1 @c This is part of the Emacs manual.
2 @c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2001, 2002,
3 @c 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
4 @c See file emacs.texi for copying conditions.
5 @node Glossary, Key Index, Intro, Top
10 An abbrev is a text string which expands into a different text string
11 when present in the buffer. For example, you might define a few letters
12 as an abbrev for a long phrase that you want to insert frequently.
16 Aborting means getting out of a recursive edit (q.v.@:). The
17 commands @kbd{C-]} and @kbd{M-x top-level} are used for this.
21 Alt is the name of a modifier bit which a keyboard input character may
22 have. To make a character Alt, type it while holding down the @key{ALT}
23 key. Such characters are given names that start with @kbd{Alt-}
24 (usually written @kbd{A-} for short). (Note that many terminals have a
25 key labeled @key{ALT} which is really a @key{META} key.) @xref{User
29 See `numeric argument.'
31 @item @acronym{ASCII} character
32 An @acronym{ASCII} character is either an @acronym{ASCII} control character or an @acronym{ASCII}
33 printing character. @xref{User Input}.
35 @item @acronym{ASCII} control character
36 An @acronym{ASCII} control character is the Control version of an upper-case
37 letter, or the Control version of one of the characters @samp{@@[\]^_?}.
39 @item @acronym{ASCII} printing character
40 @acronym{ASCII} printing characters include letters, digits, space, and these
41 punctuation characters: @samp{!@@#$%^& *()_-+=|\~` @{@}[]:;"' <>,.?/}.
44 Auto Fill mode is a minor mode in which text that you insert is
45 automatically broken into lines of a given maximum width.
49 Auto saving is the practice of saving the contents of an Emacs buffer in
50 a specially-named file, so that the information will not be lost if the
51 buffer is lost due to a system error or user error. @xref{Auto Save}.
54 Emacs automatically loads Lisp libraries when a Lisp program requests a
55 function or a variable from those libraries. This is called
56 `autoloading'. @xref{Lisp Libraries}.
59 A backtrace is a trace of a series of function calls showing how a
60 program arrived to a certain point. It is used mainly for finding and
61 correcting bugs (q.v.@:). Emacs can display a backtrace when it signals
62 an error or when you type @kbd{C-g} (see `quitting'). @xref{Checklist}.
65 A backup file records the contents that a file had before the current
66 editing session. Emacs makes backup files automatically to help you
67 track down or cancel changes you later regret making. @xref{Backup}.
69 @item Balancing Parentheses
70 Emacs can balance parentheses (or other matching delimiters) either
71 manually or automatically. You do manual balancing with the commands
72 to move over parenthetical groupings (@pxref{Moving by Parens}).
73 Automatic balancing works by blinking or highlighting the delimiter
74 that matches the one you just inserted (@pxref{Matching,,Matching
77 @item Balanced Expressions
78 A balanced expression is a syntactically recognizable expression, such
79 as a symbol, number, string constant, block, or parenthesized expression
80 in C. @xref{Expressions,Balanced Expressions}.
86 A base buffer is a buffer whose text is shared by an indirect buffer
90 To bind a key sequence means to give it a binding (q.v.@:).
94 A key sequence gets its meaning in Emacs by having a binding, which is a
95 command (q.v.@:), a Lisp function that is run when the user types that
96 sequence. @xref{Commands,Binding}. Customization often involves
97 rebinding a character to a different command function. The bindings of
98 all key sequences are recorded in the keymaps (q.v.@:). @xref{Keymaps}.
101 Blank lines are lines that contain only whitespace. Emacs has several
102 commands for operating on the blank lines in the buffer.
105 Bookmarks are akin to registers (q.v.@:) in that they record positions
106 in buffers to which you can return later. Unlike registers, bookmarks
107 persist between Emacs sessions.
110 A border is a thin space along the edge of the frame, used just for
111 spacing, not for displaying anything. An Emacs frame has an ordinary
112 external border, outside of everything including the menu bar, plus an
113 internal border that surrounds the text windows and their scroll bars
114 and separates them from the menu bar and tool bar. You can customize
115 both borders with options and resources (@pxref{Borders X}). Borders
116 are not the same as fringes (q.v.@:).
119 The buffer is the basic editing unit; one buffer corresponds to one text
120 being edited. You can have several buffers, but at any time you are
121 editing only one, the `current buffer,' though several can be visible
122 when you are using multiple windows (q.v.@:). Most buffers are visiting
123 (q.v.@:) some file. @xref{Buffers}.
125 @item Buffer Selection History
126 Emacs keeps a buffer selection history which records how recently each
127 Emacs buffer has been selected. This is used for choosing a buffer to
128 select. @xref{Buffers}.
131 A bug is an incorrect or unreasonable behavior of a program, or
132 inaccurate or confusing documentation. Emacs developers treat bug
133 reports, both in Emacs code and its documentation, very seriously and
134 ask you to report any bugs you find. @xref{Bugs}.
136 @item Button Down Event
137 A button down event is the kind of input event generated right away when
138 you press down on a mouse button. @xref{Mouse Buttons}.
143 @item Byte Compilation
147 @kbd{C-} in the name of a character is an abbreviation for Control.
148 @xref{User Input,C-}.
151 @kbd{C-M-} in the name of a character is an abbreviation for
152 Control-Meta. @xref{User Input,C-M-}.
154 @item Case Conversion
155 Case conversion means changing text from upper case to lower case or
156 vice versa. @xref{Case}, for the commands for case conversion.
159 Characters form the contents of an Emacs buffer. Also, key sequences
160 (q.v.@:) are usually made up of characters (though they may include
161 other input events as well). @xref{User Input}.
164 Emacs supports a number of character sets, each of which represents a
165 particular alphabet or script. @xref{International}.
167 @item Character Terminal
168 See `text-only terminal.'
171 A click event is the kind of input event generated when you press a
172 mouse button and release it without moving the mouse. @xref{Mouse Buttons}.
175 A clipboard is a buffer provided by the window system for transferring
176 text between applications. On the X Window system, the clipboard is
177 provided in addition to the primary selection (q.v.@:); on MS-Windows and Mac,
178 the clipboard is used @emph{instead} of the primary selection.
182 A coding system is an encoding for representing text characters in a
183 file or in a stream of information. Emacs has the ability to convert
184 text to or from a variety of coding systems when reading or writing it.
185 @xref{Coding Systems}.
188 A command is a Lisp function specially defined to be able to serve as a
189 key binding in Emacs. When you type a key sequence (q.v.@:), its
190 binding (q.v.@:) is looked up in the relevant keymaps (q.v.@:) to find
191 the command to run. @xref{Commands}.
193 @item Command History
194 See `minibuffer history.'
197 A command name is the name of a Lisp symbol which is a command
198 (@pxref{Commands}). You can invoke any command by its name using
199 @kbd{M-x} (@pxref{M-x,M-x,Running Commands by Name}).
202 A comment is text in a program which is intended only for humans reading
203 the program, and which is marked specially so that it will be ignored
204 when the program is loaded or compiled. Emacs offers special commands
205 for creating, aligning and killing comments. @xref{Comments}.
208 Common Lisp is a dialect of Lisp (q.v.@:) much larger and more powerful
209 than Emacs Lisp. Emacs provides a subset of Common Lisp in the CL
210 package. @xref{Top, Common Lisp, Overview, cl, Common Lisp Extensions}.
213 Compilation is the process of creating an executable program from source
214 code. Emacs has commands for compiling files of Emacs Lisp code
215 (@pxref{Byte Compilation,,, elisp, the Emacs Lisp
216 Reference Manual}) and programs in C and other languages
217 (@pxref{Compilation}).
220 A complete key is a key sequence which fully specifies one action to be
221 performed by Emacs. For example, @kbd{X} and @kbd{C-f} and @kbd{C-x m}
222 are complete keys. Complete keys derive their meanings from being bound
223 (q.v.@:) to commands (q.v.@:). Thus, @kbd{X} is conventionally bound to
224 a command to insert @samp{X} in the buffer; @kbd{C-x m} is
225 conventionally bound to a command to begin composing a mail message.
229 Completion is what Emacs does when it automatically fills out an
230 abbreviation for a name into the entire name. Completion is done for
231 minibuffer (q.v.@:) arguments when the set of possible valid inputs
232 is known; for example, on command names, buffer names, and
233 file names. Completion occurs when @key{TAB}, @key{SPC} or @key{RET}
234 is typed. @xref{Completion}.@refill
236 @item Continuation Line
237 When a line of text is longer than the width of the window, it
238 takes up more than one screen line when displayed. We say that the
239 text line is continued, and all screen lines used for it after the
240 first are called continuation lines. @xref{Continuation Lines}.
241 A related Emacs feature is `filling' (q.v.@:).
243 @item Control Character
244 A control character is a character that you type by holding down the
245 @key{CTRL} key. Some control characters also have their own keys, so
246 that you can type them without using @key{CTRL}. For example,
247 @key{RET}, @key{TAB}, @key{ESC} and @key{DEL} are all control
248 characters. @xref{User Input}.
251 A copyleft is a notice giving the public legal permission to
252 redistribute and modify a program or other work of art, but requiring
253 modified versions to carry similar permission. Copyright is normally
254 used to keep users divided and helpless; with copyleft we turn that
255 around to empower users and encourage them to cooperate.
257 The particular form of copyleft used by the GNU project is called the
258 GNU General Public License. @xref{Copying}.
261 The @key{CTRL} or ``control'' key is what you hold down
262 in order to enter a control character (q.v.).
265 The current buffer in Emacs is the Emacs buffer on which most editing
266 commands operate. You can select any Emacs buffer as the current one.
270 The current line is the line that point is on (@pxref{Point}).
272 @item Current Paragraph
273 The current paragraph is the paragraph that point is in. If point is
274 between two paragraphs, the current paragraph is the one that follows
275 point. @xref{Paragraphs}.
278 The current defun is the defun (q.v.@:) that point is in. If point is
279 between defuns, the current defun is the one that follows point.
283 The cursor is the rectangle on the screen which indicates the position
284 called point (q.v.@:) at which insertion and deletion takes place.
285 The cursor is on or under the character that follows point. Often
286 people speak of `the cursor' when, strictly speaking, they mean
287 `point.' @xref{Point,Cursor}.
290 Customization is making minor changes in the way Emacs works. It is
291 often done by setting variables (@pxref{Variables}) or faces
292 (@pxref{Face Customization}), or by rebinding key sequences
295 @cindex cut and paste
297 See `killing' and `yanking.'
299 @item Default Argument
300 The default for an argument is the value that will be assumed if you
301 do not specify one. When the minibuffer is used to read an argument,
302 the default argument is used if you just type @key{RET}.
306 A default is the value that is used for a certain purpose if and when
307 you do not specify a value to use.
309 @item Default Directory
310 When you specify a file name that does not start with @samp{/} or @samp{~},
311 it is interpreted relative to the current buffer's default directory.
312 (On MS-Windows and MS-DOS, file names which start with a drive letter
313 @samp{@var{x}:} are treated as absolute, not relative.)
314 @xref{Minibuffer File,Default Directory}.
317 A defun is a major definition at the top level in a program. The name
318 `defun' comes from Lisp, where most such definitions use the construct
319 @code{defun}. @xref{Defuns}.
322 @key{DEL} is a character that runs the command to delete one character
323 of text before the cursor. It is typically either the @key{DELETE}
324 key or the @key{BACKSPACE} key, whichever one is easy to type.
328 Deletion means erasing text without copying it into the kill ring
329 (q.v.@:). The alternative is killing (q.v.@:). @xref{Killing,Deletion}.
331 @item Deletion of Files
332 Deleting a file means erasing it from the file system.
333 @xref{Misc File Ops,Misc File Ops,Miscellaneous File Operations}.
335 @item Deletion of Messages
336 Deleting a message means flagging it to be eliminated from your mail
337 file. Until you expunge (q.v.@:) the Rmail file, you can still undelete
338 the messages you have deleted. @xref{Rmail Deletion}.
340 @item Deletion of Windows
341 Deleting a window means eliminating it from the screen. Other windows
342 expand to use up the space. The deleted window can never come back,
343 but no actual text is thereby lost. @xref{Windows}.
346 File directories are named collections in the file system, within which
347 you can place individual files or subdirectories. @xref{Directories}.
350 Dired is the Emacs facility that displays the contents of a file
351 directory and allows you to ``edit the directory,'' performing
352 operations on the files in the directory. @xref{Dired}.
354 @item Disabled Command
355 A disabled command is one that you may not run without special
356 confirmation. The usual reason for disabling a command is that it is
357 confusing for beginning users. @xref{Disabling}.
360 Short for `button down event' (q.v.@:).
363 A drag event is the kind of input event generated when you press a mouse
364 button, move the mouse, and then release the button. @xref{Mouse
368 A dribble file is a file into which Emacs writes all the characters that
369 you type on the keyboard. Dribble files are used to make a record
370 for debugging Emacs bugs. Emacs does not make a dribble file unless you
371 tell it to. @xref{Bugs}.
374 The echo area is the bottom line of the screen, used for echoing the
375 arguments to commands, for asking questions, and showing brief messages
376 (including error messages). The messages are stored in the buffer
377 @samp{*Messages*} so you can review them later. @xref{Echo Area}.
380 Echoing is acknowledging the receipt of input events by displaying
381 them (in the echo area). Emacs never echoes single-character key
382 sequences; longer key sequences echo only if you pause while typing
386 We say that a character is electric if it is normally self-inserting
387 (q.v.@:), but the current major mode (q.v.@:) redefines it to do something
388 else as well. For example, some programming language major modes define
389 particular delimiter characters to reindent the line or insert one or
390 more newlines in addition to self-insertion.
393 End of line is a character or a sequence of characters that indicate
394 the end of a text line. On GNU and Unix systems, this is a newline
395 (q.v.@:), but other systems have other conventions. @xref{Coding
396 Systems,end-of-line}. Emacs can recognize several end-of-line
397 conventions in files and convert between them.
399 @item Environment Variable
400 An environment variable is one of a collection of variables stored by
401 the operating system, each one having a name and a value. Emacs can
402 access environment variables set by its parent shell, and it can set
403 variables in the environment it passes to programs it invokes.
410 An error occurs when an Emacs command cannot execute in the current
411 circumstances. When an error occurs, execution of the command stops
412 (unless the command has been programmed to do otherwise) and Emacs
413 reports the error by displaying an error message (q.v.@:). Type-ahead
414 is discarded. Then Emacs is ready to read another editing command.
417 An error message is a single line of output displayed by Emacs when the
418 user asks for something impossible to do (such as, killing text
419 forward when point is at the end of the buffer). They appear in the
420 echo area, accompanied by a beep.
423 @key{ESC} is a character used as a prefix for typing Meta characters on
424 keyboards lacking a @key{META} key. Unlike the @key{META} key (which,
425 like the @key{SHIFT} key, is held down while another character is
426 typed), you press the @key{ESC} key as you would press a letter key, and
427 it applies to the next character you type.
430 See `balanced expression.'
433 Expunging an Rmail file or Dired buffer or a Gnus newsgroup buffer is an
434 operation that truly discards the messages or files you have previously
435 flagged for deletion.
438 A face is a style of displaying characters. It specifies attributes
439 such as font family and size, foreground and background colors,
440 underline and strike-through, background stipple, etc. Emacs provides
441 features to associate specific faces with portions of buffer text, in
442 order to display that text as specified by the face attributes.
446 Emacs uses file locking to notice when two different users
447 start to edit one file at the same time. @xref{Interlocking}.
450 A file name is a name that refers to a file. File names may be relative
451 or absolute; the meaning of a relative file name depends on the current
452 directory, but an absolute file name refers to the same file regardless
453 of which directory is current. On GNU and Unix systems, an absolute
454 file name starts with a slash (the root directory) or with @samp{~/} or
455 @samp{~@var{user}/} (a home directory). On MS-Windows/MS-DOS, an
456 absolute file name can also start with a drive letter and a colon
459 Some people use the term ``pathname'' for file names, but we do not;
460 we use the word ``path'' only in the term ``search path'' (q.v.@:).
462 @item File-Name Component
463 A file-name component names a file directly within a particular
464 directory. On GNU and Unix systems, a file name is a sequence of
465 file-name components, separated by slashes. For example, @file{foo/bar}
466 is a file name containing two components, @samp{foo} and @samp{bar}; it
467 refers to the file named @samp{bar} in the directory named @samp{foo} in
468 the current directory. MS-DOS/MS-Windows file names can also use
469 backslashes to separate components, as in @file{foo\bar}.
472 The fill prefix is a string that should be expected at the beginning
473 of each line when filling is done. It is not regarded as part of the
474 text to be filled. @xref{Filling}.
477 Filling text means shifting text between consecutive lines so that all
478 the lines are approximately the same length. @xref{Filling}. Some
479 other editors call this feature `line wrapping.'
482 Font Lock is a mode that highlights parts of buffer text according to
483 its syntax. @xref{Font Lock}.
486 A fontset is a named collection of fonts. A fontset specification lists
487 character sets and which font to use to display each of them. Fontsets
488 make it easy to change several fonts at once by specifying the name of a
489 fontset, rather than changing each font separately. @xref{Fontsets}.
492 Formatted text is text that displays with formatting information while
493 you edit. Formatting information includes fonts, colors, and specified
494 margins. @xref{Formatted Text}.
496 @item Formfeed Character
500 A frame is a rectangular cluster of Emacs windows. Emacs starts out
501 with one frame, but you can create more. You can subdivide each frame
502 into Emacs windows (q.v.@:). When you are using a window system
503 (q.v.@:), all the frames can be visible at the same time.
504 @xref{Frames}. Some other editors use the term ``window'' for this,
505 but in Emacs a window means something else.
508 On a graphical display (q.v.@:), there's a narrow portion of the
509 frame (q.v.@:) between the text area and the window's border. Emacs
510 displays the fringe using a special face (q.v.@:) called
511 @code{fringe}. @xref{Faces,fringe}.
514 FTP is an acronym for File Transfer Protocol. Emacs uses an FTP client
515 program to provide access to remote files (q.v.@:).
518 A function key is a key on the keyboard that sends input but does not
519 correspond to any character. @xref{Function Keys}.
522 Global means ``independent of the current environment; in effect
523 throughout Emacs.'' It is the opposite of local (q.v.@:). Particular
524 examples of the use of `global' appear below.
527 A global definition of an abbrev (q.v.@:) is effective in all major
528 modes that do not have local (q.v.@:) definitions for the same abbrev.
532 The global keymap (q.v.@:) contains key bindings that are in effect
533 except when overridden by local key bindings in a major mode's local
534 keymap (q.v.@:). @xref{Keymaps}.
536 @item Global Mark Ring
537 The global mark ring records the series of buffers you have recently
538 set a mark (q.v.@:) in. In many cases you can use this to backtrack
539 through buffers you have been editing in, or in which you have found
540 tags (see `tags table'). @xref{Global Mark Ring}.
542 @item Global Substitution
543 Global substitution means replacing each occurrence of one string by
544 another string throughout a large amount of text. @xref{Replace}.
546 @item Global Variable
547 The global value of a variable (q.v.@:) takes effect in all buffers
548 that do not have their own local (q.v.@:) values for the variable.
551 @item Graphic Character
552 Graphic characters are those assigned pictorial images rather than
553 just names. All the non-Meta (q.v.@:) characters except for the
554 Control (q.v.@:) characters are graphic characters. These include
555 letters, digits, punctuation, and spaces; they do not include
556 @key{RET} or @key{ESC}. In Emacs, typing a graphic character inserts
557 that character (in ordinary editing modes). @xref{Inserting Text}.
559 @item Graphical Display
560 A graphical display is one that can display images and multiple fonts.
561 Usually it also has a window system (q.v.@:).
564 Highlighting text means displaying it with a different foreground and/or
565 background color to make it stand out from the rest of the text in the
568 Emacs uses highlighting in several ways. It highlights the region
569 whenever it is active (@pxref{Mark}). Incremental search also
570 highlights matches (@pxref{Incremental Search}). See also `font
574 Hardcopy means printed output. Emacs has commands for making printed
575 listings of text in Emacs buffers. @xref{Printing}.
578 @key{HELP} is the Emacs name for @kbd{C-h} or @key{F1}. You can type
579 @key{HELP} at any time to ask what options you have, or to ask what any
580 command does. @xref{Help}.
583 Help echo is a short message displayed in the echo area when the mouse
584 pointer is located on portions of display that require some
585 explanations. Emacs displays help echo for menu items, parts of the
586 mode line, tool-bar buttons, etc. On graphics displays, the messages
587 can be displayed as tooltips (q.v.@:). @xref{Tooltips}.
590 A hook is a list of functions to be called on specific occasions, such
591 as saving a buffer in a file, major mode activation, etc. By
592 customizing the various hooks, you can modify Emacs's behavior without
593 changing any of its code. @xref{Hooks}.
596 Hyper is the name of a modifier bit which a keyboard input character may
597 have. To make a character Hyper, type it while holding down the
598 @key{HYPER} key. Such characters are given names that start with
599 @kbd{Hyper-} (usually written @kbd{H-} for short). @xref{User Input,
603 ``Iff'' means ``if and only if.'' This terminology comes from
604 mathematics. Try to avoid using this term in documentation, since
605 many are unfamiliar with it and mistake it for a typo.
608 An inbox is a file in which mail is delivered by the operating system.
609 Rmail transfers mail from inboxes to Rmail files (q.v.@:) in which the
610 mail is then stored permanently or until explicitly deleted.
613 @item Incremental Search
614 Emacs provides an incremental search facility, whereby Emacs searches
615 for the string as you type it. @xref{Incremental Search}.
618 Indentation means blank space at the beginning of a line. Most
619 programming languages have conventions for using indentation to
620 illuminate the structure of the program, and Emacs has special
621 commands to adjust indentation.
624 @item Indirect Buffer
625 An indirect buffer is a buffer that shares the text of another buffer,
626 called its base buffer (q.v.@:). @xref{Indirect Buffers}.
629 Info is the hypertext format used by the GNU project for writing
633 An input event represents, within Emacs, one action taken by the user on
634 the terminal. Input events include typing characters, typing function
635 keys, pressing or releasing mouse buttons, and switching between Emacs
636 frames. @xref{User Input}.
639 An input method is a system for entering non-@acronym{ASCII} text characters by
640 typing sequences of @acronym{ASCII} characters (q.v.@:). @xref{Input Methods}.
643 Insertion means copying text into the buffer, either from the keyboard
644 or from some other place in Emacs.
647 Interlocking is a feature for warning when you start to alter a file
648 that someone else is already editing.
649 @xref{Interlocking,Interlocking,Simultaneous Editing}.
652 See `incremental search.'
655 Justification means adding extra spaces within lines of text to make
656 them extend exactly to a specified width.
657 @xref{Format Justification}.
663 Keyboard macros are a way of defining new Emacs commands from
664 sequences of existing ones, with no need to write a Lisp program.
665 @xref{Keyboard Macros}.
667 @cindex keyboard shortcuts
668 @item Keyboard Shortcut
669 A keyboard shortcut is a key sequence (q.v.@:) which invokes a
670 command. What some programs call ``assigning a keyboard shortcut,''
671 Emacs calls ``binding a key sequence.'' See `binding.'
674 A key sequence (key, for short) is a sequence of input events (q.v.@:)
675 that are meaningful as a single unit. If the key sequence is enough to
676 specify one action, it is a complete key (q.v.@:); if it is not enough,
677 it is a prefix key (q.v.@:). @xref{Keys}.
680 The keymap is the data structure that records the bindings (q.v.@:) of
681 key sequences to the commands that they run. For example, the global
682 keymap binds the character @kbd{C-n} to the command function
683 @code{next-line}. @xref{Keymaps}.
685 @item Keyboard Translation Table
686 The keyboard translation table is an array that translates the character
687 codes that come from the terminal into the character codes that make up
691 The kill ring is where all text you have killed recently is saved.
692 You can reinsert any of the killed text still in the ring; this is
693 called yanking (q.v.@:). @xref{Yanking}.
696 Killing means erasing text and saving it on the kill ring so it can be
697 yanked (q.v.@:) later. Some other systems call this ``cutting.''
698 Most Emacs commands that erase text perform killing, as opposed to
699 deletion (q.v.@:). @xref{Killing}.
702 Killing a job (such as, an invocation of Emacs) means making it cease
703 to exist. Any data within it, if not saved in a file, is lost.
706 @item Language Environment
707 Your choice of language environment specifies defaults for the input
708 method (q.v.@:) and coding system (q.v.@:). @xref{Language
709 Environments}. These defaults are relevant if you edit non-@acronym{ASCII} text
710 (@pxref{International}).
716 Lisp is a programming language. Most of Emacs is written in a dialect
717 of Lisp, called Emacs Lisp, that is extended with special features which
718 make it especially suitable for text editing tasks.
721 A list is, approximately, a text string beginning with an open
722 parenthesis and ending with the matching close parenthesis. In C mode
723 and other non-Lisp modes, groupings surrounded by other kinds of matched
724 delimiters appropriate to the language, such as braces, are also
725 considered lists. Emacs has special commands for many operations on
726 lists. @xref{Moving by Parens}.
729 Local means ``in effect only in a particular context''; the relevant
730 kind of context is a particular function execution, a particular
731 buffer, or a particular major mode. It is the opposite of `global'
732 (q.v.@:). Specific uses of `local' in Emacs terminology appear below.
735 A local abbrev definition is effective only if a particular major mode
736 is selected. In that major mode, it overrides any global definition
737 for the same abbrev. @xref{Abbrevs}.
740 A local keymap is used in a particular major mode; the key bindings
741 (q.v.@:) in the current local keymap override global bindings of the
742 same key sequences. @xref{Keymaps}.
745 A local value of a variable (q.v.@:) applies to only one buffer.
749 @kbd{M-} in the name of a character is an abbreviation for @key{META},
750 one of the modifier keys that can accompany any character.
751 @xref{User Input,M-}.
754 @kbd{M-C-} in the name of a character is an abbreviation for
755 Control-Meta; it means the same thing as @kbd{C-M-}. If your
756 terminal lacks a real @key{META} key, you type a Control-Meta character by
757 typing @key{ESC} and then typing the corresponding Control character.
758 @xref{User Input,C-M-}.
761 @kbd{M-x} is the key sequence which is used to call an Emacs command by
762 name. This is how you run commands that are not bound to key sequences.
763 @xref{M-x,M-x,Running Commands by Name}.
766 Mail means messages sent from one user to another through the computer
767 system, to be read at the recipient's convenience. Emacs has commands for
768 composing and sending mail, and for reading and editing the mail you have
769 received. @xref{Sending Mail}. @xref{Rmail}, for how to read mail.
771 @item Mail Composition Method
772 A mail composition method is a program runnable within Emacs for editing
773 and sending a mail message. Emacs lets you select from several
774 alternative mail composition methods. @xref{Mail Methods}.
777 The Emacs major modes are a mutually exclusive set of options, each of
778 which configures Emacs for editing a certain sort of text. Ideally,
779 each programming language has its own major mode. @xref{Major Modes}.
782 The space between the usable part of a window (including the
783 fringe) and the window edge.
786 The mark points to a position in the text. It specifies one end of the
787 region (q.v.@:), point being the other end. Many commands operate on
788 all the text from point to the mark. Each buffer has its own mark.
792 The mark ring is used to hold several recent previous locations of the
793 mark, just in case you want to move back to them. Each buffer has its
794 own mark ring; in addition, there is a single global mark ring (q.v.@:).
798 The menu bar is the line at the top of an Emacs frame. It contains
799 words you can click on with the mouse to bring up menus, or you can use
800 a keyboard interface to navigate it. @xref{Menu Bars}.
806 Meta is the name of a modifier bit which you can use in a command
807 character. To enter a meta character, you hold down the @key{META}
808 key while typing the character. We refer to such characters with
809 names that start with @kbd{Meta-} (usually written @kbd{M-} for
810 short). For example, @kbd{M-<} is typed by holding down @key{META}
811 and at the same time typing @kbd{<} (which itself is done, on most
812 terminals, by holding down @key{SHIFT} and typing @kbd{,}).
813 @xref{User Input,Meta}.
815 On some terminals, the @key{META} key is actually labeled @key{ALT}
819 A Meta character is one whose character code includes the Meta bit.
822 The minibuffer is the window that appears when necessary inside the
823 echo area (q.v.@:), used for reading arguments to commands.
826 @item Minibuffer History
827 The minibuffer history records the text you have specified in the past
828 for minibuffer arguments, so you can conveniently use the same text
829 again. @xref{Minibuffer History}.
832 A minor mode is an optional feature of Emacs which can be switched on
833 or off independently of all other features. Each minor mode has a
834 command to turn it on or off. @xref{Minor Modes}.
836 @item Minor Mode Keymap
837 A minor mode keymap is a keymap that belongs to a minor mode and is
838 active when that mode is enabled. Minor mode keymaps take precedence
839 over the buffer's local keymap, just as the local keymap takes
840 precedence over the global keymap. @xref{Keymaps}.
843 The mode line is the line at the bottom of each window (q.v.@:), giving
844 status information on the buffer displayed in that window. @xref{Mode
847 @item Modified Buffer
848 A buffer (q.v.@:) is modified if its text has been changed since the
849 last time the buffer was saved (or since when it was created, if it
850 has never been saved). @xref{Saving}.
853 Moving text means erasing it from one place and inserting it in
854 another. The usual way to move text is by killing (q.v.@:) it and then
855 yanking (q.v.@:) it. @xref{Killing}.
858 MULE refers to the Emacs features for editing multilingual non-@acronym{ASCII} text
859 using multibyte characters (q.v.@:). @xref{International}.
861 @item Multibyte Character
862 A multibyte character is a character that takes up several bytes in a
863 buffer. Emacs uses multibyte characters to represent non-@acronym{ASCII} text,
864 since the number of non-@acronym{ASCII} characters is much more than 256.
865 @xref{International Chars, International Characters}.
868 A named mark is a register (q.v.@:) in its role of recording a
869 location in text so that you can move point to that location.
873 Narrowing means creating a restriction (q.v.@:) that limits editing in
874 the current buffer to only a part of the text in the buffer. Text
875 outside that part is inaccessible for editing until the boundaries are
876 widened again, but it is still there, and saving the file saves it
877 all. @xref{Narrowing}.
880 Control-J characters in the buffer terminate lines of text and are
881 therefore also called newlines.
886 @code{nil} is a value usually interpreted as a logical ``false.'' Its
887 opposite is @code{t}, interpreted as ``true.''
889 @item Numeric Argument
890 A numeric argument is a number, specified before a command, to change
891 the effect of the command. Often the numeric argument serves as a
892 repeat count. @xref{Arguments}.
895 Overwrite mode is a minor mode. When it is enabled, ordinary text
896 characters replace the existing text after point rather than pushing
897 it to the right. @xref{Minor Modes}.
900 A page is a unit of text, delimited by formfeed characters (@acronym{ASCII}
901 control-L, code 014) coming at the beginning of a line. Some Emacs
902 commands are provided for moving over and operating on pages.
906 Paragraphs are the medium-size unit of human-language text. There are
907 special Emacs commands for moving over and operating on paragraphs.
911 We say that certain Emacs commands parse words or expressions in the
912 text being edited. Really, all they know how to do is find the other
913 end of a word or expression. @xref{Syntax}.
916 Point is the place in the buffer at which insertion and deletion
917 occur. Point is considered to be between two characters, not at one
918 character. The terminal's cursor (q.v.@:) indicates the location of
921 @item Prefix Argument
922 See `numeric argument.'
925 A prefix key is a key sequence (q.v.@:) whose sole function is to
926 introduce a set of longer key sequences. @kbd{C-x} is an example of
927 prefix key; any two-character sequence starting with @kbd{C-x} is
928 therefore a legitimate key sequence. @xref{Keys}.
930 @item Primary Rmail File
931 Your primary Rmail file is the file named @samp{RMAIL} in your home
932 directory. That's where Rmail stores your incoming mail, unless you
933 specify a different file name. @xref{Rmail}.
935 @item Primary Selection
936 The primary selection is one particular X selection (q.v.@:); it is the
937 selection that most X applications use for transferring text to and from
940 The Emacs kill commands set the primary selection and the yank command
941 uses the primary selection when appropriate. @xref{Killing}.
944 A prompt is text used to ask the user for input. Displaying a prompt
945 is called prompting. Emacs prompts always appear in the echo area
946 (q.v.@:). One kind of prompting happens when the minibuffer is used to
947 read an argument (@pxref{Minibuffer}); the echoing which happens when
948 you pause in the middle of typing a multi-character key sequence is also
949 a kind of prompting (@pxref{Echo Area}).
952 Query-replace is an interactive string replacement feature provided by
953 Emacs. @xref{Query Replace}.
956 Quitting means canceling a partially typed command or a running
957 command, using @kbd{C-g} (or @kbd{C-@key{BREAK}} on MS-DOS). @xref{Quitting}.
960 Quoting means depriving a character of its usual special significance.
961 The most common kind of quoting in Emacs is with @kbd{C-q}. What
962 constitutes special significance depends on the context and on
963 convention. For example, an ``ordinary'' character as an Emacs command
964 inserts itself; so in this context, a special character is any character
965 that does not normally insert itself (such as @key{DEL}, for example),
966 and quoting it makes it insert itself as if it were not special. Not
967 all contexts allow quoting. @xref{Inserting Text,Quoting}.
969 @item Quoting File Names
970 Quoting a file name turns off the special significance of constructs
971 such as @samp{$}, @samp{~} and @samp{:}. @xref{Quoted File Names}.
973 @item Read-Only Buffer
974 A read-only buffer is one whose text you are not allowed to change.
975 Normally Emacs makes buffers read-only when they contain text which
976 has a special significance to Emacs; for example, Dired buffers.
977 Visiting a file that is write-protected also makes a read-only buffer.
981 A rectangle consists of the text in a given range of columns on a given
982 range of lines. Normally you specify a rectangle by putting point at
983 one corner and putting the mark at the diagonally opposite corner.
986 @item Recursive Editing Level
987 A recursive editing level is a state in which part of the execution of
988 a command involves asking you to edit some text. This text may
989 or may not be the same as the text to which the command was applied.
990 The mode line indicates recursive editing levels with square brackets
991 (@samp{[} and @samp{]}). @xref{Recursive Edit}.
994 Redisplay is the process of correcting the image on the screen to
995 correspond to changes that have been made in the text being edited.
996 @xref{Screen,Redisplay}.
999 See `regular expression.'
1002 The region is the text between point (q.v.@:) and the mark (q.v.@:).
1003 Many commands operate on the text of the region. @xref{Mark,Region}.
1006 Registers are named slots in which text or buffer positions or
1007 rectangles can be saved for later use. @xref{Registers}. A related
1008 Emacs feature is `bookmarks' (q.v.@:).
1010 @item Regular Expression
1011 A regular expression is a pattern that can match various text strings;
1012 for example, @samp{a[0-9]+} matches @samp{a} followed by one or more
1013 digits. @xref{Regexps}.
1016 A remote file is a file that is stored on a system other than your own.
1017 Emacs can access files on other computers provided that they are
1018 connected to the same network as your machine, and (obviously) that
1019 you have a supported method to gain access to those files.
1020 @xref{Remote Files}.
1023 See `numeric argument.'
1026 See `global substitution.'
1029 A buffer's restriction is the amount of text, at the beginning or the
1030 end of the buffer, that is temporarily inaccessible. Giving a buffer a
1031 nonzero amount of restriction is called narrowing (q.v.@:); removing
1032 a restriction is called widening (q.v.@:). @xref{Narrowing}.
1035 @key{RET} is a character that in Emacs runs the command to insert a
1036 newline into the text. It is also used to terminate most arguments
1037 read in the minibuffer (q.v.@:). @xref{User Input,Return}.
1040 Reverting means returning to the original state. Emacs lets you
1041 revert a buffer by re-reading its file from disk. @xref{Reverting}.
1044 An Rmail file is a file containing text in a special format used by
1045 Rmail for storing mail. @xref{Rmail}.
1048 Saving a buffer means copying its text into the file that was visited
1049 (q.v.@:) in that buffer. This is the way text in files actually gets
1050 changed by your Emacs editing. @xref{Saving}.
1053 A scroll bar is a tall thin hollow box that appears at the side of a
1054 window. You can use mouse commands in the scroll bar to scroll the
1055 window. The scroll bar feature is supported only under windowing
1056 systems. @xref{Scroll Bars}.
1059 Scrolling means shifting the text in the Emacs window so as to see a
1060 different part of the buffer. @xref{Scrolling}.
1063 Searching means moving point to the next occurrence of a specified
1064 string or the next match for a specified regular expression.
1068 A search path is a list of directory names, to be used for searching for
1069 files for certain purposes. For example, the variable @code{load-path}
1070 holds a search path for finding Lisp library files. @xref{Lisp Libraries}.
1072 @item Secondary Selection
1073 The secondary selection is one particular X selection; some X
1074 applications can use it for transferring text to and from other
1075 applications. Emacs has special mouse commands for transferring text
1076 using the secondary selection. @xref{Secondary Selection}.
1078 @item Selected Frame
1079 The selected frame is the one your input currently operates on.
1082 @item Selected Window
1083 The selected window is the one your input currently operates on.
1084 @xref{Basic Window}.
1086 @item Selecting a Buffer
1087 Selecting a buffer means making it the current (q.v.@:) buffer.
1088 @xref{Select Buffer}.
1091 Windowing systems allow an application program to specify
1092 selections whose values are text. A program can also read the
1093 selections that other programs have set up. This is the principal way
1094 of transferring text between window applications. Emacs has commands to
1095 work with the primary (q.v.@:) selection and the secondary (q.v.@:)
1096 selection, and also with the clipboard (q.v.@:).
1098 @item Self-Documentation
1099 Self-documentation is the feature of Emacs which can tell you what any
1100 command does, or give you a list of all commands related to a topic
1101 you specify. You ask for self-documentation with the help character,
1102 @kbd{C-h}. @xref{Help}.
1104 @item Self-Inserting Character
1105 A character is self-inserting if typing that character inserts that
1106 character in the buffer. Ordinary printing and whitespace characters
1107 are self-inserting in Emacs, except in certain special major modes.
1110 Emacs has commands for moving by or killing by sentences.
1114 A sexp (short for ``s-expression'') is the basic syntactic unit of
1115 Lisp in its textual form: either a list, or Lisp atom. Sexps are also
1116 the balanced expressions (q.v.@:) of the Lisp language; this is why
1117 the commands for editing balanced expressions have `sexp' in their
1118 name. @xref{Expressions,Sexps}.
1120 @item Simultaneous Editing
1121 Simultaneous editing means two users modifying the same file at once.
1122 Simultaneous editing, if not detected, can cause one user to lose his
1123 or her work. Emacs detects all cases of simultaneous editing, and
1124 warns one of the users to investigate.
1125 @xref{Interlocking,Interlocking,Simultaneous Editing}.
1128 @key{SPC} is the space character, which you enter by pressing the
1132 The speedbar is a special tall frame that provides fast access to Emacs
1133 buffers, functions within those buffers, Info nodes, and other
1134 interesting parts of text within Emacs. @xref{Speedbar}.
1136 @item Spell Checking
1137 Spell checking means checking correctness of the written form of each
1138 one of the words in a text. Emacs uses the Ispell spelling-checker
1139 program to check the spelling of parts of a buffer via a convenient user
1140 interface. @xref{Spelling}.
1143 A string is a kind of Lisp data object which contains a sequence of
1144 characters. Many Emacs variables are intended to have strings as
1145 values. The Lisp syntax for a string consists of the characters in the
1146 string with a @samp{"} before and another @samp{"} after. A @samp{"}
1147 that is part of the string must be written as @samp{\"} and a @samp{\}
1148 that is part of the string must be written as @samp{\\}. All other
1149 characters, including newline, can be included just by writing them
1150 inside the string; however, backslash sequences as in C, such as
1151 @samp{\n} for newline or @samp{\241} using an octal character code, are
1154 @item String Substitution
1155 See `global substitution'.
1157 @item Syntax Highlighting
1161 The syntax table tells Emacs which characters are part of a word,
1162 which characters balance each other like parentheses, etc.
1166 Super is the name of a modifier bit which a keyboard input character may
1167 have. To make a character Super, type it while holding down the
1168 @key{SUPER} key. Such characters are given names that start with
1169 @kbd{Super-} (usually written @kbd{s-} for short). @xref{User Input,
1173 Suspending Emacs means stopping it temporarily and returning control
1174 to its parent process, which is usually a shell. Unlike killing a job
1175 (q.v.@:), you can later resume the suspended Emacs job without losing
1176 your buffers, unsaved edits, undo history, etc. @xref{Exiting}.
1179 @key{TAB} is the tab character. In Emacs it is typically used for
1180 indentation or completion.
1183 A tags table is a file that serves as an index to the function
1184 definitions in one or more other files. @xref{Tags}.
1186 @item Termscript File
1187 A termscript file contains a record of all characters sent by Emacs to
1188 the terminal. It is used for tracking down bugs in Emacs redisplay.
1189 Emacs does not make a termscript file unless you tell it to.
1193 `Text' has two meanings (@pxref{Text}):
1197 Data consisting of a sequence of characters, as opposed to binary
1198 numbers, executable programs, and the like. The basic contents of an
1199 Emacs buffer (aside from the text properties, q.v.@:) are always text
1202 Data consisting of written human language, as opposed to programs,
1203 or following the stylistic conventions of human language.
1206 @item Text-only Terminal
1207 A text-only terminal is a display that is limited to displaying text in
1208 character units. Such a terminal cannot control individual pixels it
1209 displays. Emacs supports a subset of display features on text-only
1212 @item Text Properties
1213 Text properties are annotations recorded for particular characters in
1214 the buffer. Images in the buffer are recorded as text properties;
1215 they also specify formatting information. @xref{Editing Format Info}.
1218 The tool bar is a line (sometimes multiple lines) of icons at the top
1219 of an Emacs frame. Clicking on one of these icons executes a command.
1220 You can think of this as a graphical relative of the menu bar (q.v.@:).
1224 Tooltips are small windows displaying a help echo (q.v.@:) text that
1225 explains parts of the display, lists useful options available via mouse
1226 clicks, etc. @xref{Tooltips}.
1229 Top level is the normal state of Emacs, in which you are editing the
1230 text of the file you have visited. You are at top level whenever you
1231 are not in a recursive editing level (q.v.@:) or the minibuffer
1232 (q.v.@:), and not in the middle of a command. You can get back to top
1233 level by aborting (q.v.@:) and quitting (q.v.@:). @xref{Quitting}.
1236 Transposing two units of text means putting each one into the place
1237 formerly occupied by the other. There are Emacs commands to transpose
1238 two adjacent characters, words, balanced expressions (q.v.@:) or lines
1239 (@pxref{Transpose}).
1242 Truncating text lines in the display means leaving out any text on a
1243 line that does not fit within the right margin of the window
1244 displaying it. See also `continuation line.'
1245 @xref{Continuation Lines,Truncation}.
1248 See `text-only terminal.'
1251 Undoing means making your previous editing go in reverse, bringing
1252 back the text that existed earlier in the editing session.
1256 A user option is a face (q.v.@:) or a variable (q.v.@:) that exists so
1257 that you can customize Emacs by setting it to a new value.
1258 @xref{Easy Customization}.
1261 A variable is an object in Lisp that can store an arbitrary value.
1262 Emacs uses some variables for internal purposes, and has others (known
1263 as `user options' (q.v.@:)) just so that you can set their values to
1264 control the behavior of Emacs. The variables used in Emacs that you
1265 are likely to be interested in are listed in the Variables Index in
1266 this manual (@pxref{Variable Index}). @xref{Variables}, for
1267 information on variables.
1269 @item Version Control
1270 Version control systems keep track of multiple versions of a source file.
1271 They provide a more powerful alternative to keeping backup files (q.v.@:).
1272 @xref{Version Control}.
1275 Visiting a file means loading its contents into a buffer (q.v.@:)
1276 where they can be edited. @xref{Visiting}.
1279 Whitespace is any run of consecutive formatting characters (space,
1280 tab, newline, and backspace).
1283 Widening is removing any restriction (q.v.@:) on the current buffer;
1284 it is the opposite of narrowing (q.v.@:). @xref{Narrowing}.
1287 Emacs divides a frame (q.v.@:) into one or more windows, each of which
1288 can display the contents of one buffer (q.v.@:) at any time.
1289 @xref{Screen}, for basic information on how Emacs uses the screen.
1290 @xref{Windows}, for commands to control the use of windows. Some
1291 other editors use the term ``window'' for what we call a `frame'
1295 A window system is software that operates on a graphical display
1296 (q.v.@:), to subdivide the screen so that multiple applications can
1297 have their] own windows at the same time. All modern operating systems
1298 include a window system.
1304 Word search is searching for a sequence of words, considering the
1305 punctuation between them as insignificant. @xref{Word Search}.
1308 WYSIWYG stands for ``What you see is what you get.'' Emacs generally
1309 provides WYSIWYG editing for files of characters; in Enriched mode
1310 (@pxref{Formatted Text}), it provides WYSIWYG editing for files that
1311 include text formatting information.
1314 Yanking means reinserting text previously killed. It can be used to
1315 undo a mistaken kill, or for copying or moving text. Some other
1316 systems call this ``pasting.'' @xref{Yanking}.
1320 arch-tag: 0dd53ce1-5f09-4ac2-b13b-cf22b0f28d23