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GNU Info File | 1994-09-21 | 51KB | 901 lines

This is Info file ../info/lemacs, produced by Makeinfo-1.55 from the input file lemacs.txi. This file documents the GNU Emacs editor. Copyright (C) 1985, 1986, 1988 Richard M. Stallman. Copyright (C) 1991, 1992 Lucid, Inc. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided also that the sections entitled "The GNU Manifesto", "Distribution" and "GNU General Public License" are included exactly as in the original, and provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that the sections entitled "The GNU Manifesto", "Distribution" and "GNU General Public License" may be included in a translation approved by the author instead of in the original English. File: lemacs, Node: Character Representation, Next: Commands, Prev: Super and Hyper Keys, Up: Keystrokes Representation of Characters ============================ This section briefly discusses how characters are represented in Emacs buffers. *Note Key Sequences:: for information on representing key sequences to create key bindings. ASCII graphic characters in Emacs buffers are displayed with their graphics. LFD is the same as a newline character; it is displayed by starting a new line. TAB is displayed by moving to the next tab stop column (usually every 8 spaces). Other control characters are displayed as a caret (`^') followed by the non-control version of the character; thus, `C-a' is displayed as `^A'. Non-ASCII characters 128 and up are displayed with octal escape sequences; thus, character code 243 (octal), also called `M-#' when used as an input character, is displayed as `\243'. The variable `ctl-arrow' may be used to alter this behavior. *Note Display Vars::. File: lemacs, Node: Commands, Next: Pull-down Menus, Prev: Character Representation, Up: Top 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 "functions", and then gives keys their meanings by "binding" them to functions. A function is a Lisp object that can be executed as a program. Usually it is a Lisp symbol that has been given a function definition; every symbol has a name, usually made of a few English words separated by dashes, such as `next-line' or `forward-word'. It also has a "definition", which is a Lisp program. Only some functions can be the bindings of keys; these are functions whose definitions use `interactive' to specify how to call them interactively. Such functions are called "commands", and their names are "command names". More information on this subject will appear in the GNU Emacs Lisp Manual. The bindings between keys and functions are recorded in various tables called "keymaps". *Note Key Bindings:: for more information on key sequences you can bind commands to. *Note Keymaps:: for information on creating keymaps. When we say "`C-n' moves down vertically one line" we are glossing over a distinction that is irrelevant in ordinary use but is vital in understanding how to customize Emacs. The function `next-line' is programmed to move down vertically. `C-n' has this effect because it is bound to that function. If you rebind `C-n' to the function `forward-word' then `C-n' will move forward by words instead. Rebinding keys is a common method of customization. The rest of this manual usually ignores this subtlety to keep things simple. To give the customizer the information needed, we often state the name of the command that 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 `next-line' is a command that moves vertically down and `C-n' is a key that is standardly bound to it. While we are on the subject of information for customization only, it's a good time to 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 remember a value. Most of the variables documented in this manual exist just to facilitate customization: some command or other part of Emacs uses the variable and behaves differently depending on its setting. Until you are interested in customizing, you can ignore the information about variables. When you are ready to be interested, read the basic information on variables, then the information on individual variables will make sense. *Note Variables::. File: lemacs, Node: Pull-down Menus, Next: Mouse Selection, Prev: Commands, Up: Top Lucid GNU Emacs Pull-down Menus =============================== If you are running Lucid GNU Emacs under X, a menu bar on top of the Emacs screen provides access to pull-down menus of file, edit, and help-related commands. The menus provide convenient shortcuts and an easy interface for novice users. They do not provide additions to the functionality available via key commands; you can still invoke commands from the keyboard as in previous versions of Emacs. Perform file and buffer-related operations, such as opening and closing files, saving and printing buffers, as well as exiting Emacs. Perform standard editing operations, such as cutting, copying, pasting and killing selected text. Buffers Present a menu of buffers for selection as well as the option to display a buffer list. Access to Emacs Info. There are two ways of selecting an item from a pull-down menu: * Select an item in the menu bar by moving the cursor over it and click the left mouse-button. Then move the cursor over the item you want to choose and click left again. * Select an item in the menu bar by moving the cursor over it and click and hold the left mouse-button. With the mouse-button depressed, move the cursor over the item you want, then release it to make your selection. If a command in the pull-down menu is not applicable in a given situation, the command is disabled and its name appears faded. You cannot invoke items that are faded. For example, most commands on the Edit menu appear faded until you select text on which they are to operate; after you select a block of text, edit commands are enabled. *Note Mouse Selection:: for information on using the mouse to select text. *Note Using X Selections:: for related information. There are also `M-x' equivalents for each menu item. To find the equivalent for any left-button menu item, do the following: 1. Type `C-h k' to get the `Describe Key' prompt. 2. Select the menu item and click. Emacs displays the function associated with the menu item in a separate window, usually together with some documentation. * Menu: * File Menu:: Items on the File menu. * Edit Menu:: Items on the Edit menu. * Buffers Menu:: Information about the Buffers menu * Help Menu:: Items on the Help menu. * Menu Customization:: Adding and removing menu items and related operations. File: lemacs, Node: File Menu, Next: Edit Menu, Prev: Pull-down Menus, Up: Pull-down Menus The File Menu ............. The File menu bar item contains the items New Screen, Open File..., Save Buffer, Save Buffer As..., Revert Buffer, Print Buffer, Delete Screen, Kill Buffer and Exit Emacs on the pull-down menu. If you select a menu item, Emacs executes the equivalent command. New Screen Creates a new Emacs screen, that is, a new X window running under the same Emacs process. You can remove the screen using the Delete Screen menu item. When you remove the last screen, you exit Emacs and are prompted for confirmation. This is bound to `C-x 5' by default. Open File... Prompts you for a filename and loads that file into a new buffer. Open File... is equivalent to the Emacs command `find-file' (`C-x C-f'). Save Buffer Writes and saves the current Emacs buffer as the latest version of the current visited file. Save Buffer is equivalent to the Emacs command `save-buffer' (`C-x C-s'). Save Buffer As... Writes and saves the current Emacs buffer to the filename you specify. Save Buffer As... is equivalent to the Emacs command `write-file' (`C-x C-w'). Revert Buffer Restores the last saved version of the file to the current buffer. When you edit a buffer containing a text file, you must save the buffer before your changes become effective. Use Revert Buffer if you do not want to keep the changes you have made in the buffer. Revert Buffer is equivalent to the Emacs command `revert-file' (`M-x revert-buffer'). Print Buffer Prints a hardcopy of the current buffer. Equivalent to the Emacs command `print-buffer' (`M-x print-buffer'). Delete Screen Allows you to close all but one of the screens created by New Screen. If you created several Emacs screens belonging to the same Emacs process, you can close all but one of them. When you attempt to close the last screen, Emacs informs you that you are attempting to delete the last screen. You have to choose Exit Emacs for that. Kill Buffer... Prompts you for the name of a buffer to kill. The default is the name of the currently selected buffer. Kill Buffer is equivalent to the Emacs command `kill-buffer' (`C-x k'). Exit Emacs Shuts down (kills) the Emacs process. Equivalent to the Emacs command `save-buffers-kill-emacs' (`C-x C-c'). Before killing the Emacs process, the system asks which unsaved buffers to save by going through the list of all buffers in that Emacs process. File: lemacs, Node: Edit Menu, Next: Buffers Menu, Prev: File Menu, Up: Pull-down Menus The Edit Menu ............. The Edit pull-down menu contains the Undo, Cut, Copy, Paste and Clear menu items. When you select a menu item, Emacs executes the equivalent command. Most commands on the Edit menu work on a block of text, the X selection. They appear faded until you select a block of text (activate a region) with the mouse. *Note Using X Selections::, *note Killing::., and *note Yanking::. for more information. Undoes the previous command. Undo is equivalent to the Emacs command `undo' (`C-x u'). Removes the selected text block from the current buffer, makes it the X clipboard selection, and places it in the kill ring. Before executing this command, you have to select a region using Emacs region selection commands or with the mouse. Makes a selected text block the X clipboard selection, and places it in the kill ring. You can select text using one of the Emacs region selection commands or select a text region with the mouse. Paste Inserts the current value of the X clipboard selection in the current buffer. Note that this is not necessarily the same as the Emacs `yank' command because the Emacs kill ring and the X clipboard selection are not the same thing. You can paste in text you have placed in the clipboard using Copy or Cut. You can also use Paste to insert text that was pasted into the clipboard from other applications. Clear Removes the selected text block from the current buffer but does not place it in the kill ring or the X clipboard selection. File: lemacs, Node: Buffers Menu, Next: Help Menu, Prev: Edit Menu, Up: Pull-down Menus The Buffers Menu ................ The Buffers menu provides a selection of up to ten buffers and the item List All Buffers, which provides a Buffer List. *Note List Buffers:: for more information. File: lemacs, Node: Help Menu, Next: Menu Customization, Prev: Buffers Menu, Up: Pull-down Menus The Help Menu ............. The Help Menu gives you access to Emacs Info and provides a menu equivalents for each of the choices you have when using `C-h'. *Note Help:: for more information. The Help menu also gives access to UNIX online manual pages via the UNIX Manual Page option. File: lemacs, Node: Menu Customization, Prev: Help Menu, Up: Pull-down Menus Customizing Lucid GNU Emacs Menus --------------------------------- You can customize any of the pull-down menus by adding or removing menu items and disabling or enabling existing menu items. The following functions are available: `add-menu: (MENU-PATH MENU-NAME MENU-ITEMS &OPTIONAL BEFORE)' Add a menu to the menubar or one of its submenus. `add-menu-item: (MENU-PATH ITEM-NAME FUNCTION ENABLED-P &OPTIONAL BEFORE)' Add a menu item to a menu, creating the menu first if necessary. `delete-menu-item: (PATH)' Remove the menu item defined by PATH from the menu hierarchy. `disable-menu-item: (PATH)' Disable the specified menu item. `enable-menu-item: (PATH)' Enable the specified previously disabled menu item. `relabel-menu-item: (PATH NEW-NAME)' Change the string of the menu item specified by PATH to NEW-NAME. Use the function `add-menu' to add a new menu or submenu. If a menu or submenu of the given name exists already, it is changed. MENU-PATH identifies the menu under which the new menu should be inserted. It is a list of strings; for example, `("File")' names the top-level File menu. `("File" "Foo")' names a hypothetical submenu of File. If MENU-PATH is `nil', the menu is added to the menubar itself. MENU-NAME is the string naming the menu to be added. MENU-ITEMS is a list of menu item descriptions. Each menu item should be a vector of three elements: * A string, which is the name of the menu item. * A symbol naming a command, or a form to evaluate. * `t' or `nil' to indicate whether the item is selectable. The optional argument BEFORE is the name of the menu before which the new menu or submenu should be added. If the menu is already present, it is not moved. The function `add-menu-item' adds a menu item to the specified menu, creating the menu first if necessary. If the named item already exists, the menu remains unchanged. MENU-PATH identifies the menu into which the new menu item should be inserted. It is a list of strings; for example, `("File")' names the top-level File menu. `("File" "Foo")' names a hypothetical submenu of File. ITEM-NAME is the string naming the menu item to add. FUNCTION is the command to invoke when this menu item is selected. If it is a symbol, it is invoked with `call-interactively', in the same way that functions bound to keys are invoked. If it is a list, the list is simply evaluated. ENABLED-P controls whether the item is selectable or not. For example, to make the `rename-file' command available from the File menu, use the following code: (add-menu-item '("File") "Rename File" 'rename-file t) To add a submenu of file management commands using a File Management item, use the following code: (add-menu-item '("File" "File Management") "Copy File" 'copy-file t) (add-menu-item '("File" "File Management") "Delete File" 'delete-file t) (add-menu-item '("File" "File Management") "Rename File" 'rename-file t) The optional BEFORE argument is the name of a menu item before which the new item should be added. If the item is already present, it is not moved. To remove a specified menu item from the menu hierarchy, use `delete-menu-item'. PATH is a list of strings that identify the position of the menu item in the menu hierarchy. `("File" "Save")' means the menu item called Save under the top level File menu. `("Menu" "Foo" "Item")' means the menu item called Item under the FOO submenu of MENU. To disable a menu item, use `disable-menu-item'. The disabled menu item is grayed and can no longer be selected. To make the item selectable again, use `enable-menu-item'. `disable-menu-item' and `enable-menu-item' both have the argument PATH. To change the string of the specified menu item, use `relabel-menu-item'. This function also takes the argument PATH. NEW-NAME is the string to which the menu item will be changed. File: lemacs, Node: Entering Emacs, Next: Exiting, Prev: Mouse Selection, Up: Top Entering and Exiting Emacs ************************** The usual way to invoke Emacs is to type `emacs RET' at the shell. To invoke Lucid GNU Emacs, type `lemacs RET'. Emacs clears the screen and then displays an initial advisory message and copyright notice. You can begin typing Emacs commands immediately afterward. Some operating systems insist on discarding all type-ahead when Emacs starts up; they give Emacs no way to prevent this. Therefore, it is wise to wait until Emacs clears the screen before typing the first editing command. Before Emacs reads the first command, you have not had a chance to give a command to specify a file to edit. Since Emacs must always have a current buffer for editing, it presents a buffer, by default, a buffer named `*scratch*'. The buffer is in Lisp Interaction mode; you can use it to type Lisp expressions and evaluate them, or you can ignore that capability and simply doodle. You can specify a different major mode for this buffer by setting the variable `initial-major-mode' in your init file. *Note Init File::. It is possible to give Emacs arguments in the shell command line to specify files to visit, Lisp files to load, and functions to call. File: lemacs, Node: Exiting, Next: Command Switches, Prev: Entering Emacs, Up: Top Exiting Emacs ============= There are two commands for exiting Emacs because there are two kinds of exiting: "suspending" Emacs and "killing" Emacs. "Suspending" means stopping Emacs temporarily and returning control to its superior (usually the shell), allowing you to resume editing later in the same Emacs job, with the same files, same kill ring, same undo history, and so on. This is the usual way to exit. "Killing" Emacs means destroying the Emacs job. You can run Emacs again later, but you will get a fresh Emacs; there is no way to resume the same editing session after it has been killed. `C-z' Suspend Emacs (`suspend-emacs'). If used under the X window system, shrink the X window containing the Emacs screen to an icon. (see below) `C-x C-c' Kill Emacs (`save-buffers-kill-emacs'). If you use Lucid GNU Emacs under the X window system, `C-z' shrinks the X window containing the Emacs screen to an icon. The Emacs process is stopped temporarily, and control is returned to the window manager. If more than one screen is associated with the Emacs process, only the screen from which you used `C-z' is retained. The X windows containing the other Emacs screens are closed. To activate the "suspended" Emacs, use the appropriate window manager mouse gestures. Usually left-clicking on the icon reactivates and reopens the X window containing the Emacs screen, but the window manager you use determines what exactly happens. To actually kill the Emacs process, use `C-x C-c' or the Exit Emacs item on the File menu. On systems that do not permit programs to be suspended, `C-z' runs an inferior shell that communicates directly with the terminal, and Emacs waits until you exit the subshell. On these systems, the only way to return to the shell from which Emacs was started (to log out, for example) is to kill Emacs. `C-d' or `exit' are typical commands to exit a subshell. To kill Emacs, type `C-x C-c' (`save-buffers-kill-emacs'). A two-character key is used for this to make it harder to type. In Lucid GNU Emacs, selecting the Exit Emacs option of the File menu is an alternate way of issuing the command. Unless a numeric argument is used, this command first offers to save any modified buffers. If you do not save all buffers, you are asked for reconfirmation with `yes' before killing Emacs, since any changes not saved will be lost. If any subprocesses are still running, `C-x C-c' asks you to confirm killing them, since killing Emacs kills the subprocesses simultaneously. In most programs running on Unix, certain characters may instantly suspend or kill the program. (In Berkeley Unix these characters are normally `C-z' and `C-c'.) This Unix 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 standard Berkeley Unix meanings of `C-z' and `C-c', but that is their only relationship with Unix. You could customize these keys to do anything (*note Keymaps::.). File: lemacs, Node: Command Switches, Next: Basic, Prev: Exiting, Up: Top Command Line Switches and Arguments =================================== GNU Emacs supports command line arguments you can use to request various actions when invoking Emacs. The commands are for compatibility with other editors and for sophisticated activities. If you are using Lucid GNU Emacs under the X window system, you can also use a number of standard Xt command line arguments. Command line arguments are not usually needed for editing with Emacs; new users can skip this section. Many editors are designed to be started afresh each time you want to edit. You start the editor to edit one file; then exit the editor. The next time you want to edit either another file or the same one, you start the editor again. Under these circumstances, it makes sense to use a command line argument to say which file to edit. The recommended way to use GNU Emacs is to start it only once, just after you log in, and do all your editing in the same Emacs process. Each time you want to edit a file, you visit it using the existing Emacs. Emacs creates a new buffer for each file and (unless you kill some of the buffers), Emacs eventually has many files in it ready for editing. Usually you do not kill the Emacs process until you are about to log out. Since you usually read files by typing commands to Emacs, command line arguments for specifying a file Emacs is started are seldom needed. Emacs accepts command-line arguments that specify files to visit, functions to call, and other activities and operating modes. If you are running Lucid GNU Emacs under the X window system, a number of standard Xt command line arguments are available as well. The following sections list: * Command line arguments that you can always use. * Command line arguments that have to appear at the beginning of the argument list. * Command line arguments that are only relevant if you are running Lucid GNU Emacs under X. Command line arguments are processed in the order they appear on the command line; however, certain arguments (the ones in the second table) must be at the front of the list if they are used. Here are the arguments allowed: `FILE' Visit FILE using `find-file'. *Note Visiting::. `+LINENUM FILE' Visit FILE using `find-file', then go to line number LINENUM in it. `-l FILE' `-load FILE' Load a file FILE of Lisp code with the function `load'. *Note Lisp Libraries::. `-f FUNCTION' `-funcall FUNCTION' Call Lisp function FUNCTION with no arguments. `-i FILE' `-insert FILE' Insert the contents of FILE into the current buffer. This is like what `M-x insert-buffer' does; *Note Misc File Ops::. `-kill' Exit from Emacs without asking for confirmation. `-version' Prints version information. This implies `-batch'. % emacs -version GNU Emacs 19.4 Lucid of Mon Dec 28 1992 on thalidomide (berkeley-unix) `-help' Prints a summary of command-line options, and exits. The following arguments are recognized only at the beginning of the command line. If more than one of them appears, they must appear in the order in which they appear in this table. `-t FILE' Use FILE instead of the terminal for input and output. (This option is currently not valid in Lucid GNU Emacs) `-batch' Run Emacs in "batch mode", which means that the text being edited is not displayed and the standard Unix interrupt characters such as `C-z' and `C-c' continue to have their normal effect. Emacs in batch mode outputs to `stderr' only what would normally be printed in the echo area under program control. Batch mode is used for running programs written in Emacs Lisp from shell scripts, makefiles, and so on. Normally the `-l' switch or `-f' switch will be used as well, to invoke a Lisp program to do the batch processing. `-batch' implies `-q' (do not load an init file). It also causes Emacs to kill itself after all command switches have been processed. In addition, auto-saving is not done except in buffers for which it has been explicitly requested. `-no-init-file' Do not load your Emacs init file `~/.emacs'. `-u USER' `-user USER' Load USER's Emacs init file `~USER/.emacs' instead of your own. Note that the init file can get access to the command line argument values as the elements of a list in the variable `command-line-args'. (The arguments in the second table above will already have been processed and will not be in the list.) The init file can override the normal processing of the other arguments by setting this variable. One way to use command switches is to visit many files automatically: emacs *.c passes each `.c' file as a separate argument to Emacs, so that Emacs visits each file (*note Visiting::.). Here is an advanced example that assumes you have a Lisp program file called `hack-c-program.el' which, when loaded, performs some useful operation on the current buffer, expected to be a C program. emacs -batch foo.c -l hack-c-program -f save-buffer -kill > log Here Emacs is told to visit `foo.c', load `hack-c-program.el' (which makes changes in the visited file), save `foo.c' (note that `save-buffer' is the function that `C-x C-s' is bound to), and then exit to the shell from which the command was executed. `-batch' guarantees there will be no problem redirecting output to `log', because Emacs will not assume that it has a display terminal to work with. If you are running Lucid GNU Emacs under X, a number of options are available to control color, border, and window title and icon name: `-T TITLE' `-wn TITLE' Use TITLE as the window title. This sets the `screen-title-format' variable, which controls the title of the X window corresponding to the selected screen. This is the same format as `mode-line-format'. `-in TITLE' `-iconname TITLE' Use TITLE as the icon name. This sets the `screen-icon-title-format' variable, which controls the title of the icon corresponding to the selected screen. `-mc COLOR' Use COLOR as the mouse color. `-cr COLOR' Use COLOR as the text-cursor foreground color. In addition, Lucid GNU Emacs allows you to use a number of standard Xt command line arguments. `-bg COLOR' `-background COLOR' Use COLOR as the background color. `-bd COLOR' `-bordercolor COLOR' Use COLOR as the border color. `-bw WIDTH' `-borderwidth WIDTH' Use WIDTH as the border width. `-d DISPLAY' `-display DISPLAY' `-d DISPLAY' When running under the X window system, create the window containing the Emacs screen on the display named DISPLAY. `-fg COLOR' `-foreground COLOR' Use COLOR as the foreground color. `-fn NAME' `-font NAME' Use NAME as the font. `-g SPEC' `-geom SPEC' `-geometry SPEC' Use the geometry specified by SPEC. `- iconic' Start up iconified. `-reverse' Bring up Emacs in reverse video. `-name' Use the resource manager specified by NAME. `-xrm' Read something into the resource database for this invocation of Emacs. `-title TITLE' Same as `-wn', sets the window title using `window-title-format'. File: lemacs, Node: Basic, Next: Undo, Prev: Command Switches, Up: Top Basic Editing Commands ********************** We now give the basics of how to enter text, make corrections, and save the text in a file. If this material is new to you, you might learn it more easily by running the Emacs learn-by-doing tutorial. To do this, type `Control-h t' (`help-with-tutorial'). Inserting Text ============== To insert printing characters into the text you are editing, just type them. This inserts the characters into the buffer at the cursor (that is, at "point"; *note Point::.). The cursor moves forward. Any characters after the cursor move forward too. If the text in the buffer is `FOOBAR', with the cursor before the `B' and you type `XX', the result is `FOOXXBAR', with the cursor still before the `B'. To "delete" text you have just inserted, use DEL. DEL deletes the character BEFORE the cursor (not the one that the cursor is on top of or under; that is the character AFTER the cursor). The cursor and all characters after it move backwards. Therefore, if you type a printing character and then type DEL, they cancel out. To end a line and start typing a new one, type RET. This inserts a newline character in the buffer. If point is in the middle of a line, RET splits the line. Typing DEL when the cursor is at the beginning of a line rubs out the newline before the line, thus joining the line with the preceding line. Emacs automatically splits lines when they become too long, if you turn on a special mode called "Auto Fill" mode. *Note Filling::, for information on using Auto Fill mode. Customization information: DEL, in most modes, runs the command `delete-backward-char'; RET runs the command `newline', and self-inserting printing characters run the command `self-insert', which inserts whatever character was typed to invoke it. Some major modes rebind DEL to other commands. Direct insertion works for printing characters and SPC, but other characters act as editing commands and do not insert themselves. If you need to insert a control character or a character whose code is above 200 octal, you must "quote" it by typing the character `control-q' (`quoted-insert') first. There are two ways to use `C-q': * `Control-q' followed by any non-graphic character (even `C-g') inserts that character. * `Control-q' followed by three octal digits inserts the character with the specified character code. A numeric argument to `C-q' specifies how many copies of the quoted character should be inserted (*note Arguments::.). If you prefer to have text characters replace (overwrite) existing text instead of moving it to the right, you can enable Overwrite mode, a minor mode. *Note Minor Modes::. Changing the Location of Point ============================== To do more than insert characters, you have to know how to move point (*note Point::.). Here are a few of the available commands. `C-a' Move to the beginning of the line (`beginning-of-line'). `C-e' Move to the end of the line (`end-of-line'). `C-f' Move forward one character (`forward-char'). `C-b' Move backward one character (`backward-char'). `M-f' Move forward one word (`forward-word'). `M-b' Move backward one word (`backward-word'). `C-n' Move down one line, vertically (`next-line'). This command attempts to keep the horizontal position unchanged, so if you start in the middle of one line, you end in the middle of the next. When on the last line of text, `C-n' creates a new line and moves onto it. `C-p' Move up one line, vertically (`previous-line'). `C-l' Clear the screen and reprint everything (`recenter'). Text moves on the screen to bring point to the center of the window. `M-r' Move point to left margin on the line halfway down the screen or window (`move-to-window-line'). Text does not move on the screen. A numeric argument says how many screen lines down from the top of the window (zero for the top). A negative argument counts from the bottom (-1 for the bottom). `C-t' Transpose two characters, the ones before and after the cursor (`transpose-chars'). `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'). `M-x goto-char' Read a number N and move the cursor to character number N. Position 1 is the beginning of the buffer. `M-x goto-line' Read a number N and move cursor to line number N. Line 1 is the beginning of the buffer. `C-x C-n' Use the current column of point as the "semi-permanent goal column" for `C-n' and `C-p' (`set-goal-column'). Henceforth, those commands always move to this column in each line moved into, or as close as possible given the contents of the line. This goal column remains in effect until canceled. `C-u C-x C-n' Cancel the goal column. Henceforth, `C-n' and `C-p' once again try to avoid changing the horizontal position, as usual. If you set the variable `track-eol' to a non-`nil' value, `C-n' and `C-p' move to the end of the line when at the end of the starting line. By default, `track-eol' is `nil'. Erasing Text ============ `DEL' Delete the character before the cursor (`delete-backward-char'). `C-d' Delete the character after the cursor (`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'). In contrast to the DEL key, which deletes the character before the cursor, `Control-d' deletes the character after the cursor, causing the rest of the text on the line to shift left. If `Control-d' is typed at the end of a line, that line and the next line are joined. To erase a larger amount of text, use `Control-k', which kills a line at a time. If you use `C-k' at the beginning or in the middle of a line, it kills all the text up to the end of the line. If you use `C-k' at the end of a line, it joins that line and the next line. *Note Killing::, for more flexible ways of killing text. Files ===== The commands above are sufficient for creating and altering text in an Emacs buffer. More advanced Emacs commands just make things easier. But 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 and which you can retrieve by name. To look at or use the contents of a file in any way, including editing the file with Emacs, you must specify the file name. Consider a file named `/usr/rms/foo.c'. To begin editing this file from Emacs, type C-x C-f /usr/rms/foo.c RET The file name is given as an "argument" to the command `C-x C-f' (`find-file'). The command uses the "minibuffer" to read the argument. You have to type RET to terminate the argument (*note Minibuffer::.). You can also use the Open File... menu item from the File menu, then type the name of the file to the prompt. Emacs obeys the command by "visiting" the file: it creates a buffer, copies the contents of the file into the buffer, and then displays the buffer for you to edit. You can make changes in the buffer, and then "save" the file by typing `C-x C-s' (`save-buffer') or choosing Save Buffer from the File menu. This makes the changes permanent by copying the altered contents of the buffer back into the file `/usr/rms/foo.c'. Until then, the changes are only inside your Emacs buffer, and the file `foo.c' is not changed. To create a file, visit the file with `C-x C-f' as if it already existed or choose Open File from the File menu and provide the name for the new file in the minibuffer. Emacs will create an empty buffer in which you can insert the text you want to put in the file. When you save the buffer with `C-x C-s', or by choosing Save Buffer from the File menu, the file is created. To learn more about using files, *note Files::.. If you forget what a key does, you can use the Help character, `C-h' to find out: Type `C-h k' followed by the key you want to know about. 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' three times to get a description of all the help facilities. *Note Help::. * Menu: * Blank Lines:: Commands to make or delete blank lines. * Continuation Lines:: Lines too wide for the screen. * Position Info:: What page, line, row, or column is point on? * Arguments:: Numeric arguments for repeating a command. File: lemacs, Node: Blank Lines, Next: Continuation Lines, Prev: Basic, Up: Basic Blank Lines =========== Here are special commands and techniques for entering and removing blank lines. `C-o' Insert one or more blank lines after the cursor (`open-line'). `C-x C-o' Delete all but one of many consecutive blank lines (`delete-blank-lines'). When you want to insert a new line of text before an existing line, you just type the new line of text, followed by RET. If you prefer to first create a blank line and then insert the desired text, use the key `C-o' (`open-line'), which inserts a newline after point but leaves point in front of the newline. Then type the text into the new line. `C-o F O O' has the same effect as `F O O RET', except for the final location of point. To create several blank lines, type `C-o' several times, or give `C-o' an argument indicating how many blank lines to create. *Note Arguments::, for more information. If you have many blank lines in a row and want to get rid of them, use `C-x C-o' (`delete-blank-lines'). If point is on a blank line which is adjacent to at least one other blank line, `C-x C-o' deletes all but one of the blank lines. If point is on a blank line with no other adjacent blank line, the sole blank line is deleted. If point is on a non-blank line, `C-x C-o' deletes any blank lines following that non-blank line. File: lemacs, Node: Continuation Lines, Next: Position Info, Prev: Blank Lines, Up: Basic Continuation Lines ================== If you add too many characters to one line without breaking with a RET, the line grows to occupy two (or more) screen lines, with a curved arrow at the extreme right margin of all but the last line. The curved arrow indicates that the following screen line is not really a distinct line in the text, but just the "continuation" of a line too long to fit the screen. You can use Auto Fill mode, (*note Filling::.), to have Emacs insert newlines automatically when a line gets too long. Instead of continuation, long lines can be displayed 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. They remain in the buffer, temporarily invisible. Three diagonal dots in the last column (instead of the curved arrow inform you that truncation is in effect. To turn off continuation for a particular buffer set the variable `truncate-lines' to non-`nil' in that buffer. Truncation instead of continuation also happens whenever horizontal scrolling is in use, and optionally whenever side-by-side windows are in use (*note Windows::.). Altering the value of `truncate-lines' makes it local to the current buffer; until that time, the default value is in effect. The default is initially `nil'. *Note Locals::. File: lemacs, Node: Position Info, Next: Arguments, Prev: Continuation Lines, Up: Basic Cursor Position Information =========================== If you are accustomed to other display editors, you may be surprised that Emacs does not always display the page number or line number of point in the mode line. In Emacs, this information is only rarely needed, and a number of commands are available to compute and print it. Since text is stored in a way that makes it difficult to compute the information, it is not displayed all the time. `M-x what-page' Print page number of point, and line number within page. `M-x what-line' Print line number of point in the buffer. `M-=' Print number of lines in the current region (`count-lines-region'). `C-x =' Print character code of character after point, character position of point, and column of point (`what-cursor-position'). There are several commands for printing line numbers: * `M-x what-line' counts lines from the beginning of the file and prints the line number point is on. The first line of the file is line number 1. You can use these numbers as arguments to `M-x goto-line'. * `M-x what-page' counts pages from the beginning of the file, and counts lines within the page, printing both of them. *Note Pages::, for the command `C-x l' which counts the lines in the current page. * `M-=' (`count-lines-region'), prints the number of lines in the region (*note Mark::.). The command `C-x =' (`what-cursor-position') provides information about point and about the column the cursor is in. It prints a line in the echo area that looks like this: Char: x (0170) point=65986 of 563027(12%) x=44 (In fact, this is the output produced when point is before the `x=44' in the example.) The two values after `Char:' describe the character following point, first by showing it and second by giving its octal character code. `point=' is followed by the position of point expressed as a character count. The front of the buffer counts as position 1, one character later as 2, and so on. The next, larger number is the total number of characters in the buffer. Afterward in parentheses comes the position expressed as a percentage of the total size. `x=' is followed by the horizontal position of point, in columns 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 invisible, `C-x =' prints additional text describing the current visible range. For example, it might say Char: x (0170) point=65986 of 563025(12%) <65102 - 68533> x=44 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 visible ones. *Note Narrowing::. If point is at the end of the buffer (or the end of the visible part), `C-x =' omits any description of the character after point. The output looks like point=563026 of 563025(100%) x=0 File: lemacs, Node: Arguments, Prev: Position Info, Up: Basic Numeric Arguments ================= Any Emacs command can be given a "numeric argument". Some commands interpret the argument as a repetition count. For example, giving an argument of ten to the key `C-f' (the command `forward-char', move forward one character) moves forward ten characters. With these commands, no argument is equivalent to an argument of one. Negative arguments are allowed. Often they tell a command to move or act backwards. If your keyboard has a META key, the easiest way to specify a numeric argument is to type digits and/or a minus sign while holding down the the META key. For example, M-5 C-n moves down five lines. The characters `Meta-1', `Meta-2', and so on, as well as `Meta--', do this because they are keys bound to commands (`digit-argument' and `negative-argument') that are defined to contribute to an argument for the next command. Another way of specifying an argument is to use the `C-u' (`universal-argument') command followed by the digits of the argument. With `C-u', you can type the argument digits without holding down shift keys. To type a negative argument, start with a minus sign. Just a minus sign normally means -1. `C-u' works on all terminals. `C-u' followed by a character which is neither a digit nor a minus sign has the special meaning of "multiply by four". It multiplies the argument for the next command by four. `C-u' twice multiplies it by sixteen. Thus, `C-u C-u C-f' moves forward sixteen characters. This is a good way to move forward "fast", since it moves about 1/5 of a line in the usual size screen. 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). Some commands care only about whether there is an argument, and not about its value. For example, the command `M-q' (`fill-paragraph') with no argument fills text; with an argument, it justifies the text as well. (*Note Filling::, for more information on `M-q'.) Just `C-u' is a handy way of providing an argument for such commands. Some commands use the value of the argument as a repeat count, but do something peculiar 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 non-blank 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 will be described when they come up; they are always for reasons of convenience of use of the individual command. File: lemacs, Node: Undo, Next: Minibuffer, Prev: Basic, Up: Top Undoing Changes *************** Emacs allows you to undo all changes you make to the text of a buffer, up to a certain amount of change (8000 characters). Each buffer records changes individually, and the undo command always applies to the current buffer. Usually each editing command makes a separate entry in the undo records, but some commands such as `query-replace' make many entries, and very simple commands such as self-inserting characters are often grouped to make undoing less tedious. `C-x u' Undo one batch of changes (usually, one command worth) (`undo'). `C-_' The same. The command `C-x u' or `C-_' allows you to undo changes. The first time you give this command, it undoes the last change. Point moves to the text affected by the undo, so you can see what was undone. Consecutive repetitions of the `C-_' or `C-x u' commands undo earlier and earlier changes, back to the limit of what has been recorded. If all recorded changes have already been undone, the undo command prints an error message and does nothing. Any command other than an undo command breaks the sequence of undo commands. Starting at this moment, the previous undo commands are considered ordinary changes that can themselves be undone. Thus, you can redo changes you have undone by typing `C-f' or any other command that have no important effect, and then using more undo commands. If you notice that a buffer has been modified accidentally, the easiest way to recover is to type `C-_' repeatedly until the stars disappear from the front of the mode line. When that happens, all the modifications you made have been cancelled. If you do not remember whether you changed the buffer deliberately, type `C-_' once. When you see Emacs undo the last change you made, you probably remember why you made it. If the change was an accident, leave it undone. If it was deliberate, redo the change as described in the preceding paragraph. Whenever an undo command makes the stars disappear from the mode line, the buffer contents is the same as it was when the file was last read in or saved. Not all buffers record undo information. Buffers whose names start with spaces don't; these buffers are used internally by Emacs and its extensions to hold text that users don't normally look at or edit. Minibuffers, help buffers and documentation buffers also don't record undo information. Emacs can remember at most 8000 or so characters of deleted or modified text in any one buffer for reinsertion by the undo command. There is also a limit on the number of individual insert, delete or change actions that Emacs can remembered. There are two keys to run the `undo' command, `C-x u' and `C-_', because on some keyboards, it is not obvious how to type `C-_'. `C-x u' is an alternative you can type in the same fashion on any terminal.