GNU General Public License" may be included in a
30 translation approved by the author instead of in the original English.
33 File: xemacs.info, Node: Bugs, Prev: Lossage, Up: Top
38 Sometimes you will encounter a bug in Emacs. Although we cannot
39 promise we can or will fix the bug, and we might not even agree that it
40 is a bug, we want to hear about bugs you encounter in case we do want
43 To make it possible for us to fix a bug, you must report it. In
44 order to do so effectively, you must know when and how to do it.
49 If Emacs executes an illegal instruction, or dies with an operating
50 system error message that indicates a problem in the program (as
51 opposed to something like "disk full"), then it is certainly a bug.
53 If Emacs updates the display in a way that does not correspond to
54 what is in the buffer, then it is certainly a bug. If a command seems
55 to do the wrong thing but the problem corrects itself if you type
56 `C-l', it is a case of incorrect display updating.
58 Taking forever to complete a command can be a bug, but you must make
59 certain that it was really Emacs's fault. Some commands simply take a
60 long time. Type `C-g' and then `C-h l' to see whether the input Emacs
61 received was what you intended to type; if the input was such that you
62 KNOW it should have been processed quickly, report a bug. If you don't
63 know whether the command should take a long time, find out by looking
64 in the manual or by asking for assistance.
66 If a command you are familiar with causes an Emacs error message in a
67 case where its usual definition ought to be reasonable, it is probably a
70 If a command does the wrong thing, that is a bug. But be sure you
71 know for certain what it ought to have done. If you aren't familiar
72 with the command, or don't know for certain how the command is supposed
73 to work, then it might actually be working right. Rather than jumping
74 to conclusions, show the problem to someone who knows for certain.
76 Finally, a command's intended definition may not be best for editing
77 with. This is a very important sort of problem, but it is also a
78 matter of judgment. Also, it is easy to come to such a conclusion out
79 of ignorance of some of the existing features. It is probably best not
80 to complain about such a problem until you have checked the
81 documentation in the usual ways, feel confident that you understand it,
82 and know for certain that what you want is not available. If you are
83 not sure what the command is supposed to do after a careful reading of
84 the manual, check the index and glossary for any terms that may be
85 unclear. If you still do not understand, this indicates a bug in the
86 manual. The manual's job is to make everything clear. It is just as
87 important to report documentation bugs as program bugs.
89 If the online documentation string of a function or variable
90 disagrees with the manual, one of them must be wrong, so report the bug.
95 When you decide that there is a bug, it is important to report it
96 and to report it in a way which is useful. What is most useful is an
97 exact description of what commands you type, starting with the shell
98 command to run Emacs, until the problem happens. Always include the
99 version number of Emacs that you are using; type `M-x emacs-version' to
102 The most important principle in reporting a bug is to report FACTS,
103 not hypotheses or categorizations. It is always easier to report the
104 facts, but people seem to prefer to strain to posit explanations and
105 report them instead. If the explanations are based on guesses about
106 how Emacs is implemented, they will be useless; we will have to try to
107 figure out what the facts must have been to lead to such speculations.
108 Sometimes this is impossible. But in any case, it is unnecessary work
111 For example, suppose that you type `C-x C-f /glorp/baz.ugh <RET>',
112 visiting a file which (you know) happens to be rather large, and Emacs
113 prints out `I feel pretty today'. The best way to report the bug is
114 with a sentence like the preceding one, because it gives all the facts
115 and nothing but the facts.
117 Do not assume that the problem is due to the size of the file and
118 say, "When I visit a large file, Emacs prints out `I feel pretty
119 today'." This is what we mean by "guessing explanations". The problem
120 is just as likely to be due to the fact that there is a `z' in the file
121 name. If this is so, then when we got your report, we would try out
122 the problem with some "large file", probably with no `z' in its name,
123 and not find anything wrong. There is no way in the world that we
124 could guess that we should try visiting a file with a `z' in its name.
126 Alternatively, the problem might be due to the fact that the file
127 starts with exactly 25 spaces. For this reason, you should make sure
128 that you inform us of the exact contents of any file that is needed to
129 reproduce the bug. What if the problem only occurs when you have typed
130 the `C-x a l' command previously? This is why we ask you to give the
131 exact sequence of characters you typed since starting to use Emacs.
133 You should not even say "visit a file" instead of `C-x C-f' unless
134 you know that it makes no difference which visiting command is used.
135 Similarly, rather than saying "if I have three characters on the line,"
136 say "after I type `<RET> A B C <RET> C-p'," if that is the way you
139 If you are not in Fundamental mode when the problem occurs, you
140 should say what mode you are in.
142 If the manifestation of the bug is an Emacs error message, it is
143 important to report not just the text of the error message but a
144 backtrace showing how the Lisp program in Emacs arrived at the error.
145 To make the backtrace, you must execute the Lisp expression `(setq
146 debug-on-error t)' before the error happens (that is to say, you must
147 execute that expression and then make the bug happen). This causes the
148 Lisp debugger to run (*note Lisp Debug::.). The debugger's backtrace
149 can be copied as text into the bug report. This use of the debugger is
150 possible only if you know how to make the bug happen again. Do note
151 the error message the first time the bug happens, so if you can't make
152 it happen again, you can report at least that.
154 Check whether any programs you have loaded into the Lisp world,
155 including your `.emacs' file, set any variables that may affect the
156 functioning of Emacs. Also, see whether the problem happens in a
157 freshly started Emacs without loading your `.emacs' file (start Emacs
158 with the `-q' switch to prevent loading the init file). If the problem
159 does NOT occur then, it is essential that we know the contents of any
160 programs that you must load into the Lisp world in order to cause the
163 If the problem does depend on an init file or other Lisp programs
164 that are not part of the standard Emacs system, then you should make
165 sure it is not a bug in those programs by complaining to their
166 maintainers first. After they verify that they are using Emacs in a
167 way that is supposed to work, they should report the bug.
169 If you can tell us a way to cause the problem without visiting any
170 files, please do so. This makes it much easier to debug. If you do
171 need files, make sure you arrange for us to see their exact contents.
172 For example, it can often matter whether there are spaces at the ends
173 of lines, or a newline after the last line in the buffer (nothing ought
174 to care whether the last line is terminated, but tell that to the bugs).
176 The easy way to record the input to Emacs precisely is to write a
177 dribble file; execute the Lisp expression:
179 (open-dribble-file "~/dribble")
181 using `Meta-<ESC>' or from the `*scratch*' buffer just after starting
182 Emacs. From then on, all Emacs input will be written in the specified
183 dribble file until the Emacs process is killed.
185 For possible display bugs, it is important to report the terminal
186 type (the value of environment variable `TERM'), the complete termcap
187 entry for the terminal from `/etc/termcap' (since that file is not
188 identical on all machines), and the output that Emacs actually sent to
189 the terminal. The way to collect this output is to execute the Lisp
192 (open-termscript "~/termscript")
194 using `Meta-<ESC>' or from the `*scratch*' buffer just after starting
195 Emacs. From then on, all output from Emacs to the terminal will be
196 written in the specified termscript file as well, until the Emacs
197 process is killed. If the problem happens when Emacs starts up, put
198 this expression into your `.emacs' file so that the termscript file will
199 be open when Emacs displays the screen for the first time. Be warned:
200 it is often difficult, and sometimes impossible, to fix a
201 terminal-dependent bug without access to a terminal of the type that
204 The newsgroup `comp.emacs.xemacs' may be used for bug reports, other
205 discussions and requests for assistance.
207 If you don't have access to this newgroup, you can subscribe to the
208 mailing list version: the newsgroup is bidirectionally gatewayed into
209 the mailing list `xemacs@xemacs.org'.
211 To be added or removed from this mailing list, send mail to
212 `xemacs-request@xemacs.org'. Do not send requests for addition to the
215 The mailing lists and newsgroups are archived on our anonymous FTP
216 server, `ftp.xemacs.org', and at various other archive sites around the
217 net. You should also check the `FAQ' in `/pub/xemacs' on our anonymous
218 FTP server. It provides some introductory information and help for
219 initial configuration problems.
222 File: xemacs.info, Node: Glossary, Next: Manifesto, Prev: Intro, Up: Top
228 An abbrev is a text string which expands into a different text
229 string when present in the buffer. For example, you might define
230 a short word as an abbrev for a long phrase that you want to insert
231 frequently. *Note Abbrevs::.
234 Aborting means getting out of a recursive edit (q.v.). You can use
235 the commands `C-]' and `M-x top-level' for this. *Note Quitting::.
238 Auto Fill mode is a minor mode in which text you insert is
239 automatically broken into lines of fixed width. *Note Filling::.
242 Auto saving means that Emacs automatically stores the contents of
243 an Emacs buffer in a specially-named file so the information will
244 not be lost if the buffer is lost due to a system error or user
245 error. *Note Auto Save::.
248 A backup file records the contents that a file had before the
249 current editing session. Emacs creates backup files automatically
250 to help you track down or cancel changes you later regret. *Note
254 Emacs can balance parentheses manually or automatically. Manual
255 balancing is done by the commands to move over balanced expressions
256 (*note Lists::.). Automatic balancing is done by blinking the
257 parenthesis that matches one just inserted (*note Matching Parens:
261 To bind a key is to change its binding (q.v.). *Note Rebinding::.
264 A key gets its meaning in Emacs by having a binding which is a
265 command (q.v.), a Lisp function that is run when the key is typed.
266 *Note Binding: Commands. Customization often involves rebinding a
267 character to a different command function. The bindings of all
268 keys are recorded in the keymaps (q.v.). *Note Keymaps::.
271 Blank lines are lines that contain only whitespace. Emacs has
272 several commands for operating on the blank lines in a buffer.
275 The buffer is the basic editing unit; one buffer corresponds to one
276 piece of text being edited. You can have several buffers, but at
277 any time you are editing only one, the `selected' buffer, though
278 several buffers can be visible when you are using multiple
279 windows. *Note Buffers::.
281 Buffer Selection History
282 Emacs keeps a buffer selection history which records how recently
283 each Emacs buffer was selected. Emacs uses this list when
284 choosing a buffer to select. *Note Buffers::.
287 `C' in the name of a character is an abbreviation for Control.
288 *Note C-: Keystrokes.
291 `C-M-' in the name of a character is an abbreviation for
292 Control-Meta. *Note C-M-: Keystrokes.
295 Case conversion means changing text from upper case to lower case
296 or vice versa. *Note Case::, for the commands for case conversion.
299 Characters form the contents of an Emacs buffer; also, Emacs
300 commands are invoked by keys (q.v.), which are sequences of one or
301 more characters. *Note Keystrokes::.
304 A command is a Lisp function specially defined to be able to serve
305 as a key binding in Emacs. When you type a key (q.v.), Emacs
306 looks up its binding (q.v.) in the relevant keymaps (q.v.) to find
307 the command to run. *Note Commands::.
310 A command name is the name of a Lisp symbol which is a command
311 (*note Commands::.). You can invoke any command by its name using
312 `M-x' (*note M-x::.).
315 A comment is text in a program which is intended only for the
316 people reading the program, and is marked specially so that it
317 will be ignored when the program is loaded or compiled. Emacs
318 offers special commands for creating, aligning, and killing
319 comments. *Note Comments::.
322 Compilation is the process of creating an executable program from
323 source code. Emacs has commands for compiling files of Emacs Lisp
324 code (*note Lisp Libraries::.) and programs in C and other
325 languages (*note Compilation::.).
328 A complete key is a character or sequence of characters which,
329 when typed by the user, fully specifies one action to be performed
330 by Emacs. For example, `X' and `Control-f' and `Control-x m' are
331 keys. Keys derive their meanings from being bound (q.v.) to
332 commands (q.v.). Thus, `X' is conventionally bound to a command
333 to insert `X' in the buffer; `C-x m' is conventionally bound to a
334 command to begin composing a mail message. *Note Keystrokes::.
337 When Emacs automatically fills an abbreviation for a name into the
338 entire name, that process is called completion. Completion is
339 done for minibuffer (q.v.) arguments when the set of possible
340 valid inputs is known; for example, on command names, buffer
341 names, and file names. Completion occurs when you type <TAB>,
342 <SPC>, or <RET>. *Note Completion::.
345 When a line of text is longer than the width of the frame, it
346 takes up more than one screen line when displayed. We say that the
347 text line is continued, and all screen lines used for it after the
348 first are called continuation lines. *Note Continuation: Basic.
351 ASCII characters with octal codes 0 through 037, and also code
352 0177, do not have graphic images assigned to them. These are the
353 control characters. Any control character can be typed by holding
354 down the <CTRL> key and typing some other character; some have
355 special keys on the keyboard. <RET>, <TAB>, <ESC>, <LFD>, and
356 <DEL> are all control characters. *Note Keystrokes::.
359 A copyleft is a notice giving the public legal permission to
360 redistribute a program or other work of art. Copylefts are used
361 by leftists to enrich the public just as copyrights are used by
362 rightists to gain power over the public.
365 The current buffer in Emacs is the Emacs buffer on which most
366 editing commands operate. You can select any Emacs buffer as the
367 current one. *Note Buffers::.
370 The line point is on (*note Point::.).
373 The paragraph that point is in. If point is between paragraphs,
374 the current paragraph is the one that follows point. *Note
378 The defun (q.v.) that point is in. If point is between defuns, the
379 current defun is the one that follows point. *Note Defuns::.
382 The cursor is the rectangle on the screen which indicates the
383 position called point (q.v.) at which insertion and deletion takes
384 place. The cursor is on or under the character that follows
385 point. Often people speak of `the cursor' when, strictly
386 speaking, they mean `point'. *Note Cursor: Basic.
389 Customization is making minor changes in the way Emacs works. It
390 is often done by setting variables (*note Variables::.) or by
391 rebinding keys (*note Keymaps::.).
394 The default for an argument is the value that is used if you do not
395 specify one. When Emacs prompts you in the minibuffer for an
396 argument, the default argument is used if you just type <RET>.
400 When you specify a file name that does not start with `/' or `~',
401 it is interpreted relative to the current buffer's default
402 directory. *Note Default Directory: Minibuffer File.
405 A defun is a list at the top level of parenthesis or bracket
406 structure in a program. It is so named because most such lists in
407 Lisp programs are calls to the Lisp function `defun'. *Note
411 The <DEL> character runs the command that deletes one character of
412 text. *Note DEL: Basic.
415 Deleting text means erasing it without saving it. Emacs deletes
416 text only when it is expected not to be worth saving (all
417 whitespace, or only one character). The alternative is killing
418 (q.v.). *Note Deletion: Killing.
421 Deleting a file means removing it from the file system. *Note
425 Deleting a message means flagging it to be eliminated from your
426 mail file. Until the mail file is expunged, you can undo this by
427 undeleting the message.
430 When working under the multi-frame X-based version of XEmacs, you
431 can delete individual frames using the Close menu item from the
435 When you delete a subwindow of an Emacs frame, you eliminate it
436 from the frame. Other windows expand to use up the space. The
437 deleted window can never come back, but no actual text is lost.
441 Files in the Unix file system are grouped into file directories.
442 *Note Directories: ListDir.
445 Dired is the Emacs facility that displays the contents of a file
446 directory and allows you to "edit the directory", performing
447 operations on the files in the directory. *Note Dired::.
450 A disabled command is one that you may not run without special
451 confirmation. Commands are usually disabled because they are
452 confusing for beginning users. *Note Disabling::.
455 A file into which Emacs writes all the characters that the user
456 types on the keyboard. Dribble files are used to make a record for
457 debugging Emacs bugs. Emacs does not make a dribble file unless
458 you tell it to. *Note Bugs::.
461 The area at the bottom of the Emacs frame which is used for
462 echoing the arguments to commands, for asking questions, and for
463 printing brief messages (including error messages). *Note Echo
467 Echoing refers to acknowledging the receipt of commands by
468 displaying them (in the echo area). Emacs never echoes
469 single-character keys; longer keys echo only if you pause while
473 An error occurs when an Emacs command cannot execute in the current
474 circumstances. When an error occurs, execution of the command
475 stops (unless the command has been programmed to do otherwise) and
476 Emacs reports the error by printing an error message (q.v.).
477 Type-ahead is discarded. Then Emacs is ready to read another
481 Error messages are single lines of output printed by Emacs when the
482 user asks for something impossible to do (such as killing text
483 forward when point is at the end of the buffer). They appear in
484 the echo area, accompanied by a beep.
487 <ESC> is a character used as a prefix for typing Meta characters on
488 keyboards lacking a <META> key. Unlike the <META> key (which,
489 like the <SHIFT> key, is held down while another character is
490 typed), the <ESC> key is pressed and released, and applies to the
491 next character typed.
494 The fill prefix is a string that Emacs enters at the beginning of
495 each line when it performs filling. It is not regarded as part of
496 the text to be filled. *Note Filling::.
499 Filling text means moving text from line to line so that all the
500 lines are approximately the same length. *Note Filling::.
503 When running Emacs on a TTY terminal, "frame" means the terminal's
504 screen. When running Emacs under X, you can have multiple frames,
505 each corresponding to a top-level X window and each looking like
506 the screen on a TTY. Each frame contains one or more
507 non-overlapping Emacs windows (possibly with associated
508 scrollbars, under X), an echo area, and (under X) possibly a
512 Global means `independent of the current environment; in effect
513 throughout Emacs'. It is the opposite of local (q.v.). Examples
514 of the use of `global' appear below.
517 A global definition of an abbrev (q.v.) is effective in all major
518 modes that do not have local (q.v.) definitions for the same
519 abbrev. *Note Abbrevs::.
522 The global keymap (q.v.) contains key bindings that are in effect
523 unless local key bindings in a major mode's local keymap (q.v.)
524 override them.*Note Keymaps::.
527 Global substitution means replacing each occurrence of one string
528 by another string through a large amount of text. *Note Replace::.
531 The global value of a variable (q.v.) takes effect in all buffers
532 that do not have their own local (q.v.) values for the variable.
536 Graphic characters are those assigned pictorial images rather than
537 just names. All the non-Meta (q.v.) characters except for the
538 Control (q.v.) character are graphic characters. These include
539 letters, digits, punctuation, and spaces; they do not include
540 <RET> or <ESC>. In Emacs, typing a graphic character inserts that
541 character (in ordinary editing modes). *Note Basic Editing: Basic.
544 Grinding means adjusting the indentation in a program to fit the
545 nesting structure. *Note Grinding: Indentation.
548 Hardcopy means printed output. Emacs has commands for making
549 printed listings of text in Emacs buffers. *Note Hardcopy::.
552 You can type <HELP> at any time to ask what options you have, or
553 to ask what any command does. <HELP> is really `Control-h'.
557 An inbox is a file in which mail is delivered by the operating
558 system. Some mail handlers transfers mail from inboxes to mail
559 files (q.v.) in which the mail is then stored permanently or until
563 Indentation means blank space at the beginning of a line. Most
564 programming languages have conventions for using indentation to
565 illuminate the structure of the program, and Emacs has special
566 features to help you set up the correct indentation. *Note
570 Insertion means copying text into the buffer, either from the
571 keyboard or from some other place in Emacs.
574 Justification means adding extra spaces to lines of text to make
575 them come exactly to a specified width. *Note Justification:
579 Keyboard macros are a way of defining new Emacs commands from
580 sequences of existing ones, with no need to write a Lisp program.
581 *Note Keyboard Macros::.
584 A key is a sequence of characters that, when input to Emacs,
585 specify or begin to specify a single action for Emacs to perform.
586 That is, the sequence is considered a single unit. If the key is
587 enough to specify one action, it is a complete key (q.v.); if it
588 is less than enough, it is a prefix key (q.v.). *Note
592 The keymap is the data structure that records the bindings (q.v.)
593 of keys to the commands that they run. For example, the keymap
594 binds the character `C-n' to the command function `next-line'.
598 The kill ring is the place where all text you have killed recently
599 is saved. You can re-insert any of the killed text still in the
600 ring; this is called yanking (q.v.). *Note Yanking::.
603 Killing means erasing text and saving it on the kill ring so it
604 can be yanked (q.v.) later. Some other systems call this
605 "cutting." Most Emacs commands to erase text do killing, as
606 opposed to deletion (q.v.). *Note Killing::.
609 Killing a job (such as, an invocation of Emacs) means making it
610 cease to exist. Any data within it, if not saved in a file, is
611 lost. *Note Exiting::.
614 A list is, approximately, a text string beginning with an open
615 parenthesis and ending with the matching close parenthesis. In C
616 mode and other non-Lisp modes, groupings surrounded by other kinds
617 of matched delimiters appropriate to the language, such as braces,
618 are also considered lists. Emacs has special commands for many
619 operations on lists. *Note Lists::.
622 Local means `in effect only in a particular context'; the relevant
623 kind of context is a particular function execution, a particular
624 buffer, or a particular major mode. Local is the opposite of
625 `global' (q.v.). Specific uses of `local' in Emacs terminology
629 A local abbrev definition is effective only if a particular major
630 mode is selected. In that major mode, it overrides any global
631 definition for the same abbrev. *Note Abbrevs::.
634 A local keymap is used in a particular major mode; the key bindings
635 (q.v.) in the current local keymap override global bindings of the
636 same keys. *Note Keymaps::.
639 A local value of a variable (q.v.) applies to only one buffer.
643 `M-' in the name of a character is an abbreviation for <META>, one
644 of the modifier keys that can accompany any character. *Note
648 `M-C-' in the name of a character is an abbreviation for
649 Control-Meta; it means the same thing as `C-M-'. If your terminal
650 lacks a real <META> key, you type a Control-Meta character by
651 typing <ESC> and then typing the corresponding Control character.
652 *Note C-M-: Keystrokes.
655 `M-x' is the key which is used to call an Emacs command by name.
656 You use it to call commands that are not bound to keys. *Note
660 Mail means messages sent from one user to another through the
661 computer system, to be read at the recipient's convenience. Emacs
662 has commands for composing and sending mail, and for reading and
663 editing the mail you have received. *Note Sending Mail::.
666 The major modes are a mutually exclusive set of options each of
667 which configures Emacs for editing a certain sort of text.
668 Ideally, each programming language has its own major mode. *Note
672 The mark points to a position in the text. It specifies one end
673 of the region (q.v.), point being the other end. Many commands
674 operate on the whole region, that is, all the text from point to
675 the mark. *Note Mark::.
678 The mark ring is used to hold several recent previous locations of
679 the mark, just in case you want to move back to them. *Note Mark
686 Meta is the name of a modifier bit which a command character may
687 have. It is present in a character if the character is typed with
688 the <META> key held down. Such characters are given names that
689 start with `Meta-'. For example, `Meta-<' is typed by holding down
690 <META> and at the same time typing `<' (which itself is done, on
691 most terminals, by holding down <SHIFT> and typing `,'). *Note
695 A Meta character is one whose character code includes the Meta bit.
698 The minibuffer is the window that Emacs displays inside the echo
699 area (q.v.) when it prompts you for arguments to commands. *Note
703 A minor mode is an optional feature of Emacs which can be switched
704 on or off independent of the major mode. Each minor mode has a
705 command to turn it on or off. *Note Minor Modes::.
708 The mode line is the line at the bottom of each text window (q.v.),
709 which gives status information on the buffer displayed in that
710 window. *Note Mode Line::.
713 A buffer (q.v.) is modified if its text has been changed since the
714 last time the buffer was saved (or since it was created, if it has
715 never been saved). *Note Saving::.
718 Moving text means erasing it from one place and inserting it in
719 another. This is done by killing (q.v.) and then yanking (q.v.).
723 A named mark is a register (q.v.) in its role of recording a
724 location in text so that you can move point to that location.
728 Narrowing means creating a restriction (q.v.) that limits editing
729 in the current buffer to only a part of the text in the buffer.
730 Text outside that part is inaccessible to the user until the
731 boundaries are widened again, but it is still there, and saving
732 the file saves the invisible text. *Note Narrowing::.
735 <LFD> characters in the buffer terminate lines of text and are
736 called newlines. *Note Newline: Keystrokes.
739 A numeric argument is a number, specified before a command, to
740 change the effect of the command. Often the numeric argument
741 serves as a repeat count. *Note Arguments::.
744 An option is a variable (q.v.) that allows you to customize Emacs
745 by giving it a new value. *Note Variables::.
748 Overwrite mode is a minor mode. When it is enabled, ordinary text
749 characters replace the existing text after point rather than
750 pushing it to the right. *Note Minor Modes::.
753 A page is a unit of text, delimited by formfeed characters (ASCII
754 Control-L, code 014) coming at the beginning of a line. Some Emacs
755 commands are provided for moving over and operating on pages.
759 Paragraphs are the medium-size unit of English text. There are
760 special Emacs commands for moving over and operating on paragraphs.
764 We say that Emacs parses words or expressions in the text being
765 edited. Really, all it knows how to do is find the other end of a
766 word or expression. *Note Syntax::.
769 Point is the place in the buffer at which insertion and deletion
770 occur. Point is considered to be between two characters, not at
771 one character. The terminal's cursor (q.v.) indicates the
772 location of point. *Note Point: Basic.
775 A prefix key is a key (q.v.) whose sole function is to introduce a
776 set of multi-character keys. `Control-x' is an example of a prefix
777 key; any two-character sequence starting with `C-x' is also a
778 legitimate key. *Note Keystrokes::.
781 A prompt is text printed to ask the user for input. Printing a
782 prompt is called prompting. Emacs prompts always appear in the
783 echo area (q.v.). One kind of prompting happens when the
784 minibuffer is used to read an argument (*note Minibuffer::.); the
785 echoing which happens when you pause in the middle of typing a
786 multi-character key is also a kind of prompting (*note Echo
790 Quitting means cancelling a partially typed command or a running
791 command, using `C-g'. *Note Quitting::.
794 Quoting means depriving a character of its usual special
795 significance. In Emacs this is usually done with `Control-q'.
796 What constitutes special significance depends on the context and
797 on convention. For example, an "ordinary" character as an Emacs
798 command inserts itself; so in this context, a special character is
799 any character that does not normally insert itself (such as <DEL>,
800 for example), and quoting it makes it insert itself as if it were
801 not special. Not all contexts allow quoting. *Note Quoting:
805 A read-only buffer is one whose text you are not allowed to change.
806 Normally Emacs makes buffers read-only when they contain text which
807 has a special significance to Emacs, such asDired buffers.
808 Visiting a file that is write-protected also makes a read-only
809 buffer. *Note Buffers::.
811 Recursive Editing Level
812 A recursive editing level is a state in which part of the
813 execution of a command involves asking the user to edit some text.
814 This text may or may not be the same as the text to which the
815 command was applied. The mode line indicates recursive editing
816 levels with square brackets (`[' and `]'). *Note Recursive Edit::.
819 Redisplay is the process of correcting the image on the screen to
820 correspond to changes that have been made in the text being edited.
821 *Note Redisplay: Frame.
824 See `regular expression'.
827 The region is the text between point (q.v.) and the mark (q.v.).
828 Many commands operate on the text of the region. *Note Region:
832 Registers are named slots in which text or buffer positions or
833 rectangles can be saved for later use. *Note Registers::.
836 A regular expression is a pattern that can match various text
837 strings; for example, `l[0-9]+' matches `l' followed by one or more
838 digits. *Note Regexps::.
841 See `global substitution'.
844 A buffer's restriction is the amount of text, at the beginning or
845 the end of the buffer, that is temporarily invisible and
846 inaccessible. Giving a buffer a nonzero amount of restriction is
847 called narrowing (q.v.). *Note Narrowing::.
850 <RET> is the character than runs the command to insert a newline
851 into the text. It is also used to terminate most arguments read
852 in the minibuffer (q.v.). *Note Return: Keystrokes.
855 Saving a buffer means copying its text into the file that was
856 visited (q.v.) in that buffer. To actually change a file you have
857 edited in Emacs, you have to save it. *Note Saving::.
860 Scrolling means shifting the text in the Emacs window to make a
861 different part ot the buffer visible. *Note Scrolling: Display.
864 Searching means moving point to the next occurrence of a specified
865 string. *Note Search::.
868 Selecting a buffer means making it the current (q.v.) buffer.
869 *Note Selecting: Buffers.
872 Self-documentation is the feature of Emacs which can tell you what
873 any command does, or can give you a list of all commands related
874 to a topic you specify. You ask for self-documentation with the
875 help character, `C-h'. *Note Help::.
878 Emacs has commands for moving by or killing by sentences. *Note
882 An sexp (short for `s-expression,' itself short for `symbolic
883 expression') is the basic syntactic unit of Lisp in its textual
884 form: either a list, or Lisp atom. Many Emacs commands operate on
885 sexps. The term `sexp' is generalized to languages other than
886 Lisp to mean a syntactically recognizable expression. *Note
890 Simultaneous editing means two users modifying the same file at
891 once. If simultaneous editing is not detected, you may lose your
892 work. Emacs detects all cases of simultaneous editing and warns
893 the user to investigate them. *Note Simultaneous Editing:
897 A string is a kind of Lisp data object which contains a sequence of
898 characters. Many Emacs variables are intended to have strings as
899 values. The Lisp syntax for a string consists of the characters in
900 the string with a `"' before and another `"' after. Write a `"'
901 that is part of the string as `\"' and a `\' that is part of the
902 string as `\\'. You can include all other characters, including
903 newline, just by writing them inside the string. You can also
904 include escape sequences as in C, such as `\n' for newline or
905 `\241' using an octal character code.
908 See `global substitution'.
911 The syntax table tells Emacs which characters are part of a word,
912 which characters balance each other like parentheses, etc. *Note
916 A tag table is a file that serves as an index to the function
917 definitions in one or more other files. *Note Tags::.
920 A termscript file contains a record of all characters Emacs sent to
921 the terminal. It is used for tracking down bugs in Emacs
922 redisplay. Emacs does not make a termscript file unless
923 explicitly instructed to do so. *Note Bugs::.
926 Text has two meanings (*note Text::.):
928 * Data consisting of a sequence of characters, as opposed to
929 binary numbers, images, graphics commands, executable
930 programs, and the like. The contents of an Emacs buffer are
931 always text in this sense.
933 * Data consisting of written human language, as opposed to
934 programs, or something that follows the stylistic conventions
938 Top level is the normal state of Emacs, in which you are editing
939 the text of the file you have visited. You are at top level
940 whenever you are not in a recursive editing level (q.v.) or the
941 minibuffer (q.v.), and not in the middle of a command. You can
942 get back to top level by aborting (q.v.) and quitting (q.v.).
946 Transposing two units of text means putting each one into the place
947 formerly occupied by the other. There are Emacs commands to
948 transpose two adjacent characters, words, sexps (q.v.), or lines
949 (*note Transpose::.).
952 Truncating text lines in the display means leaving out any text on
953 a line that does not fit within the right margin of the window
954 displaying it. See also `continuation line'. *Note Truncation:
958 Undoing means making your previous editing go in reverse, bringing
959 back the text that existed earlier in the editing session. *Note
963 A variable is Lisp object that can store an arbitrary value.
964 Emacs uses some variables for internal purposes, and has others
965 (known as `options' (q.v.)) you can set to control the behavior of
966 Emacs. The variables used in Emacs that you are likely to be
967 interested in are listed in the Variables Index of this manual.
968 *Note Variables::, for information on variables.
971 Visiting a file means loading its contents into a buffer (q.v.)
972 where they can be edited. *Note Visiting::.
975 Whitespace is any run of consecutive formatting characters (spaces,
976 tabs, newlines, and backspaces).
979 Widening is removing any restriction (q.v.) on the current buffer;
980 it is the opposite of narrowing (q.v.). *Note Narrowing::.
983 Emacs divides the frame into one or more windows, each of which can
984 display the contents of one buffer (q.v.) at any time. *Note
985 Frame::, for basic information on how Emacs uses the frame. *Note
986 Windows::, for commands to control the use of windows. Note that if
987 you are running Emacs under X, terminology can be confusing: Each
988 Emacs frame occupies a separate X window and can, in turn, be
989 divided into different subwindows.
992 Synonymous with `abbrev'.
995 Word search is searching for a sequence of words, considering the
996 punctuation between them as insignificant. *Note Word Search::.
999 Yanking means reinserting text previously killed. It can be used
1000 to undo a mistaken kill, or for copying or moving text. Some other
1001 systems call this "pasting". *Note Yanking::.
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