This is ../../info/emacs, produced by makeinfo version 4.13 from
emacs.texi.

This is the Sixteenth edition of the `GNU Emacs Manual',
updated for Emacs version 23.4.

   Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1996, 1997, 1998,
1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
2011, 2012  Free Software Foundation, Inc.

     Permission is granted to copy, distribute and/or modify this
     document under the terms of the GNU Free Documentation License,
     Version 1.3 or any later version published by the Free Software
     Foundation; with the Invariant Sections being "The GNU Manifesto,"
     "Distribution" and "GNU GENERAL PUBLIC LICENSE," with the
     Front-Cover texts being "A GNU Manual," and with the Back-Cover
     Texts as in (a) below.  A copy of the license is included in the
     section entitled "GNU Free Documentation License."

     (a) The FSF's Back-Cover Text is: "You have the freedom to copy and
     modify this GNU manual.  Buying copies from the FSF supports it in
     developing GNU and promoting software freedom."

INFO-DIR-SECTION Emacs
START-INFO-DIR-ENTRY
* Emacs: (emacs).       The extensible self-documenting text editor.
END-INFO-DIR-ENTRY


File: emacs,  Node: Top,  Next: Distrib,  Prev: (dir),  Up: (dir)

The Emacs Editor
****************

Emacs is the extensible, customizable, self-documenting real-time
display editor.  This Info file describes how to edit with Emacs and
some of how to customize it; it corresponds to GNU Emacs version
23.4.

   To learn more about the Info documentation system, type `h', to
visit a programmed instruction sequence for the Info commands.

   For information on extending Emacs, see *note Emacs Lisp: (elisp)Top.

   This is the Sixteenth edition of the `GNU Emacs Manual',
updated for Emacs version 23.4.

   Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1996, 1997, 1998,
1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
2011, 2012  Free Software Foundation, Inc.

     Permission is granted to copy, distribute and/or modify this
     document under the terms of the GNU Free Documentation License,
     Version 1.3 or any later version published by the Free Software
     Foundation; with the Invariant Sections being "The GNU Manifesto,"
     "Distribution" and "GNU GENERAL PUBLIC LICENSE," with the
     Front-Cover texts being "A GNU Manual," and with the Back-Cover
     Texts as in (a) below.  A copy of the license is included in the
     section entitled "GNU Free Documentation License."

     (a) The FSF's Back-Cover Text is: "You have the freedom to copy and
     modify this GNU manual.  Buying copies from the FSF supports it in
     developing GNU and promoting software freedom."

* Menu:

* Distrib::             How to get the latest Emacs distribution.
* Intro::               An introduction to Emacs concepts.
* Glossary::            Terms used in this manual.

Indexes (each index contains a large menu)
* Key Index::           An item for each standard Emacs key sequence.
* Option Index::        An item for every command-line option.
* Command Index::       An item for each command name.
* Variable Index::      An item for each documented variable.
* Concept Index::       An item for each concept.

* Acknowledgments::     Major contributors to GNU Emacs.

Important General Concepts
* Screen::              How to interpret what you see on the screen.
* User Input::          Kinds of input events (characters, buttons,
                          function keys).
* Keys::                Key sequences: what you type to request one
                          editing action.
* Commands::            Named functions run by key sequences to do editing.
* Entering Emacs::      Starting Emacs from the shell.
* Exiting::             Stopping or killing Emacs.

Fundamental Editing Commands
* Basic::               The most basic editing commands.
* Minibuffer::          Entering arguments that are prompted for.
* M-x::                 Invoking commands by their names.
* Help::                Commands for asking Emacs about its commands.

Important Text-Changing Commands
* Mark::                The mark: how to delimit a ``region'' of text.
* Killing::             Killing (cutting) text.
* Yanking::             Recovering killed text.  Moving text. (Pasting.)
* Accumulating Text::   Other ways of copying text.
* Rectangles::          Operating on the text inside a rectangle on the screen.
* CUA Bindings::        Using C-x, C-c, C-v for copy
                          and paste, with enhanced rectangle support.
* Registers::           Saving a text string or a location in the buffer.
* Display::             Controlling what text is displayed.
* Search::              Finding or replacing occurrences of a string.
* Fixit::               Commands especially useful for fixing typos.
* Keyboard Macros::     A keyboard macro records a sequence of
                          keystrokes to be replayed with a single command.

Major Structures of Emacs
* Files::               All about handling files.
* Buffers::             Multiple buffers; editing several files at once.
* Windows::             Viewing two pieces of text at once.
* Frames::              Running the same Emacs session in multiple X windows.
* International::       Using non-ASCII character sets.

Advanced Features
* Major Modes::         Text mode vs. Lisp mode vs. C mode...
* Indentation::         Editing the white space at the beginnings of lines.
* Text::                Commands and modes for editing English.
* Programs::            Commands and modes for editing programs.
* Building::            Compiling, running and debugging programs.
* Maintaining::         Features for maintaining large programs.
* Abbrevs::             How to define text abbreviations to reduce
                          the number of characters you must type.

* Picture Mode::        Editing pictures made up of characters using
                          the quarter-plane screen model.
* Sending Mail::        Sending mail in Emacs.
* Rmail::               Reading mail in Emacs.
* Dired::               You can ``edit'' a directory to manage files in it.
* Calendar/Diary::      The calendar and diary facilities.
* Document View::       Viewing PDF, PS and DVI files.
* Gnus::                How to read netnews with Emacs.
* Shell::               Executing shell commands from Emacs.
* Emacs Server::        Using Emacs as an editing server for `mail', etc.
* Printing::            Printing hardcopies of buffers or regions.
* Sorting::             Sorting lines, paragraphs or pages within Emacs.
* Narrowing::           Restricting display and editing to a portion
                          of the buffer.
* Two-Column::          Splitting apart columns to edit them
                          in side-by-side windows.
* Editing Binary Files::Using Hexl mode to edit binary files.
* Saving Emacs Sessions:: Saving Emacs state from one session to the next.
* Recursive Edit::      A command can allow you to do editing
                          "within the command".  This is called a
                          "recursive editing level".
* Emulation::           Emulating some other editors with Emacs.
* Hyperlinking::        Following links in buffers.
* Dissociated Press::   Dissociating text for fun.
* Amusements::          Various games and hacks.
* Customization::       Modifying the behavior of Emacs.

Recovery from Problems
* Quitting::            Quitting and aborting.
* Lossage::             What to do if Emacs is hung or malfunctioning.
* Bugs::                How and when to report a bug.
* Contributing::        How to contribute improvements to Emacs.
* Service::             How to get help for your own Emacs needs.

Appendices
* Copying::             The GNU General Public License gives you permission
                          to redistribute GNU Emacs on certain terms;
                          it also explains that there is no warranty.
* GNU Free Documentation License:: The license for this documentation.
* Emacs Invocation::    Hairy startup options.
* X Resources::         X resources for customizing Emacs.
* Antinews::            Information about Emacs version 22.
* Mac OS / GNUstep::    Using Emacs under Mac OS and GNUstep.
* Microsoft Windows::   Using Emacs on Microsoft Windows and MS-DOS.
* Manifesto::           What's GNU?  Gnu's Not Unix!


 --- The Detailed Node Listing ---
 ---------------------------------

Here are some other nodes which are really inferiors of the ones
already listed, mentioned here so you can get to them in one step:

The Organization of the Screen

* Point::               The place in the text where editing commands operate.
* Echo Area::           Short messages appear at the bottom of the screen.
* Mode Line::           Interpreting the mode line.
* Menu Bar::            How to use the menu bar.

Basic Editing Commands

* Inserting Text::      Inserting text by simply typing it.
* Moving Point::        Moving the cursor to the place where you want to
                        change something.
* Erasing::             Deleting and killing text.
* Basic Undo::          Undoing recent changes in the text.
* Basic Files::         Visiting, creating, and saving files.
* Basic Help::          Asking what a character does.
* Blank Lines::         Making and deleting blank lines.
* Continuation Lines::  How Emacs displays lines too wide for the screen.
* Position Info::       What page, line, row, or column is point on?
* Arguments::           Numeric arguments for repeating a command N times.
* Repeating::           Repeating the previous command quickly.

The Minibuffer

* Minibuffer File::     Entering file names with the minibuffer.
* Minibuffer Edit::     How to edit in the minibuffer.
* Completion::          An abbreviation facility for minibuffer input.
* Minibuffer History::  Reusing recent minibuffer arguments.
* Repetition::          Re-executing commands that used the minibuffer.
* Passwords::           Entering passwords in the echo area.

Completion

* Completion Example::  Examples of using completion.
* Completion Commands:: A list of completion commands.
* Strict Completion::   Different types of completion.
* Completion Options::  Options for completion.

Help

* 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.
* Help Mode::           Special features of Help mode and Help buffers.
* Library Keywords::    Finding Lisp libraries by keywords (topics).
* Language Help::       Help relating to international language support.
* Misc Help::           Other help commands.
* Help Files::          Commands to display pre-written help files.
* Help Echo::           Help on active text and tooltips (`balloon help').

The Mark and the Region

* Setting Mark::        Commands to set the mark.
* Marking Objects::     Commands to put region around textual units.
* Using Region::        Summary of ways to operate on contents of the region.
* Mark Ring::           Previous mark positions saved so you can go back there.
* Global Mark Ring::    Previous mark positions in various buffers.
* Shift Selection::     Using shifted cursor motion keys.
* Persistent Mark::     Keeping the mark active all the time.

Killing and Moving Text

* Deletion::            Commands for deleting small amounts of text and
                          blank areas.
* Killing by Lines::    How to kill entire lines of text at one time.
* Other Kill Commands:: Commands to kill large regions of text and
                          syntactic units such as words and sentences.
* Kill Options::        Options that affect killing.

Yanking

* Kill Ring::           Where killed text is stored.  Basic yanking.
* Appending Kills::     Several kills in a row all yank together.
* Earlier Kills::       Yanking something killed some time ago.

Registers

* RegPos::              Saving positions in registers.
* RegText::             Saving text in registers.
* RegRect::             Saving rectangles in registers.
* RegConfig::           Saving window configurations in registers.
* RegNumbers::          Numbers in registers.
* RegFiles::            File names in registers.
* Bookmarks::           Bookmarks are like registers, but persistent.

Controlling the Display

* Scrolling::              Commands to move text up and down in a window.
* Auto Scrolling::         Redisplay scrolls text automatically when needed.
* Horizontal Scrolling::   Moving text left and right in a window.
* Follow Mode::            Follow mode lets two windows scroll as one.
* Faces::                  How to change the display style using faces.
* Standard Faces::         Emacs' predefined faces.
* Temporary Face Changes:: Commands to temporarily modify the default text face
* Font Lock::              Minor mode for syntactic highlighting using faces.
* Highlight Interactively:: Tell Emacs what text to highlight.
* Fringes::                Enabling or disabling window fringes.
* Displaying Boundaries::  Displaying top and bottom of the buffer.
* Useless Whitespace::     Showing possibly-spurious trailing whitespace.
* Selective Display::      Hiding lines with lots of indentation.
* Optional Mode Line::     Optional mode line display features.
* Text Display::           How text characters are normally displayed.
* Cursor Display::         Features for displaying the cursor.
* Line Truncation::        Truncating lines to fit the screen width instead
                             of continuing them to multiple screen lines.
* Visual Line Mode::       Word wrap and screen line-based editing.
* Display Custom::         Information on variables for customizing display.

Searching and Replacement

* Incremental Search::     Search happens as you type the string.
* Nonincremental Search::  Specify entire string and then search.
* Word Search::            Search for sequence of words.
* Regexp Search::          Search for match for a regexp.
* Regexps::                Syntax of regular expressions.
* Regexp Backslash::       Regular expression constructs starting with `\'.
* Regexp Example::         A complex regular expression explained.
* Search Case::            To ignore case while searching, or not.
* Replace::                Search, and replace some or all matches.
* Other Repeating Search:: Operating on all matches for some regexp.

Incremental Search

* Basic Isearch::       Basic incremental search commands.
* Repeat Isearch::      Searching for the same string again.
* Error in Isearch::    When your string is not found.
* Special Isearch::     Special input in incremental search.
* Isearch Yank::        Commands that grab text into the search string
                          or else edit the search string.
* Isearch Scroll::      Scrolling during an incremental search.
* Isearch Minibuffer::  Incremental search of the minibuffer history.
* Slow Isearch::        Incremental search features for slow terminals.

Replacement Commands

* Unconditional Replace::  Replacing all matches for a string.
* Regexp Replace::         Replacing all matches for a regexp.
* Replacement and Case::   How replacements preserve case of letters.
* Query Replace::          How to use querying.

Commands for Fixing Typos

* Undo::                The Undo commands.
* Transpose::           Exchanging two characters, words, lines, lists...
* Fixing Case::         Correcting case of last word entered.
* Spelling::            Apply spelling checker to a word, or a whole file.

Keyboard Macros

* Basic Keyboard Macro::     Defining and running keyboard macros.
* Keyboard Macro Ring::      Where previous keyboard macros are saved.
* Keyboard Macro Counter::   Inserting incrementing numbers in macros.
* Keyboard Macro Query::     Making keyboard macros do different things each time.
* Save Keyboard Macro::      Giving keyboard macros names; saving them in files.
* Edit Keyboard Macro::      Editing keyboard macros.
* Keyboard Macro Step-Edit:: Interactively executing and editing a keyboard
                                macro.

File Handling

* File Names::          How to type and edit file-name arguments.
* Visiting::            Visiting a file prepares Emacs to edit the file.
* Saving::              Saving makes your changes permanent.
* Reverting::           Reverting cancels all the changes not saved.
* Autorevert::          Auto Reverting non-file buffers.
* Auto Save::           Auto Save periodically protects against loss of data.
* File Aliases::        Handling multiple names for one file.
* Directories::         Creating, deleting, and listing file directories.
* Comparing Files::     Finding where two files differ.
* Diff Mode::           Mode for editing file differences.
* Misc File Ops::       Other things you can do on files.
* Compressed Files::    Accessing compressed files.
* File Archives::       Operating on tar, zip, jar etc. archive files.
* Remote Files::        Accessing files on other sites.
* Quoted File Names::   Quoting special characters in file names.
* File Name Cache::     Completion against a list of files you often use.
* File Conveniences::   Convenience Features for Finding Files.
* Filesets::            Handling sets of files.

Saving Files

* Save Commands::       Commands for saving files.
* Backup::              How Emacs saves the old version of your file.
* Customize Save::      Customizing the saving of files.
* Interlocking::        How Emacs protects against simultaneous editing
                          of one file by two users.
* File Shadowing::      Copying files to "shadows" automatically.
* Time Stamps::         Emacs can update time stamps on saved files.

Backup Files

* Backup Names::        How backup files are named.
* Backup Deletion::     Emacs deletes excess numbered backups.
* Backup Copying::      Backups can be made by copying or renaming.

Auto Reverting Non-File Buffers

* Auto Reverting the Buffer Menu:: Auto Revert of the Buffer Menu.
* Auto Reverting Dired::           Auto Revert of Dired buffers.
* Supporting additional buffers::  How to add more Auto Revert support.

Auto-Saving: Protection Against Disasters

* Auto Save Files::     The file where auto-saved changes are
                          actually made until you save the file.
* Auto Save Control::   Controlling when and how often to auto-save.
* Recover::             Recovering text from auto-save files.

Using Multiple Buffers

* Select Buffer::       Creating a new buffer or reselecting an old one.
* List Buffers::        Getting a list of buffers that exist.
* Misc Buffer::         Renaming; changing read-onlyness; copying text.
* Kill Buffer::         Killing buffers you no longer need.
* Several Buffers::     How to go through the list of all buffers
                          and operate variously on several of them.
* Indirect Buffers::    An indirect buffer shares the text of another buffer.
* Buffer Convenience::  Convenience and customization features for
                          buffer handling.

Convenience Features and Customization of Buffer Handling

* Uniquify::            Making buffer names unique with directory parts.
* Iswitchb::            Switching between buffers with substrings.
* Buffer Menus::        Configurable buffer menu.

Multiple Windows

* Basic Window::        Introduction to Emacs windows.
* Split Window::        New windows are made by splitting existing windows.
* Other Window::        Moving to another window or doing something to it.
* Pop Up Window::       Finding a file or buffer in another window.
* Force Same Window::   Forcing certain buffers to appear in the selected
                          window rather than in another window.
* Change Window::       Deleting windows and changing their sizes.
* Window Convenience::  Convenience functions for window handling.

Frames and Graphical Displays

* Cut and Paste::       Mouse commands for cut and paste.
* Mouse References::    Using the mouse to select an item from a list.
* Menu Mouse Clicks::   Mouse clicks that bring up menus.
* Mode Line Mouse::     Mouse clicks on the mode line.
* Creating Frames::     Creating additional Emacs frames with various contents.
* Frame Commands::      Iconifying, deleting, and switching frames.
* Fonts::               Changing the frame font.
* Speedbar::            How to make and use a speedbar frame.
* Multiple Displays::   How one Emacs job can talk to several displays.
* Special Buffer Frames::  You can make certain buffers have their own frames.
* Frame Parameters::    Changing the colors and other modes of frames.
* Scroll Bars::         How to enable and disable scroll bars; how to use them.
* Wheeled Mice::        Using mouse wheels for scrolling.
* Drag and Drop::       Using drag and drop to open files and insert text.
* Menu Bars::           Enabling and disabling the menu bar.
* Tool Bars::           Enabling and disabling the tool bar.
* Dialog Boxes::        Controlling use of dialog boxes.
* Tooltips::            Displaying information at the current mouse position.
* Mouse Avoidance::     Moving the mouse pointer out of the way.
* Non-Window Terminals::  Multiple frames on terminals that show only one.
* Text-Only Mouse::     Using the mouse in text-only terminals.

Killing and Yanking on Graphical Displays

* Mouse Commands::      Moving, cutting, and pasting, with the mouse.
* Word and Line Mouse:: Mouse commands for selecting whole words or lines.
* Cut/Paste Other App:: Transfering text between Emacs and other apps.
* Secondary Selection:: Cutting without altering point and mark.
* Clipboard::           Using the clipboard for selections.

International Character Set Support

* International Chars::     Basic concepts of multibyte characters.
* Enabling Multibyte::      Controlling whether to use multibyte characters.
* Language Environments::   Setting things up for the language you use.
* Input Methods::           Entering text characters not on your keyboard.
* Select Input Method::     Specifying your choice of input methods.
* Coding Systems::          Character set conversion when you read and
                              write files, and so on.
* Recognize Coding::        How Emacs figures out which conversion to use.
* Specify Coding::          Specifying a file's coding system explicitly.
* Output Coding::           Choosing coding systems for output.
* Text Coding::             Choosing conversion to use for file text.
* Communication Coding::    Coding systems for interprocess communication.
* File Name Coding::        Coding systems for file _names_.
* Terminal Coding::         Specifying coding systems for converting
                              terminal input and output.
* Fontsets::                Fontsets are collections of fonts
                              that cover the whole spectrum of characters.
* Defining Fontsets::       Defining a new fontset.
* Modifying Fontsets::      Modifying an existing fontset.
* Undisplayable Characters::When characters don't display.
* Unibyte Mode::            You can pick one European character set
                              to use without multibyte characters.
* Charsets::                How Emacs groups its internal character codes.

Major Modes

* Choosing Modes::      How major modes are specified or chosen.

Indentation

* Indentation Commands::  Various commands and techniques for indentation.
* Tab Stops::             You can set arbitrary "tab stops" and then
                            indent to the next tab stop when you want to.
* Just Spaces::           You can request indentation using just spaces.

Commands for Human Languages

* Words::               Moving over and killing words.
* Sentences::           Moving over and killing sentences.
* Paragraphs::          Moving over paragraphs.
* Pages::               Moving over pages.
* Filling::             Filling or justifying text.
* Case::                Changing the case of text.
* Text Mode::           The major modes for editing text files.
* Outline Mode::        Editing outlines.
* TeX Mode::            Editing input to the formatter TeX.
* HTML Mode::           Editing HTML and SGML files.
* Nroff Mode::          Editing input to the formatter nroff.
* Formatted Text::      Editing formatted text directly in WYSIWYG fashion.
* Text Based Tables::   Editing text-based tables in WYSIWYG fashion.

Filling Text

* Auto Fill::           Auto Fill mode breaks long lines automatically.
* Fill Commands::       Commands to refill paragraphs and center lines.
* Fill Prefix::         Filling paragraphs that are indented
                          or in a comment, etc.
* Adaptive Fill::       How Emacs can determine the fill prefix automatically.
* Refill::              Keeping paragraphs filled.
* Longlines::           Editing text with very long lines.

Outline Mode

* Outline Format::      What the text of an outline looks like.
* Outline Motion::      Special commands for moving through
                          outlines.
* Outline Visibility::  Commands to control what is visible.
* Outline Views::       Outlines and multiple views.
* Foldout::             Folding means zooming in on outlines.

TeX Mode

* TeX Editing::         Special commands for editing in TeX mode.
* LaTeX Editing::       Additional commands for LaTeX input files.
* TeX Print::           Commands for printing part of a file with TeX.
* TeX Misc::            Customization of TeX mode, and related features.

Editing Formatted Text

* Requesting Formatted Text::   Entering and exiting Enriched mode.
* Hard and Soft Newlines::      There are two different kinds of newlines.
* Editing Format Info::         How to edit text properties.
* Format Faces::                Bold, italic, underline, etc.
* Format Colors::               Changing the color of text.
* Format Indentation::          Changing the left and right margins.
* Format Justification::        Centering, setting text flush with the
                                  left or right margin, etc.
* Format Properties::           The "special" text properties submenu.
* Forcing Enriched Mode::       How to force use of Enriched mode.


Editing Text-based Tables

* Table Definition::    What is a text based table.
* Table Creation::      How to create a table.
* Table Recognition::   How to activate and deactivate tables.
* Cell Commands::       Cell-oriented commands in a table.
* Cell Justification::  Justifying cell contents.
* Row Commands::        Manipulating rows of table cell.
* Column Commands::     Manipulating columns of table cell.
* Fixed Width Mode::    Fixing cell width.
* Table Conversion::    Converting between plain text and tables.
* Measuring Tables::    Analyzing table dimension.
* Table Misc::          Table miscellany.

Editing Programs

* Program Modes::       Major modes for editing programs.
* Defuns::              Commands to operate on major top-level parts
                          of a program.
* Program Indent::      Adjusting indentation to show the nesting.
* Parentheses::         Commands that operate on parentheses.
* Comments::            Inserting, killing, and aligning comments.
* Documentation::       Getting documentation of functions you plan to call.
* Hideshow::            Displaying blocks selectively.
* Symbol Completion::   Completion on symbol names of your program or language.
* Glasses::             Making identifiersLikeThis more readable.
* Semantic::            Suite of editing tools based on source code parsing.
* Misc for Programs::   Other Emacs features useful for editing programs.
* C Modes::             Special commands of C, C++, Objective-C,
                          Java, and Pike modes.
* Asm Mode::            Asm mode and its special features.
* Fortran::             Fortran mode and its special features.

Top-Level Definitions, or Defuns

* Left Margin Paren::   An open-paren or similar opening delimiter
                          starts a defun if it is at the left margin.
* Moving by Defuns::    Commands to move over or mark a major definition.
* Imenu::               Making buffer indexes as menus.
* Which Function::      Which Function mode shows which function you are in.

Indentation for Programs

* Basic Indent::        Indenting a single line.
* Multi-line Indent::   Commands to reindent many lines at once.
* Lisp Indent::         Specifying how each Lisp function should be indented.
* C Indent::            Extra features for indenting C and related modes.
* Custom C Indent::     Controlling indentation style for C and related modes.

Commands for Editing with Parentheses

* Expressions::         Expressions with balanced parentheses.
* Moving by Parens::    Commands for moving up, down and across
                          in the structure of parentheses.
* Matching::            Insertion of a close-delimiter flashes matching open.

Manipulating Comments

* Comment Commands::    Inserting, killing, and aligning comments.
* Multi-Line Comments:: Commands for adding and editing multi-line comments.
* Options for Comments::Customizing the comment features.

Documentation Lookup

* Info Lookup::         Looking up library functions and commands
                          in Info files.
* Man Page::            Looking up man pages of library functions and commands.
* Lisp Doc::            Looking up Emacs Lisp functions, etc.

C and Related Modes

* Motion in C::         Commands to move by C statements, etc.
* Electric C::          Colon and other chars can automatically reindent.
* Hungry Delete::       A more powerful DEL command.
* Other C Commands::    Filling comments, viewing expansion of macros,
                          and other neat features.

Fortran Mode

* Fortran Motion::      Moving point by statements or subprograms.
* Fortran Indent::      Indentation commands for Fortran.
* Fortran Comments::    Inserting and aligning comments.
* Fortran Autofill::    Auto fill support for Fortran.
* Fortran Columns::     Measuring columns for valid Fortran.
* Fortran Abbrev::      Built-in abbrevs for Fortran keywords.

Fortran Indentation

* ForIndent Commands::  Commands for indenting and filling Fortran.
* ForIndent Cont::      How continuation lines indent.
* ForIndent Num::       How line numbers auto-indent.
* ForIndent Conv::      Conventions you must obey to avoid trouble.
* ForIndent Vars::      Variables controlling Fortran indent style.

Compiling and Testing Programs

* Compilation::         Compiling programs in languages other
                          than Lisp (C, Pascal, etc.).
* Compilation Mode::    The mode for visiting compiler errors.
* Compilation Shell::   Customizing your shell properly
                          for use in the compilation buffer.
* Grep Searching::      Searching with grep.
* Flymake::             Finding syntax errors on the fly.
* Debuggers::           Running symbolic debuggers for non-Lisp programs.
* Executing Lisp::      Various modes for editing Lisp programs,
                          with different facilities for running
                          the Lisp programs.
* Lisp Libraries::      Creating Lisp programs to run in Emacs.
* Lisp Eval::           Executing a single Lisp expression in Emacs.
* Lisp Interaction::    Executing Lisp in an Emacs buffer.
* External Lisp::       Communicating through Emacs with a separate Lisp.

Running Debuggers Under Emacs

* Starting GUD::        How to start a debugger subprocess.
* Debugger Operation::  Connection between the debugger and source buffers.
* Commands of GUD::     Key bindings for common commands.
* GUD Customization::   Defining your own commands for GUD.
* GDB Graphical Interface::  An enhanced mode that uses GDB features to
                          implement a graphical debugging environment through
                          Emacs.

GDB Graphical Interface

* GDB-UI Layout::       Control the number of displayed buffers.
* Source Buffers::      Use the mouse in the fringe/margin to
                          control your program.
* Breakpoints Buffer::  A breakpoint control panel.
* Stack Buffer::        Select a frame from the call stack.
* Other GDB-UI Buffers::Input/output, locals, registers,
                          assembler, threads and memory buffers.
* Watch Expressions::   Monitor variable values in the speedbar.

Maintaining Large Programs

* Version Control::     Using version control systems.
* Change Log::          Maintaining a change history for your program.
* Tags::                Go directly to any function in your program in one
                          command.  Tags remembers which file it is in.
* EDE::                 An integrated development environment for Emacs.
* Emerge::              A convenient way of merging two versions of a program.

Version Control

* Introduction to VC::  How version control works in general.
* VC Mode Line::        How the mode line shows version control status.
* Basic VC Editing::    How to edit a file under version control.
* Log Buffer::          Features available in log entry buffers.
* Old Revisions::       Examining and comparing old versions.
* Secondary VC Commands:: The commands used a little less frequently.
* VC Directory Mode::   Listing files managed by version control.
* Branches::            Multiple lines of development.
* Remote Repositories:: Efficient access to remote CVS servers.
* Revision Tags::       Symbolic names for revisions.
* Miscellaneous VC::    Various other commands and features of VC.
* Customizing VC::      Variables that change VC's behavior.

Introduction to Version Control

* Why Version Control?::    Understanding the problems it addresses.
* Version Control Systems:: Supported version control back-end systems.
* VCS Concepts::            Words and concepts related to version control.
* VCS Merging::             How file conflicts are handled.
* VCS Changesets::          Changesets in version control.
* VCS Repositories::        Where version control repositories are stored.
* Types of Log File::       The VCS log in contrast to the ChangeLog.

Basic Editing under Version Control

* VC With A Merging VCS::  Without locking: default mode for CVS.
* VC With A Locking VCS::  RCS in its default mode, SCCS, and optionally CVS.
* Advanced C-x v v::       Advanced features available with a prefix argument.

The Secondary Commands of VC

* Registering::         Putting a file under version control.
* VC Change Log::       Viewing the VC Change Log.
* VC Undo::             Canceling changes before or after check-in.

VC Directory Mode

* VC Directory Buffer::   What the buffer looks like and means.
* VC Directory Commands:: Commands to use in a VC directory buffer.

Multiple Branches of a File

* Switching Branches::    How to get to another existing branch.
* Creating Branches::     How to start a new branch.
* Merging::               Transferring changes between branches.
* Multi-User Branching::  Multiple users working at multiple branches
                            in parallel.

Remote Repositories

* Version Backups::       Keeping local copies of repository versions.
* Local Version Control:: Using another version system for local editing.

Revision Tags

* Making Revision Tags::  The tag facilities.
* Revision Tag Caveats::  Things to be careful of when using tags.

Miscellaneous Commands and Features of VC

* Change Logs and VC::    Generating a change log file from log entries.
* Renaming and VC::       A command to rename both the source and master
                            file correctly.
* Version Headers::       Inserting version control headers into working files.

Customizing VC

* General VC Options::    Options that apply to multiple back ends.
* RCS and SCCS::          Options for RCS and SCCS.
* CVS Options::           Options for CVS.

Change Logs

* Change Log Commands:: Commands for editing change log files.
* Format of ChangeLog:: What the change log file looks like.

Tags Tables

* Tag Syntax::          Tag syntax for various types of code and text files.
* Create Tags Table::   Creating a tags table with `etags'.
* Etags Regexps::       Create arbitrary tags using regular expressions.
* Select Tags Table::   How to visit a tags table.
* Find Tag::            Commands to find the definition of a specific tag.
* Tags Search::         Using a tags table for searching and replacing.
* List Tags::           Listing and finding tags defined in a file.

Merging Files with Emerge

* Overview of Emerge::  How to start Emerge.  Basic concepts.
* Submodes of Emerge::  Fast mode vs. Edit mode.
                          Skip Prefers mode and Auto Advance mode.
* State of Difference:: You do the merge by specifying state A or B
                          for each difference.
* Merge Commands::      Commands for selecting a difference,
                          changing states of differences, etc.
* Exiting Emerge::      What to do when you've finished the merge.
* Combining in Emerge::     How to keep both alternatives for a difference.
* Fine Points of Emerge::   Miscellaneous issues.

Abbrevs

* Abbrev Concepts::     Fundamentals of defined abbrevs.
* Defining Abbrevs::    Defining an abbrev, so it will expand when typed.
* Expanding Abbrevs::   Controlling expansion: prefixes, canceling expansion.
* Editing Abbrevs::     Viewing or editing the entire list of defined abbrevs.
* Saving Abbrevs::      Saving the entire list of abbrevs for another session.
* Dynamic Abbrevs::     Abbreviations for words already in the buffer.
* Dabbrev Customization:: What is a word, for dynamic abbrevs.  Case handling.


Editing Pictures

* Basic Picture::         Basic concepts and simple commands of Picture Mode.
* Insert in Picture::     Controlling direction of cursor motion
                            after "self-inserting" characters.
* Tabs in Picture::       Various features for tab stops and indentation.
* Rectangles in Picture:: Clearing and superimposing rectangles.

Sending Mail

* Mail Format::         Format of the mail being composed.
* Mail Headers::        Details of some standard mail header fields.
* Mail Aliases::        Abbreviating and grouping mail addresses.
* Mail Commands::       Special commands for editing mail being composed.
* Mail Signature::      Adding a signature to every message.
* Mail Amusements::     Distracting the NSA; adding fortune messages.
* Mail Methods::        Using alternative mail-composition methods.

Mail Commands

* Mail Sending::        Commands to send the message.
* Header Editing::      Commands to move to header fields and edit them.
* Citing Mail::         Quoting a message you are replying to.
* Mail Misc::           Attachments, spell checking, etc.

Reading Mail with Rmail

* Rmail Basics::        Basic concepts of Rmail, and simple use.
* Rmail Scrolling::     Scrolling through a message.
* Rmail Motion::        Moving to another message.
* Rmail Deletion::      Deleting and expunging messages.
* Rmail Inbox::         How mail gets into the Rmail file.
* Rmail Files::         Using multiple Rmail files.
* Rmail Output::        Copying message out to files.
* Rmail Labels::        Classifying messages by labeling them.
* Rmail Attributes::    Certain standard labels, called attributes.
* Rmail Reply::         Sending replies to messages you are viewing.
* Rmail Summary::       Summaries show brief info on many messages.
* Rmail Sorting::       Sorting messages in Rmail.
* Rmail Display::       How Rmail displays a message; customization.
* Rmail Coding::        How Rmail handles decoding character sets.
* Rmail Editing::       Editing message text and headers in Rmail.
* Rmail Digest::        Extracting the messages from a digest message.
* Rmail Rot13::         Reading messages encoded in the rot13 code.
* Movemail::            More details of fetching new mail.
* Remote Mailboxes::    Retrieving mail from remote mailboxes.
* Other Mailbox Formats:: Retrieving mail from local mailboxes in
                          various formats.

Summaries

* Rmail Make Summary::       Making various sorts of summaries.
* Rmail Summary Edit::       Manipulating messages from the summary.

Dired, the Directory Editor

* Dired Enter::              How to invoke Dired.
* Dired Navigation::         Special motion commands in the Dired buffer.
* Dired Deletion::           Deleting files with Dired.
* Flagging Many Files::      Flagging files based on their names.
* Dired Visiting::           Other file operations through Dired.
* Marks vs Flags::           Flagging for deletion vs marking.
* Operating on Files::       How to copy, rename, print, compress, etc.
                               either one file or several files.
* Shell Commands in Dired::  Running a shell command on the marked files.
* Transforming File Names::  Using patterns to rename multiple files.
* Comparison in Dired::      Running `diff' by way of Dired.
* Subdirectories in Dired::  Adding subdirectories to the Dired buffer.
* Subdir Switches::          Subdirectory switches in Dired.
* Subdirectory Motion::      Moving across subdirectories, and up and down.
* Hiding Subdirectories::    Making subdirectories visible or invisible.
* Dired Updating::           Discarding lines for files of no interest.
* Dired and Find::           Using `find' to choose the files for Dired.
* Wdired::                   Operating on files by editing the Dired buffer.
* Image-Dired::              Viewing image thumbnails in Dired.
* Misc Dired Features::      Various other features.

The Calendar and the Diary

* Calendar Motion::     Moving through the calendar; selecting a date.
* Scroll Calendar::     Bringing earlier or later months onto the screen.
* Counting Days::       How many days are there between two dates?
* General Calendar::    Exiting or recomputing the calendar.
* Writing Calendar Files:: Writing calendars to files of various formats.
* Holidays::            Displaying dates of holidays.
* Sunrise/Sunset::      Displaying local times of sunrise and sunset.
* Lunar Phases::        Displaying phases of the moon.
* Other Calendars::     Converting dates to other calendar systems.
* Diary::               Displaying events from your diary.
* Appointments::        Reminders when it's time to do something.
* Importing Diary::     Converting diary events to/from other formats.
* Daylight Saving::    How to specify when daylight saving time is active.
* Time Intervals::      Keeping track of time intervals.
* Advanced Calendar/Diary Usage:: Advanced Calendar/Diary customization.

Movement in the Calendar

* Calendar Unit Motion::      Moving by days, weeks, months, and years.
* Move to Beginning or End::  Moving to start/end of weeks, months, and years.
* Specified Dates::           Moving to the current date or another
                                specific date.

Conversion To and From Other Calendars

* Calendar Systems::       The calendars Emacs understands
                             (aside from Gregorian).
* To Other Calendar::      Converting the selected date to various calendars.
* From Other Calendar::    Moving to a date specified in another calendar.
* Mayan Calendar::         Moving to a date specified in a Mayan calendar.

The Diary

* Displaying the Diary::   Viewing diary entries and associated calendar dates.
* Format of Diary File::   Entering events in your diary.
* Date Formats::           Various ways you can specify dates.
* Adding to Diary::        Commands to create diary entries.
* Special Diary Entries::  Anniversaries, blocks of dates, cyclic entries, etc.

Customizing the Calendar and Diary

* Calendar Customizing::   Calendar layout and hooks.
* Holiday Customizing::    Defining your own holidays.
* Date Display Format::    Changing the format.
* Time Display Format::    Changing the format.
* Diary Customizing::      Defaults you can set.
* Non-Gregorian Diary::    Diary entries based on other calendars.
* Diary Display::          A choice of ways to display the diary.
* Fancy Diary Display::    Sorting diary entries, using included diary files.
* Sexp Diary Entries::     More flexible diary entries.

Document Viewing

* Navigation::  Navigation inside DocView buffers.
* Searching::   Searching inside documents.
* Slicing::     Specifying which part of pages should be displayed.
* Conversion::  Influencing and triggering conversion.

Gnus

* Buffers of Gnus::     The group, summary, and article buffers.
* Gnus Startup::        What you should know about starting Gnus.
* Summary of Gnus::     A short description of the basic Gnus commands.

Running Shell Commands from Emacs

* Single Shell::        How to run one shell command and return.
* Interactive Shell::   Permanent shell taking input via Emacs.
* Shell Mode::          Special Emacs commands used with permanent shell.
* Shell Prompts::       Two ways to recognize shell prompts.
* Shell History::       Repeating previous commands in a shell buffer.
* Directory Tracking::  Keeping track when the subshell changes directory.
* Shell Options::       Options for customizing Shell mode.
* Terminal emulator::   An Emacs window as a terminal emulator.
* Term Mode::           Special Emacs commands used in Term mode.
* Paging in Term::      Paging in the terminal emulator.
* Remote Host::         Connecting to another computer.
* Serial Terminal::     Connecting to a serial port.

Shell Command History

* Shell Ring::           Fetching commands from the history list.
* Shell History Copying::Moving to a command and then copying it.
* History References::   Expanding `!'-style history references.

Using Emacs as a Server

* Invoking emacsclient:: Connecting to the Emacs server.
* emacsclient Options::  Emacs client startup options.

Printing Hard Copies

* PostScript::           Printing buffers or regions as PostScript.
* PostScript Variables:: Customizing the PostScript printing commands.
* Printing Package::     An optional advanced printing interface.

Hyperlinking and Navigation Features

* Browse-URL::          Following URLs.
* Goto Address mode::   Activating URLs.
* FFAP::                Finding files etc. at point.

Customization

* Minor Modes::         Each minor mode is a feature you can turn on
                          independently of any others.
* Easy Customization::  Convenient way to browse and change settings.
* Variables::           Many Emacs commands examine Emacs variables
                          to decide what to do; by setting variables,
                          you can control their functioning.
* Key Bindings::        The keymaps say what command each key runs.
                          By changing them, you can "redefine keys".
* Syntax::              The syntax table controls how words and
                          expressions are parsed.
* Init File::           How to write common customizations in the
                          `.emacs' file.

Easy Customization Interface

* Customization Groups::     How settings are classified in a structure.
* Browsing Custom::          Browsing and searching for settings.
* Changing a Variable::      How to edit an option's value and set the option.
* Saving Customizations::    Specifying the file for saving customizations.
* Face Customization::       How to edit the attributes of a face.
* Specific Customization::   Making a customization buffer for specific
                                variables, faces, or groups.
* Custom Themes::            How to define collections of customized options
                                that can be loaded and unloaded together.

Variables

* Examining::           Examining or setting one variable's value.
* Hooks::               Hook variables let you specify programs for parts
                          of Emacs to run on particular occasions.
* Locals::              Per-buffer values of variables.
* File Variables::      How files can specify variable values.
* Directory Variables:: How variable values can be specified by directory.

Local Variables in Files

* Specifying File Variables:: Specifying file local variables.
* Safe File Variables::       Making sure file local variables are safe.

Customizing Key Bindings

* Keymaps::             Generalities.  The global keymap.
* Prefix Keymaps::      Keymaps for prefix keys.
* Local Keymaps::       Major and minor modes have their own keymaps.
* Minibuffer Maps::     The minibuffer uses its own local keymaps.
* Rebinding::           How to redefine one key's meaning conveniently.
* Init Rebinding::      Rebinding keys with your init file, `.emacs'.
* Modifier Keys::       Using modifier keys in key bindings.
* Function Keys::       Rebinding terminal function keys.
* Named ASCII Chars::   Distinguishing <TAB> from C-i, and so on.
* Mouse Buttons::       Rebinding mouse buttons in Emacs.
* Disabling::           Disabling a command means confirmation is required
                          before it can be executed.  This is done to protect
                          beginners from surprises.

The Init File, `~/.emacs'

* Init Syntax::         Syntax of constants in Emacs Lisp.
* Init Examples::       How to do some things with an init file.
* Terminal Init::       Each terminal type can have an init file.
* Find Init::           How Emacs finds the init file.
* Init Non-ASCII::      Using non-ASCII characters in an init file.

Dealing with Emacs Trouble

* DEL Does Not Delete:: What to do if <DEL> doesn't delete.
* Stuck Recursive::     `[...]' in mode line around the parentheses.
* Screen Garbled::      Garbage on the screen.
* Text Garbled::        Garbage in the text.
* Memory Full::         How to cope when you run out of memory.
* After a Crash::       Recovering editing in an Emacs session that crashed.
* Emergency Escape::    Emergency escape---
                          What to do if Emacs stops responding.
* Total Frustration::   When you are at your wits' end.

Reporting Bugs

* Known Problems::      How to read about known problems and bugs.
* Bug Criteria::        Have you really found a bug?
* Understanding Bug Reporting:: How to report a bug effectively.
* Checklist::           Steps to follow for a good bug report.
* Sending Patches::     How to send a patch for GNU Emacs.

Command Line Arguments for Emacs Invocation

* Action Arguments::    Arguments to visit files, load libraries,
                          and call functions.
* Initial Options::     Arguments that take effect while starting Emacs.
* Command Example::     Examples of using command line arguments.
* Resume Arguments::    Specifying arguments when you resume a running Emacs.
* Environment::         Environment variables that Emacs uses.
* Display X::           Changing the default display and using remote login.
* Font X::              Choosing a font for text, under X.
* Colors::              Choosing display colors.
* Window Size X::       Start-up window size, under X.
* Borders X::           Internal and external borders, under X.
* Title X::             Specifying the initial frame's title.
* Icons X::             Choosing what sort of icon to use, under X.
* Misc X::              Other display options.

Environment Variables

* General Variables::   Environment variables that all versions of Emacs use.
* Misc Variables::      Certain system-specific variables.
* MS-Windows Registry:: An alternative to the environment on MS-Windows.

X Options and Resources

* Resources::           Using X resources with Emacs (in general).
* Table of Resources::  Table of specific X resources that affect Emacs.
* Face Resources::      X resources for customizing faces.
* Lucid Resources::     X resources for Lucid menus.
* LessTif Resources::   X resources for LessTif and Motif menus.
* GTK resources::       Resources for GTK widgets.

GTK resources

* GTK widget names::      How widgets in GTK are named in general.
* GTK Names in Emacs::    GTK widget names in Emacs.
* GTK styles::            What can be customized in a GTK widget.

Emacs and Mac OS / GNUstep

* Mac / GNUstep Basics::        Basic Emacs usage under GNUstep or Mac OS.
* Mac / GNUstep Customization:: Customizations under GNUstep or Mac OS.
* Mac / GNUstep Events::        How window system events are handled.
* GNUstep Support::             Details on status of GNUstep support.

Emacs and Microsoft Windows/MS-DOS

* Windows Startup::     How to start Emacs on Windows.
* Text and Binary::     Text files use CRLF to terminate lines.
* Windows Files::       File-name conventions on Windows.
* ls in Lisp::          Emulation of `ls' for Dired.
* Windows HOME::        Where Emacs looks for your `.emacs'.
* Windows Keyboard::    Windows-specific keyboard features.
* Windows Mouse::       Windows-specific mouse features.
* Windows Processes::   Running subprocesses on Windows.
* Windows Printing::    How to specify the printer on MS-Windows.
* Windows Fonts::       Specifying fonts on MS-Windows.
* Windows Misc::        Miscellaneous Windows features.
* MS-DOS::              Using Emacs on MS-DOS (otherwise known as "MS-DOG").

Emacs and MS-DOS

* MS-DOS Keyboard::     Keyboard conventions on MS-DOS.
* MS-DOS Mouse::        Mouse conventions on MS-DOS.
* MS-DOS Display::      Fonts, frames and display size on MS-DOS.
* MS-DOS File Names::   File name conventions on MS-DOS.
* MS-DOS Printing::     Printing specifics on MS-DOS.
* MS-DOS and MULE::     Support for internationalization on MS-DOS.
* MS-DOS Processes::    Running subprocesses on MS-DOS.


File: emacs,  Node: Distrib,  Next: Intro,  Prev: Top,  Up: Top

Distribution
************

GNU Emacs is "free software"; this means that everyone is free to use
it and free to redistribute it on certain conditions.  GNU Emacs is not
in the public domain; it is copyrighted and there are restrictions on
its distribution, but these restrictions are designed to permit
everything that a good cooperating citizen would want to do.  What is
not allowed is to try to prevent others from further sharing any
version of GNU Emacs that they might get from you.  The precise
conditions are found in the GNU General Public License that comes with
Emacs and also appears in this manual(1).  *Note Copying::.

   One way to get a copy of GNU Emacs is from someone else who has it.
You need not ask for our permission to do so, or tell any one else;
just copy it.  If you have access to the Internet, you can get the
latest distribution version of GNU Emacs by anonymous FTP; see
`http://www.gnu.org/software/emacs' on our website for more information.

   You may also receive GNU Emacs when you buy a computer.  Computer
manufacturers are free to distribute copies on the same terms that
apply to everyone else.  These terms require them to give you the full
sources, including whatever changes they may have made, and to permit
you to redistribute the GNU Emacs received from them under the usual
terms of the General Public License.  In other words, the program must
be free for you when you get it, not just free for the manufacturer.

   You can also order copies of GNU Emacs from the Free Software
Foundation.  This is a convenient and reliable way to get a copy; it is
also a good way to help fund our work.  We also sell hardcopy versions
of this manual and `An Introduction to Programming in Emacs Lisp', by
Robert J. Chassell.  You can visit our online store at
`http://shop.fsf.org/'.  For further information, write to

     Free Software Foundation
     51 Franklin Street, Fifth Floor
     Boston, MA 02110-1301
     USA

   The income from sales goes to support the foundation's purpose: the
development of new free software, and improvements to our existing
programs including GNU Emacs.

   If you find GNU Emacs useful, please *send a donation* to the Free
Software Foundation to support our work.  Donations to the Free
Software Foundation are tax deductible in the US.  If you use GNU Emacs
at your workplace, please suggest that the company make a donation.  If
company policy is unsympathetic to the idea of donating to charity, you
might instead suggest ordering a CD-ROM from the Foundation
occasionally, or subscribing to periodic updates.

   ---------- Footnotes ----------

   (1) This manual is itself covered by the GNU Free Documentation
License (see the reverse title page in the printed manual or view the
full source for online formats to see the precise conditions).  This
license is similar in spirit to the General Public License, but is more
suitable for documentation.  *Note GNU Free Documentation License::.


File: emacs,  Node: Intro,  Next: Glossary,  Prev: Distrib,  Up: Top

Introduction
************

You are reading about GNU Emacs, the GNU incarnation of the advanced,
self-documenting, customizable, extensible editor Emacs.  (The `G' in
`GNU' is not silent.)

   We call Emacs "advanced" because it can do much more than simple
insertion and deletion of text.  It can control subprocesses, indent
programs automatically, show multiple files at once, and more.  Emacs
editing commands operate in terms of characters, words, lines,
sentences, paragraphs, and pages, as well as expressions and comments
in various programming languages.

   "Self-documenting" means that at any time you can use special
commands, known as "help commands", to find out what your options are,
or to find out what any command does, or to find all the commands that
pertain to a given topic.  *Note Help::.

   "Customizable" means that you can easily alter the behavior of Emacs
commands in simple ways.  For instance, if you use a programming
language in which comments start with `<**' and end with `**>', you can
tell the Emacs comment manipulation commands to use those strings
(*note Comments::).  To take another example, you can rebind the basic
cursor motion commands (up, down, left and right) to any keys on the
keyboard that you find comfortable.  *Note Customization::.

   "Extensible" means that you can go beyond simple customization and
create entirely new commands.  New commands are simply programs written
in the Lisp language, which are run by Emacs's own Lisp interpreter.
Existing commands can even be redefined in the middle of an editing
session, without having to restart Emacs.  Most of the editing commands
in Emacs are written in Lisp; the few exceptions could have been
written in Lisp but use C instead for efficiency.  Writing an extension
is programming, but non-programmers can use it afterwards.  *Note Emacs
Lisp Intro: (eintr)Top, if you want to learn Emacs Lisp programming.


File: emacs,  Node: Screen,  Next: User Input,  Prev: Acknowledgments,  Up: Top

1 The Organization of the Screen
********************************

On a text-only terminal, the Emacs display occupies the entire terminal
screen.  On a graphical display, such as on GNU/Linux using the X
Window System, Emacs creates its own windows to use.  We use the term
"frame" to mean the entire terminal screen or graphical window used by
Emacs.  Emacs uses both kinds of frames, in the same way, to display
your editing.  Emacs normally starts out with just one frame, but you
can create additional frames if you wish (*note Frames::).

   The frame consists of several distinct regions.  At the top of the
frame is a "menu bar", which allows you to access commands via a series
of menus.  On a graphical display, directly below the menu bar is a
"tool bar", a row of icons that perform editing commands if you click
on them.  At the very bottom of the frame is a special "echo area",
where short informative messages are displayed and where you enter
information when Emacs asks for it.

   The main area of the frame, below the tool bar (if one exists) and
above the echo area, is called "the window".  This is where Emacs
displays the "buffer": the text that you are editing.  On a graphical
display, the window possesses a "scroll bar" on one side, which you can
use to display different parts of the buffer in the window.  The last
line of the window is a "mode line".  This displays various information
about what is going on in the buffer, such as whether there are unsaved
changes, the editing modes that are in use, the current line number,
and so forth.

   When you start Emacs, there is normally only one window in the
frame.  However, you can subdivide this window horizontally or
vertically to create multiple windows, each of which can independently
display a buffer (*note Windows::).  In this manual, the word "window"
refers to the initial large window if not subdivided, or any one of the
multiple windows you have subdivided it into.

   At any time, one window is the "selected window".  On graphical
displays, the selected window normally shows a more prominent cursor
(usually solid and blinking) while other windows show a weaker cursor
(such as a hollow box).  Text terminals have just one cursor, so it
always appears in the selected window.  The buffer displayed in the
selected window is called the "current buffer", and it is where editing
happens.  Most Emacs commands implicitly apply to the current buffer;
the text displayed in unselected windows is mostly visible for
reference.  If you use multiple frames on a graphical display,
selecting a particular frame selects a window in that frame.

* Menu:

* Point::             The place in the text where editing commands operate.
* Echo Area::         Short messages appear at the bottom of the screen.
* Mode Line::         Interpreting the mode line.
* Menu Bar::          How to use the menu bar.


File: emacs,  Node: Point,  Next: Echo Area,  Up: Screen

1.1 Point
=========

The active cursor shows the location at which editing commands will
take effect, which is called "point"(1).  Many Emacs commands move
point to different places in the buffer; for example, you can place
point by clicking mouse button 1 (normally the left button) at the
desired location.

   While the cursor appears to be _on_ a character, you should think of
point as _between_ two characters; it points _before_ the character
that appears under the cursor.  For example, if your text looks like
`frob' with the cursor over the `b', then point is between the `o' and
the `b'.  If you insert the character `!' at that position, the result
is `fro!b', with point between the `!' and the `b'.  Thus, the cursor
remains over the `b', as before.

   Sometimes people speak of "the cursor" when they mean "point," or
speak of commands that move point as "cursor motion" commands.

   If you are editing several files in Emacs, each in its own buffer,
each buffer has its own point location.  A buffer that is not currently
displayed remembers its point location in case you display it again
later.  When Emacs displays multiple windows, each window has its own
point location.  If the same buffer appears in more than one window,
each window has its own point position in that buffer.

   On a graphical display, Emacs shows a cursor in each window; the
selected window's cursor is solid and blinking, and the other cursors
are hollow.  On a text-only terminal, there is just one cursor, in the
selected window; even though the unselected windows have their own
point positions, they do not display a cursor.  *Note Cursor Display::,
for customizable variables that control cursor display.

   ---------- Footnotes ----------

   (1) The term "point" comes from the character `.', which was the
command in TECO (the language in which the original Emacs was written)
for accessing the value now called "point."


File: emacs,  Node: Echo Area,  Next: Mode Line,  Prev: Point,  Up: Screen

1.2 The Echo Area
=================

The line at the very bottom of the frame is the "echo area".  It is
used to display small amounts of text for various purposes.

   "Echoing" means displaying the characters that you type.
Single-character commands, including most simple editing operations,
are not echoed.  Multi-character commands are echoed if you pause while
typing them: if you pause for more than a second in the middle of a
command, Emacs echoes all the characters of the command so far, to
prompt you for the rest of the command.  The echoed characters are
displayed in the echo area.  Once echoing has started, the rest of the
command echoes immediately as you type it.  This behavior is designed
to give confident users fast response, while giving hesitant users
maximum feedback.  *Note Display Custom::.

   If a command cannot do its job, it may display an "error message".
Error messages are also displayed in the echo area.  They may be
accompanied by beeping or by flashing the screen.

   Some commands display informative messages in the echo area.  Unlike
error messages, these messages are not announced with a beep or flash.
Sometimes the message tells you what the command has done, when this is
not obvious from looking at the text being edited.  Other times, the
sole purpose of a command is to show you a message giving you specific
information.  For example, `C-x =' (hold down <CTRL> and type `x', then
let go of <CTRL> and type `=') displays a message describing the
character position of point in the text and its current column in the
window.  Commands that take a long time often display messages ending
in `...' while they are working, and add `done' at the end when they
are finished.  They may also indicate progress with percentages.

   Informative echo-area messages are saved in a special buffer named
`*Messages*'.  (We have not explained buffers yet; see *note Buffers::,
for more information about them.)  If you miss a message that appeared
briefly on the screen, you can switch to the `*Messages*' buffer to see
it again.  The `*Messages*' buffer is limited to a certain number of
lines, specified by the variable `message-log-max'.  (We have not
explained variables either; see *note Variables::, for more information
about them.)  Beyond this limit, one line is deleted from the beginning
whenever a new message line is added at the end.

   The echo area is also used to display the "minibuffer", a special
window where you can input arguments to commands, such as the name of a
file to be edited.  When the minibuffer is in use, the text displayed
in the echo area begins with a "prompt string" (usually ending with a
colon); also, the active cursor appears within the minibuffer, which is
temporarily considered the selected window.  You can always get out of
the minibuffer by typing `C-g'.  *Note Minibuffer::.


File: emacs,  Node: Mode Line,  Next: Menu Bar,  Prev: Echo Area,  Up: Screen

1.3 The Mode Line
=================

At the bottom of each window is a "mode line", which describes what is
going on in the current buffer.  When there is only one window, the
mode line appears right above the echo area; it is the next-to-last
line in the frame.  On a graphical display, the mode line is drawn with
a 3D box appearance, and the mode line of the selected window has a
brighter color than that of unselected windows to make it stand out.
On a text-only terminal, the mode line is usually drawn in inverse
video.

   The text displayed in the mode line has the following format:

     -CS:CH-FR  BUF      POS LINE   (MAJOR MINOR)------

The CS string and the colon character after it describe the character
set and newline convention used for the current buffer.  Normally,
Emacs handles these settings intelligently, but it is sometimes useful
to have this information.

   CS describes the character set of the buffer (*note Coding
Systems::).  If it is a dash (`-'), that indicates the default state of
affairs: no special character set handling, except for the end-of-line
translations described in the next paragraph.  `=' means no conversion
whatsoever.  Letters represent various nontrivial "coding systems"--for
example, `1' represents ISO Latin-1.  On a text-only terminal, CS is
preceded by two additional characters that describe the coding system
for keyboard input and the coding system for terminal output.
Furthermore, if you are using an input method, CS is preceded by a
string that identifies the input method, which takes the form `I>',
`I+', or `I@' (*note Input Methods::).

   The character after CS is usually a colon.  However, under some
circumstances a different string is displayed, which indicates a
nontrivial end-of-line convention.  Usually, lines of text are
separated by "newline characters", but two other conventions are
sometimes used.  The MS-DOS convention is to use a "carriage-return"
character followed by a "linefeed" character; when editing such files,
the colon changes to either a backslash (`\') or `(DOS)', depending on
the operating system.  The Macintosh end-of-line convention is to use a
"carriage-return" character instead of a newline; when editing such
files, the colon indicator changes to either a forward slash (`/') or
`(Mac)'.  On some systems, Emacs displays `(Unix)' instead of the colon
for files that use newline as the line separator.

   The next element on the mode line is the string indicated by CH.
This shows two dashes (`--') if the buffer displayed in the window has
the same contents as the corresponding file on the disk; i.e., if the
buffer is "unmodified".  If the buffer is modified, it shows two stars
(`**').  For a read-only buffer, it shows `%*' if the buffer is
modified, and `%%' otherwise.

   The character after CH is normally a dash (`-').  However, if the
default-directory for the current buffer is on a remote machine, `@' is
displayed instead (*note File Names::).

   FR gives the selected frame name (*note Frames::).  It appears only
on text-only terminals.  The initial frame's name is `F1'.

   BUF is the name of the buffer displayed in the window.  Usually,
this is the same as the name of a file you are editing.  *Note
Buffers::.

   POS tells you whether there is additional text above the top of the
window, or below the bottom.  If your buffer is small and it is all
visible in the window, POS is `All'.  Otherwise, it is `Top' if you are
looking at the beginning of the buffer, `Bot' if you are looking at the
end of the buffer, or `NN%', where NN is the percentage of the buffer
above the top of the window.  With Size Indication mode, you can
display the size of the buffer as well.  *Note Optional Mode Line::.

   LINE is the character `L' followed by the line number at point.
(You can display the current column number too, by turning on Column
Number mode.  *Note Optional Mode Line::.)

   MAJOR is the name of the "major mode" used in the buffer.  A major
mode is a principal editing mode for the buffer, such as Text mode,
Lisp mode, C mode, and so forth.  *Note Major Modes::.

   Some major modes display additional information after the major mode
name.  For example, Rmail buffers display the current message number and
the total number of messages.  Compilation buffers and Shell buffers
display the status of the subprocess.

   MINOR is a list of some of the "minor modes" turned on in the
buffer.  Minor modes are optional editing modes that provide additional
features on top of the major mode.  *Note Minor Modes::.

   Some features are listed together with the minor modes whenever they
are turned on, even though they are not really minor modes.  `Narrow'
means that the buffer being displayed has editing restricted to only a
portion of its text (*note Narrowing::).  `Def' means that a keyboard
macro is currently being defined (*note Keyboard Macros::).

   In addition, if Emacs is inside a recursive editing level, square
brackets (`[...]') appear around the parentheses that surround the
modes.  If Emacs is in one recursive editing level within another,
double square brackets appear, and so on.  Since recursive editing
levels affect Emacs globally, not just one buffer, the square brackets
appear in every window's mode line or not in any of them.  *Note
Recursive Edit::.

   You can change the appearance of the mode line as well as the format
of its contents.  *Note Optional Mode Line::.  In addition, the mode
line is mouse-sensitive; clicking on different parts of the mode line
performs various commands.  *Note Mode Line Mouse::.


File: emacs,  Node: Menu Bar,  Prev: Mode Line,  Up: Screen

1.4 The Menu Bar
================

Each Emacs frame normally has a "menu bar" at the top which you can use
to perform common operations.  There's no need to list them here, as
you can more easily see them yourself.

   On a graphical display, you can use the mouse to choose a command
from the menu bar.  A right-arrow at the end of a menu item means it
leads to a subsidiary menu, or "submenu".  A `...' at the end of a menu
item means that the command invoked will prompt you for further input
before it actually does anything.

   Some of the commands in the menu bar have ordinary key bindings as
well; if so, a key binding is shown in parentheses after the item
itself.  To view the full command name and documentation for a menu
item, type `C-h k', and then select the menu bar with the mouse in the
usual way (*note Key Help::).

   Instead of using the mouse, you can also invoke the first menu bar
item by pressing <F10> (to run the command `menu-bar-open').  You can
then navigate the menus with the arrow keys.  To activate a selected
menu item, press <RET>; to cancel menu navigation, press <ESC>.

   On text-only terminals with no mouse, you can use the menu bar by
typing `M-`' or <F10> (these run the command `tmm-menubar').  This lets
you select a menu item with the keyboard.  A provisional choice appears
in the echo area.  You can use the up and down arrow keys to move
through the menu to different items, and then you can type <RET> to
select the item.

   Each menu item also has an assigned letter or digit which designates
that item; it is usually the initial of some word in the item's name.
This letter or digit is separated from the item name by `=>'.  You can
type the item's letter or digit to select the item.


File: emacs,  Node: User Input,  Next: Keys,  Prev: Screen,  Up: Top

2 Kinds of User Input
*********************

GNU Emacs is primarily designed for use with the keyboard.  While it is
possible to use the mouse to issue editing commands through the menu
bar and tool bar, that is not as efficient as using the keyboard.
Therefore, this manual mainly documents how to edit with the keyboard.

   Keyboard input into Emacs is based on a heavily-extended version of
ASCII.  The simplest characters that you can input into Emacs
correspond to graphic symbols such as `a', `B', `3', `=', the space
character (conventionally denoted as <SPC>), and so on.  Entering these
using the keyboard is straightforward.  Certain characters found on
non-English keyboards also fall into this category (*note
International::).

   In addition to these simple characters, Emacs recognizes "control
characters" such as <RET>, <TAB>, <DEL>, <ESC>, <F1>, <Home>, <left>,
etc.  Most keyboards have special keys for entering these.

   Emacs also recognizes control characters that are entered using
"modifier keys".  Two commonly-used modifier keys are <Control> (which
is usually labelled as <Ctrl>), and <Meta> (which is usually labeled as
<Alt>)(1).  For example, `Control-a' is entered by holding down the
<Ctrl> key while pressing `a'; we will refer to this as `C-a' for short.
Similarly `Meta-a', or `M-a' for short, is entered by holding down the
<Alt> key and pressing `a'.

   You can also type Meta characters using two-character sequences
starting with <ESC>.  Thus, you can enter `M-a' by typing `<ESC> a'.
You can enter `C-M-a' by typing `<ESC> C-a'.  Unlike <Meta>, <ESC> is
entered as a separate character.  You don't hold down <ESC> while
typing the next character; instead, press <ESC> and release it, then
enter the next character.  This feature is useful on certain text-only
terminals where the <Meta> key does not function reliably.

   Modifier keys can apply not only to alphanumerical characters, but
also to special input characters, such as the arrow keys and mouse
buttons.

   *Note Input Events: (elisp)Input Events, for the full Lisp-level
details about keyboard and mouse input, which are collectively referred
to as "input events".  If you are not doing Lisp programming, but
simply want to redefine the meaning of some characters or non-character
events, see *note Customization::.

   On graphical displays, the window manager is likely to block the
character `M-<TAB>' before Emacs can see it.  It may also block
`M-<SPC>', `C-M-d' and `C-M-l'.  If you have these problems, we
recommend that you customize your window manager to turn off those
commands, or put them on key combinations that Emacs does not use.

   ---------- Footnotes ----------

   (1) We refer to <Alt> as <Meta> for historical reasons.


File: emacs,  Node: Keys,  Next: Commands,  Prev: User Input,  Up: Top

3 Keys
******

Some Emacs commands are invoked by just one input event; for example,
`C-f' moves forward one character in the buffer.  But Emacs also has
commands that take two or more input events to invoke, such as `C-x
C-f' and `C-x 4 C-f'.

   A "key sequence", or "key" for short, is a sequence of one or more
input events that is meaningful as a unit.  If a key sequence invokes a
command, we call it a "complete key"; for example, `C-f', `C-x C-f' and
`C-x 4 C-f' are all complete keys.  If a key sequence isn't long enough
to invoke a command, we call it a "prefix key"; from the preceding
example, we see that `C-x' and `C-x 4' are prefix keys.  Every key is
either a complete key or a prefix key.

   A prefix key combines with the following input event to make a
longer key sequence, which may itself be complete or a prefix.  For
example, `C-x' is a prefix key, so `C-x' and the next input event
combine to make a two-event key sequence.  This two-event key sequence
could itself be a prefix key (such as `C-x 4'), or a complete key (such
as `C-x C-f').  There is no limit to the length of a key sequence, but
in practice people rarely use sequences longer than three or four input
events.

   You can't add input events onto a complete key.  For example, the
two-event sequence `C-f C-k' is not a key, because the `C-f' is a
complete key in itself, so `C-f C-k' cannot have an independent meaning
as a command.  `C-f C-k' is two key sequences, not one.

   By default, the prefix keys in Emacs are `C-c', `C-h', `C-x', `C-x
<RET>', `C-x @', `C-x a', `C-x n', `C-x r', `C-x v', `C-x 4', `C-x 5',
`C-x 6', <ESC>, `M-g', and `M-o'.  (<F1> and <F2> are aliases for `C-h'
and `C-x 6'.)  This list is not cast in stone; if you customize Emacs,
you can make new prefix keys.  You could even eliminate some of the
standard ones, though this is not recommended for most users; for
example, if you remove the prefix definition of `C-x 4', then `C-x 4
ANYTHING' would become an invalid key sequence.  *Note Key Bindings::.

   Typing the help character (`C-h' or <F1>) after a prefix key
displays a list of the commands starting with that prefix.  The sole
exception to this rule is <ESC>: `<ESC>C-h' is equivalent to `C-M-h',
which does something else entirely.  You can, however, use <F1> to
displays a list of the commands starting with <ESC>.


File: emacs,  Node: Commands,  Next: Entering Emacs,  Prev: Keys,  Up: Top

4 Keys and Commands
*******************

This manual is full of passages that tell you what particular keys do.
But Emacs does not assign meanings to keys directly.  Instead, Emacs
assigns meanings to named "commands", and then gives keys their
meanings by "binding" them to commands.

   Every command has a name chosen by a programmer.  The name is
usually made of a few English words separated by dashes; for example,
`next-line' or `forward-word'.  A command also has a "function
definition" which is a Lisp program; this is how the command does its
work.  In Emacs Lisp, a command is a Lisp function with special
properties that make it suitable for interactive use.  For more
information on commands and functions, see *note What Is a Function:
(elisp)What Is a Function.

   The bindings between keys and commands are recorded in tables called
"keymaps".  *Note Keymaps::.

   When we say that "`C-n' moves down vertically one line" we are
glossing over a subtle distinction that is irrelevant in ordinary use,
but vital for Emacs customization.  The command `next-line' does a
vertical move downward.  `C-n' has this effect _because_ it is bound to
`next-line'.  If you rebind `C-n' to the command `forward-word', `C-n'
will move forward one word instead.

   In this manual, we will often speak of keys like `C-n' as commands,
even though strictly speaking the key is bound to a command.  Usually
we state the name of the command which really does the work in
parentheses after mentioning the key that runs it.  For example, we
will say that "The command `C-n' (`next-line') moves point vertically
down," meaning that the command `next-line' moves vertically down, and
the key `C-n' is normally bound to it.

   Since we are discussing customization, we should tell you about
"variables".  Often the description of a command will say, "To change
this, set the variable `mumble-foo'."  A variable is a name used to
store a value.  Most of the variables documented in this manual are
meant for customization: some command or other part of Emacs examines
the variable and behaves differently according to the value that you
set.  You can ignore the information about variables until you are
interested in customizing them.  Then read the basic information on
variables (*note Variables::) and the information about specific
variables will make sense.


File: emacs,  Node: Entering Emacs,  Next: Exiting,  Prev: Commands,  Up: Top

5 Entering Emacs
****************

The usual way to invoke Emacs is with the shell command `emacs'.  From
a terminal window running in the X Window System, you can also run
Emacs in the background with `emacs&'; this way, Emacs won't tie up the
terminal window, so you can use it to run other shell commands.

   When Emacs starts up, the initial frame displays a special buffer
named `*GNU Emacs*'.  This buffer contains some information about
Emacs, and includes "links" to common tasks that might be useful to
beginning users.  For instance, activating the `Emacs Tutorial' link
opens the Emacs tutorial; this does the same thing as the command `C-h
t' (`help-with-tutorial').  To activate a link, either move point onto
it and type `<RET>', or click on it with `mouse-1' (the left mouse
button).

   Using a command line argument, you can tell Emacs to visit one or
more specific files as soon as it starts up.  For example, `emacs
foo.txt' starts Emacs with a buffer displaying the contents of the file
`foo.txt'.  This feature exists mainly for compatibility with other
editors, which are designed to edit one file at a time: once you are
done with that file, you exit the editor, and start it again the next
time you need it.

   Using Emacs in this way--starting it afresh each time you want to
edit a file--is unnecessary and wasteful.  Emacs can visit more than
one file in a single editing session, and exiting the Emacs session
loses valuable accumulated context, such as the kill ring, registers,
undo history, and mark ring.  These features, described later in the
manual, are useful for performing edits across multiple files, or
continuing edits to a single file.

   The recommended way to use Emacs is to start it only once, just
after you log in, and do all your editing in the same Emacs session.
Each time you edit a file, visit it with the existing Emacs, which
eventually has many files in it ready for editing.  *Note Files::, for
more information on visiting more than one file.

   To edit a file from another program while Emacs is running, you can
use the `emacsclient' helper program to open a file in the already
running Emacs.  *Note Emacs Server::.

   Emacs accepts other command line arguments that tell it to load
certain Lisp files, call certain functions, and so forth.  These
features exist mainly for advanced users.  *Note Emacs Invocation::.

   If the variable `inhibit-startup-screen' is non-`nil', Emacs does
not display the startup screen.  In that case, if one or more files
were specified on the command line, Emacs simply displays those files;
otherwise, it displays a buffer named `*scratch*', which can be used to
evaluate Emacs Lisp expressions interactively.  *Note Lisp
Interaction::.  You can set the variable `inhibit-startup-screen' using
the Customize facility (*note Easy Customization::), or by editing your
initialization file (*note Init File::).(1)

   You can also force Emacs to display a file or directory at startup
by setting the variable `initial-buffer-choice' to a non-`nil' value.
(In that case, even if you specify one or more files on the command
line, Emacs opens but does not display them.)  The value of
`initial-buffer-choice' can be either the name of the desired file or
directory, or `t', which means to display the `*scratch*' buffer.

   ---------- Footnotes ----------

   (1) Note that setting `inhibit-startup-screen' in `site-start.el'
doesn't work, because the startup screen is set up before reading
`site-start.el'.  *Note Init File::, for information about
`site-start.el'.


File: emacs,  Node: Exiting,  Next: Basic,  Prev: Entering Emacs,  Up: Top

6 Exiting Emacs
***************

`C-x C-c'
     Kill Emacs (`save-buffers-kill-terminal').

`C-z'
     On a text terminal, suspend Emacs; on a graphical display,
     "minimize" the selected frame (`suspend-emacs').

   "Killing" Emacs means terminating the Emacs program.  To do this,
type `C-x C-c' (`save-buffers-kill-terminal').  A two-character key is
used to make it harder to type by accident.  If there are any modified
file-visiting buffers when you type `C-x C-c', Emacs first offers to
save these buffers.  If you do not save them all, it asks for
confirmation again, since the unsaved changes will be lost.  Emacs also
asks for confirmation if any subprocesses are still running, since
killing Emacs will also kill the subprocesses (*note Shell::).

   `C-x C-c' behaves specially if you are using Emacs as a server.  If
you type it from a "client frame", it closes the client connection.
*Note Emacs Server::.

   Emacs can, optionally, record certain session information when you
kill it, such as the files you were visiting at the time.  This
information is then available the next time you start Emacs.  *Note
Saving Emacs Sessions::.

   If the value of the variable `confirm-kill-emacs' is non-`nil', `C-x
C-c' assumes that its value is a predicate function, and calls that
function.  If the result of the function call is non-`nil', the session
is killed, otherwise Emacs continues to run.  One convenient function
to use as the value of `confirm-kill-emacs' is the function
`yes-or-no-p'.  The default value of `confirm-kill-emacs' is `nil'.

   To kill Emacs without being prompted about saving, type `M-x
kill-emacs'.

   You can "exit" Emacs in two other ways.  On a graphical display, you
can "minimize" (or "iconify") an Emacs frame; depending on the window
system, this either replaces the Emacs frame with a tiny "icon" or
conceals the frame entirely (*note Frames::).  On a text-only terminal,
you can "suspend" Emacs; this means stopping the Emacs program
temporarily, returning control to its parent process (usually a shell).

   `C-z' runs the command `suspend-frame'.  On a graphical display,
this "minimizes" (or "iconifies") the selected Emacs frame.  On a text
terminal, this suspends the Emacs process.

   After minimizing or suspending Emacs, you can return to it and
continue editing wherever you left off.  The way to do this depends on
the window system or shell.  In most common shells, you can resume
Emacs after suspending it with the shell command `%emacs'.

   On very old systems that don't support suspending programs, `C-z'
starts an inferior shell that communicates directly with the terminal,
and Emacs waits until you exit the subshell.  (The way to exit the
subshell is usually `C-d' or `exit'.)  On these systems, you can only
get back to the shell from which Emacs was run (to log out, for
example) when you kill Emacs.  Suspending can also fail if you run
Emacs under a shell that doesn't support suspending jobs, even if the
system itself does support it.  In this case, you can set the variable
`cannot-suspend' to a non-`nil' value to force `C-z' to start an
inferior shell.

   Text-only terminals usually listen for certain special characters
whose meaning is to kill or suspend the program you are running.  This
terminal feature is turned off while you are in Emacs.  The meanings of
`C-z' and `C-x C-c' as keys in Emacs were inspired by the use of `C-z'
and `C-c' on several operating systems as the characters for stopping
or killing a program, but that is their only relationship with the
operating system.  You can customize these keys to run any commands of
your choice (*note Keymaps::).


File: emacs,  Node: Basic,  Next: Minibuffer,  Prev: Exiting,  Up: Top

7 Basic Editing Commands
************************

Here we explain the basics of how to enter text, make corrections, and
save the text in a file.  If this material is new to you, we suggest
you first run the Emacs learn-by-doing tutorial, by typing `Control-h
t' inside Emacs.  (`help-with-tutorial').

* Menu:


* Inserting Text::      Inserting text by simply typing it.
* Moving Point::        Moving the cursor to the place where you want to
                          change something.
* Erasing::             Deleting and killing text.
* Basic Undo::          Undoing recent changes in the text.
* Files: Basic Files.   Visiting, creating, and saving files.
* Help: Basic Help.     Asking what a character does.
* Blank Lines::         Making and deleting blank lines.
* Continuation Lines::  How Emacs displays lines too wide for the screen.
* Position Info::       What page, line, row, or column is point on?
* Arguments::           Numeric arguments for repeating a command N times.
* Repeating::           Repeating the previous command quickly.


File: emacs,  Node: Inserting Text,  Next: Moving Point,  Up: Basic

7.1 Inserting Text
==================

You can insert an ordinary "graphic character" (e.g., `a', `B', `3',
and `=') by typing the associated key.  This adds the character to the
buffer at point.  Insertion moves point forward, so that point remains
just after the inserted text.  *Note Point::.

   To end a line and start a new one, type <RET>.  This key may be
labeled <Return> or <Enter> on your keyboard, but we refer to it as
<RET> in this manual.  Pressing it inserts a newline character in the
buffer.  If point is at the end of the line, this creates a new blank
line after it; if point is in the middle of a line, the line is split
at that position.

   As we explain later in this manual, you can change the way Emacs
handles text insertion by turning on "minor modes".  For instance, if
you turn on a minor mode called "Auto Fill" mode, Emacs can split lines
automatically when they become too long (*note Filling::).  If you turn
on a minor mode called "Overwrite" mode, inserted characters replace
(overwrite) existing text, instead of shoving it to the right.  *Note
Minor Modes::.

   Only graphic characters can be inserted by typing the associated
key; other keys act as editing commands and do not insert themselves.
For instance, `DEL' runs the command `delete-backward-char' by default
(some modes bind it to a different command); it does not insert a
literal `DEL' character (ASCII character code 127).

   To insert a non-graphic character, or a character that your keyboard
does not support, first "quote" it by typing `C-q' (`quoted-insert').
There are two ways to use `C-q':

   * `C-q' followed by any non-graphic character (even `C-g') inserts
     that character.  For instance, `C-q <DEL>' inserts a literal `DEL'
     character.

   * `C-q' followed by a sequence of octal digits inserts the character
     with the specified octal character code.  You can use any number of
     octal digits; any non-digit terminates the sequence.  If the
     terminating character is <RET>, it serves only to terminate the
     sequence.  Any other non-digit terminates the sequence and then
     acts as normal input--thus, `C-q 1 0 1 B' inserts `AB'.

     The use of octal sequences is disabled in ordinary non-binary
     Overwrite mode, to give you a convenient way to insert a digit
     instead of overwriting with it.

To use decimal or hexadecimal instead of octal, set the variable
`read-quoted-char-radix' to 10 or 16.  If the radix is 16, the letters
`a' to `f' serve as part of a character code, just like digits.  Case
is ignored.

   A numeric argument tells `C-q' how many copies of the quoted
character to insert (*note Arguments::).

   Instead of `C-q', you can use `C-x 8 <RET>' (`ucs-insert') to insert
a character based on its Unicode name or code-point.  This command
prompts for a character to insert, using the minibuffer; you can
specify the character using either (i) the character's name in the
Unicode standard, or (ii) the character's code-point in the Unicode
standard.  If you specify the character's name, the command provides
completion.


File: emacs,  Node: Moving Point,  Next: Erasing,  Prev: Inserting Text,  Up: Basic

7.2 Changing the Location of Point
==================================

To do more than insert characters, you have to know how to move point
(*note Point::).  The keyboard commands `C-f', `C-b', `C-n', and `C-p'
move point to the right, left, up and down respectively.  These are
equivalent to the commands `<right>', `<left>', `<down>', and `<up>',
entered using the "arrow keys" present on many keyboards.  Many Emacs
users find that it is slower to use the arrow keys than the equivalent
control keys.  You can also click the left mouse button to move point
to the position clicked.  Emacs also provides a variety of additional
keyboard commands that move point in more sophisticated ways.

`C-a'
`<Home>'
     Move to the beginning of the line (`move-beginning-of-line').

`C-e'
`<End>'
     Move to the end of the line (`move-end-of-line').

`C-f'
`<right>'
     Move forward one character (`forward-char').

`C-b'
`<left>'
     Move backward one character (`backward-char').

`M-f'
`M-<right>'
`C-<right>'
     Move forward one word (`forward-word').

`M-b'
`M-<left>'
`C-<left>'
     Move backward one word (`backward-word').

`C-n'
`<down>'
     Move down one screen line (`next-line').  This command attempts to
     keep the horizontal position unchanged, so if you start in the
     middle of one line, you move to the middle of the next.

`C-p'
`<up>'
     Move up one screen line (`previous-line').  This command preserves
     position within the line, like `C-n'.

`M-r'
     Without moving the text on the screen, reposition point on the left
     margin of the center-most text line of the window; on subsequent
     consecutive invocations, move point to the left margin of the
     top-most line, the bottom-most line, and so forth, in cyclic order
     (`move-to-window-line-top-bottom').

     A numeric argument says which screen line to place point on,
     counting downward from the top of the window (zero means the top
     line).  A negative argument counts lines up from the bottom (-1
     means the bottom line).

`M-<'
     Move to the top of the buffer (`beginning-of-buffer').  With
     numeric argument N, move to N/10 of the way from the top.  *Note
     Arguments::, for more information on numeric arguments.

`M->'
     Move to the end of the buffer (`end-of-buffer').

`C-v'
`<PageDown>'
`<next>'
     Scroll the display one screen forward, and move point if necessary
     to put it on the screen (`scroll-up').  If your keyboard has a
     <PageDown> key (sometimes labelled <next>), it does the same thing
     as <C-v>.  Scrolling commands are described further in *note
     Scrolling::.

`M-v'
`<PageUp>'
`<prior>'
     Scroll one screen backward, and move point if necessary to put it
     on the screen (`scroll-down').  If your keyboard has a <PageUp>
     key (sometimes labelled <prior>), it does the same thing as `M-v'.

`M-x goto-char'
     Read a number N and move point to buffer position N.  Position 1
     is the beginning of the buffer.

`M-g M-g'
`M-g g'
     Read a number N and move point to the beginning of line number N
     (`goto-line').  Line 1 is the beginning of the buffer.  If point
     is on or just after a number in the buffer, that is the default
     for N.  Just type <RET> in the minibuffer to use it.  You can also
     specify N by giving `M-g M-g' a numeric prefix argument.  *Note
     Select Buffer::, for the behavior of `M-g M-g' when you give it a
     plain prefix argument.

`C-x C-n'
     Use the current column of point as the "semipermanent goal column"
     for `C-n' and `C-p' (`set-goal-column').  When a semipermanent
     goal column is in effect, those commands always try to move to
     this column, or as close as possible to it, after moving
     vertically.  The goal column remains in effect until canceled.

`C-u C-x C-n'
     Cancel the goal column.  Henceforth, `C-n' and `C-p' try to
     preserve the horizontal position, as usual.

   When a line of text in the buffer is longer than the width of the
window, Emacs usually displays it on two or more "screen lines".  For
convenience, `C-n' and `C-p' move point by screen lines, as do the
equivalent keys `<down>' and `<up>'.  You can force these commands to
move according to "logical lines" (i.e., according to the text lines in
the buffer) by setting the variable `line-move-visual' to `nil'; if a
logical line occupies multiple screen lines, the cursor then skips over
the additional screen lines.  Moving by logical lines was the default
behavior prior to Emacs 23.1.  For details, see *note Continuation
Lines::.  *Note Variables::, for how to set variables such as
`line-move-visual'.

   Unlike `C-n' and `C-p', most of the Emacs commands that work on
lines work on _logical_ lines.  For instance, `C-a'
(`move-beginning-of-line') and `C-e' (`move-end-of-line') respectively
move to the beginning and end of the logical line.  Whenever we
encounter commands that work on screen lines, such as `C-n' and `C-p',
we will point these out.

   When `line-move-visual' is `nil', you can also set the variable
`track-eol' to a non-`nil' value.  Then `C-n' and `C-p', when starting
at the end of the logical line, move to the end of the next logical
line.  Normally, `track-eol' is `nil'.

   `C-n' normally stops at the end of the buffer when you use it on the
last line of the buffer.  However, if you set the variable
`next-line-add-newlines' to a non-`nil' value, `C-n' on the last line
of a buffer creates an additional line at the end and moves down into
it.


File: emacs,  Node: Erasing,  Next: Basic Undo,  Prev: Moving Point,  Up: Basic

7.3 Erasing Text
================

`<DEL>'
`<Backspace>'
     Delete the character before point (`delete-backward-char').

`C-d'
`<Delete>'
     Delete the character after point (`delete-char').

`C-k'
     Kill to the end of the line (`kill-line').

`M-d'
     Kill forward to the end of the next word (`kill-word').

`M-<DEL>'
     Kill back to the beginning of the previous word
     (`backward-kill-word').

   The key `<DEL>' (`delete-backward-char') removes the character
before point, moving the cursor and all the characters after it
backwards.  On most keyboards, <DEL> is labelled <Backspace>, but we
refer to it as <DEL> in this manual.  Do not confuse <DEL> with another
key, labelled <Delete>, that exists on many keyboards; we will discuss
<Delete> momentarily.

   Typing <DEL> when the cursor is at the beginning of a line deletes
the preceding newline character, joining the line with the one before
it.

   On some text-only terminals, Emacs may not recognize the <DEL> key
properly.  If <DEL> does not do the right thing (e.g., if it deletes
characters forwards), see *note DEL Does Not Delete::.

   The key `C-d' (`delete-char') deletes the character after point,
i.e., the character under the cursor.  This shifts the rest of the text
on the line to the left.  If you type `C-d' at the end of a line, it
joins that line with the following line.  This command is also bound to
the key labelled <Delete> on many keyboards.

   To erase a larger amount of text, use the `C-k' key, which erases
(kills) a line at a time.  If you type `C-k' at the beginning or middle
of a line, it kills all the text up to the end of the line.  If you
type `C-k' at the end of a line, it joins that line with the following
line.

   To learn more about killing text, see *note Killing::.


File: emacs,  Node: Basic Undo,  Next: Basic Files,  Prev: Erasing,  Up: Basic

7.4 Undoing Changes
===================

`C-/'
     Undo one entry of the undo records--usually, one command worth
     (`undo').

`C-x u'

`C-_'
     The same.

   Emacs records a list of changes made in the buffer text, so you can
undo recent changes.  This is done using the `undo' command, which is
bound to `C-/' (as well as `C-x u' and `C-_').  Normally, this command
undoes the last change, moving point back to where it was before the
change.  The undo command applies only to changes in the buffer; you
can't use it to undo cursor motion.

   Although each editing command usually makes a separate entry in the
undo records, very simple commands may be grouped together.  Sometimes,
an entry may cover just part of a complex command.

   If you repeat `C-/' (or its aliases), each repetition undoes
another, earlier change, back to the limit of the undo information
available.  If all recorded changes have already been undone, the undo
command displays an error message and does nothing.

   To learn more about the `undo' command, see *note Undo::.


File: emacs,  Node: Basic Files,  Next: Basic Help,  Prev: Basic Undo,  Up: Basic

7.5 Files
=========

Text that you insert in an Emacs buffer lasts only as long as the Emacs
session.  To keep any text permanently, you must put it in a "file".
Files are named units of text which are stored by the operating system
for you to retrieve later by name.  To use the contents of a file in
any way, including editing it with Emacs, you must specify the file
name.

   Suppose there is a file named `test.emacs' in your home directory.
To begin editing this file in Emacs, type

     C-x C-f test.emacs <RET>

Here the file name is given as an "argument" to the command `C-x C-f'
(`find-file').  That command uses the "minibuffer" to read the
argument, and you type <RET> to terminate the argument (*note
Minibuffer::).

   Emacs obeys this command by "visiting" the file: it creates a
buffer, copies the contents of the file into the buffer, and then
displays the buffer for editing.  If you alter the text, you can "save"
the new text in the file by typing `C-x C-s' (`save-buffer').  This
copies the altered buffer contents back into the file `test.emacs',
making them permanent.  Until you save, the changed text exists only
inside Emacs, and the file `test.emacs' is unaltered.

   To create a file, just visit it with `C-x C-f' as if it already
existed.  This creates an empty buffer, in which you can insert the
text you want to put in the file.  Emacs actually creates the file the
first time you save this buffer with `C-x C-s'.

   To learn more about using files in Emacs, see *note Files::.


File: emacs,  Node: Basic Help,  Next: Blank Lines,  Prev: Basic Files,  Up: Basic

7.6 Help
========

If you forget what a key does, you can find out with the Help
character, which is `C-h' (or <F1>, which is an alias for `C-h').  Type
`C-h k', followed by the key of interest; for example, `C-h k C-n'
tells you what `C-n' does.  `C-h' is a prefix key; `C-h k' is just one
of its subcommands (the command `describe-key').  The other subcommands
of `C-h' provide different kinds of help.  Type `C-h' twice to get a
description of all the help facilities.  *Note Help::.


File: emacs,  Node: Blank Lines,  Next: Continuation Lines,  Prev: Basic Help,  Up: Basic

7.7 Blank Lines
===============

Here are special commands and techniques for inserting and deleting
blank lines.

`C-o'
     Insert a blank line after the cursor (`open-line').

`C-x C-o'
     Delete all but one of many consecutive blank lines
     (`delete-blank-lines').

   We have seen how `<RET>' (`newline') starts a new line of text.
However, it may be easier to see what you are doing if you first make a
blank line and then insert the desired text into it.  This is easy to
do using the key `C-o' (`open-line'), which inserts a newline after
point but leaves point in front of the newline.  After `C-o', type the
text for the new line.

   You can make several blank lines by typing `C-o' several times, or
by giving it a numeric argument specifying how many blank lines to make.
*Note Arguments::, for how.  If you have a fill prefix, the `C-o'
command inserts the fill prefix on the new line, if typed at the
beginning of a line.  *Note Fill Prefix::.

   The easy way to get rid of extra blank lines is with the command
`C-x C-o' (`delete-blank-lines').  If point lies within a run of
several blank lines, `C-x C-o' deletes all but one of them.  If point
is on a single blank line, `C-x C-o' deletes it.  If point is on a
nonblank line, `C-x C-o' deletes all following blank lines, if any
exists.


File: emacs,  Node: Continuation Lines,  Next: Position Info,  Prev: Blank Lines,  Up: Basic

7.8 Continuation Lines
======================

Sometimes, a line of text in the buffer--a "logical line"--is too long
to fit in the window, and Emacs displays it as two or more "screen
lines".  This is called "line wrapping" or "continuation", and the long
logical line is called a "continued line".  On a graphical display,
Emacs indicates line wrapping with small bent arrows in the left and
right window fringes.  On a text-only terminal, Emacs indicates line
wrapping by displaying a `\' character at the right margin.

   Most commands that act on lines act on logical lines, not screen
lines.  For instance, `C-k' kills a logical line.  As described
earlier, `C-n' (`next-line') and `C-p' (`previous-line') are special
exceptions: they move point down and up, respectively, by one screen
line (*note Moving Point::).

   Emacs can optionally "truncate" long logical lines instead of
continuing them.  This means that every logical line occupies a single
screen line; if it is longer than the width of the window, the rest of
the line is not displayed.  On a graphical display, a truncated line is
indicated by a small straight arrow in the right fringe; on a text-only
terminal, it is indicated by a `$' character in the right margin.
*Note Line Truncation::.

   By default, continued lines are wrapped at the right window edge.
Since the wrapping may occur in the middle of a word, continued lines
can be difficult to read.  The usual solution is to break your lines
before they get too long, by inserting newlines.  If you prefer, you
can make Emacs insert a newline automatically when a line gets too
long, by using Auto Fill mode.  *Note Filling::.

   Sometimes, you may need to edit files containing many long logical
lines, and it may not be practical to break them all up by adding
newlines.  In that case, you can use Visual Line mode, which enables
"word wrapping": instead of wrapping long lines exactly at the right
window edge, Emacs wraps them at the word boundaries (i.e., space or
tab characters) nearest to the right window edge.  Visual Line mode
also redefines editing commands such as `C-a', `C-n', and `C-k' to
operate on screen lines rather than logical lines.  *Note Visual Line
Mode::.


File: emacs,  Node: Position Info,  Next: Arguments,  Prev: Continuation Lines,  Up: Basic

7.9 Cursor Position Information
===============================

Here are commands to get information about the size and position of
parts of the buffer, and to count lines.

`M-x what-page'
     Display the page number of point, and the line number within that
     page.

`M-x what-line'
     Display the line number of point in the whole buffer.

`M-x line-number-mode'
`M-x column-number-mode'
     Toggle automatic display of the current line number or column
     number.  *Note Optional Mode Line::.

`M-x count-lines-region'
     Display the number of lines in the current region.  Normally bound
     to `M-=', except in a few specialist modes.  *Note Mark::, for
     information about the region.

`C-x ='
     Display the character code of character after point, character
     position of point, and column of point (`what-cursor-position').

`M-x hl-line-mode'
     Enable or disable highlighting of the current line.  *Note Cursor
     Display::.

`M-x size-indication-mode'
     Toggle automatic display of the size of the buffer.  *Note
     Optional Mode Line::.

   `M-x what-line' displays the current line number in the echo area.
This command is usually redundant, because the current line number is
shown in the mode line (*note Mode Line::).  However, if you narrow the
buffer, the mode line shows the line number relative to the accessible
portion (*note Narrowing::).  By contrast, `what-line' displays both
the line number relative to the narrowed region and the line number
relative to the whole buffer.

   `M-x what-page' counts pages from the beginning of the file, and
counts lines within the page, showing both numbers in the echo area.
*Note Pages::.

   Use `M-x count-lines-region' (normally bound to `M-=') to display
the number of lines in the region (*note Mark::).  *Note Pages::, for
the command `C-x l' which counts the lines in the current page.

   The command `C-x =' (`what-cursor-position') shows information about
the current cursor position and the buffer contents at that position.
It displays a line in the echo area that looks like this:

     Char: c (99, #o143, #x63) point=28062 of 36168 (78%) column=53

   After `Char:', this shows the character in the buffer at point.  The
text inside the parenthesis shows the corresponding decimal, octal and
hex character codes; for more information about how `C-x =' displays
character information, see *note International Chars::.  After `point='
is the position of point as a character count (the first character in
the buffer is position 1, the second character is position 2, and so
on).  The number after that is the total number of characters in the
buffer, and the number in parenthesis expresses the position as a
percentage of the total.  After `column=' is the horizontal position of
point, in columns counting from the left edge of the window.

   If the buffer has been narrowed, making some of the text at the
beginning and the end temporarily inaccessible, `C-x =' displays
additional text describing the currently accessible range.  For
example, it might display this:

     Char: C (67, #o103, #x43) point=252 of 889 (28%) <231-599> column=0

where the two extra numbers give the smallest and largest character
position that point is allowed to assume.  The characters between those
two positions are the accessible ones.  *Note Narrowing::.


File: emacs,  Node: Arguments,  Next: Repeating,  Prev: Position Info,  Up: Basic

7.10 Numeric Arguments
======================

In the terminology of mathematics and computing, "argument" means "data
provided to a function or operation."  You can give any Emacs command a
"numeric argument" (also called a "prefix argument").  Some commands
interpret the argument as a repetition count.  For example, giving
`C-f' an argument of ten causes it to move point forward by ten
characters instead of one.  With these commands, no argument is
equivalent to an argument of one, and negative arguments cause them to
move or act in the opposite direction.

   The easiest way to specify a numeric argument is to type a digit
and/or a minus sign while holding down the <META> key.  For example,

     M-5 C-n

moves down five lines.  The keys `M-1', `M-2', and so on, as well as
`M--', are bound to commands (`digit-argument' and `negative-argument')
that set up an argument for the next command.  `Meta--' without digits
normally means -1.

   If you enter more than one digit, you need not hold down the <META>
key for the second and subsequent digits.  Thus, to move down fifty
lines, type

     M-5 0 C-n

Note that this _does not_ insert five copies of `0' and move down one
line, as you might expect--the `0' is treated as part of the prefix
argument.

   (What if you do want to insert five copies of `0'?  Type `M-5 C-u
0'.  Here, `C-u' "terminates" the prefix argument, so that the next
keystroke begins the command that you want to execute.  Note that this
meaning of `C-u' applies only to this case.  For the usual role of
`C-u', see below.)

   Instead of typing `M-1', `M-2', and so on, another way to specify a
numeric argument is to type `C-u' (`universal-argument') followed by
some digits, or (for a negative argument) a minus sign followed by
digits.  A minus sign without digits normally means -1.

   `C-u' alone has the special meaning of "four times": it multiplies
the argument for the next command by four.  `C-u C-u' multiplies it by
sixteen.  Thus, `C-u C-u C-f' moves forward sixteen characters.  Other
useful combinations are `C-u C-n', `C-u C-u C-n' (move down a good
fraction of a screen), `C-u C-u C-o' (make "a lot" of blank lines), and
`C-u C-k' (kill four lines).

   You can use a numeric argument before a self-inserting character to
insert multiple copies of it.  This is straightforward when the
character is not a digit; for example, `C-u 6 4 a' inserts 64 copies of
the character `a'.  But this does not work for inserting digits; `C-u 6
4 1' specifies an argument of 641.  You can separate the argument from
the digit to insert with another `C-u'; for example, `C-u 6 4 C-u 1'
does insert 64 copies of the character `1'.

   Some commands care whether there is an argument, but ignore its
value.  For example, the command `M-q' (`fill-paragraph') fills text;
with an argument, it justifies the text as well.  (*Note Filling::, for
more information on `M-q'.)  For these commands, it is enough to the
argument with a single `C-u'.

   Some commands use the value of the argument as a repeat count, but
do something special when there is no argument.  For example, the
command `C-k' (`kill-line') with argument N kills N lines, including
their terminating newlines.  But `C-k' with no argument is special: it
kills the text up to the next newline, or, if point is right at the end
of the line, it kills the newline itself.  Thus, two `C-k' commands
with no arguments can kill a nonblank line, just like `C-k' with an
argument of one.  (*Note Killing::, for more information on `C-k'.)

   A few commands treat a plain `C-u' differently from an ordinary
argument.  A few others may treat an argument of just a minus sign
differently from an argument of -1.  These unusual cases are described
when they come up; they exist to make an individual command more
convenient, and they are documented in that command's documentation
string.

   We use the term "prefix argument" as well as "numeric argument," to
emphasize that you type these argument before the command, and to
distinguish them from minibuffer arguments that come after the command.


File: emacs,  Node: Repeating,  Prev: Arguments,  Up: Basic

7.11 Repeating a Command
========================

Many simple commands, such as those invoked with a single key or with
`M-x COMMAND-NAME <RET>', can be repeated by invoking them with a
numeric argument that serves as a repeat count (*note Arguments::).
However, if the command you want to repeat prompts for input, or uses a
numeric argument in another way, that method won't work.

   The command `C-x z' (`repeat') provides another way to repeat an
Emacs command many times.  This command repeats the previous Emacs
command, whatever that was.  Repeating a command uses the same arguments
that were used before; it does not read new arguments each time.

   To repeat the command more than once, type additional `z''s: each
`z' repeats the command one more time.  Repetition ends when you type a
character other than `z', or press a mouse button.

   For example, suppose you type `C-u 2 0 C-d' to delete 20 characters.
You can repeat that command (including its argument) three additional
times, to delete a total of 80 characters, by typing `C-x z z z'.  The
first `C-x z' repeats the command once, and each subsequent `z' repeats
it once again.


File: emacs,  Node: Minibuffer,  Next: M-x,  Prev: Basic,  Up: Top

8 The Minibuffer
****************

The "minibuffer" is where Emacs commands read complicated arguments,
such as file names, buffer names, Emacs command names, or Lisp
expressions.  We call it the "minibuffer" because it's a
special-purpose buffer with a small amount of screen space.  You can
use the usual Emacs editing commands in the minibuffer to edit the
argument text.

   When the minibuffer is in use, it appears in the echo area, with a
cursor.  The minibuffer display starts with a "prompt" in a distinct
color, usually ending with a colon.  The prompt states what kind of
input is expected, and how it will be used.

   The simplest way to enter a minibuffer argument is to type the text,
then <RET> to submit the argument and exit the minibuffer.  You can
cancel the minibuffer, and the command that wants the argument, by
typing `C-g'.

   Sometimes, a "default argument" appears in the prompt, inside
parentheses before the colon.  The default will be used as the argument
value if you just type <RET>.  For example, commands that read buffer
names usually show a buffer name as the default; you can type <RET> to
operate on that default buffer.

   Since the minibuffer appears in the echo area, it can conflict with
other uses of the echo area.  If an error occurs while the minibuffer
is active, the error message hides the minibuffer for a few seconds, or
until you type something; then the minibuffer comes back.  If a command
such as `C-x =' needs to display a message in the echo area, the
message hides the minibuffer for a few seconds, or until you type
something; then the minibuffer comes back.  While the minibuffer is in
use, keystrokes do not echo.

* Menu:

* Minibuffer File::       Entering file names with the minibuffer.
* Minibuffer Edit::       How to edit in the minibuffer.
* Completion::            An abbreviation facility for minibuffer input.
* Minibuffer History::    Reusing recent minibuffer arguments.
* Repetition::            Re-executing commands that used the minibuffer.
* Passwords::             Entering passwords in the echo area.


File: emacs,  Node: Minibuffer File,  Next: Minibuffer Edit,  Up: Minibuffer

8.1 Minibuffers for File Names
==============================

Commands such as `C-x C-f' (`find-file') use the minibuffer to read a
file name argument (*note Basic Files::).  When the minibuffer is used
to read a file name, it typically starts out with some initial text
ending in a slash.  This is the "default directory".  For example, it
may start out like this:

     Find File: /u2/emacs/src/

Here, `Find File: ' is the prompt and `/u2/emacs/src/' is the default
directory.  If you now type `buffer.c' as input, that specifies the
file `/u2/emacs/src/buffer.c'.  *Note File Names::, for information
about the default directory.

   You can specify the parent directory with `..': `/a/b/../foo.el' is
equivalent to `/a/foo.el'.  Alternatively, you can use `M-<DEL>' to
kill directory names backwards (*note Words::).

   To specify a file in a completely different directory, you can kill
the entire default with `C-a C-k' (*note Minibuffer Edit::).
Alternatively, you can ignore the default, and enter an absolute file
name starting with a slash or a tilde after the default directory.  For
example, you can specify `/etc/termcap' as follows:

     Find File: /u2/emacs/src//etc/termcap

Emacs interprets a double slash as "ignore everything before the second
slash in the pair."  In the example above, `/u2/emacs/src/' is ignored,
so the argument you supplied is `/etc/termcap'.  The ignored part of
the file name is dimmed if the terminal allows it (to disable this
dimming, turn off File Name Shadow mode with the command `M-x
file-name-shadow-mode'.)

   Emacs interprets `~/' as your home directory.  Thus, `~/foo/bar.txt'
specifies a file named `bar.txt', inside a directory named `foo', which
is in turn located in your home directory.  In addition, `~USER-ID/'
means the home directory of a user whose login name is USER-ID.  Any
leading directory name in front of the `~' is ignored: thus,
`/u2/emacs/~/foo/bar.txt' is equivalent to `~/foo/bar.txt'.

   On MS-Windows and MS-DOS systems, where a user doesn't always have a
home directory, Emacs uses several alternatives.  For MS-Windows, see
*note Windows HOME::; for MS-DOS, see *note HOME on MS-DOS: MS-DOS File
Names.  On these systems, the `~USER-ID/' construct is supported only
for the current user, i.e., only if USER-ID is the current user's login
name.

   To prevent Emacs from inserting the default directory when reading
file names, change the variable `insert-default-directory' to `nil'.
In that case, the minibuffer starts out empty.  Nonetheless, relative
file name arguments are still interpreted based on the same default
directory.


File: emacs,  Node: Minibuffer Edit,  Next: Completion,  Prev: Minibuffer File,  Up: Minibuffer

8.2 Editing in the Minibuffer
=============================

The minibuffer is an Emacs buffer, albeit a peculiar one, and the usual
Emacs commands are available for editing the argument text.  (The
prompt, however, is "read-only", and cannot be changed.)

   Since <RET> in the minibuffer is defined to exit the minibuffer, you
can't use it to insert a newline in the minibuffer.  To do that, type
`C-o' or `C-q C-j'.  (The newline character is really the ASCII
character control-J.)

   Inside a minibuffer, the keys `<TAB>', `<SPC>', and `<?>' are often
bound to commands that perform "completion".  *Note Completion::.  You
can use `C-q' (`quoted-insert') to insert a <TAB>, <SPC>, or <?>
character.  For example, `C-q <TAB>' inserts a <TAB> character.  *Note
Inserting Text::.

   For convenience, `C-a' (`move-beginning-of-line') in a minibuffer
moves point to the beginning of the argument text, not the beginning of
the prompt.  For example, this allows you to erase the entire argument
with `C-a C-k'.

   When the minibuffer is active, the echo area is treated much like an
ordinary Emacs window.  For instance, you can switch to another window
(with `C-x o'), edit text there, then return to the minibuffer window
to finish the argument.  You can even kill text in another window,
return to the minibuffer window, and yank the text into the argument.
There are some restrictions on the minibuffer window, however: for
instance, you cannot split it.  *Note Windows::.

   Normally, the minibuffer window occupies a single screen line.
However, if you add two or more lines' worth of text into the
minibuffer, it expands automatically to accommodate the text.  The
variable `resize-mini-windows' controls the resizing of the minibuffer.
The default value is `grow-only', which means the behavior we have just
described.  If the value is `t', the minibuffer window will also shrink
automatically if you remove some lines of text from the minibuffer,
down to a minimum of one screen line.  If the value is `nil', the
minibuffer window never changes size automatically, but you can use the
usual window-resizing commands on it (*note Windows::).

   The variable `max-mini-window-height' controls the maximum height
for resizing the minibuffer window.  A floating-point number specifies
a fraction of the frame's height; an integer specifies the maximum
number of lines; `nil' means do not resize the minibuffer window
automatically.  The default value is 0.25.

   The `C-M-v' command in the minibuffer scrolls the help text from
commands that display help text of any sort in another window.  You can
also scroll the help text with `M-<prior>' and `M-<next>' (or,
equivalently, `M-<PageUp>' and `M-<PageDown>').  This is especially
useful with long lists of possible completions.  *Note Other Window::.

   Emacs normally disallows most commands that use the minibuffer while
the minibuffer is active.  To allow such commands in the minibuffer,
set the variable `enable-recursive-minibuffers' to `t'.


File: emacs,  Node: Completion,  Next: Minibuffer History,  Prev: Minibuffer Edit,  Up: Minibuffer

8.3 Completion
==============

Sometimes, you can use a feature called "completion" to help you enter
arguments.  This means that after you type part of the argument, Emacs
can fill in the rest, or some of it, based on what you have typed so
far.

   When completion is available, certain keys (usually <TAB>, <RET>,
and <SPC>) are rebound to complete the text in the minibuffer into a
longer string chosen from a set of "completion alternatives".  The set
of completion alternatives depends on the command that requested the
argument, and on what you have typed so far.  In addition, you can
usually type `?' to display a list of possible completions.

   For example, `M-x' uses the minibuffer to read the name of a
command, so completion works by matching the minibuffer text against
the names of existing Emacs commands.  So, to run the command
`insert-buffer', you can type `M-x ins <SPC> b <RET>' instead of the
full `M-x insert-buffer <RET>'.

   Case is significant in completion when it is significant in the
argument you are entering, such as command names.  Thus,
`insert-buffer' is not a valid completion for `IN'.  Completion ignores
case distinctions for certain arguments in which case does not matter.

* Menu:

* Example: Completion Example.    Examples of using completion.
* Commands: Completion Commands.  A list of completion commands.
* Strict Completion::             Different types of completion.
* Options: Completion Options.    Options for completion.


File: emacs,  Node: Completion Example,  Next: Completion Commands,  Up: Completion

8.3.1 Completion Example
------------------------

A concrete example may help here.  If you type `M-x a u <TAB>', the
<TAB> looks for alternatives (in this case, command names) that start
with `au'.  There are several, including `auto-fill-mode' and
`autoconf-mode', but they all begin with `auto', so the `au' in the
minibuffer completes to `auto'.

   If you type <TAB> again immediately, it cannot determine the next
character; it could be `-', `a', or `c'.  So it does not add any
characters; instead, <TAB> displays a list of all possible completions
in another window.

   Next, type `- f'.  The minibuffer now contains `auto-f', and the
only command name that starts with this is `auto-fill-mode'.  If you
now type <TAB>, completion fills in the rest of the argument
`auto-fill-mode' into the minibuffer.  You have been able to enter
`auto-fill-mode' by typing just `a u <TAB> - f <TAB>'.


File: emacs,  Node: Completion Commands,  Next: Strict Completion,  Prev: Completion Example,  Up: Completion

8.3.2 Completion Commands
-------------------------

Here is a list of the completion commands defined in the minibuffer
when completion is allowed.

`<TAB>'
     Complete the text in the minibuffer as much as possible; if unable
     to complete, display a list of possible completions
     (`minibuffer-complete').

`<SPC>'
     Complete up to one word from the minibuffer text before point
     (`minibuffer-complete-word').  <SPC> for completion is not
     available when entering a file name, since file names often include
     spaces.

`<RET>'
     Submit the text in the minibuffer as the argument, possibly
     completing first as described in the next node
     (`minibuffer-complete-and-exit').  *Note Strict Completion::.

`?'
     Display a list of possible completions of the text before point
     (`minibuffer-completion-help').

   <TAB> (`minibuffer-complete') is the most fundamental completion
command.  It searches for all possible completion alternatives that
match the existing minibuffer text, and attempts to complete as much as
it can.  The matching of completion alternatives to the minibuffer text
is performed according to somewhat intricate rules, which are designed
so that plausible completions are offered under most circumstances.  A
valid completion alternative must satisfy the following criteria:

   * The minibuffer text before point must be the same as the beginning
     of the completion alternative.  If there is any minibuffer text
     after point, it must be a substring of the remainder of the
     completion alternative.

   * If no completion alternative satisfies the above rules, try using
     "partial completion" rules: divide the minibuffer text into words
     separated by hyphens or spaces, and complete each word separately.
     Thus, when completing command names, `em-l-m' completes to
     `emacs-lisp-mode'.

   * If there is still no completion alternative, try the first rule
     again, but ignore the minibuffer text after point (i.e., don't try
     matching it).

When performing these comparisons, a `*' in the minibuffer text acts as
a "wildcard"--it matches any character at the corresponding position in
the completion alternative.

   <SPC> (`minibuffer-complete-word') completes like <TAB>, but only up
to the next hyphen or space.  If you have `auto-f' in the minibuffer
and type <SPC>, it finds that the completion is `auto-fill-mode', but
it only inserts `ill-', giving `auto-fill-'.  Another <SPC> at this
point completes all the way to `auto-fill-mode'.

   If <TAB> or <SPC> is unable to complete, it displays a list of
possible completions (if there are any) in a separate window.  You can
choose a completion from this list using the following commands:

`Mouse-1'
`Mouse-2'
     Clicking mouse button 1 or 2 on a completion possibility chooses
     that completion (`mouse-choose-completion').

`M-v'
`<PageUp>'
`<prior>'
     Typing `M-v', while in the minibuffer, selects the window showing
     the completion list buffer (`switch-to-completions').  This paves
     the way for using the commands below.  Typing <PageUp> or <prior>
     does the same, as does selecting that window in other ways.

`<RET>'
     Typing <RET>, while in the completion list buffer, chooses the
     completion that point is in or next to (`choose-completion').  To
     use this command, you must first switch to the completion list
     window.

`<Right>'
     Typing the right-arrow key <Right>, while in the completion list
     buffer, moves point to the following completion possibility
     (`next-completion').

`<Left>'
     Typing the left-arrow key <Left>, while in the completion list
     buffer, moves point to the previous completion possibility
     (`previous-completion').


File: emacs,  Node: Strict Completion,  Next: Completion Options,  Prev: Completion Commands,  Up: Completion

8.3.3 Strict Completion
-----------------------

There are three different ways that <RET> can do completion, depending
on how the argument will be used.

   * "Strict" completion accepts only known completion candidates.  For
     example, when `C-x k' reads the name of a buffer to kill, only the
     name of an existing buffer makes sense.  In strict completion,
     <RET> refuses to exit if the text in the minibuffer does not
     complete to an exact match.

   * "Cautious" completion is similar to strict completion, except that
     <RET> exits only if the text is an already exact match.
     Otherwise, <RET> does not exit, but it does complete the text.  If
     that completes to an exact match, a second <RET> will exit.

     Cautious completion is used for reading file names for files that
     must already exist, for example.

   * "Permissive" completion allows any input; the completion
     candidates are just suggestions.  For example, when `C-x C-f'
     reads the name of a file to visit, any file name is allowed,
     including nonexistent file (in case you want to create a file).
     In permissive completion, <RET> does not complete, it just submits
     the argument as you have entered it.

   The completion commands display a list of all possible completions
whenever they can't determine even one more character by completion.
Also, typing `?' explicitly requests such a list.  You can scroll the
list with `C-M-v' (*note Other Window::).


File: emacs,  Node: Completion Options,  Prev: Strict Completion,  Up: Completion

8.3.4 Completion Options
------------------------

If `completion-auto-help' is set to `nil', the completion commands
never display the completion list buffer; you must type `?'  to display
the list.  If the value is `lazy', Emacs only shows the completion list
buffer on the second attempt to complete.  In other words, if there is
nothing to complete, the first <TAB> echoes `Next char not unique'; the
second <TAB> does the completion list buffer.

   When completing file names, certain file names are usually ignored.
The variable `completion-ignored-extensions' contains a list of
strings; a file name ending in any of those strings is ignored as a
completion candidate.  The standard value of this variable has several
elements including `".o"', `".elc"', and `"~"'.  For example, if a
directory contains `foo.c' and `foo.elc', `foo' completes to `foo.c'.
However, if _all_ possible completions end in "ignored" strings, they
are not ignored: in the previous example, `foo.e' completes to
`foo.elc'.  Displaying a list of possible completions disregards
`completion-ignored-extensions'; it shows them all.

   If an element of `completion-ignored-extensions' ends in a slash
(`/'), it's a subdirectory name; that directory and its contents are
ignored.  Elements of `completion-ignored-extensions' that do not end
in a slash are ordinary file names.

   When completing file names, Emacs ignores case differences if the
variable `read-file-name-completion-ignore-case' is non-`nil'.  The
default value is `nil' on systems that have case-sensitive file-names,
such as GNU/Linux; it is non-`nil' on systems that have
case-insensitive file-names, such as Microsoft Windows.  When
completing buffer names, Emacs ignores case differences if
`read-buffer-completion-ignore-case' is non-`nil' (the default value is
`nil').

   You can customize the matching rules for completion alternatives
using the variable `completion-styles'.  Its value should be a list of
symbols, each representing a "completion style"; valid style symbols
are `basic', `partial-completion', `emacs22', `emacs21', and
`initials'.  When completing, Emacs attempts to use the first
completion style in the list; if this does not return any completion
alternatives, it tries the next completion style in the list, and so
on.  The completion rules described in *note Completion Commands::
correspond to the default value of `completion-styles', which is
`(basic partial-completion emacs22)'.

   Icomplete mode presents a constantly-updated display that tells you
what completions are available for the text you've entered so far.  The
command to enable or disable this minor mode is `M-x icomplete-mode'.


File: emacs,  Node: Minibuffer History,  Next: Repetition,  Prev: Completion,  Up: Minibuffer

8.4 Minibuffer History
======================

Every argument that you enter with the minibuffer is saved in a
"minibuffer history list" so you can easily use it again later.  You
can use the following arguments to quickly fetch an earlier argument
into the minibuffer:

`M-p'
`<Up>'
     Move to the previous item in the minibuffer history, an earlier
     argument (`previous-history-element').

`M-n'
`<Down>'
     Move to the next item in the minibuffer history
     (`next-history-element').

`M-r REGEXP <RET>'
     Move to an earlier item in the minibuffer history that matches
     REGEXP (`previous-matching-history-element').

`M-s REGEXP <RET>'
     Move to a later item in the minibuffer history that matches REGEXP
     (`next-matching-history-element').

   While in the minibuffer, typing `M-p' or <Up>
(`previous-history-element') moves up through the minibuffer history
list, one item at a time.  Each `M-p' fetches an earlier item from the
history list into the minibuffer, replacing its existing contents.
Similarly, typing `M-n' or <Down> (`next-history-element') moves back
down the history list, fetching later entries into the minibuffer.  You
can think of these commands as "backwards" and "forwards" through the
history list.

   If you type `M-n' in the minibuffer when there are no later entries
in the minibuffer history (e.g., if you haven't previously typed
`M-p'), Emacs tries fetching from a list of default argument: values
that you are likely to enter.  You can think of this as moving through
the "future list" instead of the "history list".

   The input that `M-p' or `M-n' fetches into the minibuffer entirely
replaces the existing contents of the minibuffer, so you can simply
type <RET> to use it as an argument.  You can also edit the text before
you reuse it; this does not change the history element that you "moved"
to, but your new argument does go at the end of the history list in its
own right.

   There are also commands to search forward or backward through the
history; they search for history elements that match a regular
expression.  `M-r' (`previous-matching-history-element') searches older
elements in the history, while `M-s' (`next-matching-history-element')
searches newer elements.  These commands are unusual: they use the
minibuffer to read the regular expression even though they are invoked
from the minibuffer.  As with incremental searching, an upper-case
letter in the regular expression makes the search case-sensitive (*note
Search Case::).  You can also search through the history using an
incremental search (*note Isearch Minibuffer::).

   All uses of the minibuffer record your input on a history list, but
there are separate history lists for different kinds of arguments.  For
example, there is a list for file names, used by all the commands that
read file names.  (As a special feature, this history list records the
absolute file name, even if the name you entered was not absolute.)

   There are several other specific history lists, including one for
buffer names, one for arguments of commands like `query-replace', one
used by `M-x' for command names, and one used by `compile' for
compilation commands.  Finally, there is one "miscellaneous" history
list that most minibuffer arguments use.

   The variable `history-length' specifies the maximum length of a
minibuffer history list; adding a new element deletes the oldest
element if the list gets too long.  If the value of `history-length' is
`t', there is no maximum length.

   The variable `history-delete-duplicates' specifies whether to delete
duplicates in history.  If it is non-`nil', adding a new element
deletes from the list all other elements that are equal to it.  The
default is `nil'.


File: emacs,  Node: Repetition,  Next: Passwords,  Prev: Minibuffer History,  Up: Minibuffer

8.5 Repeating Minibuffer Commands
=================================

Every command that uses the minibuffer once is recorded on a special
history list, the "command history", together with the values of its
arguments, so that you can repeat the entire command.  In particular,
every use of `M-x' is recorded there, since `M-x' uses the minibuffer
to read the command name.

`C-x <ESC> <ESC>'
     Re-execute a recent minibuffer command from the command history
     (`repeat-complex-command').

`M-x list-command-history'
     Display the entire command history, showing all the commands `C-x
     <ESC> <ESC>' can repeat, most recent first.

   `C-x <ESC> <ESC>' is used to re-execute a recent command that used
the minibuffer.  With no argument, it repeats the last such command.  A
numeric argument specifies which command to repeat; 1 means the last
one, 2 the previous, and so on.

   `C-x <ESC> <ESC>' works by turning the previous command into a Lisp
expression and then entering a minibuffer initialized with the text for
that expression.  Even if you don't understand Lisp syntax, it will
probably be obvious which command is displayed for repetition.  If you
type just <RET>, that repeats the command unchanged.  You can also
change the command by editing the Lisp expression before you execute
it.  The repeated command is added to the front of the command history
unless it is identical to the most recent item.

   Once inside the minibuffer for `C-x <ESC> <ESC>', you can use the
minibuffer history commands (`M-p', `M-n', `M-r', `M-s'; *note
Minibuffer History::) to move through the history list of saved entire
commands.  After finding the desired previous command, you can edit its
expression as usual and then repeat it by typing <RET>.

   Incremental search does not, strictly speaking, use the minibuffer.
Therefore, although it behaves like a complex command, it normally does
not appear in the history list for `C-x <ESC> <ESC>'.  You can make
incremental search commands appear in the history by setting
`isearch-resume-in-command-history' to a non-`nil' value.  *Note
Incremental Search::.

   The list of previous minibuffer-using commands is stored as a Lisp
list in the variable `command-history'.  Each element is a Lisp
expression which describes one command and its arguments.  Lisp programs
can re-execute a command by calling `eval' with the `command-history'
element.


File: emacs,  Node: Passwords,  Prev: Repetition,  Up: Minibuffer

8.6 Entering passwords
======================

Sometimes, you may need to enter a password into Emacs.  For instance,
when you tell Emacs to visit a file on another machine via a network
protocol such as FTP, you often need to supply a password to gain
access to the machine (*note Remote Files::).

   Entering a password is, in a basic sense, similar to using a
minibuffer.  Emacs displays a prompt in the echo area (such as
`Password: '); after you type the required password, press <RET> to
submit it.  To prevent others from seeing your password, every
character you type is displayed as a dot (`.') instead of its usual
form.

   Most of the features and commands associated with the minibuffer can
_not_ be used when entering a password.  There is no history or
completion, and you cannot change windows or perform any other action
with Emacs until you have submitted the password.

   While you are typing the password, you may press <DEL> to delete
backwards, removing the last character entered.  <C-u> deletes
everything you have typed so far.  `C-g' quits the password prompt
(*note Quitting::).  `C-y' inserts the current kill into the password
(*note Killing::).  You may type either <RET> or <ESC> to submit the
password.  Any other self-inserting character key inserts the
associated character into the password, and all other input is ignored.


File: emacs,  Node: M-x,  Next: Help,  Prev: Minibuffer,  Up: Top

9 Running Commands by Name
**************************

Every Emacs command has a name that you can use to run it.  For
convenience, many commands also have key bindings.  You can run those
commands by typing the keys, or run them by name.  Most Emacs commands
have no key bindings, so the only way to run them is by name.  (*Note
Key Bindings::, for how to set up key bindings.)

   By convention, a command name consists of one or more words,
separated by hyphens; for example, `auto-fill-mode' or `manual-entry'.
Command names mostly use complete English words to make them easier to
remember.

   To run a command by name, start with `M-x', type the command name,
then terminate it with <RET>.  `M-x' uses the minibuffer to read the
command name.  The string `M-x' appears at the beginning of the
minibuffer as a "prompt" to remind you to enter a command name to be
run.  <RET> exits the minibuffer and runs the command.  *Note
Minibuffer::, for more information on the minibuffer.

   You can use completion to enter the command name.  For example, to
invoke the command `forward-char', you can type

     M-x forward-char <RET>

or

     M-x forw <TAB> c <RET>

Note that `forward-char' is the same command that you invoke with the
key `C-f'.  The existence of a key binding does not stop you from
running the command by name.

   To cancel the `M-x' and not run a command, type `C-g' instead of
entering the command name.  This takes you back to command level.

   To pass a numeric argument to the command you are invoking with
`M-x', specify the numeric argument before `M-x'.  The argument value
appears in the prompt while the command name is being read, and finally
`M-x' passes the argument to that command.

   When the command you run with `M-x' has a key binding, Emacs
mentions this in the echo area after running the command.  For example,
if you type `M-x forward-word', the message says that you can run the
same command by typing `M-f'.  You can turn off these messages by
setting the variable `suggest-key-bindings' to `nil'.

   In this manual, when we speak of running a command by name, we often
omit the <RET> that terminates the name.  Thus we might say `M-x
auto-fill-mode' rather than `M-x auto-fill-mode <RET>'.  We mention the
<RET> only for emphasis, such as when the command is followed by
arguments.

   `M-x' works by running the command `execute-extended-command', which
is responsible for reading the name of another command and invoking it.


File: emacs,  Node: Help,  Next: Mark,  Prev: M-x,  Up: Top

10 Help
*******

Emacs provides extensive help features, all accessible through the
"help character", `C-h'.  This is a prefix key that is used for
commands that display documentation; the next character you type should
be a "help option", to ask for a particular kind of help.  You can
cancel the `C-h' command with `C-g'.  The function key <F1> is
equivalent to `C-h'.

   `C-h' itself is one of the help options; `C-h C-h' displays a list
of help options, with a brief description of each one
(`help-for-help').  You can scroll the list with <SPC> and <DEL>, then
type the help option you want.  To cancel, type `C-g'.

   `C-h' or <F1> means "help" in various other contexts as well.  For
instance, you can type them after a prefix key to display a list of the
keys that can follow the prefix key.  (A few prefix keys don't support
`C-h' in this way, because they define other meanings for it, but they
all support <F1> for help.)

   Most help buffers use a special major mode, Help mode, which lets
you scroll conveniently with <SPC> and <DEL>.  You can also follow
hyperlinks to URLs, and to other facilities including Info nodes and
customization buffers.  *Note Help Mode::.

   If you are looking for a certain feature, but don't know what it is
called or where to look, we recommend three methods.  First, try an
apropos command, then try searching the manual index, then look in the
FAQ and the package keywords.

`C-h a TOPICS <RET>'
     This searches for commands whose names match the argument TOPICS.
     The argument can be a keyword, a list of keywords, or a regular
     expression (*note Regexps::).  *Note Apropos::.

`C-h i d m emacs <RET> i TOPIC <RET>'
     This searches for TOPIC in the indices of the on-line Emacs
     manual, and displays the first match found.  Press `,' to see
     subsequent matches.  You can use a regular expression as TOPIC.

`C-h i d m emacs <RET> s TOPIC <RET>'
     Similar, but searches the _text_ of the manual rather than the
     indices.

`C-h C-f'
     This displays the Emacs FAQ.  You can use the Info commands to
     browse it.

`C-h p'
     This displays the available Emacs packages based on keywords.
     *Note Library Keywords::.

* 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.
* Help Mode::           Special features of Help mode and Help buffers.
* Library Keywords::    Finding Lisp libraries by keywords (topics).
* Language Help::       Help relating to international language support.
* Misc Help::           Other help commands.
* Help Files::          Commands to display pre-written help files.
* Help Echo::           Help on active text and tooltips (`balloon help').


File: emacs,  Node: Help Summary,  Next: Key Help,  Up: Help

10.1 Help Summary
=================

   Here is a summary of the Emacs interactive help commands.  (The
character that follows `C-h' is the "help option.")  See *note Help
Files::, for other help commands that display fixed files of
information.

`C-h a TOPICS <RET>'
     Display a list of commands whose names match TOPICS
     (`apropos-command'; *note Apropos::).

`C-h b'
     Display all active key bindings; minor mode bindings first, then
     those of the major mode, then global bindings
     (`describe-bindings').

`C-h c KEY'
     Given a key sequence KEY, show the name of the command that it
     runs (`describe-key-briefly').  Here `c' stands for "character."
     For more extensive information on KEY, use `C-h k'.

`C-h d TOPICS <RET>'
     Display the commands and variables whose documentation matches
     TOPICS (`apropos-documentation').

`C-h e'
     Display the `*Messages*' buffer (`view-echo-area-messages').

`C-h f FUNCTION <RET>'
     Display documentation on the Lisp function named FUNCTION
     (`describe-function').  Since commands are Lisp functions, this
     works for commands too.

`C-h h'
     Display the `HELLO' file, which shows examples of various character
     sets.

`C-h i'
     Run Info, the GNU documentation browser (`info').  The complete
     Emacs manual is available on-line in Info.

`C-h k KEY'
     Display the name and documentation of the command that KEY runs
     (`describe-key').

`C-h l'
     Display a description of your last 300 keystrokes (`view-lossage').

`C-h m'
     Display documentation of the current major mode (`describe-mode').

`C-h n'
     Display news of recent Emacs changes (`view-emacs-news').

`C-h p'
     Find packages by topic keyword (`finder-by-keyword').  For an
     alternative interface to the same information, try the
     `info-finder' command.

`C-h r'
     Display the Emacs manual in Info (`info-emacs-manual').

`C-h s'
     Display the current contents of the syntax table, with an
     explanation of what they mean (`describe-syntax').  *Note Syntax::.

`C-h t'
     Enter the Emacs interactive tutorial (`help-with-tutorial').

`C-h v VAR <RET>'
     Display the documentation of the Lisp variable VAR
     (`describe-variable').

`C-h w COMMAND <RET>'
     Show which keys run the command named COMMAND (`where-is').

`C-h C CODING <RET>'
     Describe the coding system CODING (`describe-coding-system').

`C-h C <RET>'
     Describe the coding systems currently in use.

`C-h F COMMAND <RET>'
     Enter Info and go to the node that documents the Emacs command
     COMMAND (`Info-goto-emacs-command-node').

`C-h I METHOD <RET>'
     Describe the input method METHOD (`describe-input-method').

`C-h K KEY'
     Enter Info and go to the node that documents the key sequence KEY
     (`Info-goto-emacs-key-command-node').

`C-h L LANGUAGE-ENV <RET>'
     Display information on the character sets, coding systems, and
     input methods used in language environment LANGUAGE-ENV
     (`describe-language-environment').

`C-h S SYMBOL <RET>'
     Display the Info documentation on symbol SYMBOL according to the
     programming language you are editing (`info-lookup-symbol').

`C-h .'
     Display the help message for a special text area, if point is in
     one (`display-local-help').  (These include, for example, links in
     `*Help*' buffers.)


File: emacs,  Node: Key Help,  Next: Name Help,  Prev: Help Summary,  Up: Help

10.2 Documentation for a Key
============================

The help commands to get information about a key sequence are `C-h c'
and `C-h k'.  `C-h c KEY' displays in the echo area the name of the
command that KEY is bound to.  For example, `C-h c C-f' displays
`forward-char'.  Since command names are chosen to describe what the
commands do, this gives you a very brief description of what KEY does.

   `C-h k KEY' is similar but gives more information: it displays the
documentation string of the command as well as its name.  It displays
this information in a window, since it may not fit in the echo area.

   To find the documentation of a key sequence KEY, type `C-h K KEY'.
This displays the appropriate manual section which contains the
documentation of KEY.

   `C-h c', `C-h k' and `C-h K' work for any sort of key sequences,
including function keys, menus, and mouse events.  For instance, after
`C-h k' you can select a menu item from the menu bar, to view the
documentation string of the command it runs.

   `C-h w COMMAND <RET>' lists the keys that are bound to COMMAND.  It
displays the list in the echo area.  If it says the command is not on
any key, that means you must use `M-x' to run it.  `C-h w' runs the
command `where-is'.


File: emacs,  Node: Name Help,  Next: Apropos,  Prev: Key Help,  Up: Help

10.3 Help by Command or Variable Name
=====================================

`C-h f FUNCTION <RET>' (`describe-function') displays the documentation
of Lisp function FUNCTION, in a window.  Since commands are Lisp
functions, you can use this method to view the documentation of any
command whose name you know.  For example,

     C-h f auto-fill-mode <RET>

displays the documentation of `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 `M-x').

   `C-h f' is also useful for Lisp functions that you use in a Lisp
program.  For example, if you have just written the expression
`(make-vector len)' and want to check that you are using `make-vector'
properly, type `C-h f make-vector <RET>'.  Because `C-h f' allows all
function names, not just command names, you may find that some of your
favorite completion abbreviations that work in `M-x' don't work in `C-h
f'.  An abbreviation that is unique among command names may not be
unique among all function names.

   If you type `C-h f <RET>', it describes the function called by the
innermost Lisp expression in the buffer around point, _provided_ that
function name is a valid, defined Lisp function.  (That name appears as
the default while you enter the argument.)  For example, if point is
located following the text `(make-vector (car x)', the innermost list
containing point is the one that starts with `(make-vector', so `C-h f
<RET>' will describe the function `make-vector'.

   `C-h f' is also useful just to verify that you spelled a function
name correctly.  If the minibuffer prompt for `C-h f' shows the
function name from the buffer as the default, it means that name is
defined as a Lisp function.  Type `C-g' to cancel the `C-h f' command
if you don't really want to view the documentation.

   `C-h v' (`describe-variable') is like `C-h f' but describes Lisp
variables instead of Lisp functions.  Its default is the Lisp symbol
around or before point, if that is the name of a defined Lisp variable.
*Note Variables::.

   Help buffers that describe Emacs variables and functions normally
have hyperlinks to the corresponding source definition, if you have the
source files installed.  (*Note Hyperlinking::.)  If you know Lisp (or
C), this provides the ultimate documentation.  If you don't know Lisp,
you should learn it.  (The Introduction to Emacs Lisp Programming,
available from the FSF through fsf.org, is a good way to get started.)
If Emacs feels you are just _using_ it, treating it as an object
program, its feelings may be hurt.  For real intimacy, read the Emacs
source code.

   To find a command's documentation in a manual, use `C-h F'
(`Info-goto-emacs-command-node').  This knows about various manuals,
not just the Emacs manual, and finds the right one.


File: emacs,  Node: Apropos,  Next: Help Mode,  Prev: Name Help,  Up: Help

10.4 Apropos
============

The "apropos" commands answer questions like, "What are the commands
for working with files?"  More precisely, you specify an "apropos
pattern", which means either a word, a list of words, or a regular
expression.  Each apropos command displays a list of items that match
the pattern, in a separate buffer.

`C-h a PATTERN <RET>'
     Search for commands whose names match PATTERN.

`M-x apropos <RET> PATTERN <RET>'
     Search for functions and variables whose names match PATTERN.
     Both interactive functions (commands) and noninteractive functions
     can be found by this command.

`M-x apropos-variable <RET> PATTERN <RET>'
     Search for user-option variables whose names match PATTERN.

`M-x apropos-value <RET> PATTERN <RET>'
     Search for functions whose definitions match PATTERN, and
     variables whose values match PATTERN.

`C-h d PATTERN <RET>'
     Search for functions and variables whose *documentation strings*
     match PATTERN.

   The simplest kind of apropos pattern is one word.  Anything which
contains that word matches the pattern.  Thus, to find the commands
that work on files, type `C-h a file <RET>'.  This displays a list of
all command names that contain `file', including `copy-file',
`find-file', and so on.  Each command name comes with a brief
description and a list of keys you can currently invoke it with.  In
our example, it would say that you can invoke `find-file' by typing
`C-x C-f'.

   The `a' in `C-h a' stands for "Apropos"; `C-h a' runs the command
`apropos-command'.  This command normally checks only commands
(interactive functions); if you specify a prefix argument, it checks
noninteractive functions as well.

   For more information about a function definition, variable or symbol
property listed in the apropos buffer, you can click on it with
`Mouse-1' or `Mouse-2', or move there and type <RET>.

   When you specify more than one word in the apropos pattern, a name
must contain at least two of the words in order to match.  Thus, if you
are looking for commands to kill a chunk of text before point, you
could try `C-h a kill back backward behind before <RET>'.  The real
command name `kill-backward' will match that; if there were a command
`kill-text-before', it would also match, since it contains two of the
specified words.

   For even greater flexibility, you can specify a regular expression
(*note Regexps::).  An apropos pattern is interpreted as a regular
expression if it contains any of the regular expression special
characters, `^$*+?.\['.

   Following the conventions for naming Emacs commands, here are some
words that you'll find useful in apropos patterns.  By using them in
`C-h a', you will also get a feel for the naming conventions.

     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.

   Use `M-x apropos' instead of `C-h a' to list all the Lisp symbols
that match an apropos pattern, not just the symbols that are commands.
This command does not list key bindings by default; specify a numeric
argument if you want it to list them.

   Use `M-x apropos-variable' to list user-customizable variables that
match an apropos pattern.  If you specify a prefix argument, it lists
all matching variables.

   The `apropos-documentation' command is like `apropos' except that it
searches documentation strings instead of symbol names for matches.

   The `apropos-value' command is like `apropos' except that it
searches variables' values for matches for the apropos pattern.  With a
prefix argument, it also checks symbols' function definitions and
property lists.

   If the variable `apropos-do-all' is non-`nil', the apropos commands
always behave as if they had been given a prefix argument.

   By default, apropos lists the search results in alphabetical order.
If the variable `apropos-sort-by-scores' is non-`nil', the apropos
commands try to guess the relevance of each result, and display the
most relevant ones first.

   By default, apropos lists the search results for
`apropos-documentation' in order of relevance of the match.  If the
variable `apropos-documentation-sort-by-scores' is `nil', apropos lists
the symbols found in alphabetical order.


File: emacs,  Node: Help Mode,  Next: Library Keywords,  Prev: Apropos,  Up: Help

10.5 Help Mode Commands
=======================

Help buffers provide the same commands as View mode (*note Misc File
Ops::), plus a few special commands of their own.

`<SPC>'
     Scroll forward.

`<DEL>'
     Scroll backward.

`<RET>'
     Follow a cross reference at point.

`<TAB>'
     Move point forward to the next cross reference.

`S-<TAB>'
     Move point back to the previous cross reference.

`Mouse-1'
`Mouse-2'
     Follow a cross reference that you click on.

`C-c C-c'
     Show all documentation about the symbol at point.

   When a function name (*note Running Commands by Name: M-x.),
variable name (*note Variables::), or face name (*note Faces::) appears
in the documentation, it normally appears inside paired single-quotes.
To view the documentation of that command, variable or face, you can
click on the name with `Mouse-1' or `Mouse-2', or move point there and
type <RET>.  Use `C-c C-b' to retrace your steps.

   You can follow cross references to URLs (web pages) also.  This uses
the `browse-url' command to view the page in the browser you choose.
*Note Browse-URL::.

   There are convenient commands to move point to cross references in
the help text.  <TAB> (`help-next-ref') moves point down to the next
cross reference.  `S-<TAB>' moves up to the previous cross reference
(`help-previous-ref').

   To view all documentation about any symbol name that appears in the
text, move point to the symbol name and type `C-c C-c'
(`help-follow-symbol').  This shows all available documentation about
the symbol as a variable, function and/or face.  As above, use `C-c
C-b' to retrace your steps.


File: emacs,  Node: Library Keywords,  Next: Language Help,  Prev: Help Mode,  Up: Help

10.6 Keyword Search for Lisp Libraries
======================================

The `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:

abbrev        abbreviation handling, typing shortcuts, macros.
bib           code related to the `bib' bibliography processor.
c             support for the C language and related languages.
calendar      calendar and time management support.
comm          communications, networking, remote access to files.
convenience   convenience features for faster editing.
data          support for editing files of data.
docs          support for Emacs documentation.
emulations    emulations of other editors.
extensions    Emacs Lisp language extensions.
faces         support for multiple fonts.
files         support for editing and manipulating files.
frames        support for Emacs frames and window systems.
games         games, jokes and amusements.
hardware      support for interfacing with exotic hardware.
help          support for on-line help systems.
hypermedia    support for links between text or other media types.
i18n          internationalization and alternate character-set support.
internal      code for Emacs internals, build process, defaults.
languages     specialized modes for editing programming languages.
lisp          Lisp support, including Emacs Lisp.
local         code local to your site.
maint         maintenance aids for the Emacs development group.
mail          modes for electronic-mail handling.
matching      various sorts of searching and matching.
mouse         mouse support.
multimedia    images and sound support.
news          support for netnews reading and posting.
oop           support for object-oriented programming.
outlines      support for hierarchical outlining.
processes     process, subshell, compilation, and job control support.
terminals     support for terminal types.
tex           supporting code for the TeX formatter.
tools         programming tools.
unix          front-ends/assistants for, or emulators of, UNIX-like
              features.
wp            word processing.


File: emacs,  Node: Language Help,  Next: Misc Help,  Prev: Library Keywords,  Up: Help

10.7 Help for International Language Support
============================================

You can use the command `C-h L' (`describe-language-environment') to
get information about a specific language environment.  *Note Language
Environments::.  This tells you which languages this language
environment supports.  It also lists the character sets, coding
systems, and input methods that work with this language environment,
and finally shows some sample text to illustrate scripts.

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

   The command `C-h I' (`describe-input-method') describes an input
method--either a specified input method, or by default the input method
currently in use.  *Note Input Methods::.

   The command `C-h C' (`describe-coding-system') describes coding
systems--either a specified coding system, or the ones currently in
use.  *Note Coding Systems::.


File: emacs,  Node: Misc Help,  Next: Help Files,  Prev: Language Help,  Up: Help

10.8 Other Help Commands
========================

`C-h i' (`info') runs the Info program, which browses structured
documentation files.  The entire Emacs manual is available within Info,
along with many other manuals for the GNU system.  Type `h' after
entering Info to run a tutorial on using Info.

   With a numeric argument N, `C-h i' selects the Info buffer
`*info*<N>'.  This is useful if you want to browse multiple Info
manuals simultaneously.  If you specify just `C-u' as the prefix
argument, `C-h i' prompts for the name of a documentation file, so you
can browse a file which doesn't have an entry in the top-level Info
menu.

   The help commands `C-h F FUNCTION <RET>' and `C-h K KEY', described
above, enter Info and go straight to the documentation of FUNCTION or
KEY.

   When editing a program, if you have an Info version of the manual
for the programming language, you can use `C-h S'
(`info-lookup-symbol') to find an entry for a symbol (keyword, function
or variable) in the proper manual.  The details of how this command
works depend on the major mode.

   If something surprising happens, and you are not sure what you typed,
use `C-h l' (`view-lossage').  `C-h l' displays your last 300 input
keystrokes.  If you see commands that you don't know, you can use `C-h
c' to find out what they do.

   To review recent echo area messages, use `C-h e'
(`view-echo-area-messages').  This displays the buffer `*Messages*',
where those messages are kept.

   Each Emacs major mode typically redefines a few keys and makes other
changes in how editing works.  `C-h m' (`describe-mode') displays
documentation on the current major mode, which normally describes the
commands and features that are changed in this mode.

   `C-h b' (`describe-bindings') and `C-h s' (`describe-syntax') show
other information about the current environment within Emacs.  `C-h b'
displays a list of all the key bindings now in effect: first the local
bindings of the current minor modes, then the local bindings defined by
the current major mode, and finally the global bindings (*note Key
Bindings::).  `C-h s' displays the contents of the syntax table, with
explanations of each character's syntax (*note Syntax::).

   You can get a list of subcommands for a particular prefix key by
typing `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
`C-h'.  One of these is <ESC>, because `<ESC> C-h' is actually `C-M-h',
which marks a defun.)


File: emacs,  Node: Help Files,  Next: Help Echo,  Prev: Misc Help,  Up: Help

10.9 Help Files
===============

The Emacs help commands described above display dynamic help based on
the current state within Emacs, or refer to manuals.  Other help
commands display pre-written, static help files.

   Except for `C-h g', these commands all have the form `C-h C-CHAR';
that is, `C-h' followed by a control character.

`C-h C-c'
     Display the Emacs copying conditions (`describe-copying').  These
     are the rules under which you can copy and redistribute Emacs.

`C-h C-d'
     Display help for debugging Emacs (`view-emacs-debugging').

`C-h C-f'
     Display the Emacs frequently-answered-questions list
     (`view-emacs-FAQ').

`C-h g'
     Display general information about the GNU Project
     (`describe-gnu-project').

`C-h C-m'
     Display how to order printed copies of Emacs manuals
     (`view-order-manuals').

`C-h C-n'
     Display the Emacs "news" file, which lists new features in the most
     recent version of Emacs (`view-emacs-news').

`C-h C-o'
     Display how to order or download the latest version of Emacs and
     other GNU software (`describe-distribution').

`C-h C-p'
     Display the list of known Emacs problems, sometimes with suggested
     workarounds (`view-emacs-problems').

`C-h C-t'
     Display the Emacs to-do list (`view-emacs-todo').

`C-h C-w'
     Display the full details on the complete absence of warranty for
     GNU Emacs (`describe-no-warranty').


File: emacs,  Node: Help Echo,  Prev: Help Files,  Up: Help

10.10 Help on Active Text and Tooltips
======================================

When text on the screen is "active", so that it does something special
in response to mouse clicks or `RET', it often has associated help
text.  For instance, most parts of the mode line have help text.  On
terminals that support mouse tracking, Emacs displays the help text as a
"tooltip" (sometimes known as "balloon help") or in the echo area,
whenever you leave the mouse stationary over the active text.  *Note
Tooltips::.

   If your terminal doesn't support mouse-tracking, you can display the
help text for active buffer text using the keyboard.  `C-h .'
(`display-local-help') displays any help text associated with the
character after point, using the echo area.  To display help text
automatically whenever it is available on the character after point, set
the variable `help-at-pt-display-when-idle' to `t'.


File: emacs,  Node: Mark,  Next: Killing,  Prev: Help,  Up: Top

11 The Mark and the Region
**************************

Many Emacs commands operate on an arbitrary contiguous part of the
current buffer.  To specify the text for such a command to operate on,
you set "the mark" at one end of it, and move point to the other end.
The text between point and the mark is called "the region".  The region
always extends between point and the mark, no matter which one comes
earlier in the text; each time you move point, the region changes.

   Setting the mark at a position in the text also "activates" it.
When the mark is active, Emacs indicates the extent of the region by
highlighting the text within it, using the `region' face (*note Face
Customization::).  After certain non-motion commands, including any
command that changes the text in the buffer, Emacs automatically
"deactivates" the mark; this turns off the highlighting.  You can also
explicitly deactivate the mark at any time, by typing `C-g' (*note
Quitting::).

   This default behavior of the mark is known as Transient Mark mode.
Disabling Transient Mark mode switches Emacs to an alternative
behavior, in which the mark is always active, which was the default
prior to Emacs 23.  *Note Persistent Mark::.

   Setting the mark in one buffer has no effect on the marks in other
buffers.  When you return to a buffer with an active mark, the mark is
at the same place as before.  When multiple windows show the same
buffer, they can have different values of point, and thus different
regions, but they all share one common mark position.  *Note Windows::.
Ordinarily, only the selected window highlights its region; however, if
the variable `highlight-nonselected-windows' is non-`nil', each window
highlights its own region.

* Menu:

* Setting Mark::        Commands to set the mark.
* Marking Objects::     Commands to put region around textual units.
* Using Region::        Summary of ways to operate on contents of the region.
* Mark Ring::           Previous mark positions saved so you can go back there.
* Global Mark Ring::    Previous mark positions in various buffers.
* Shift Selection::     Using shifted cursor motion keys.
* Persistent Mark::     Keeping the mark active all the time.


File: emacs,  Node: Setting Mark,  Next: Marking Objects,  Up: Mark

11.1 Setting the Mark
=====================

Here are some commands for setting the mark:

`C-<SPC>'
     Set the mark at point, and activate it (`set-mark-command').

`C-@'
     The same.

`C-x C-x'
     Set the mark at point, and move point where the mark was
     (`exchange-point-and-mark').

`Drag-Mouse-1'
     Set point and the mark around the text you drag across.

`Mouse-3'
     Set the mark at point, then move point to where you click
     (`mouse-save-then-kill').

``Shifted motion keys''
     Set the mark at point if the mark is inactive, then move point.

   The most common way to set the mark is with `C-<SPC>'
(`set-mark-command')(1).  This sets the mark where point is, and
activates it.  You can then move point away, leaving the mark behind.

   For example, suppose you wish to convert part of the buffer to upper
case.  To accomplish this, go to the beginning of the desired text,
type `C-<SPC>', and move point until the desired portion of text is
highlighted.  Now type `C-x C-u' (`upcase-region').  This converts the
text in the region to upper case, and then deactivates the mark.

   The command `C-x C-x' (`exchange-point-and-mark') exchanges the
positions of point and the mark, keeping the region unchanged.  If the
mark is inactive, Emacs first reactivates the mark wherever it was last
set.  `C-x C-x' is useful when you are satisfied with the position of
point but want to move the other end of the region (where the mark is).
Using `C-x C-x' a second time, if necessary, puts the mark at the new
position with point back at its original position.

   You can also set the mark with the mouse.  If you press the left
mouse button (`down-mouse-1') and drag the mouse across a range of text
while holding down this button, this sets the mark where you first
pressed the mouse button and puts point where you release it.
Alternatively, clicking the right mouse button (`mouse-3') sets the
mark at point and then moves point to where you clicked.  Using the
mouse to mark a region also copies the region into the kill ring (*note
Kill Ring::).  *Note Mouse Commands::, for a more detailed description
of these mouse commands.

   Finally, you can set the mark by holding down the shift key while
typing certain cursor motion commands (such as `S-<right>', `S-C-f',
`S-C-n', etc.)  This is referred to as "shift-selection".  This sets
the mark at point before moving point, but only if there is no active
mark set via shift-selection.  The mark set by mouse commands and by
shift-selection behaves slightly differently from the usual mark: any
subsequent unshifted cursor motion command deactivates it
automatically.  For details, *Note Shift Selection::.

   Whenever the mark is active, you can deactivate it by typing `C-g'
(*note Quitting::).  The mark is also automatically deactivated after
certain non-motion commands.

   ---------- Footnotes ----------

   (1) There is no `C-<SPC>' character in ASCII; usually, typing
`C-<SPC>' on a text terminal gives the character `C-@'.  This key is
also bound to `set-mark-command', so unless you are unlucky enough to
have a text terminal that behaves differently, you might as well think
of `C-@' as `C-<SPC>'.


File: emacs,  Node: Marking Objects,  Next: Using Region,  Prev: Setting Mark,  Up: Mark

11.2 Commands to Mark Textual Objects
=====================================

Here are the commands for placing point and the mark around a textual
object such as a word, list, paragraph or page:

`M-@'
     Set mark after end of next word (`mark-word').  This does not move
     point.

`C-M-@'
     Set mark after end of following balanced expression (`mark-sexp').
     This does not move point.

`M-h'
     Move point to the beginning of the current paragraph, and set mark
     at the end (`mark-paragraph').

`C-M-h'
     Move point to the beginning of the current defun, and set mark at
     the end (`mark-defun').

`C-x C-p'
     Move point to the beginning of the current page, and set mark at
     the end (`mark-page').

`C-x h'
     Move point to the beginning of the buffer, and set mark at the end
     (`mark-whole-buffer').

   `M-@' (`mark-word') puts the mark at the end of the next word, while
`C-M-@' (`mark-sexp') puts it at the end of the next balanced
expression (*note Expressions::).  These commands handle arguments just
like `M-f' and `C-M-f'.

   The other commands in the above list set both point and mark, so as
to delimit an object in the buffer.  `M-h' (`mark-paragraph') moves
point to the beginning of the paragraph that surrounds or follows
point, and sets the mark at the end of that paragraph (*note
Paragraphs::).  As a special exception, repeated invocations of `M-h'
extend the region to subsequent paragraphs.  This is convenient for
indenting, case-converting, or killing entire paragraphs.

   The `M-h' command accepts prefix arguments.  If the argument's value
is positive, `M-h' marks that many paragraphs starting with the one
surrounding point; therefore, `C-u M-h' is equivalent to `M-h M-h M-h
M-h'.  If the prefix argument is -N, `M-h' marks N paragraphs running
back from the one surrounding point; in this case, point moves forward
to the end of that paragraph, and the mark goes at the start of the
region.

   Similarly, `C-M-h' (`mark-defun') sets mark and point around major
top-level definitions (*note Moving by Defuns::), and `C-x C-p'
(`mark-page') does the same for pages (*note Pages::).  These treat
repeated invocations and prefix arguments similarly to `mark-paragraph'.

   Finally, `C-x h' (`mark-whole-buffer') sets up the entire buffer as
the region, by putting point at the beginning and the mark at the end.
(In some programs this is called "select all.")


File: emacs,  Node: Using Region,  Next: Mark Ring,  Prev: Marking Objects,  Up: Mark

11.3 Operating on the Region
============================

Once you have a region, here are some of the ways you can operate on it:

   * Kill it with `C-w' (*note Killing::).

   * Copy it to the kill ring with `M-w' (*note Yanking::).

   * Convert case with `C-x C-l' or `C-x C-u' (*note Case::).

   * Undo changes within it using `C-u C-/' (*note Undo::).

   * Replace text within it using `M-%' (*note Query Replace::).

   * Indent it with `C-x <TAB>' or `C-M-\' (*note Indentation::).

   * Fill it as text with `M-x fill-region' (*note Filling::).

   * Print hardcopy with `M-x print-region' (*note Printing::).

   * Evaluate it as Lisp code with `M-x eval-region' (*note Lisp
     Eval::).

   * Save it in a register with `C-x r s' (*note Registers::).

   * Save it in a buffer or a file (*note Accumulating Text::).

   Most commands that operate on the text in the region have the word
`region' in their names.

   Some commands have a default behavior when the mark is inactive, but
operate on the text in the region if the mark is active.  For example,
`M-$' (`ispell-word') normally checks the spelling of the word at
point, but it checks the text in the region if the region is active
(*note Spelling::).  Normally, such commands use their default behavior
if the region is empty (i.e., if mark and point are at the same
position).  If you want them to operate on the empty region, change the
variable `use-empty-active-region' to `t'.

   If you enable Delete Selection mode, a minor mode, then inserting
text while the mark is active causes the selected text to be deleted
first.  This also deactivates the mark.  Many graphical applications
follow this convention, but Emacs does not.  To toggle Delete Selection
mode on or off, type `M-x delete-selection-mode'.  Another effect of
this mode is that some keys, such as <DEL> and `C-d', always kill the
region if one exists.


File: emacs,  Node: Mark Ring,  Next: Global Mark Ring,  Prev: Using Region,  Up: Mark

11.4 The Mark Ring
==================

Aside from delimiting the region, the mark is also useful for
remembering spots that you may want to go back to.  Each buffer
remembers 16 previous locations of the mark, in the "mark ring".
Commands that set the mark also push the old mark onto this ring.

`C-<SPC> C-<SPC>'
     Set the mark, pushing it onto the mark ring, without activating it.

`C-u C-<SPC>'
     Move point to where the mark was, and restore the mark from the
     ring of former marks.

   The command C-<SPC> C-<SPC> is handy when you want to use the mark
to remember a position to which you may wish to return.  It pushes the
current point onto the mark ring, without activating the mark (which
would cause Emacs to highlight the region).  This is actually two
consecutive invocations of `C-<SPC>' (`set-mark-command'); the first
`C-<SPC>' sets the mark, and the second `C-<SPC>' deactivates it.
(When Transient Mark mode is off, C-<SPC> C-<SPC> instead activates
Transient Mark mode temporarily.  *Note Persistent Mark::.)

   To return to a marked position, use `set-mark-command' with a prefix
argument: `C-u C-<SPC>'.  This moves point to where the mark was, and
deactivates the mark if it was active.  Each subsequent `C-u C-<SPC>'
jumps to a prior position stored in the mark ring.  The positions you
move through in this way are not lost; they go to the end of the ring.

   If you set `set-mark-command-repeat-pop' to non-`nil', then
immediately after you type `C-u C-<SPC>', you can type `C-<SPC>'
instead of `C-u C-<SPC>' to cycle through the mark ring.  By default,
`set-mark-command-repeat-pop' is `nil'.

   Each buffer has its own mark ring.  All editing commands use the
current buffer's mark ring.  In particular, `C-u C-<SPC>' always stays
in the same buffer.

   The variable `mark-ring-max' specifies the maximum number of entries
to keep in the mark ring.  If that many entries exist and another one
is pushed, the earliest one in the list is discarded.  Repeating `C-u
C-<SPC>' cycles through the positions currently in the ring.

   If the variable `mark-even-if-inactive' is `nil', commands can only
use the mark and the region when it is active.  This variable is
non-`nil' by default.

   If you want to move back to the same place over and over, the mark
ring may not be convenient enough.  If so, you can record the position
in a register for later retrieval (*note Saving Positions in Registers:
RegPos.).


File: emacs,  Node: Global Mark Ring,  Next: Shift Selection,  Prev: Mark Ring,  Up: Mark

11.5 The Global Mark Ring
=========================

In addition to the ordinary mark ring that belongs to each buffer,
Emacs has a single "global mark ring".  Each time you set a mark, in
any buffer, this is recorded in the global mark ring in addition to the
current buffer's own mark ring.

   The command `C-x C-<SPC>' (`pop-global-mark') jumps to the buffer
and position of the latest entry in the global ring.  It also rotates
the ring, so that successive uses of `C-x C-<SPC>' take you to earlier
buffers and mark positions.


File: emacs,  Node: Shift Selection,  Next: Persistent Mark,  Prev: Global Mark Ring,  Up: Mark

11.6 Shift Selection
====================

If you hold down the shift key while typing a cursor motion command,
this sets the mark before moving point, so that the region extends from
the original position of point to its new position.  This feature,
newly introduced in Emacs 23, is referred to as "shift-selection".  It
is similar to the way text is selected in other editors.

   The mark set via shift-selection behaves a little differently from
what we have described above.  Firstly, in addition to the usual ways
of deactivating the mark (such as changing the buffer text or typing
`C-g'), the mark is deactivated by any _unshifted_ cursor motion
command.  Secondly, any subsequent _shifted_ cursor motion command
avoids setting the mark anew.  Therefore, a series of shifted cursor
motion commands will continuously extend the region.

   Shift-selection only works if the shifted cursor motion key is not
already bound to a separate command (*note Customization::).  For
example, if you bind `S-C-f' to another command, typing `S-C-f' runs
that command instead of performing a shift-selected version of `C-f'
(`forward-char').

   A mark set via mouse commands behaves the same as a mark set via
shift-selection (*note Setting Mark::).  For example, if you specify a
region by dragging the mouse, you can continue to extend the region
using shifted cursor motion commands.  In either case, any unshifted
cursor motion command deactivates the mark.

   To turn off shift-selection, set `shift-select-mode' to `nil'.
Doing this does not disable setting the mark via mouse commands.


File: emacs,  Node: Persistent Mark,  Prev: Shift Selection,  Up: Mark

11.7 Persistent Marks
=====================

By default, the mark is activated by setting it, and deactivated by
most non-motion commands (including all commands that change the text
in the buffer).  This behavior is called Transient Mark mode(1).

   Turning off Transient Mark mode switches Emacs to an alternative
mode of operation, which was the default prior to Emacs 23.  When
Transient Mark mode is off, the mark is _never_ deactivated, but it can
be set to different locations using commands such as `C-<SPC>'.  Emacs
does not highlight the region, because that would be a nuisance.  As a
special exception, the region is temporarily highlighted if you set it
with the mouse (*note Setting Mark::), or with shift-selection (*note
Shift Selection::).

   To turn off Transient Mark mode, type `M-x transient-mark-mode'.
This command toggles the mode; you can use the same command to turn it
on again.  You can also toggle Transient Mark mode using the `Active
Region Highlighting' menu item in the `Options' menu.

   Here are the details of how Emacs behaves when Transient Mark mode
is off:

   * Emacs does not show where the mark is located--you have to
     remember.  The usual solution to this problem is to set the mark
     and then use it soon, before you forget where it is.
     Alternatively, you can check the location of the mark by using
     `C-x C-x', which exchanges the positions of the point and the mark
     (*note Setting Mark::).

   * Many commands that insert text, such as `C-y' (`yank'), position
     point and the mark at opposite ends of the inserted text, so that
     the region consists of the text just inserted.  You can tell when
     a command sets the mark because it displays `Mark set' in the echo
     area.

   * Many commands that move point long distances, like `M-<' and
     `C-s', first set the mark where point was.

   * Some commands, which ordinarily act on the region when the mark is
     active, no longer do so.  For example, normally `M-%'
     (`query-replace') performs replacements within the region, if the
     mark is active.  When Transient Mark mode is off, it always
     operates from point to the end of the buffer.  Commands that act
     this way are identified in their own documentation.

   While Transient Mark mode is off, you can activate it temporarily
using `C-<SPC> C-<SPC>' or `C-u C-x C-x'.

`C-<SPC> C-<SPC>'
     Set the mark at point (like plain `C-<SPC>') and enable Transient
     Mark mode just once, until the mark is deactivated.  (This is not
     really a separate command; you are using the `C-<SPC>' command
     twice.)

`C-u C-x C-x'
     Activate the mark and enable Transient Mark mode temporarily, until
     the mark is next deactivated.  (This is the `C-x C-x' command,
     `exchange-point-and-mark', with a prefix argument.)

   These commands set or activate the mark, and enable Transient Mark
mode only until the mark is deactivated.  One reason you may want to
use them is that some commands operate on the entire buffer instead of
the region when Transient Mark mode is off.  Enabling Transient Mark
mode momentarily gives you a way to use these commands on the region.

   ---------- Footnotes ----------

   (1) It is also sometimes called "Zmacs mode", because the Zmacs
editor on the MIT Lisp Machine handled the mark in a similar way.


File: emacs,  Node: Killing,  Next: Yanking,  Prev: Mark,  Up: Top

12 Killing and Moving Text
**************************

"Killing" means erasing text and copying it into the "kill ring", from
which you can bring it back into the buffer by "yanking" it.  (Some
applications use the terms "cutting" and "pasting" for similar
operations.)  This is the most common way of moving or copying text
within Emacs.  It is very versatile, because there are commands for
killing many different types of syntactic units.

   Most commands which erase text from the buffer save it in the kill
ring.  These are known as "kill" commands.  The kill ring stores
several recent kills, not just the last one, so killing is a very safe
operation: when you make a new kill, you don't have to worry much about
losing text that you previously killed.

   You can yank text from the kill ring into any position in a buffer,
including a position in a different buffer; the kill ring is shared by
all buffers.  The `C-/' (`undo') command can undo both kill and delete
commands (*note Undo::); the importance of the kill ring is that you
can yank the text in a different place.

   Commands that erase text but do not save it in the kill ring are
known as "delete" commands.  These include `C-d' (`delete-char') and
<DEL> (`delete-backward-char'), which delete only one character at a
time, and those commands that delete only spaces or newlines.  Commands
that can erase significant amounts of nontrivial data generally do a
kill operation instead.  The commands' names and individual
descriptions use the words `kill' and `delete' to say which kind of
operation they perform.

   You can also use the mouse to kill and yank.  *Note Cut and Paste::.

* Menu:

* Deletion::            Commands for deleting small amounts of text and
                          blank areas.
* Killing by Lines::    How to kill entire lines of text at one time.
* Other Kill Commands:: Commands to kill large regions of text and
                          syntactic units such as words and sentences.
* Kill Options::        Options that affect killing.


File: emacs,  Node: Deletion,  Next: Killing by Lines,  Up: Killing

12.1 Deletion
=============

Deletion means erasing text and not saving it in the kill ring.  For
the most part, the Emacs commands that delete text are those that erase
just one character or only whitespace.

`C-d'
`<Delete>'
     Delete next character (`delete-char').

`<DEL>'
`<Backspace>'
     Delete previous character (`delete-backward-char').

`M-\'
     Delete spaces and tabs around point (`delete-horizontal-space').

`M-<SPC>'
     Delete spaces and tabs around point, leaving one space
     (`just-one-space').

`C-x C-o'
     Delete blank lines around the current line (`delete-blank-lines').

`M-^'
     Join two lines by deleting the intervening newline, along with any
     indentation following it (`delete-indentation').

   We have already described the basic deletion commands `C-d'
(`delete-char') and <DEL> (`delete-backward-char').  *Note Erasing::.

   The other delete commands are those that delete only whitespace
characters: spaces, tabs and newlines.  `M-\'
(`delete-horizontal-space') deletes all the spaces and tab characters
before and after point.  With a prefix argument, this only deletes
spaces and tab characters before point.  `M-<SPC>' (`just-one-space')
does likewise but leaves a single space after point, regardless of the
number of spaces that existed previously (even if there were none
before).  With a numeric argument N, it leaves N spaces after point.

   `C-x C-o' (`delete-blank-lines') deletes all blank lines after the
current line.  If the current line is blank, it deletes all blank lines
preceding the current line as well (leaving one blank line, the current
line).  On a solitary blank line, it deletes that line.

   `M-^' (`delete-indentation') joins the current line and the previous
line, by deleting a newline and all surrounding spaces, usually leaving
a single space.  *Note M-^: Indentation.


File: emacs,  Node: Killing by Lines,  Next: Other Kill Commands,  Prev: Deletion,  Up: Killing

12.2 Killing by Lines
=====================

`C-k'
     Kill rest of line or one or more lines (`kill-line').

`C-S-backspace'
     Kill an entire line at once (`kill-whole-line')

   The simplest kill command is `C-k'.  If given at the beginning of a
line, it kills all the text on the line(1), leaving it blank.  When
used on a blank line, it kills the whole line including its newline.

   More precisely, `C-k' kills from point up to the end of the line,
unless it is at the end of a line.  In that case it kills the newline
following point, thus merging the next line into the current one.
Spaces and tabs at the end of the line are ignored when deciding which
case applies, so as long as point is after the last visible character
in the line, you can be sure that `C-k' will kill the newline.  To kill
an entire non-blank line, go to the beginning and type `C-k' twice.

   When `C-k' is given a positive argument N, it kills N lines and the
newlines that follow them (text on the current line before point is not
killed).  With a negative argument -N, it kills N lines preceding the
current line, together with the text on the current line before point.
`C-k' with an argument of zero kills the text before point on the
current line.

   If the variable `kill-whole-line' is non-`nil', `C-k' at the very
beginning of a line kills the entire line including the following
newline.  This variable is normally `nil'.

   `C-S-backspace' (`kill-whole-line') will kill a whole line including
its newline regardless of the position of point within the line.  Note
that many character terminals will prevent you from typing the key
sequence `C-S-backspace'.

   ---------- Footnotes ----------

   (1) Here, "line" means a logical text line, not a screen line.
*Note Continuation Lines::.


File: emacs,  Node: Other Kill Commands,  Next: Kill Options,  Prev: Killing by Lines,  Up: Killing

12.3 Other Kill Commands
========================

`C-w'
     Kill region (`kill-region').  *Note Mark::.

`M-w'
     Save region as last killed text without actually killing it
     (`kill-ring-save').  Some programs call this "copying."

`M-d'
     Kill word (`kill-word').  *Note Words::.

`M-<DEL>'
     Kill word backwards (`backward-kill-word').

`C-x <DEL>'
     Kill back to beginning of sentence (`backward-kill-sentence').
     *Note Sentences::.

`M-k'
     Kill to end of sentence (`kill-sentence').

`C-M-k'
     Kill the following balanced expression (`kill-sexp').  *Note
     Expressions::.

`M-z CHAR'
     Kill through the next occurrence of CHAR (`zap-to-char').

   Apart from `C-k', the most commonly-used kill command is `C-w'
(`kill-region'), which kills the text in the region (i.e., between
point and mark).  *Note Mark::.  If the mark is inactive when you type
`C-w', it first reactivates the mark where it was last set.  The mark
is deactivated at the end of the command.

   The command `M-w' (`kill-ring-save') copies the region into the kill
ring without removing it from the buffer.  This is approximately
equivalent to `C-w' followed by `C-/', except that `M-w' does not alter
the undo history.

   Emacs also provides commands to kill specific syntactic units:
words, with `M-<DEL>' and `M-d' (*note Words::); balanced expressions,
with `C-M-k' (*note Expressions::); and sentences, with `C-x <DEL>' and
`M-k' (*note Sentences::).

   The command `M-z' (`zap-to-char') combines killing with searching:
it reads a character and kills from point up to (and including) the
next occurrence of that character in the buffer.  A numeric argument
acts as a repeat count; a negative argument means to search backward
and kill text before point.


File: emacs,  Node: Kill Options,  Prev: Other Kill Commands,  Up: Killing

12.4 Options for Killing
========================

Some specialized buffers contain "read-only text", which cannot be
modified and therefore cannot be killed.  But some users like to use
the kill commands to copy read-only text into the kill ring, without
actually changing it.  Therefore, the kill commands work specially in a
read-only buffer: they move over text, and copy it to the kill ring,
without actually deleting it from the buffer.  Normally, kill commands
beep and display an error message when this happens.  But if you set
the variable `kill-read-only-ok' to a non-`nil' value, they just print
a message in the echo area to explain why the text has not been erased.

   If you change the variable `kill-do-not-save-duplicates' to a
non-`nil' value, identical subsequent kills yield a single kill-ring
entry, without duplication.


File: emacs,  Node: Yanking,  Next: Accumulating Text,  Prev: Killing,  Up: Top

13 Yanking
**********

"Yanking" means reinserting text previously killed.  The usual way to
move or copy text is to kill it and then yank it elsewhere one or more
times.

`C-y'
     Yank last killed text (`yank').

`M-y'
     Replace text just yanked with an earlier batch of killed text
     (`yank-pop').

`C-M-w'
     Append next kill to last batch of killed text (`append-next-kill').

   On graphical displays with window systems, if there is a current
selection in some other application, and you selected it more recently
than you killed any text in Emacs, `C-y' copies the selection instead
of text killed within Emacs.

* Menu:

* Kill Ring::           Where killed text is stored.  Basic yanking.
* Appending Kills::     Several kills in a row all yank together.
* Earlier Kills::       Yanking something killed some time ago.


File: emacs,  Node: Kill Ring,  Next: Appending Kills,  Up: Yanking

13.1 The Kill Ring
==================

All killed text is recorded in the "kill ring", a list of blocks of
text that have been killed.  There is only one kill ring, shared by all
buffers, so you can kill text in one buffer and yank it in another
buffer.  This is the usual way to move text from one file to another.
(There are several other methods: for instance, you could store the
text in a register.  *Note Registers::, for information about
registers.  *Note Accumulating Text::, for some other ways to move text
around.)

   The command `C-y' (`yank') reinserts the text of the most recent
kill, leaving the cursor at the end of the text.  It also adds the
position of the beginning of the text to the mark ring, without
activating the mark; this allows you to jump easily to that position
with `C-x C-x' (*note Setting Mark::).  With a plain prefix argument
(`C-u C-y'), it instead leaves the cursor in front of the text, and
adds the position of the end of the text to the mark ring.  Using other
sort of prefix argument specifies an earlier kill; for example, `C-u 4
C-y' reinserts the fourth most recent kill.  *Note Earlier Kills::.

   The yank commands discard certain properties from the yanked text.
These are properties that might lead to annoying results, such as
causing the text to respond to the mouse or specifying key bindings.
The list of properties to discard is stored in the variable
`yank-excluded-properties'.  Yanking of register contents and
rectangles also discard these properties.  *Note Text Properties:
(elisp)Text Properties, for more information about text properties.


File: emacs,  Node: Appending Kills,  Next: Earlier Kills,  Prev: Kill Ring,  Up: Yanking

13.2 Appending Kills
====================

Normally, each kill command pushes a new entry onto the kill ring.
However, two or more kill commands in a row combine their text into a
single entry, so that a single `C-y' yanks all the text as a unit, just
as it was before it was killed.

   Thus, if you want to yank text as a unit, you need not kill all of it
with one command; you can keep killing line after line, or word after
word, until you have killed it all, and you can still get it all back at
once.

   Commands that kill forward from point add onto the end of the
previous killed text.  Commands that kill backward from point add text
onto the beginning.  This way, any sequence of mixed forward and
backward kill commands puts all the killed text into one entry without
rearrangement.  Numeric arguments do not break the sequence of
appending kills.  For example, suppose the buffer contains this text:

     This is a line -!-of sample text.

with point shown by -!-.  If you type `M-d M-<DEL> M-d M-<DEL>',
killing alternately forward and backward, you end up with `a line of
sample' as one entry in the kill ring, and `This is  text.' in the
buffer.  (Note the double space between `is' and `text', which you can
clean up with `M-<SPC>' or `M-q'.)

   Another way to kill the same text is to move back two words with
`M-b M-b', then kill all four words forward with `C-u M-d'.  This
produces exactly the same results in the buffer and in the kill ring.
`M-f M-f C-u M-<DEL>' kills the same text, all going backward; once
again, the result is the same.  The text in the kill ring entry always
has the same order that it had in the buffer before you killed it.

   If a kill command is separated from the last kill command by other
commands (not just numeric arguments), it starts a new entry on the kill
ring.  But you can force it to append by first typing the command
`C-M-w' (`append-next-kill') right before it.  The `C-M-w' tells the
following command, if it is a kill command, to append the text it kills
to the last killed text, instead of starting a new entry.  With
`C-M-w', you can kill several separated pieces of text and accumulate
them to be yanked back in one place.

   A kill command following `M-w' (`kill-ring-save') does not append to
the text that `M-w' copied into the kill ring.


File: emacs,  Node: Earlier Kills,  Prev: Appending Kills,  Up: Yanking

13.3 Yanking Earlier Kills
==========================

To recover killed text that is no longer the most recent kill, use the
`M-y' command (`yank-pop').  It takes the text previously yanked and
replaces it with the text from an earlier kill.  So, to recover the
text of the next-to-the-last kill, first use `C-y' to yank the last
kill, and then use `M-y' to replace it with the previous kill.  `M-y'
is allowed only after a `C-y' or another `M-y'.

   You can understand `M-y' in terms of a "last yank" pointer which
points at an entry in the kill ring.  Each time you kill, the "last
yank" pointer moves to the newly made entry at the front of the ring.
`C-y' yanks the entry which the "last yank" pointer points to.  `M-y'
moves the "last yank" pointer to a different entry, and the text in the
buffer changes to match.  Enough `M-y' commands can move the pointer to
any entry in the ring, so you can get any entry into the buffer.
Eventually the pointer reaches the end of the ring; the next `M-y'
loops back around to the first entry again.

   `M-y' moves the "last yank" pointer around the ring, but it does not
change the order of the entries in the ring, which always runs from the
most recent kill at the front to the oldest one still remembered.

   `M-y' can take a numeric argument, which tells it how many entries
to advance the "last yank" pointer by.  A negative argument moves the
pointer toward the front of the ring; from the front of the ring, it
moves "around" to the last entry and continues forward from there.

   Once the text you are looking for is brought into the buffer, you can
stop doing `M-y' commands and it will stay there.  It's just a copy of
the kill ring entry, so editing it in the buffer does not change what's
in the ring.  As long as no new killing is done, the "last yank"
pointer remains at the same place in the kill ring, so repeating `C-y'
will yank another copy of the same previous kill.

   If you know how many `M-y' commands it would take to find the text
you want, you can yank that text in one step using `C-y' with a numeric
argument.  `C-y' with an argument restores the text from the specified
kill ring entry, counting back from the most recent as 1.  Thus, `C-u 2
C-y' gets the next-to-the-last block of killed text--it is equivalent
to `C-y M-y'.  `C-y' with a numeric argument starts counting from the
"last yank" pointer, and sets the "last yank" pointer to the entry that
it yanks.

   The length of the kill ring is controlled by the variable
`kill-ring-max'; no more than that many blocks of killed text are saved.

   The actual contents of the kill ring are stored in a variable named
`kill-ring'; you can view the entire contents of the kill ring with the
command `C-h v kill-ring'.


File: emacs,  Node: Accumulating Text,  Next: Rectangles,  Prev: Yanking,  Up: Top

14 Accumulating Text
********************

Usually we copy or move text by killing it and yanking it, but there
are other convenient methods for copying one block of text in many
places, or for copying many scattered blocks of text into one place.
Here we describe the commands to accumulate scattered pieces of text
into a buffer or into a file.

`M-x append-to-buffer'
     Append region to the contents of a specified buffer.

`M-x prepend-to-buffer'
     Prepend region to the contents of a specified buffer.

`M-x copy-to-buffer'
     Copy region into a specified buffer, deleting that buffer's old
     contents.

`M-x insert-buffer'
     Insert the contents of a specified buffer into current buffer at
     point.

`M-x append-to-file'
     Append region to the contents of a specified file, at the end.

   To accumulate text into a buffer, use `M-x append-to-buffer'.  This
reads a buffer name, then inserts a copy of the region into the buffer
specified.  If you specify a nonexistent buffer, `append-to-buffer'
creates the buffer.  The text is inserted wherever point is in that
buffer.  If you have been using the buffer for editing, the copied text
goes into the middle of the text of the buffer, starting from wherever
point happens to be at that moment.

   Point in that buffer is left at the end of the copied text, so
successive uses of `append-to-buffer' accumulate the text in the
specified buffer in the same order as they were copied.  Strictly
speaking, `append-to-buffer' does not always append to the text already
in the buffer--it appends only if point in that buffer is at the end.
However, if `append-to-buffer' is the only command you use to alter a
buffer, then point is always at the end.

   `M-x prepend-to-buffer' is just like `append-to-buffer' except that
point in the other buffer is left before the copied text, so successive
prependings add text in reverse order.  `M-x copy-to-buffer' is
similar, except that any existing text in the other buffer is deleted,
so the buffer is left containing just the text newly copied into it.

   The command `M-x insert-buffer' can be used to retrieve the
accumulated text from another buffer.  This prompts for the name of a
buffer, and inserts a copy of all the text in that buffer into the
current buffer at point, leaving point at the beginning of the inserted
text.  It also adds the position of the end of the inserted text to the
mark ring, without activating the mark.  *Note Buffers::, for
background information on buffers.

   Instead of accumulating text in a buffer, you can append text
directly into a file with `M-x append-to-file'.  This prompts for a
filename, and adds the text of the region to the end of the specified
file.  The file is changed immediately on disk.

   You should use `append-to-file' only with files that are _not_ being
visited in Emacs.  Using it on a file that you are editing in Emacs
would change the file behind Emacs's back, which can lead to losing
some of your editing.

   Another way to move text around is to store it in a register.  *Note
Registers::.


File: emacs,  Node: Rectangles,  Next: CUA Bindings,  Prev: Accumulating Text,  Up: Top

15 Rectangles
*************

"Rectangle" commands operate on rectangular areas of the text: all the
characters between a certain pair of columns, in a certain range of
lines.  Emacs has commands to kill rectangles, yank killed rectangles,
clear them out, fill them with blanks or text, or delete them.
Rectangle commands are useful with text in multicolumn formats, and for
changing text into or out of such formats.

   When you must specify a rectangle for a command to work on, you do it
by putting the mark at one corner and point at the opposite corner.  The
rectangle thus specified is called the "region-rectangle" because you
control it in much the same way as the region is controlled.  But
remember that a given combination of point and mark values can be
interpreted either as a region or as a rectangle, depending on the
command that uses them.

   If point and the mark are in the same column, the rectangle they
delimit is empty.  If they are in the same line, the rectangle is one
line high.  This asymmetry between lines and columns comes about
because point (and likewise the mark) is between two columns, but within
a line.

`C-x r k'
     Kill the text of the region-rectangle, saving its contents as the
     "last killed rectangle" (`kill-rectangle').

`C-x r d'
     Delete the text of the region-rectangle (`delete-rectangle').

`C-x r y'
     Yank the last killed rectangle with its upper left corner at point
     (`yank-rectangle').

`C-x r o'
     Insert blank space to fill the space of the region-rectangle
     (`open-rectangle').  This pushes the previous contents of the
     region-rectangle rightward.

`C-x r c'
     Clear the region-rectangle by replacing all of its contents with
     spaces (`clear-rectangle').

`M-x delete-whitespace-rectangle'
     Delete whitespace in each of the lines on the specified rectangle,
     starting from the left edge column of the rectangle.

`C-x r t STRING <RET>'
     Replace rectangle contents with STRING on each line
     (`string-rectangle').

`M-x string-insert-rectangle <RET> STRING <RET>'
     Insert STRING on each line of the rectangle.

   The rectangle operations fall into two classes: commands for
deleting and inserting rectangles, and commands for blank rectangles.

   There are two ways to get rid of the text in a rectangle: you can
discard the text (delete it) or save it as the "last killed" rectangle.
The commands for these two ways are `C-x r d' (`delete-rectangle') and
`C-x r k' (`kill-rectangle').  In either case, the portion of each line
that falls inside the rectangle's boundaries is deleted, causing any
following text on the line to move left into the gap.

   Note that "killing" a rectangle is not killing in the usual sense;
the rectangle is not stored in the kill ring, but in a special place
that can only record the most recent rectangle killed.  This is because
yanking a rectangle is so different from yanking linear text that
different yank commands have to be used.  It is hard to define
yank-popping for rectangles, so we do not try.

   To yank the last killed rectangle, type `C-x r y'
(`yank-rectangle').  Yanking a rectangle is the opposite of killing
one.  Point specifies where to put the rectangle's upper left corner.
The rectangle's first line is inserted there, the rectangle's second
line is inserted at the same horizontal position, but one line
vertically down, and so on.  The number of lines affected is determined
by the height of the saved rectangle.

   You can convert single-column lists into double-column lists using
rectangle killing and yanking; kill the second half of the list as a
rectangle and then yank it beside the first line of the list.  *Note
Two-Column::, for another way to edit multi-column text.

   You can also copy rectangles into and out of registers with `C-x r r
R' and `C-x r i R'.  *Note Rectangle Registers: RegRect.

   There are two commands you can use for making blank rectangles: `C-x
r c' (`clear-rectangle') which blanks out existing text, and `C-x r o'
(`open-rectangle') which inserts a blank rectangle.  Clearing a
rectangle is equivalent to deleting it and then inserting a blank
rectangle of the same size.

   The command `M-x delete-whitespace-rectangle' deletes horizontal
whitespace starting from a particular column.  This applies to each of
the lines in the rectangle, and the column is specified by the left
edge of the rectangle.  The right edge of the rectangle does not make
any difference to this command.

   The command `C-x r t' (`string-rectangle') replaces the contents of
a region-rectangle with a string on each line.  The string's width need
not be the same as the width of the rectangle.  If the string's width
is less, the text after the rectangle shifts left; if the string is
wider than the rectangle, the text after the rectangle shifts right.

   The command `M-x string-insert-rectangle' is similar to
`string-rectangle', but inserts the string on each line, shifting the
original text to the right.


File: emacs,  Node: CUA Bindings,  Next: Registers,  Prev: Rectangles,  Up: Top

16 CUA Bindings
***************

The command `M-x cua-mode' sets up key bindings that are compatible
with the Common User Access (CUA) system used in many other
applications.  `C-x' means cut (kill), `C-c' copy, `C-v' paste (yank),
and `C-z' undo.  Standard Emacs commands like `C-x C-c' still work,
because `C-x' and `C-c' only take effect when the mark is active (and
the region is highlighted).  However, if you don't want to override
these bindings in Emacs at all, set `cua-enable-cua-keys' to `nil'.

   To enter an Emacs command like `C-x C-f' while the mark is active,
use one of the following methods: either hold `Shift' together with the
prefix key, e.g. `S-C-x C-f', or quickly type the prefix key twice,
e.g. `C-x C-x C-f'.

   In CUA mode, typed text replaces the active region as in
Delete-Selection mode (*note Mouse Commands::).

   CUA mode provides enhanced rectangle support with visible rectangle
highlighting.  Use `C-RET' to start a rectangle, extend it using the
movement commands, and cut or copy it using `C-x' or `C-c'.  `RET'
moves the cursor to the next (clockwise) corner of the rectangle, so
you can easily expand it in any direction.  Normal text you type is
inserted to the left or right of each line in the rectangle (on the
same side as the cursor).

   With CUA you can easily copy text and rectangles into and out of
registers by providing a one-digit numeric prefix to the kill, copy,
and yank commands, e.g. `C-1 C-c' copies the region into register `1',
and `C-2 C-v' yanks the contents of register `2'.

   CUA mode also has a global mark feature which allows easy moving and
copying of text between buffers.  Use `C-S-SPC' to toggle the global
mark on and off.  When the global mark is on, all text that you kill or
copy is automatically inserted at the global mark, and text you type is
inserted at the global mark rather than at the current position.

   For example, to copy words from various buffers into a word list in
a given buffer, set the global mark in the target buffer, then navigate
to each of the words you want in the list, mark it (e.g. with `S-M-f'),
copy it to the list with `C-c' or `M-w', and insert a newline after the
word in the target list by pressing <RET>.


File: emacs,  Node: Registers,  Next: Display,  Prev: CUA Bindings,  Up: Top

17 Registers
************

Emacs "registers" are compartments where you can save text, rectangles,
positions, and other things for later use.  Once you save text or a
rectangle in a register, you can copy it into the buffer once, or many
times; once you save a position in a register, you can jump back to
that position once, or many times.

   Each register has a name that consists of a single character, which
we will denote by R; R can be a letter (such as `a') or a number (such
as `1'); case matters, so register `a' is not the same as register `A'.

   A register can store a position, a piece of text, a rectangle, a
number, a window configuration, or a file name, but only one thing at
any given time.  Whatever you store in a register remains there until
you store something else in that register.  To see what register R
contains, use `M-x view-register':

`M-x view-register <RET> R'
     Display a description of what register R contains.

   "Bookmarks" record files and positions in them, so you can return to
those positions when you look at the file again.  Bookmarks are similar
enough in spirit to registers that they seem to belong in this chapter.

* Menu:

* Position: RegPos.           Saving positions in registers.
* Text: RegText.              Saving text in registers.
* Rectangle: RegRect.         Saving rectangles in registers.
* Configurations: RegConfig.  Saving window configurations in registers.
* Numbers: RegNumbers.        Numbers in registers.
* Files: RegFiles.            File names in registers.
* Bookmarks::                 Bookmarks are like registers, but persistent.


File: emacs,  Node: RegPos,  Next: RegText,  Up: Registers

17.1 Saving Positions in Registers
==================================

`C-x r <SPC> R'
     Record the position of point and the current buffer in register R
     (`point-to-register').

`C-x r j R'
     Jump to the position and buffer saved in register R
     (`jump-to-register').

   Typing `C-x r <SPC>' (`point-to-register'), followed by a character
`R', saves both the position of point and the current buffer in
register R.  The register retains this information until you store
something else in it.

   The command `C-x r j R' switches to the buffer recorded in register
R, and moves point to the recorded position.  The contents of the
register are not changed, so you can jump to the saved position any
number of times.

   If you use `C-x r j' to go to a saved position, but the buffer it
was saved from has been killed, `C-x r j' tries to create the buffer
again by visiting the same file.  Of course, this works only for buffers
that were visiting files.


File: emacs,  Node: RegText,  Next: RegRect,  Prev: RegPos,  Up: Registers

17.2 Saving Text in Registers
=============================

When you want to insert a copy of the same piece of text several times,
it may be inconvenient to yank it from the kill ring, since each
subsequent kill moves that entry further down the ring.  An alternative
is to store the text in a register and later retrieve it.

`C-x r s R'
     Copy region into register R (`copy-to-register').

`C-x r i R'
     Insert text from register R (`insert-register').

`M-x append-to-register <RET> R'
     Append region to text in register R.

`M-x prepend-to-register <RET> R'
     Prepend region to text in register R.

   `C-x r s R' stores a copy of the text of the region into the
register named R.  If the mark is inactive, Emacs first reactivates the
mark where it was last set.  The mark is deactivated at the end of this
command.  *Note Mark::.  `C-u C-x r s R', the same command with a
prefix argument, copies the text into register R and deletes the text
from the buffer as well; you can think of this as "moving" the region
text into the register.

   `M-x append-to-register <RET> R' appends the copy of the text in the
region to the text already stored in the register named R.  If invoked
with a prefix argument, it deletes the region after appending it to the
register.  The command `prepend-to-register' is similar, except that it
_prepends_ the region text to the text in the register instead of
_appending_ it.

   `C-x r i R' inserts in the buffer the text from register R.
Normally it leaves point before the text and places the mark after, but
with a numeric argument (`C-u') it puts point after the text and the
mark before.


File: emacs,  Node: RegRect,  Next: RegConfig,  Prev: RegText,  Up: Registers

17.3 Saving Rectangles in Registers
===================================

A register can contain a rectangle instead of linear text.  *Note
Rectangles::, for basic information on how to specify a rectangle in
the buffer.

`C-x r r R'
     Copy the region-rectangle into register R
     (`copy-rectangle-to-register').  With numeric argument, delete it
     as well.

`C-x r i R'
     Insert the rectangle stored in register R (if it contains a
     rectangle) (`insert-register').

   The `C-x r i R' command inserts a text string if the register
contains one, and inserts a rectangle if the register contains one.

   See also the command `sort-columns', which you can think of as
sorting a rectangle.  *Note Sorting::.


File: emacs,  Node: RegConfig,  Next: RegNumbers,  Prev: RegRect,  Up: Registers

17.4 Saving Window Configurations in Registers
==============================================

You can save the window configuration of the selected frame in a
register, or even the configuration of all windows in all frames, and
restore the configuration later.  *Note Windows::, for information
about window configurations.

`C-x r w R'
     Save the state of the selected frame's windows in register R
     (`window-configuration-to-register').

`C-x r f R'
     Save the state of all frames, including all their windows, in
     register R (`frame-configuration-to-register').

   Use `C-x r j R' to restore a window or frame configuration.  This is
the same command used to restore a cursor position.  When you restore a
frame configuration, any existing frames not included in the
configuration become invisible.  If you wish to delete these frames
instead, use `C-u C-x r j R'.


File: emacs,  Node: RegNumbers,  Next: RegFiles,  Prev: RegConfig,  Up: Registers

17.5 Keeping Numbers in Registers
=================================

There are commands to store a number in a register, to insert the
number in the buffer in decimal, and to increment it.  These commands
can be useful in keyboard macros (*note Keyboard Macros::).

`C-u NUMBER C-x r n R'
     Store NUMBER into register R (`number-to-register').

`C-u NUMBER C-x r + R'
     Increment the number in register R by NUMBER
     (`increment-register').

`C-x r i R'
     Insert the number from register R into the buffer.

   `C-x r i' is the same command used to insert any other sort of
register contents into the buffer.  `C-x r +' with no numeric argument
increments the register value by 1; `C-x r n' with no numeric argument
stores zero in the register.


File: emacs,  Node: RegFiles,  Next: Bookmarks,  Prev: RegNumbers,  Up: Registers

17.6 Keeping File Names in Registers
====================================

If you visit certain file names frequently, you can visit them more
conveniently if you put their names in registers.  Here's the Lisp code
used to put a file name in a register:

     (set-register ?R '(file . NAME))

For example,

     (set-register ?z '(file . "/gd/gnu/emacs/19.0/src/ChangeLog"))

puts the file name shown in register `z'.

   To visit the file whose name is in register R, type `C-x r j R'.
(This is the same command used to jump to a position or restore a frame
configuration.)


File: emacs,  Node: Bookmarks,  Prev: RegFiles,  Up: Registers

17.7 Bookmarks
==============

"Bookmarks" are somewhat like registers in that they record positions
you can jump to.  Unlike registers, they have long names, and they
persist automatically from one Emacs session to the next.  The
prototypical use of bookmarks is to record "where you were reading" in
various files.

`C-x r m <RET>'
     Set the bookmark for the visited file, at point.

`C-x r m BOOKMARK <RET>'
     Set the bookmark named BOOKMARK at point (`bookmark-set').

`C-x r b BOOKMARK <RET>'
     Jump to the bookmark named BOOKMARK (`bookmark-jump').

`C-x r l'
     List all bookmarks (`list-bookmarks').

`M-x bookmark-save'
     Save all the current bookmark values in the default bookmark file.

   The prototypical use for bookmarks is to record one current position
in each of several files.  So the command `C-x r m', which sets a
bookmark, uses the visited file name as the default for the bookmark
name.  If you name each bookmark after the file it points to, then you
can conveniently revisit any of those files with `C-x r b', and move to
the position of the bookmark at the same time.

   To display a list of all your bookmarks in a separate buffer, type
`C-x r l' (`list-bookmarks').  If you switch to that buffer, you can
use it to edit your bookmark definitions or annotate the bookmarks.
Type `C-h m' in the bookmark buffer for more information about its
special editing commands.

   When you kill Emacs, Emacs offers to save your bookmark values in
your default bookmark file, `~/.emacs.bmk', if you have changed any
bookmark values.  You can also save the bookmarks at any time with the
`M-x bookmark-save' command.  The bookmark commands load your default
bookmark file automatically.  This saving and loading is how bookmarks
persist from one Emacs session to the next.

   If you set the variable `bookmark-save-flag' to 1, each command that
sets a bookmark will also save your bookmarks; this way, you don't lose
any bookmark values even if Emacs crashes.  (The value, if a number,
says how many bookmark modifications should go by between saving.)

   Bookmark position values are saved with surrounding context, so that
`bookmark-jump' can find the proper position even if the file is
modified slightly.  The variable `bookmark-search-size' says how many
characters of context to record on each side of the bookmark's position.

   Here are some additional commands for working with bookmarks:

`M-x bookmark-load <RET> FILENAME <RET>'
     Load a file named FILENAME that contains a list of bookmark
     values.  You can use this command, as well as `bookmark-write', to
     work with other files of bookmark values in addition to your
     default bookmark file.

`M-x bookmark-write <RET> FILENAME <RET>'
     Save all the current bookmark values in the file FILENAME.

`M-x bookmark-delete <RET> BOOKMARK <RET>'
     Delete the bookmark named BOOKMARK.

`M-x bookmark-insert-location <RET> BOOKMARK <RET>'
     Insert in the buffer the name of the file that bookmark BOOKMARK
     points to.

`M-x bookmark-insert <RET> BOOKMARK <RET>'
     Insert in the buffer the _contents_ of the file that bookmark
     BOOKMARK points to.


File: emacs,  Node: Display,  Next: Search,  Prev: Registers,  Up: Top

18 Controlling the Display
**************************

Since only part of a large buffer fits in the window, Emacs tries to
show a part that is likely to be interesting.  Display-control commands
and variables allow you to specify which part of the text you want to
see, and how to display it.

* Menu:

* Scrolling::              Commands to move text up and down in a window.
* Auto Scrolling::         Redisplay scrolls text automatically when needed.
* Horizontal Scrolling::   Moving text left and right in a window.
* Follow Mode::            Follow mode lets two windows scroll as one.
* Faces::                  How to change the display style using faces.
* Standard Faces::         Emacs' predefined faces.
* Temporary Face Changes:: Commands to temporarily modify the default text face
* Font Lock::              Minor mode for syntactic highlighting using faces.
* Highlight Interactively:: Tell Emacs what text to highlight.
* Fringes::                Enabling or disabling window fringes.
* Displaying Boundaries::  Displaying top and bottom of the buffer.
* Useless Whitespace::     Showing possibly-spurious trailing whitespace.
* Selective Display::      Hiding lines with lots of indentation.
* Optional Mode Line::     Optional mode line display features.
* Text Display::           How text characters are normally displayed.
* Cursor Display::         Features for displaying the cursor.
* Line Truncation::        Truncating lines to fit the screen width instead
                             of continuing them to multiple screen lines.
* Visual Line Mode::       Word wrap and screen line-based editing.
* Display Custom::         Information on variables for customizing display.


File: emacs,  Node: Scrolling,  Next: Auto Scrolling,  Up: Display

18.1 Scrolling
==============

If a buffer contains text that is too large to fit entirely within a
window that is displaying the buffer, Emacs shows a contiguous portion
of the text.  The portion shown always contains point.

   "Scrolling" means moving text up or down in the window so that
different parts of the text are visible.  Scrolling "forward" or "up"
means that text moves up, and new text appears at the bottom.
Scrolling "backward" or "down" moves text down, and new text appears at
the top.

   Scrolling happens automatically if you move point past the bottom or
top of the window.  You can also scroll explicitly with these commands:

`C-l'
     Scroll the selected window so that the current line is the
     center-most text line; on subsequent consecutive invocations, make
     the current line the top-most line, the bottom-most line, and so
     forth in cyclic order; also, maybe redisplay the screen
     (`recenter-top-bottom').

`C-v'
`<next>'
`<PageDown>'
     Scroll forward by nearly a full window (`scroll-up').

`M-v'
`<prior>'
`<PageUp>'
     Scroll backward (`scroll-down').

`C-M-l'
     Scroll heuristically to bring useful information onto the screen
     (`reposition-window').

   `C-l' (`recenter-top-bottom') is a basic scrolling command.  It
"recenters" the selected window, scrolling it so that the current
screen line is exactly in the center of the window, or as close to the
center as possible.

   Typing `C-l' twice in a row (`C-l C-l') scrolls the window so that
point is on the topmost screen line.  Typing a third `C-l' scrolls the
window so that point is on the bottom-most screen line.  Each
successive `C-l' cycles through these three screen positions.

   You can change the cycling order by customizing the list variable
`recenter-positions'.  Each list element should be the symbol `top',
`middle', or `bottom', or a number; an integer number means to move the
line to the specified screen line, while a floating-point number
between 0.0 and 1.0 specifies a percentage of the screen space from the
top.  The default, `(middle top bottom)', is the cycling order
described above.  Furthermore, if you change the variable
`scroll-margin' to a non-zero value N, Emacs always leaves N screen
lines between point and the top or bottom of the window (*note Auto
Scrolling::).

   You can also supply `C-l' with a prefix argument.  With a plain
prefix argument, `C-u C-l', Emacs simply recenters point.  With a
positive argument N, it scrolls to place point N lines down from the
top of the window.  An argument of zero puts point on the topmost line.
A negative argument -N puts point N lines from the bottom of the
window.  For example, `C-u - 1 C-l' puts point on the bottom line, and
`C-u - 5 C-l' puts it five lines from the bottom.  When given an
argument, `C-l' does not clear the screen or cycle through different
screen positions.

   The more primitive command `recenter' behaves like
`recenter-top-bottom', but does not cycle among screen positions.
Prior to Emacs 23, `C-l' was bound to `recenter'.

   If the variable `recenter-redisplay' has a non-`nil' value, Emacs
clears and redisplays the screen each time `C-l' recenters the window;
the special value `tty' (the default) says to do this on text-terminal
frames only.  Redisplaying is useful in case the screen becomes garbled
for any reason (*note Screen Garbled::).

   To read the buffer a windowful at a time, type `C-v' (`scroll-up').
This scrolls forward by nearly the whole window height.  The effect is
to take the two lines at the bottom of the window and put them at the
top, followed by lines that were not previously visible.  If point was
in the text that scrolled off the top, it ends up at the new top of the
window.

   `M-v' (`scroll-down') scrolls backward in a similar way.

   The variable `next-screen-context-lines' controls the number of
lines of overlap left by `C-v' or `M-v'; by default, it is 2.  The
function keys <next> and <prior>, or <PageDown> and <PageUp>, are
equivalent to `C-v' and `M-v' respectively.

   You can supply `C-v' or `M-v' with a numeric prefix argument N.
This scrolls the window by N lines, while attempting to leave point
unchanged (so that the text and point move up or down together).  `C-v'
with a negative argument is like `M-v' and vice versa.

   The names of scroll commands are based on the direction that the
text moves in the window.  Thus, the command to scroll forward is
called `scroll-up' because it moves the text upward on the screen.  The
keys <PageUp> and <PageDown> derive their names and customary meanings
from a different convention that developed elsewhere; hence the strange
result that <PageDown> runs `scroll-up'.

   Some users like the full-screen scroll commands to keep point at the
same screen position.  To enable this behavior, set the variable
`scroll-preserve-screen-position' to a non-`nil' value.  Then, whenever
a command scrolls the text around point offscreen (or within
`scroll-margin' lines of the edge), Emacs moves point to keep it at the
same vertical and horizontal position within the window.  This mode is
convenient for browsing through a file by scrolling by screenfuls; if
you come back to the screen where you started, point goes back to the
line where it started.

   The `C-M-l' command (`reposition-window') scrolls the current window
heuristically in a way designed to get useful information onto the
screen.  For example, in a Lisp file, this command tries to get the
entire current defun onto the screen if possible.


File: emacs,  Node: Auto Scrolling,  Next: Horizontal Scrolling,  Prev: Scrolling,  Up: Display

18.2 Automatic Scrolling
========================

Emacs performs "automatic scrolling" when point moves out of the
visible portion of the text.

   Normally, this centers point vertically within the window.  However,
if you set `scroll-conservatively' to a small number N, then if you
move point just a little off the screen (less than N lines), Emacs
scrolls the text just far enough to bring point back on screen.  By
default, `scroll-conservatively' is 0.

   When the window does scroll by a longer distance, you can control
how aggressively it scrolls by setting the variables
`scroll-up-aggressively' and `scroll-down-aggressively'.  The value of
`scroll-up-aggressively' should be either `nil', or a fraction F
between 0 and 1.  A fraction specifies where on the screen to put point
when scrolling upward, i.e. when point moves forward in the buffer, and
therefore text scrolls up in the window.  When point goes off the
window end, the new start position is chosen to put point F parts of
the window height from the bottom.  Thus, larger F means more aggressive
scrolling: more new text is brought into view.  The default value,
`nil', is equivalent to 0.5.

   Likewise, `scroll-down-aggressively' is used for scrolling down,
i.e. moving point back in the buffer.  The value specifies how far
point should be placed from the top of the window; thus, as with
`scroll-up-aggressively', a larger value is more aggressive.

   The variable `scroll-margin' restricts how close point can come to
the top or bottom of a window.  Its value is a number of screen lines;
if point comes within that many lines of the top or bottom of the
window, Emacs performs automatic scrolling.  By default,
`scroll-margin' is 0.


File: emacs,  Node: Horizontal Scrolling,  Next: Follow Mode,  Prev: Auto Scrolling,  Up: Display

18.3 Horizontal Scrolling
=========================

"Horizontal scrolling" means shifting all the lines sideways within a
window, so that some of the text near the left margin is not displayed.
When the text in a window is scrolled horizontally, text lines are
truncated rather than continued (*note Line Truncation::).  If a window
shows truncated lines, Emacs performs automatic horizontal scrolling
whenever point moves off the left or right edge of the screen.  To
disable automatic horizontal scrolling, set the variable
`auto-hscroll-mode' to `nil'.  Note that when the automatic horizontal
scrolling is turned off, if point moves off the edge of the screen, the
cursor disappears to indicate that.  (On text-mode terminals, the
cursor is left at the edge instead.)

   The variable `hscroll-margin' controls how close point can get to
the window's edges before automatic scrolling occurs.  It is measured
in columns.  For example, if the value is 5, then moving point within 5
columns of an edge causes horizontal scrolling away from that edge.

   The variable `hscroll-step' determines how many columns to scroll
the window when point gets too close to the edge.  Zero, the default
value, means to center point horizontally within the window.  A
positive integer value specifies the number of columns to scroll by.  A
floating-point number specifies the fraction of the window's width to
scroll by.

   You can also perform explicit horizontal scrolling with the
following commands:

`C-x <'
     Scroll text in current window to the left (`scroll-left').

`C-x >'
     Scroll to the right (`scroll-right').

   `C-x <' (`scroll-left') scrolls text in the selected window to the
left by the full width of the window, less two columns.  (In other
words, the text in the window moves left relative to the window.)  With
a numeric argument N, it scrolls by N columns.

   If the text is scrolled to the left, and point moves off the left
edge of the window, the cursor will freeze at the left edge of the
window, until point moves back to the displayed portion of the text.
This is independent of the current setting of `auto-hscroll-mode',
which, for text scrolled to the left, only affects the behavior at the
right edge of the window.

   `C-x >' (`scroll-right') scrolls similarly to the right.  The window
cannot be scrolled any farther to the right once it is displayed
normally, with each line starting at the window's left margin;
attempting to do so has no effect.  This means that you don't have to
calculate the argument precisely for `C-x >'; any sufficiently large
argument will restore the normal display.

   If you use those commands to scroll a window horizontally, that sets
a lower bound for automatic horizontal scrolling.  Automatic scrolling
will continue to scroll the window, but never farther to the right than
the amount you previously set by `scroll-left'.


File: emacs,  Node: Follow Mode,  Next: Faces,  Prev: Horizontal Scrolling,  Up: Display

18.4 Follow Mode
================

"Follow mode" is a minor mode that makes two windows, both showing the
same buffer, scroll as a single tall "virtual window."  To use Follow
mode, go to a frame with just one window, split it into two
side-by-side windows using `C-x 3', and then type `M-x follow-mode'.
From then on, you can edit the buffer in either of the two windows, or
scroll either one; the other window follows it.

   In Follow mode, if you move point outside the portion visible in one
window and into the portion visible in the other window, that selects
the other window--again, treating the two as if they were parts of one
large window.

   To turn off Follow mode, type `M-x follow-mode' a second time.


File: emacs,  Node: Faces,  Next: Standard Faces,  Prev: Follow Mode,  Up: Display

18.5 Faces: Controlling Text Display Style
==========================================

Emacs can display text in several different styles, which are called
"faces".  Each face can specify various "face attributes", such as the
font, height, weight and slant, the foreground and background color,
and underlining or overlining.  A face does not have to specify all of
these attributes; often it inherits most of them from another face.

   On a text-only terminal, not all face attributes are meaningful.
Some text-only terminals support inverse video, bold, and underline
attributes; some support colors.  Text-only terminals generally do not
support changing the height, width or font.

   Most major modes assign faces to the text automatically through the
work of Font Lock mode.  *Note Font Lock::, for more information about
Font Lock mode and syntactic highlighting.  You can print the current
buffer with the highlighting that appears on your screen using the
command `ps-print-buffer-with-faces'.  *Note PostScript::.

   Enriched mode, the mode for editing formatted text, provides
commands and menus for specifying faces for text in the buffer.  *Note
Format Faces::.

   To alter the appearance of a face, use the customization buffer.
*Note Face Customization::.  You can also use X resources to specify
attributes of any particular face (*note Resources::).  When displaying
a character, any attribute that isn't specified by its face is taken
from the `default' face, whose attributes reflect the default settings
of the frame itself.

   You can also change the foreground and background colors of a
specific face with `M-x set-face-foreground' and `M-x
set-face-background'.  These commands prompt in the minibuffer for a
face name and a color name, with completion, and then set that face to
use the specified color.  *Note Face Customization::, for information
about color names.  These commands affect the face colors on all
frames, both existing and those to be created in the future.  These
changes do not, however, persist for future Emacs sessions; to make
lasting changes, use the customization buffer (*note Face
Customization::).

   You can also set foreground and background colors for the current
frame only; see *note Frame Parameters::.

   Emacs can display variable-width fonts, but some of the Emacs
commands that calculate width and indentation do not know how to
calculate variable widths.  This can sometimes lead to incorrect
results when you use variable-width fonts.  In particular, indentation
commands can give inconsistent results, so we recommend you avoid
variable-width fonts, especially for editing program source code.


File: emacs,  Node: Standard Faces,  Next: Temporary Face Changes,  Prev: Faces,  Up: Display

18.6 Standard Faces
===================

To see what faces are currently defined, and what they look like, type
`M-x list-faces-display'.  It's possible for a given face to look
different in different frames; this command shows the appearance in the
frame in which you type it.  With a prefix argument, this prompts for a
regular expression, and displays only faces with names matching that
regular expression.

   Here are the standard faces for specifying text appearance.  You can
apply them to specific text when you want the effects they produce.

`default'
     This face is used for ordinary text that doesn't specify any face.

`bold'
     This face uses a bold variant of the default font.

`italic'
     This face uses an italic variant of the default font.

`bold-italic'
     This face uses a bold italic variant of the default font.

`underline'
     This face underlines text.

`fixed-pitch'
     This face forces use of a fixed-width font.  It's reasonable to
     customize this face to use a different fixed-width font, if you
     like, but you should not make it a variable-width font.

`variable-pitch'
     This face forces use of a variable-width font.

`shadow'
     This face is used for making the text less noticeable than the
     surrounding ordinary text.  Usually this can be achieved by using
     shades of gray in contrast with either black or white default
     foreground color.

   Here's an incomplete list of faces used to highlight parts of the
text temporarily for specific purposes.  (Many other modes define their
own faces for this purpose.)

`highlight'
     This face is used for highlighting portions of text, in various
     modes.  For example, mouse-sensitive text is highlighted using
     this face.

`isearch'
     This face is used for highlighting the current Isearch match
     (*note Incremental Search::).

`query-replace'
     This face is used for highlighting the current Query Replace match
     (*note Replace::).

`lazy-highlight'
     This face is used for lazy highlighting of Isearch and Query
     Replace matches other than the current one.

`region'
     This face is used for displaying a selected region (*note Mark::).

`secondary-selection'
     This face is used for displaying a secondary X selection (*note
     Secondary Selection::).

`trailing-whitespace'
     The face for highlighting excess spaces and tabs at the end of a
     line when `show-trailing-whitespace' is non-`nil'; see *note
     Useless Whitespace::.

`nobreak-space'
     The face for displaying the character "nobreak space."

`escape-glyph'
     The face for highlighting the `\' or `^' that indicates a control
     character.  It's also used when `\' indicates a nobreak space or
     nobreak (soft) hyphen.

   These faces control the appearance of parts of the Emacs frame.
They exist as faces to provide a consistent way to customize the
appearance of these parts of the frame.

`mode-line'
     This face is used for the mode line of the currently selected
     window, and for menu bars when toolkit menus are not used.  By
     default, it's drawn with shadows for a "raised" effect on
     graphical displays, and drawn as the inverse of the default face
     on non-windowed terminals.

`mode-line-inactive'
     Like `mode-line', but used for mode lines of the windows other
     than the selected one (if `mode-line-in-non-selected-windows' is
     non-`nil').  This face inherits from `mode-line', so changes in
     that face affect mode lines in all windows.

`mode-line-highlight'
     Like `highlight', but used for portions of text on mode lines.

`mode-line-buffer-id'
     This face is used for buffer identification parts in the mode line.

`header-line'
     Similar to `mode-line' for a window's header line, which appears
     at the top of a window just as the mode line appears at the bottom.
     Most windows do not have a header line--only some special modes,
     such Info mode, create one.

`vertical-border'
     This face is used for the vertical divider between windows.  By
     default this face inherits from the `mode-line-inactive' face on
     character terminals.  On graphical displays the foreground color of
     this face is used for the vertical line between windows without
     scrollbars.

`minibuffer-prompt'
     This face is used for the prompt strings displayed in the
     minibuffer.  By default, Emacs automatically adds this face to the
     value of `minibuffer-prompt-properties', which is a list of text
     properties used to display the prompt text.  (This variable takes
     effect when you enter the minibuffer.)

`fringe'
     The face for the fringes to the left and right of windows on
     graphic displays.  (The fringes are the narrow portions of the
     Emacs frame between the text area and the window's right and left
     borders.)  *Note Fringes::.

`scroll-bar'
     This face determines the visual appearance of the scroll bar.
     *Note Scroll Bars::.

`border'
     This face determines the color of the frame border.

`cursor'
     This face determines the color of the cursor.

`mouse'
     This face determines the color of the mouse pointer.

`tool-bar'
     This face determines the color of tool bar icons.  *Note Tool
     Bars::.

`tooltip'
     This face is used for tooltips.  *Note Tooltips::.

`menu'
     This face determines the colors and font of Emacs's menus.  *Note
     Menu Bars::.  This has no effect in Emacs built with GTK and in the
     MS-Windows/Mac ports; you need to use system-wide styles and
     options to change the appearance of GTK, Windows, or Mac menus.
     Setting the font of LessTif/Motif menus is currently not
     supported; attempts to set the font are ignored in this case.


File: emacs,  Node: Temporary Face Changes,  Next: Font Lock,  Prev: Standard Faces,  Up: Display

18.7 Temporary Face Changes
===========================

The following commands change the default face within a buffer.

   To increase the height of the default face in the current buffer,
type `C-x C-+' or `C-x C-='.  To decrease it, type `C-x C--'.  To
restore the default (global) face height, type `C-x C-0'.  These keys
are all bound to the same command, `text-scale-adjust', which looks at
the last key typed to determine which action to take.

   The final key of these commands may be repeated without the leading
`C-x'.  For instance, `C-x C-= C-= C-=' increases the face height by
three steps.  Each step scales the height of the default face by the
value of the variable `text-scale-mode-step'.  As a special case, an
argument of 0 removes any scaling currently active.

   The commands `text-scale-increase' and `text-scale-decrease'
increase or decrease the height of the default face, just like `C-x
C-+' and `C-x C--' respectively.  You may find it convenient to bind to
these commands, rather than `text-scale-adjust'.

   The command `text-scale-set' sets the height of the default face in
the current buffer to an absolute level specified by its prefix
argument.

   The above commands automatically enable or disable the minor mode
`text-scale-mode', depending on whether the current font scaling is
other than 1 or not.

   To temporarily change the face in the current buffer to a
variable-pitch ("proportional") font, use the command `M-x
variable-pitch-mode' to enable or disable the Variable Pitch minor mode.


File: emacs,  Node: Font Lock,  Next: Highlight Interactively,  Prev: Temporary Face Changes,  Up: Display

18.8 Font Lock mode
===================

Font Lock mode is a minor mode, always local to a particular buffer,
which highlights (or "fontifies") the buffer contents according to the
syntax of the text you are editing.  It can recognize comments and
strings in most programming languages; in several languages, it can
also recognize and properly highlight various other important
constructs, such as names of functions being defined or reserved
keywords.  Some special modes, such as Occur mode and Info mode, have
completely specialized ways of assigning fonts for Font Lock mode.

   Font Lock mode is turned on by default in all modes which support it.
You can toggle font-lock for each buffer with the command `M-x
font-lock-mode'.  Using a positive argument unconditionally turns Font
Lock mode on, and a negative or zero argument turns it off.

   If you do not wish Font Lock mode to be turned on by default,
customize the variable `global-font-lock-mode' using the Customize
interface (*note Easy Customization::), or use the function
`global-font-lock-mode' in your `.emacs' file, like this:

     (global-font-lock-mode 0)

This variable, like all the variables that control Font Lock mode, take
effect whenever fontification is done; that is, potentially at any time.

   If you have disabled Global Font Lock mode, you can still enable Font
Lock for specific major modes by adding the function
`turn-on-font-lock' to the mode hooks (*note Hooks::).  For example, to
enable Font Lock mode for editing C files, you can do this:

     (add-hook 'c-mode-hook 'turn-on-font-lock)

   Font Lock mode uses several specifically named faces to do its job,
including `font-lock-string-face', `font-lock-comment-face', and
others.  The easiest way to find them all is to use `M-x
customize-group <RET> font-lock-faces <RET>'.  You can then use that
customization buffer to customize the appearance of these faces.  *Note
Face Customization::.

   The variable `font-lock-maximum-decoration' specifies the preferred
level of fontification, for modes that provide multiple levels.  Level
1 is the least amount of fontification; some modes support levels as
high as 3.  The normal default is "as high as possible."  You can
specify an integer, which applies to all modes, or you can specify
different numbers for particular major modes; for example, to use level
1 for C/C++ modes, and the default level otherwise, use this:

     (setq font-lock-maximum-decoration
           '((c-mode . 1) (c++-mode . 1)))

   Fontification can be too slow for large buffers, so you can suppress
it for buffers above a certain size.  The variable
`font-lock-maximum-size' specifies a buffer size, beyond which buffer
fontification is suppressed.

   Comment and string fontification (or "syntactic" fontification)
relies on analysis of the syntactic structure of the buffer text.  For
the sake of speed, some modes, including Lisp mode, rely on a special
convention: an open-parenthesis or open-brace in the leftmost column
always defines the beginning of a defun, and is thus always outside any
string or comment.  (*Note Left Margin Paren::.)  If you don't follow
this convention, Font Lock mode can misfontify the text that follows an
open-parenthesis or open-brace in the leftmost column that is inside a
string or comment.

   The variable `font-lock-beginning-of-syntax-function', which is
always buffer-local, specifies how Font Lock mode can find a position
guaranteed to be outside any comment or string.  In modes which use the
leftmost column parenthesis convention, the default value of the
variable is `beginning-of-defun'--that tells Font Lock mode to use the
convention.  If you set this variable to `nil', Font Lock no longer
relies on the convention.  This avoids incorrect results, but the price
is that, in some cases, fontification for a changed text must rescan
buffer text from the beginning of the buffer.  This can considerably
slow down redisplay while scrolling, particularly if you are close to
the end of a large buffer.

   Font Lock highlighting patterns already exist for many modes, but you
may want to fontify additional patterns.  You can use the function
`font-lock-add-keywords', to add your own highlighting patterns for a
particular mode.  For example, to highlight `FIXME:' words in C
comments, use this:

     (add-hook 'c-mode-hook
               (lambda ()
                (font-lock-add-keywords nil
                 '(("\\<\\(FIXME\\):" 1
                    font-lock-warning-face t)))))

   To remove keywords from the font-lock highlighting patterns, use the
function `font-lock-remove-keywords'.  *Note Search-based
Fontification: (elisp)Search-based Fontification.

   Fontifying large buffers can take a long time.  To avoid large
delays when a file is visited, Emacs fontifies only the visible portion
of a buffer.  As you scroll through the buffer, each portion that
becomes visible is fontified as soon as it is displayed; this type of
Font Lock is called "Just-In-Time" (or "JIT") Lock.  You can control
how JIT Lock behaves, including telling it to perform fontification
while idle, by customizing variables in the customization group
`jit-lock'.  *Note Specific Customization::.


File: emacs,  Node: Highlight Interactively,  Next: Fringes,  Prev: Font Lock,  Up: Display

18.9 Interactive Highlighting
=============================

Highlight Changes mode is a minor mode that "highlights" the parts of
the buffer were changed most recently, by giving that text a different
face.  To enable or disable Highlight Changes mode, use `M-x
highlight-changes-mode'.

   Hi Lock mode is a minor mode that highlights text that matches
regular expressions you specify.  For example, you can use it to
highlight all the references to a certain variable in a program source
file, highlight certain parts in a voluminous output of some program,
or highlight certain names in an article.  To enable or disable Hi Lock
mode, use the command `M-x hi-lock-mode'.  To enable Hi Lock mode for
all buffers, use `M-x global-hi-lock-mode' or place
`(global-hi-lock-mode 1)' in your `.emacs' file.

   Hi Lock mode works like Font Lock mode (*note Font Lock::), except
that you specify explicitly the regular expressions to highlight.  You
control them with these commands:

`C-x w h REGEXP <RET> FACE <RET>'
     Highlight text that matches REGEXP using face FACE
     (`highlight-regexp').  The highlighting will remain as long as the
     buffer is loaded.  For example, to highlight all occurrences of
     the word "whim" using the default face (a yellow background) `C-x
     w h whim <RET> <RET>'.  Any face can be used for highlighting, Hi
     Lock provides several of its own and these are pre-loaded into a
     list of default values.  While being prompted for a face use `M-n'
     and `M-p' to cycle through them.

     You can use this command multiple times, specifying various regular
     expressions to highlight in different ways.

`C-x w r REGEXP <RET>'
     Unhighlight REGEXP (`unhighlight-regexp').

     If you invoke this from the menu, you select the expression to
     unhighlight from a list.  If you invoke this from the keyboard, you
     use the minibuffer.  It will show the most recently added regular
     expression; use `M-p' to show the next older expression and `M-n'
     to select the next newer expression.  (You can also type the
     expression by hand, with completion.)  When the expression you
     want to unhighlight appears in the minibuffer, press `<RET>' to
     exit the minibuffer and unhighlight it.

`C-x w l REGEXP <RET> FACE <RET>'
     Highlight entire lines containing a match for REGEXP, using face
     FACE (`highlight-lines-matching-regexp').

`C-x w b'
     Insert all the current highlighting regexp/face pairs into the
     buffer at point, with comment delimiters to prevent them from
     changing your program.  (This key binding runs the
     `hi-lock-write-interactive-patterns' command.)

     These patterns are extracted from the comments, if appropriate, if
     you invoke `M-x hi-lock-find-patterns', or if you visit the file
     while Hi Lock mode is enabled (since that runs
     `hi-lock-find-patterns').

`C-x w i'
     Extract regexp/face pairs from comments in the current buffer
     (`hi-lock-find-patterns').  Thus, you can enter patterns
     interactively with `highlight-regexp', store them into the file
     with `hi-lock-write-interactive-patterns', edit them (perhaps
     including different faces for different parenthesized parts of the
     match), and finally use this command (`hi-lock-find-patterns') to
     have Hi Lock highlight the edited patterns.

     The variable `hi-lock-file-patterns-policy' controls whether Hi
     Lock mode should automatically extract and highlight patterns
     found in a file when it is visited.  Its value can be `nil' (never
     highlight), `ask' (query the user), or a function.  If it is a
     function, `hi-lock-find-patterns' calls it with the patterns as
     argument; if the function returns non-`nil', the patterns are
     used.  The default is `ask'.  Note that patterns are always
     highlighted if you call `hi-lock-find-patterns' directly,
     regardless of the value of this variable.

     Also, `hi-lock-find-patterns' does nothing if the current major
     mode's symbol is a member of the list `hi-lock-exclude-modes'.


File: emacs,  Node: Fringes,  Next: Displaying Boundaries,  Prev: Highlight Interactively,  Up: Display

18.10 Window Fringes
====================

On a graphical display, each Emacs window normally has narrow "fringes"
on the left and right edges.  The fringes are used to display symbols
that provide information about the text in the window.

   The most common use of the fringes is to indicate a continuation
line, when one line of text is split into multiple lines on the screen.
The left fringe shows a curving arrow for each screen line except the
first, indicating that "this is not the real beginning."  The right
fringe shows a curving arrow for each screen line except the last,
indicating that "this is not the real end."

   The fringes indicate line truncation with short horizontal arrows
meaning "there's more text on this line which is scrolled horizontally
out of view;" clicking the mouse on one of the arrows scrolls the
display horizontally in the direction of the arrow.   The fringes can
also indicate other things, such as empty lines, or where a program you
are debugging is executing (*note Debuggers::).

   You can enable and disable the fringes for all frames using `M-x
fringe-mode'.  To enable and disable the fringes for the selected
frame, use `M-x set-fringe-style'.


File: emacs,  Node: Displaying Boundaries,  Next: Useless Whitespace,  Prev: Fringes,  Up: Display

18.11 Displaying Boundaries
===========================

On a graphical display, Emacs can indicate the buffer boundaries in the
fringes.  It indicates the first line and the last line with angle
images in the fringes.  This can be combined with up and down arrow
images which say whether it is possible to scroll the window up and
down.

   The buffer-local variable `indicate-buffer-boundaries' controls how
the buffer boundaries and window scrolling is indicated in the fringes.
If the value is `left' or `right', both angle and arrow bitmaps are
displayed in the left or right fringe, respectively.

   If value is an alist, each element `(INDICATOR .  POSITION)'
specifies the position of one of the indicators.  The INDICATOR must be
one of `top', `bottom', `up', `down', or `t' which specifies the default
position for the indicators not present in the alist.  The POSITION is
one of `left', `right', or `nil' which specifies not to show this
indicator.

   For example, `((top . left) (t . right))' places the top angle
bitmap in left fringe, the bottom angle bitmap in right fringe, and
both arrow bitmaps in right fringe.  To show just the angle bitmaps in
the left fringe, but no arrow bitmaps, use `((top .  left) (bottom .
left))'.


File: emacs,  Node: Useless Whitespace,  Next: Selective Display,  Prev: Displaying Boundaries,  Up: Display

18.12 Useless Whitespace
========================

It is easy to leave unnecessary spaces at the end of a line, or empty
lines at the end of a file, without realizing it.  In most cases, this
"trailing whitespace" has no effect, but there are special
circumstances where it matters, and it can be a nuisance.

   You can make trailing whitespace at the end of a line visible by
setting the buffer-local variable `show-trailing-whitespace' to `t'.
Then Emacs displays trailing whitespace, using the face
`trailing-whitespace'.

   This feature does not apply when point is at the end of the line
containing the whitespace.  Strictly speaking, that is "trailing
whitespace" nonetheless, but displaying it specially in that case looks
ugly while you are typing in new text.  In this special case, the
location of point is enough to show you that the spaces are present.

   Type `M-x delete-trailing-whitespace <RET>' to delete all trailing
whitespace within the buffer's accessible portion (*note Narrowing::).
This command does not remove newline characters.

   Emacs can indicate unused lines at the end of the window with a
small image in the left fringe (*note Fringes::).  The image appears
for window lines that do not correspond to any buffer text.  Blank
lines at the end of the buffer then stand out because they do not have
this image in the fringe.

   To enable this feature, set the buffer-local variable
`indicate-empty-lines' to a non-`nil' value.  You can enable or disable
this feature for all new buffers by setting the default value of this
variable, e.g. `(setq-default indicate-empty-lines t)';.  (This feature
currently doesn't work on text-only terminals.)


File: emacs,  Node: Selective Display,  Next: Optional Mode Line,  Prev: Useless Whitespace,  Up: Display

18.13 Selective Display
=======================

Emacs has the ability to hide lines indented more than a given number
of columns.  You can use this to get an overview of a part of a program.

   To hide lines in the current buffer, type `C-x $'
(`set-selective-display') with a numeric argument N.  Then lines with
at least N columns of indentation disappear from the screen.  The only
indication of their presence is that three dots (`...') appear at the
end of each visible line that is followed by one or more hidden ones.

   The commands `C-n' and `C-p' move across the hidden lines as if they
were not there.

   The hidden lines are still present in the buffer, and most editing
commands see them as usual, so you may find point in the middle of the
hidden text.  When this happens, the cursor appears at the end of the
previous line, after the three dots.  If point is at the end of the
visible line, before the newline that ends it, the cursor appears before
the three dots.

   To make all lines visible again, type `C-x $' with no argument.

   If you set the variable `selective-display-ellipses' to `nil', the
three dots do not appear at the end of a line that precedes hidden
lines.  Then there is no visible indication of the hidden lines.  This
variable becomes local automatically when set.

   See also *note Outline Mode:: for another way to hide part of the
text in a buffer.


File: emacs,  Node: Optional Mode Line,  Next: Text Display,  Prev: Selective Display,  Up: Display

18.14 Optional Mode Line Features
=================================

The buffer percentage POS indicates the percentage of the buffer above
the top of the window.  You can additionally display the size of the
buffer by typing `M-x size-indication-mode' to turn on Size Indication
mode.  The size will be displayed immediately following the buffer
percentage like this:

     POS of SIZE

Here SIZE is the human readable representation of the number of
characters in the buffer, which means that `k' for 10^3, `M' for 10^6,
`G' for 10^9, etc., are used to abbreviate.

   The current line number of point appears in the mode line when Line
Number mode is enabled.  Use the command `M-x line-number-mode' to turn
this mode on and off; normally it is on.  The line number appears after
the buffer percentage POS, with the letter `L' to indicate what it is.

   Similarly, you can display the current column number by turning on
Column number mode with `M-x column-number-mode'.  The column number is
indicated by the letter `C'.  However, when both of these modes are
enabled, the line and column numbers are displayed in parentheses, the
line number first, rather than with `L' and `C'.  For example:
`(561,2)'.  *Note Minor Modes::, for more information about minor modes
and about how to use these commands.

   If you have narrowed the buffer (*note Narrowing::), the displayed
line number is relative to the accessible portion of the buffer.  Thus,
it isn't suitable as an argument to `goto-line'.  (Use `what-line'
command to see the line number relative to the whole file.)

   If the buffer is very large (larger than the value of
`line-number-display-limit'), Emacs won't compute the line number,
because that would be too slow; therefore, the line number won't appear
on the mode-line.  To remove this limit, set
`line-number-display-limit' to `nil'.

   Line-number computation can also be slow if the lines in the buffer
are too long.  For this reason, Emacs doesn't display line numbers if
the average width, in characters, of lines near point is larger than
the value of `line-number-display-limit-width'.  The default value is
200 characters.

   Emacs can optionally display the time and system load in all mode
lines.  To enable this feature, type `M-x display-time' or customize
the option `display-time-mode'.  The information added to the mode line
usually appears after the buffer name, before the mode names and their
parentheses.  It looks like this:

     HH:MMpm L.LL

Here HH and MM are the hour and minute, followed always by `am' or
`pm'.  L.LL is the average number, collected for the last few minutes,
of processes in the whole system that were either running or ready to
run (i.e. were waiting for an available processor).  (Some fields may
be missing if your operating system cannot support them.)  If you
prefer time display in 24-hour format, set the variable
`display-time-24hr-format' to `t'.

   The word `Mail' appears after the load level if there is mail for
you that you have not read yet.  On a graphical display you can use an
icon instead of `Mail' by customizing `display-time-use-mail-icon';
this may save some space on the mode line.  You can customize
`display-time-mail-face' to make the mail indicator prominent.  Use
`display-time-mail-file' to specify the mail file to check, or set
`display-time-mail-directory' to specify the directory to check for
incoming mail (any nonempty regular file in the directory is considered
as "newly arrived mail").

   When running Emacs on a laptop computer, you can display the battery
charge on the mode-line, by using the command `display-battery-mode' or
customizing the variable `display-battery-mode'.  The variable
`battery-mode-line-format' determines the way the battery charge is
displayed; the exact mode-line message depends on the operating system,
and it usually shows the current battery charge as a percentage of the
total charge.

   By default, the mode line is drawn on graphics displays with
3D-style highlighting, like that of a button when it is not being
pressed.  If you don't like this effect, you can disable the 3D
highlighting of the mode line, by customizing the attributes of the
`mode-line' face.  *Note Face Customization::.

   By default, the mode line of nonselected windows is displayed in a
different face, called `mode-line-inactive'.  Only the selected window
is displayed in the `mode-line' face.  This helps show which window is
selected.  When the minibuffer is selected, since it has no mode line,
the window from which you activated the minibuffer has its mode line
displayed using `mode-line'; as a result, ordinary entry to the
minibuffer does not change any mode lines.

   You can disable use of `mode-line-inactive' by setting variable
`mode-line-in-non-selected-windows' to `nil'; then all mode lines are
displayed in the `mode-line' face.

   You can customize the mode line display for each of the end-of-line
formats by setting each of the variables `eol-mnemonic-unix',
`eol-mnemonic-dos', `eol-mnemonic-mac', and `eol-mnemonic-undecided' to
the strings you prefer.


File: emacs,  Node: Text Display,  Next: Cursor Display,  Prev: Optional Mode Line,  Up: Display

18.15 How Text Is Displayed
===========================

ASCII printing characters (octal codes 040 through 0176) in Emacs
buffers are displayed with their graphics, as are non-ASCII multibyte
printing characters (octal codes above 0400).

   Some ASCII control characters are displayed in special ways.  The
newline character (octal code 012) is displayed by starting a new line.
The tab character (octal code 011) is displayed by moving to the next
tab stop column (normally every 8 columns).  The number of spaces per
tab is controlled by the variable `tab-width', which must have an
integer value between 1 and 1000, inclusive, and is made buffer-local
by changing it.  Note that how the tab character in the buffer is
displayed has nothing to do with the definition of <TAB> as a command.

   Other ASCII control characters are normally displayed as a caret
(`^') followed by the non-control version of the character; thus,
control-A is displayed as `^A'.  The caret appears in face
`escape-glyph'.

   Non-ASCII characters 0200 through 0237 (octal) are displayed with
octal escape sequences; thus, character code 0230 (octal) is displayed
as `\230'.  The backslash appears in face `escape-glyph'.

   If the variable `ctl-arrow' is `nil', control characters in the
buffer are displayed with octal escape sequences, except for newline
and tab.  Altering the value of `ctl-arrow' makes it local to the
current buffer; until that time, the default value is in effect.  The
default is initially `t'.

   The display of character codes 0240 through 0377 (octal) may be
either as escape sequences or as graphics.  They do not normally occur
in multibyte buffers, but if they do, they are displayed as Latin-1
graphics.  In unibyte mode, if you enable European display they are
displayed using their graphics (assuming your terminal supports them),
otherwise as escape sequences.  *Note Unibyte Mode::.

   Some character sets define "no-break" versions of the space and
hyphen characters, which are used where a line should not be broken.
Emacs normally displays these characters with special faces
(respectively, `nobreak-space' and `escape-glyph') to distinguish them
from ordinary spaces and hyphens.  You can turn off this feature by
setting the variable `nobreak-char-display' to `nil'.  If you set the
variable to any other value, that means to prefix these characters with
an escape character.

   You can customize the way any particular character code is displayed
by means of a display table.  *Note Display Tables: (elisp)Display
Tables.


File: emacs,  Node: Cursor Display,  Next: Line Truncation,  Prev: Text Display,  Up: Display

18.16 Displaying the Cursor
===========================

You can customize the cursor's color, and whether it blinks, using the
`cursor' Custom group (*note Easy Customization::).  On a graphical
display, the command `M-x blink-cursor-mode' enables or disables the
blinking of the cursor.  (On text terminals, the terminal itself blinks
the cursor, and Emacs has no control over it.)  You can control how the
cursor appears when it blinks off by setting the variable
`blink-cursor-alist'.

   Some text terminals offer two different cursors: the normal cursor
and the very visible cursor, where the latter may be e.g. bigger or
blinking.  By default Emacs uses the very visible cursor, and switches
to it when you start or resume Emacs.  If the variable `visible-cursor'
is `nil' when Emacs starts or resumes, it doesn't switch, so it uses
the normal cursor.

   Normally, the cursor appears in non-selected windows without
blinking, with the same appearance as when the blinking cursor blinks
"off."  For a box cursor, this is a hollow box; for a bar cursor, this
is a thinner bar.  To turn off cursors in non-selected windows,
customize the variable `cursor-in-non-selected-windows' and assign it a
`nil' value.

   On graphical displays, Emacs can optionally draw the block cursor as
wide as the character under the cursor--for example, if the cursor is
on a tab character, it would cover the full width occupied by that tab
character.  To enable this feature, set the variable `x-stretch-cursor'
to a non-`nil' value.

   To make the cursor even more visible, you can use HL Line mode, a
minor mode that highlights the line containing point.  Use `M-x
hl-line-mode' to enable or disable it in the current buffer.  `M-x
global-hl-line-mode' enables or disables the same mode globally.


File: emacs,  Node: Line Truncation,  Next: Visual Line Mode,  Prev: Cursor Display,  Up: Display

18.17 Truncation of Lines
=========================

As an alternative to continuation (*note Continuation Lines::), Emacs
can display long lines by "truncation".  This means that all the
characters that do not fit in the width of the screen or window do not
appear at all.  On graphical displays, a small straight arrow in the
fringe indicates truncation at either end of the line.  On text-only
terminals, `$' appears in the first column when there is text truncated
to the left, and in the last column when there is text truncated to the
right.

   Horizontal scrolling automatically causes line truncation (*note
Horizontal Scrolling::).  You can explicitly enable line truncation for
a particular buffer with the command `M-x toggle-truncate-lines'.  This
works by locally changing the variable `truncate-lines'.  If that
variable is non-`nil', long lines are truncated; if it is `nil', they
are continued onto multiple screen lines.  Setting the variable
`truncate-lines' in any way makes it local to the current buffer; until
that time, the default value is in effect.  The default value is
normally `nil'.

   If the variable `truncate-partial-width-windows' is non-`nil', it
forces truncation rather than continuation in any window less than the
full width of the screen or frame, regardless of the value of
`truncate-lines'.  See also *note Display: (elisp)Display.

   If the variable `overflow-newline-into-fringe' is non-`nil' on a
graphical display, then Emacs does not continue or truncate a line
which is exactly as wide as the window.  Instead, the newline overflows
into the right fringe, and the cursor appears in the fringe when
positioned on that newline.


File: emacs,  Node: Visual Line Mode,  Next: Display Custom,  Prev: Line Truncation,  Up: Display

18.18 Visual Line Mode
======================

Another alternative to ordinary line continuation is to use "word
wrap".  Here, each long logical line is divided into two or more screen
lines, like in ordinary line continuation.  However, Emacs attempts to
wrap the line at word boundaries near the right window edge.  This
makes the text easier to read, as wrapping does not occur in the middle
of words.

   Word wrap is enabled by Visual Line mode, an optional minor mode.
To turn on Visual Line mode in the current buffer, type `M-x
visual-line-mode'; repeating this command turns it off.  You can also
turn on Visual Line mode using the menu bar: in the Options menu,
select the `Line Wrapping in this Buffer' submenu, followed by the
`Word Wrap (Visual Line Mode)' menu item.  While Visual Line mode is
enabled, the mode-line shows the string `wrap' in the mode display.
The command `M-x global-visual-line-mode' toggles Visual Line mode in
all buffers.

   In Visual Line mode, some editing commands work on screen lines
instead of logical lines: `C-a' (`beginning-of-visual-line') moves to
the beginning of the screen line, `C-e' (`end-of-visual-line') moves to
the end of the screen line, and `C-k' (`kill-visual-line') kills text
to the end of the screen line.

   To move by logical lines, use the commands `M-x next-logical-line'
and `M-x previous-logical-line'.  These move point to the next logical
line and the previous logical line respectively, regardless of whether
Visual Line mode is enabled.  If you use these commands frequently, it
may be convenient to assign key bindings to them.  *Note Init
Rebinding::.

   By default, word-wrapped lines do not display fringe indicators.
Visual Line mode is often used to edit files that contain many long
logical lines, so having a fringe indicator for each wrapped line would
be visually distracting.  You can change this by customizing the
variable `visual-line-fringe-indicators'.


File: emacs,  Node: Display Custom,  Prev: Visual Line Mode,  Up: Display

18.19 Customization of Display
==============================

This section describes variables (*note Variables::) that you can
change to customize how Emacs displays.  Beginning users can skip it.

   If the variable `visible-bell' is non-`nil', Emacs attempts to make
the whole screen blink when it would normally make an audible bell
sound.  This variable has no effect if your terminal does not have a way
to make the screen blink.

   The variable `echo-keystrokes' controls the echoing of
multi-character keys; its value is the number of seconds of pause
required to cause echoing to start, or zero, meaning don't echo at all.
The value takes effect when there is someting to echo.  *Note Echo
Area::.

   The variable `baud-rate' holds the output speed of the terminal.
Setting this variable does not change the speed of actual data
transmission, but the value is used for calculations.  On text-only
terminals, it affects padding, and decisions about whether to scroll
part of the screen or redraw it instead.  It also affects the behavior
of incremental search.  On graphical displays, `baud-rate' is only used
to determine how frequently to look for pending input during display
updating.  A higher value of `baud-rate' means that check for pending
input will be done less frequently.

   On graphical displays, Emacs displays the mouse pointer as an
hourglass if Emacs is busy.  To disable this feature, set the variable
`display-hourglass' to `nil'.  The variable `hourglass-delay'
determines the number of seconds of "busy time" before the hourglass is
shown; the default is 1.

   If the mouse pointer lies inside an Emacs frame, Emacs makes it
invisible each time you type a character to insert text, to prevent it
from obscuring the text.  (To be precise, the hiding occurs when you
type a "self-inserting" character.  *Note Inserting Text::.)  Moving
the mouse pointer makes it visible again.  To disable this feature, set
the variable `make-pointer-invisible' to `nil'.

   On graphical displays, the variable `underline-minimum-offset'
determines the minimum distance between the baseline and underline, in
pixels, for underlined text.  By default, the value is 1; increasing it
may improve the legibility of underlined text for certain fonts.
(However, Emacs will never draw the underline below the current line
area.)  The variable `x-underline-at-descent-line' determines how to
draw underlined text.  The default is `nil', which means to draw it at
the baseline level of the font; if you change it to `nil', Emacs draws
the underline at the same height as the font's descent line.

   The variable `overline-margin' specifies the vertical position of an
overline above the text, including the height of the overline itself,
in pixels; the default is 2.

   On some text-only terminals, bold face and inverse video together
result in text that is hard to read.  Call the function
`tty-suppress-bold-inverse-default-colors' with a non-`nil' argument to
suppress the effect of bold-face in this case.

   On a text-only terminal, when you reenter Emacs after suspending,
Emacs normally clears the screen and redraws the entire display.  On
some terminals with more than one page of memory, it is possible to
arrange the termcap entry so that the `ti' and `te' strings (output to
the terminal when Emacs is entered and exited, respectively) switch
between pages of memory so as to use one page for Emacs and another
page for other output.  On such terminals, you might want to set the
variable `no-redraw-on-reenter' non-`nil'; this tells Emacs to assume,
when resumed, that the screen page it is using still contains what
Emacs last wrote there.


File: emacs,  Node: Search,  Next: Fixit,  Prev: Display,  Up: Top

19 Searching and Replacement
****************************

Like other editors, Emacs has commands to search for occurrences of a
string.  Emacs also has commands to replace occurrences of a string
with a different string.  There are also commands that do the same
thing, but search for patterns instead of fixed strings.

   You can also search multiple files under the control of a tags table
(*note Tags Search::) or through the Dired `A' command (*note Operating
on Files::), or ask the `grep' program to do it (*note Grep
Searching::).

* Menu:

* Incremental Search::        Search happens as you type the string.
* Nonincremental Search::     Specify entire string and then search.
* Word Search::               Search for sequence of words.
* Regexp Search::             Search for match for a regexp.
* Regexps::                   Syntax of regular expressions.
* Regexp Backslash::          Regular expression constructs starting with `\'.
* Regexp Example::            A complex regular expression explained.
* Search Case::               To ignore case while searching, or not.
* Replace::                   Search, and replace some or all matches.
* Other Repeating Search::    Operating on all matches for some regexp.


File: emacs,  Node: Incremental Search,  Next: Nonincremental Search,  Up: Search

19.1 Incremental Search
=======================

The principal search command in Emacs is "incremental": it begins
searching as soon as you type the first character of the search string.
As you type in the search string, Emacs shows you where the string (as
you have typed it so far) would be found.  When you have typed enough
characters to identify the place you want, you can stop.  Depending on
what you plan to do next, you may or may not need to terminate the
search explicitly with <RET>.

`C-s'
     Incremental search forward (`isearch-forward').

`C-r'
     Incremental search backward (`isearch-backward').

* Menu:

* Basic Isearch::       Basic incremental search commands.
* Repeat Isearch::      Searching for the same string again.
* Error in Isearch::    When your string is not found.
* Special Isearch::     Special input in incremental search.
* Isearch Yank::        Commands that grab text into the search string
                          or else edit the search string.
* Isearch Scroll::      Scrolling during an incremental search.
* Isearch Minibuffer::  Incremental search of the minibuffer history.
* Slow Isearch::        Incremental search features for slow terminals.


File: emacs,  Node: Basic Isearch,  Next: Repeat Isearch,  Up: Incremental Search

19.1.1 Basics of Incremental Search
-----------------------------------

`C-s'
     Begin incremental search (`isearch-forward').

`C-r'
     Begin reverse incremental search (`isearch-backward').

   `C-s' (`isearch-forward') starts a forward incremental search.  It
reads characters from the keyboard, and moves point just past the end
of the next occurrence of those characters in the buffer.

   For instance, if you type `C-s' and then `F', that puts the cursor
after the first `F' that occurs in the buffer after the starting point.
Then if you then type `O', the cursor moves to just after the first
`FO'; the `F' in that `FO' might not be the first `F' previously found.
After another `O', the cursor moves to just after the first `FOO'.

   At each step, Emacs highlights the "current match"--the buffer text
that matches the search string--using the `isearch' face (*note
Faces::).  The current search string is also displayed in the echo area.

   If you make a mistake typing the search string, type <DEL>.  Each
<DEL> cancels the last character of the search string.

   When you are satisfied with the place you have reached, type <RET>.
This stops searching, leaving the cursor where the search brought it.
Also, any command not specially meaningful in searches stops the
searching and is then executed.  Thus, typing `C-a' exits the search
and then moves to the beginning of the line.  <RET> is necessary only
if the next command you want to type is a printing character, <DEL>,
<RET>, or another character that is special within searches (`C-q',
`C-w', `C-r', `C-s', `C-y', `M-y', `M-r', `M-c', `M-e', and some others
described below).

   As a special exception, entering <RET> when the search string is
empty launches nonincremental search (*note Nonincremental Search::).

   When you exit the incremental search, it adds the original value of
point to the mark ring, without activating the mark; you can thus use
`C-u C-<SPC>' to return to where you were before beginning the search.
*Note Mark Ring::.  It only does this if the mark was not already
active.

   To search backwards, use `C-r' (`isearch-backward') instead of `C-s'
to start the search.  A backward search finds matches that end before
the starting point, just as a forward search finds matches that begin
after it.


File: emacs,  Node: Repeat Isearch,  Next: Error in Isearch,  Prev: Basic Isearch,  Up: Incremental Search

19.1.2 Repeating Incremental Search
-----------------------------------

Suppose you search forward for `FOO' and find a match, but not the one
you expected to find: the `FOO' you were aiming for occurs later in the
buffer.  In this event, type another `C-s' to move to the next
occurrence of the search string.  You can repeat this any number of
times.  If you overshoot, you can cancel some `C-s' characters with
<DEL>.  Similarly, each `C-r' in a backward incremental search repeats
the backward search.

   If you pause for a little while during incremental search, Emacs
highlights all the other possible matches for the search string that
are present on the screen.  This helps you anticipate where you can get
to by typing `C-s' or `C-r' to repeat the search.  The other matches
are highlighted differently from the current match, using the
customizable face `lazy-highlight' (*note Faces::).  If you don't like
this feature, you can disable it by setting `isearch-lazy-highlight' to
`nil'.

   After exiting a search, you can search for the same string again by
typing just `C-s C-s'.  The first `C-s' is the key that invokes
incremental search, and the second `C-s' means "search again."
Similarly, `C-r C-r' searches backward for the last search string.  In
determining the last search string, it doesn't matter whether the
string was searched for with `C-s' or `C-r'.

   If you are searching forward but you realize you were looking for
something before the starting point, type `C-r' to switch to a backward
search, leaving the search string unchanged.  Similarly, `C-s' in a
backward search switches to a forward search.

   If a search is failing and you ask to repeat it by typing another
`C-s', it starts again from the beginning of the buffer.  Repeating a
failing reverse search with `C-r' starts again from the end.  This is
called "wrapping around", and `Wrapped' appears in the search prompt
once this has happened.  If you keep on going past the original
starting point of the search, it changes to `Overwrapped', which means
that you are revisiting matches that you have already seen.

   To reuse earlier search strings, use the "search ring".  The
commands `M-p' and `M-n' move through the ring to pick a search string
to reuse.  These commands leave the selected search ring element in the
minibuffer, where you can edit it.  To edit the current search string
in the minibuffer without replacing it with items from the search ring,
type `M-e'.  Type `C-s' or `C-r' to terminate editing the string and
search for it.


File: emacs,  Node: Error in Isearch,  Next: Special Isearch,  Prev: Repeat Isearch,  Up: Incremental Search

19.1.3 Errors in Incremental Search
-----------------------------------

If your string is not found at all, the echo area says `Failing
I-Search'.  The cursor is after the place where Emacs found as much of
your string as it could.  Thus, if you search for `FOOT', and there is
no `FOOT', you might see the cursor after the `FOO' in `FOOL'.  In the
echo area, the part of the search string that failed to match is
highlighted using the customizable face `isearch-fail'.

   At this point, there are several things you can do.  If your string
was mistyped, you can use <DEL> to erase some of it and correct it.  If
you like the place you have found, you can type <RET> to remain there.
Or you can type `C-g', which removes from the search string the
characters that could not be found (the `T' in `FOOT'), leaving those
that were found (the `FOO' in `FOOT').  A second `C-g' at that point
cancels the search entirely, returning point to where it was when the
search started.

   The quit command, `C-g', does special things during searches; just
what it does depends on the status of the search.  If the search has
found what you specified and is waiting for input, `C-g' cancels the
entire search, moving the cursor back to where you started the search.
If `C-g' is typed when there are characters in the search string that
have not been found--because Emacs is still searching for them, or
because it has failed to find them--then the search string characters
which have not been found are discarded from the search string.  With
them gone, the search is now successful and waiting for more input, so
a second `C-g' will cancel the entire search.


File: emacs,  Node: Special Isearch,  Next: Isearch Yank,  Prev: Error in Isearch,  Up: Incremental Search

19.1.4 Special Input for Incremental Search
-------------------------------------------

Some of the characters you type during incremental search have special
effects.

   If the search string you entered contains only lower-case letters,
the search is case-insensitive; as long as an upper-case letter exists
in the search string, the search becomes case-sensitive.  If you delete
the upper-case character from the search string, it ceases to have this
effect.  *Note Search Case::.

   To search for a newline character, type `C-j'.

   To search for other control characters, such as <control-S>, quote
it by typing `C-q' first (*note Inserting Text::).  To search for
non-ASCII characters, you can either use `C-q' and enter its octal
code, or use an input method (*note Input Methods::).  If an input
method is enabled in the current buffer when you start the search, you
can use it in the search string also.  While typing the search string,
you can toggle the input method with the command `C-\'
(`isearch-toggle-input-method').  You can also turn on a non-default
input method with `C-^' (`isearch-toggle-specified-input-method'),
which prompts for the name of the input method.  When an input method
is active during incremental search, the search prompt includes the
input method mnemonic, like this:

     I-search [IM]:

where IM is the mnemonic of the active input method.  Any input method
you enable during incremental search remains enabled in the current
buffer afterwards.

   Typing `M-%' in incremental search invokes `query-replace' or
`query-replace-regexp' (depending on search mode) with the current
search string used as the string to replace.  *Note Query Replace::.

   Typing `M-<TAB>' in incremental search invokes `isearch-complete',
which attempts to complete the search string using the search ring as a
list of completion alternatives.  *Note Completion::.  In many
operating systems, the `M-<TAB>' key sequence is captured by the window
manager; you then need to rebind `isearch-complete' to another key
sequence if you want to use it (*note Rebinding::).

   When incremental search is active, you can type `C-h C-h' to access
interactive help options, including a list of special keybindings.
These keybindings are part of the keymap `isearch-mode-map' (*note
Keymaps::).


File: emacs,  Node: Isearch Yank,  Next: Isearch Scroll,  Prev: Special Isearch,  Up: Incremental Search

19.1.5 Isearch Yanking
----------------------

Within incremental search, you can use `C-w' and `C-y' to grab text
from the buffer into the search string.  This makes it convenient to
search for another occurrence of text at point.

   `C-w' copies the character or word after point and adds it to the
search string, advancing point over it.  (The decision, whether to copy
a character or a word, is heuristic.)

   `C-y' is similar to `C-w' but copies all the rest of the current
line into the search string.  If point is already at the end of a line,
it grabs the entire next line.  If the search is currently
case-insensitive, both `C-y' and `C-w' convert the text they copy to
lower case, so that the search remains case-insensitive.

   `C-M-w' and `C-M-y' modify the search string by only one character
at a time: `C-M-w' deletes the last character from the search string
and `C-M-y' copies the character after point to the end of the search
string.  An alternative method to add the character after point into
the search string is to enter the minibuffer by `M-e' and to type `C-f'
at the end of the search string in the minibuffer.

   The character `M-y' copies text from the kill ring into the search
string.  It uses the same text that `C-y' would yank.  `Mouse-2' in the
echo area does the same.  *Note Yanking::.


File: emacs,  Node: Isearch Scroll,  Next: Isearch Minibuffer,  Prev: Isearch Yank,  Up: Incremental Search

19.1.6 Scrolling During Incremental Search
------------------------------------------

You can enable the use of vertical scrolling during incremental search
(without exiting the search) by setting the customizable variable
`isearch-allow-scroll' to a non-`nil' value.  This applies to using the
vertical scroll-bar and to certain keyboard commands such as <prior>
(`scroll-down'), <next> (`scroll-up') and `C-l' (`recenter').  You must
run these commands via their key sequences to stay in the search--typing
`M-x' will terminate the search.  You can give prefix arguments to
these commands in the usual way.

   This feature won't let you scroll the current match out of
visibility, however.

   The feature also affects some other commands, such as `C-x 2'
(`split-window-vertically') and `C-x ^' (`enlarge-window') which don't
exactly scroll but do affect where the text appears on the screen.  In
general, it applies to any command whose name has a non-`nil'
`isearch-scroll' property.  So you can control which commands are
affected by changing these properties.

   For example, to make `C-h l' usable within an incremental search in
all future Emacs sessions, use `C-h c' to find what command it runs.
(You type `C-h c C-h l'; it says `view-lossage'.)  Then you can put the
following line in your `.emacs' file (*note Init File::):

     (put 'view-lossage 'isearch-scroll t)

This feature can be applied to any command that doesn't permanently
change point, the buffer contents, the match data, the current buffer,
or the selected window and frame.  The command must not itself attempt
an incremental search.


File: emacs,  Node: Isearch Minibuffer,  Next: Slow Isearch,  Prev: Isearch Scroll,  Up: Incremental Search

19.1.7 Searching the Minibuffer
-------------------------------

If you start an incremental search while the minibuffer is active,
Emacs searches the contents of the minibuffer.  Unlike searching an
ordinary buffer, the search string is not shown in the echo area,
because that is used to display the minibuffer.

   If an incremental search fails in the minibuffer, it tries searching
the minibuffer history.  *Note Minibuffer History::.  You can visualize
the minibuffer and its history as a series of "pages", with the
earliest history element on the first page and the current minibuffer
on the last page.  A forward search, `C-s', searches forward to later
pages; a reverse search, `C-r', searches backwards to earlier pages.
Like in ordinary buffer search, a failing search can wrap around, going
from the last page to the first page or vice versa.

   When the current match is on a history element, that history element
is pulled into the minibuffer.  If you exit the incremental search
normally (e.g. by typing <RET>), it remains in the minibuffer
afterwards.  Cancelling the search, with `C-g', restores the contents
of the minibuffer when you began the search.


File: emacs,  Node: Slow Isearch,  Prev: Isearch Minibuffer,  Up: Incremental Search

19.1.8 Slow Terminal Incremental Search
---------------------------------------

Incremental search on a slow terminal uses a modified style of display
that is designed to take less time.  Instead of redisplaying the buffer
at each place the search gets to, it creates a new single-line window
and uses that to display the line that the search has found.  The
single-line window comes into play as soon as point moves outside of
the text that is already on the screen.

   When you terminate the search, the single-line window is removed.
Emacs then redisplays the window in which the search was done, to show
its new position of point.

   The slow terminal style of display is used when the terminal baud
rate is less than or equal to the value of the variable
`search-slow-speed', initially 1200.  See also the discussion of the
variable `baud-rate' (*note Customization of Display: baud-rate.).

   The number of lines to use in slow terminal search display is
controlled by the variable `search-slow-window-lines'.  Its normal
value is 1.

