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This is Info file ../info/emacs, produced by Makeinfo-1.54 from the input file emacs.texi. File: emacs, Node: File Variables, Prev: Locals, Up: Variables Local Variables in Files ------------------------ A file can specify local variable values for use when you edit the file with Emacs. Visiting the file checks for local variables specifications; it automatically makes these variables local to the buffer, and sets them to the values specified in the file. There are two ways to specify local variable values: in the first line, or with a local variables list. Here's how to do this with the first line: -*- mode: MODENAME; VAR: VALUE; ... -*- You can specify any number of variables/value pairs in this way, each pair with a colon and semicolon as shown above. The major mode should come first, if it is mentioned at all. Here is an example that specifies Lisp mode and sets two variables with numeric values: ;; -*-Mode: Lisp; fill-column: 75; comment-column: 50; -*- A "local variables list" goes near the end of the file, in the last page. (It is often best to put it on a page by itself.) The local variables list starts with a line containing the string `Local Variables:', and ends with a line containing the string `End:'. In between come the variable names and values, one set per line, as `VARIABLE: VALUE'. The VALUEs are not evaluated; they are used literally. Here is an example of a local variables list: ;;; Local Variables: *** ;;; mode:lisp *** ;;; comment-column:0 *** ;;; comment-start: ";;; " *** ;;; comment-end:"***" *** ;;; End: *** As you see, each line starts with the prefix `;;; ' and each line ends with the suffix ` ***'. Emacs recognizes these as the prefix and suffix based on the first line of the list, by finding them surrounding the magic string `Local Variables:'; so it automatically discards them from the other lines of the list. The usual reason for using a prefix and/or suffix is to embed the local variables list in a comment, so it won't confuse other programs that the file is intended as input for. The example above is for a language where comment lines start with `;;; ' and end with `***'; the local values for `comment-start' and `comment-end' customize the rest of Emacs for this unusual syntax. Don't use a prefix (or a suffix) if you don't need one. Two "variable names" have special meanings in a local variables list: a value for the variable `mode' really sets the major mode, and a value for the variable `eval' is simply evaluated as an expression and the value is ignored. `mode' and `eval' are not real variables; setting such variables in any other context has no such effect. If `mode' is used in a local variables list, it should be the first entry in the list. The start of the local variables list must be no more than 3000 characters from the end of the file, and must be in the last page if the file is divided into pages. Otherwise, Emacs will not notice it is there. The purpose of this is so that a stray `Local Variables:' not in the last page does not confuse Emacs, and so that visiting a long file that is all one page and has no local variables list need not take the time to search the whole file. You may be tempted to try to turn on Auto Fill mode with a local variable list. That is a mistake. The choice of Auto Fill mode or not is a matter of individual taste, not a matter of the contents of particular files. If you want to use Auto Fill, set up major mode hooks with your `.emacs' file to turn it on (when appropriate) for you alone (*note Init File::.). Don't try to use a local variable list that would impose your taste on everyone. The variable `enable-local-variables' controls whether to process local variables lists, and thus gives you a chance to override them. Its default value is `t', which means to process local variables lists. If you set the value to `nil', Emacs simply ignores local variables lists. Any other value says to query you about each local variables list, showing you the local variables list to consider. The `eval' "variable" creates special risks, so there is a separate variable `enable-local-eval' to control whether Emacs processes `eval' variables. The three possibilities for the value are `t', `nil', and anything else, just as for `enable-local-variables'. The default is `maybe', which is neither `t' nor `nil', so normally Emacs queries about `eval' variable settings. Use the command `normal-mode' to reset the local variables and major mode of a buffer according to the file name and contents, including the local variables list if any. *Note Choosing Modes::. File: emacs, Node: Keyboard Macros, Next: Key Bindings, Prev: Variables, Up: Customization Keyboard Macros =============== A "keyboard macro" is a command defined by the user to abbreviate a sequence of keys. For example, if you discover that you are about to type `C-n C-d' forty times, you can speed your work by defining a keyboard macro to do `C-n C-d' and calling it with a repeat count of forty. `C-x (' Start defining a keyboard macro (`start-kbd-macro'). `C-x )' End the definition of a keyboard macro (`end-kbd-macro'). `C-x e' Execute the most recent keyboard macro (`call-last-kbd-macro'). `C-u C-x (' Re-execute last keyboard macro, then add more keys to its definition. `C-x q' When this point is reached during macro execution, ask for confirmation (`kbd-macro-query'). `M-x name-last-kbd-macro' Give a command name (for the duration of the session) to the most recently defined keyboard macro. `M-x insert-kbd-macro' Insert in the buffer a keyboard macro's definition, as Lisp code. Keyboard macros differ from ordinary Emacs commands in that they are written in the Emacs command language rather than in Lisp. This makes it easier for the novice to write them, and makes them more convenient as temporary hacks. However, the Emacs command language is not powerful enough as a programming language to be useful for writing anything intelligent or general. For such things, Lisp must be used. You define a keyboard macro while executing the commands which are the definition. Put differently, as you define a keyboard macro, the definition is being executed for the first time. This way, you can see what the effects of your commands are, so that you don't have to figure them out in your head. When you are finished, the keyboard macro is defined and also has been, in effect, executed once. You can then do the whole thing over again by invoking the macro. * Menu: * Basic Kbd Macro:: Defining and running keyboard macros. * Save Kbd Macro:: Giving keyboard macros names; saving them in files. * Kbd Macro Query:: Keyboard macros that do different things each use. File: emacs, Node: Basic Kbd Macro, Next: Save Kbd Macro, Up: Keyboard Macros Basic Use --------- To start defining a keyboard macro, type the `C-x (' command (`start-kbd-macro'). From then on, your keys continue to be executed, but also become part of the definition of the macro. `Def' appears in the mode line to remind you of what is going on. When you are finished, the `C-x )' command (`end-kbd-macro') terminates the definition (without becoming part of it!). For example C-x ( M-f foo C-x ) defines a macro to move forward a word and then insert `foo'. The macro thus defined can be invoked again with the `C-x e' command (`call-last-kbd-macro'), which may be given a repeat count as a numeric argument to execute the macro many times. `C-x )' can also be given a repeat count as an argument, in which case it repeats the macro that many times right after defining it, but defining the macro counts as the first repetition (since it is executed as you define it). So, giving `C-x )' an argument of 4 executes the macro immediately 3 additional times. An argument of zero to `C-x e' or `C-x )' means repeat the macro indefinitely (until it gets an error or you type `C-g'). If you wish to repeat an operation at regularly spaced places in the text, define a macro and include as part of the macro the commands to move to the next place you want to use it. For example, if you want to change each line, you should position point at the start of a line, and define a macro to change that line and leave point at the start of the next line. Then repeating the macro will operate on successive lines. After you have terminated the definition of a keyboard macro, you can add to the end of its definition by typing `C-u C-x ('. This is equivalent to plain `C-x (' followed by retyping the whole definition so far. As a consequence it re-executes the macro as previously defined. You can use function keys in a keyboard macro, just like keyboard keys. You can even use mouse events, but be careful about that: when the macro replays the mouse event, it uses the original mouse position of that event, the position that the mouse had while you were defining the macro. The effect of this may be hard to predict. (Using the current mouse position would be even less predictable.) One thing that doesn't always work well in a keyboard macro is the command `C-M-c' (`exit-recursive-edit'). When this command exits a recursive edit that started within the macro, it works as you'd expect. But if it exits a recursive edit that started before you invoked the keyboard macro, it also necessarily exits the keyboard macro as part of the process. File: emacs, Node: Save Kbd Macro, Next: Kbd Macro Query, Prev: Basic Kbd Macro, Up: Keyboard Macros Naming and Saving Keyboard Macros --------------------------------- If you wish to save a keyboard macro for longer than until you define the next one, you must give it a name using `M-x name-last-kbd-macro'. This reads a name as an argument using the minibuffer and defines that name to execute the macro. The macro name is a Lisp symbol, and defining it in this way makes it a valid command name for calling with `M-x' or for binding a key to with `global-set-key' (*note Keymaps::.). If you specify a name that has a prior definition other than another keyboard macro, an error message is printed and nothing is changed. Once a macro has a command name, you can save its definition in a file. Then it can be used in another editing session. First, visit the file you want to save the definition in. Then use this command: M-x insert-kbd-macro RET MACRONAME RET This inserts some Lisp code that, when executed later, will define the same macro with the same definition it has now. (You need not understand Lisp code to do this, because `insert-kbd-macro' writes the Lisp code for you.) Then save the file. You can load the file later with `load-file' (*note Lisp Libraries::.). If the file you save in is your init file `~/.emacs' (*note Init File::.) then the macro will be defined each time you run Emacs. If you give `insert-kbd-macro' a prefix argument, it makes additional Lisp code to record the keys (if any) that you have bound to the keyboard macro, so that the macro will be reassigned the same keys when you load the file. File: emacs, Node: Kbd Macro Query, Prev: Save Kbd Macro, Up: Keyboard Macros Executing Macros with Variations -------------------------------- Using `C-x q' (`kbd-macro-query'), you can get an effect similar to that of `query-replace', where the macro asks you each time around whether to make a change. When you are defining the macro, type `C-x q' at the point where you want the query to occur. During macro definition, the `C-x q' does nothing, but when you run the macro later, `C-x q' asks you interactively whether to continue. The valid responses when `C-x q' asks are SPC (or `y'), DEL (or `n'), ESC (or `q'), `C-l' and `C-r'. The answers are the same as in query replace, though not all of the query-replace options are meaningful. Specifically, SPC means to continue. DEL means to skip the remainder of this repetition of the macro and start right away with the next repetition. ESC means to skip the remainder of this repetition and cancel further repetition. `C-l' redraws the screen and asks you again for a character to say what to do. `C-r' enters a recursive editing level, in which you can perform editing which is not part of the macro. When you exit the recursive edit using `C-M-c', you are asked again how to continue with the keyboard macro. If you type a SPC at this time, the rest of the macro definition is executed. It is up to you to leave point and the text in a state such that the rest of the macro will do what you want. `C-u C-x q', which is `C-x q' with a numeric argument, performs a different function. It enters a recursive edit reading input from the keyboard, both when you type it during the definition of the macro, and when it is executed from the macro. During definition, the editing you do inside the recursive edit does not become part of the macro. During macro execution, the recursive edit gives you a chance to do some particularized editing. *Note Recursive Edit::. File: emacs, Node: Key Bindings, Next: Keyboard Translations, Prev: Keyboard Macros, Up: Customization Customizing Key Bindings ======================== This section describes "key bindings" which map keys to commands, and the "keymaps" which record key bindings. It also explains how to customize key bindings. Recall that a command is a Lisp function whose definition provides for interactive use. Like every Lisp function, a command has a function name which usually consists of lower case letters and hyphens. * Menu: * 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'. * Function Keys:: Rebinding terminal function keys. * 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. File: emacs, Node: Keymaps, Next: Prefix Keymaps, Up: Key Bindings Keymaps ------- The bindings between key sequences and command functions are recorded in data structures called "keymaps". Emacs has many of these, each used on particular occasions. Recall that a "key sequence" ("key", for short) is a sequence of "input events" that have a meaning as a unit. Input events include characters, function keys and mouse buttons--all the inputs that you can send to the computer with your terminal. A key sequence gets its meaning from its "binding", which says what command it runs. The function of keymaps is to record these bindings. The "global" keymap is the most important keymap because it is always in effect. The global keymap defines keys for Fundamental mode; most of these definitions are common to all (or most) major modes. Each major or minor mode can have its own keymap which overrides the definitions of some keys. For example, a self-inserting character such as `g' is self-inserting because the global keymap binds it to the command `self-insert-command'. The standard Emacs editing characters such as `C-a' also get their standard meanings from the global keymap. Commands to rebind keys, such as `M-x global-set-key', actually work by storing the new binding in the proper place in the global map. *Note Rebinding::. Meta characters work differently; Emacs translates each Meta character into a pair of characters starting with ESC. When you type the character `M-a' in a key sequence, Emacs replaces it with `ESC a'. A meta key comes in as a single input event, but becomes two events for purposes of key bindings. The reason for this is historical, and we might change in someday. Most modern keyboards have function keys as well as character keys. Function keys send input events just as character keys do, and keymaps can have bindings for them. On many terminals, typing a function key actually sends the computer a sequence of characters; the precise details of the sequence depends on which function key and on the model of terminal you are using. (Often he sequence starts with `ESC ['.) If Emacs understands your terminal type properly, it recognizes the character sequences forming function keys wherever they occur in a key sequence (not just at the beginning). Thus, for most purposes, you can pretend the function keys reach Emacs directly and ignore their encoding as character sequences. Mouse buttons also produce input events. These events come with other data--the window and position where you pressed or released the button, and a timestamp. But only the choice of button matters for key bindings; the other data matters only if a command looks at it. (Commands designed for mouse invocation usually do look at the other data.) A keymap records definitions for single events. Interpreting a key sequence of multiple events involves a chain of keymaps. The first keymap gives a definition for the first event; this definition is another keymap, which is used to look up the second event in the sequence, and so on. Key sequences can mix function keys and characters. For example, `C-x SELECT' makes sense. If you make SELECT a prefix key, then `SELECT C-n' makes sense. You can even mix mouse events with keyboard events, but we recommend against it, because such sequences are inconvenient to type in. File: emacs, Node: Prefix Keymaps, Next: Local Keymaps, Prev: Keymaps, Up: Key Bindings Prefix Keymaps -------------- A prefix key such as `C-x' or ESC has its own keymap, which holds the definition for the event that immediately follows that prefix. The definition of a prefix key is the keymap to use for looking up the following event. The definition can also be a Lisp symbol whose function definition is the following keymap; the effect is the same, but it provides a command name for the prefix key that can be used as a description of what the prefix key is for. Thus, the binding of `C-x' is the symbol `Ctl-X-Prefix', whose function definition is the keymap for `C-x' commands. The definitions of `C-c', `C-x', `C-h' and ESC as prefix keys appear in the global map, so these prefix keys are always available. Some prefix keymaps are stored in variables with names: * `ctl-x-map' is the variable name for the map used for characters that follow `C-x'. * `help-map' is for characters that follow `C-h'. * `esc-map' is for characters that follow ESC. Thus, all Meta characters are actually defined by this map. * `ctl-x-4-map' is for characters that follow `C-x 4'. * `mode-specific-map' is for characters that follow `C-c'. File: emacs, Node: Local Keymaps, Next: Minibuffer Maps, Prev: Prefix Keymaps, Up: Key Bindings Local Keymaps ------------- So far we have explained the ins and outs of the global map. Major modes customize Emacs by providing their own key bindings in "local keymaps". For example, C mode overrides TAB to make it indent the current line for C code. Portions of text in the buffer can specify their own keymaps to substitute for the keymap of the buffer's major mode. Minor modes can also have local keymaps. Whenever a minor mode is in effect, the definitions in its keymap override both the major mode's local keymap and the global keymap. The local keymaps for Lisp mode, C mode, and several other major modes always exist even when not in use. These are kept in variables named `lisp-mode-map', `c-mode-map', and so on. For major modes less often used, the local keymap is normally constructed only when the mode is used for the first time in a session. This is to save space. All minor mode keymaps are created in advance. There is no way to defer their creation until the minor mode is enabled. A local keymap can locally redefine a key as a prefix key by defining it as a prefix keymap. If the key is also defined globally as a prefix, then its local and global definitions (both keymaps) effectively combine: both of them are used to look up the event that follows the prefix key. Thus, if the mode's local keymap defines `C-c' as another keymap, and that keymap defines `C-z' as a command, this provides a local meaning for `C-c C-z'. This does not affect other sequences that start with `C-c'; If those sequences don't have their own local bindings, their global bindings remain in effect. Another way to think of this is that Emacs handles a multi-event key sequence by looking in several keymaps, one by one, for a binding of the whole key sequence. First it checks the minor mode keymaps for minor modes that are enabled, then it checks the major mode's keymap, and then it checks the global keymap. This is not precisely how key lookup works, but it's good enough for understanding ordinary circumstances. File: emacs, Node: Minibuffer Maps, Next: Rebinding, Prev: Local Keymaps, Up: Key Bindings Minibuffer Keymaps ------------------ The minibuffer has its own set of local keymaps; they contain various completion and exit commands. * `minibuffer-local-map' is used for ordinary input (no completion). * `minibuffer-local-ns-map' is similar, except that SPC exits just like RET. This is used mainly for Mocklisp compatibility. * `minibuffer-local-completion-map' is for permissive completion. * `minibuffer-local-must-match-map' is for strict completion and for cautious completion. File: emacs, Node: Rebinding, Next: Init Rebinding, Prev: Minibuffer Maps, Up: Key Bindings Changing Key Bindings Interactively ----------------------------------- The way to redefine an Emacs key is to change its entry in a keymap. You can change the global keymap, in which case the change is effective in all major modes (except those that have their own overriding local definitions for the same key). Or you can change the current buffer's local map, which affects all buffers using the same major mode. `M-x global-set-key RET KEY CMD RET' Define KEY globally to run CMD. `M-x local-set-key RET KEY CMD RET' Define KEY locally (in the major mode now in effect) to run CMD. `M-x global-unset-key RET KEY' Make KEY undefined in the global map. `M-x local-unset-key RET KEY' Make KEY undefined locally (in the major mode now in effect). For example, suppose you like to execute commands in a subshell within an Emacs buffer, instead of suspending Emacs and executing commands in your login shell. Normally, `C-z' is bound to the function `suspend-emacs', but you can change `C-z' to invoke an interactive subshell within Emacs, by binding it to `shell' as follows: M-x global-set-key RET C-z shell RET `global-set-key' reads the command name after the key. After you press the key, a message like this appears so that you can confirm that you are binding the key you want: Set key C-z to command: You can redefine function keys and mouse events in the same way; just type the function key or click the mouse when it's time to specify the key to rebind. You can rebind a key that contains more than one event in the same way. Emacs keeps reading the key to rebind until it is a complete key (that is, not a prefix key). Thus, if you type `C-f' for KEY, that's the end; the minibuffer is entered immediately to read CMD. But if you type `C-x', another character is read; if that is `4', another character is read, and so on. For example, M-x global-set-key RET C-x 4 $ spell-other-window RET would redefine `C-x 4 $' to run the (fictitious) command `spell-other-window'. You can remove the global definition of a key with `global-unset-key'. This makes the key "undefined"; if you type it, Emacs will just beep. Similarly, `local-unset-key' makes a key undefined in the current major mode keymap, which makes the global definition (or lack of one) come back into effect in that major mode. If you have redefined (or undefined) a key and you subsequently wish to retract the change, undefining the key will not do the job--you need to redefine the key with its standard definition. To find the name of the standard definition of a key, go to a Fundamental mode buffer and use `C-h c'. The documentation of keys in this manual also lists their command names. If you want to prevent yourself from invoking a command by mistake, it is better to disable the command than to undefine the key. A disabled command is less work to invoke when you really want to. *Note Disabling::. File: emacs, Node: Init Rebinding, Next: Function Keys, Prev: Rebinding, Up: Key Bindings Rebinding Keys in Your Init File -------------------------------- If you have a set of default definitions that you like to use all the time, you can put commands in your `.emacs' file by using their Lisp syntax. Thus, the first `global-set-key' command in this section could be put in an `.emacs' file in either of the two following formats: (global-set-key "\C-z" 'shell) or as: (global-set-key [?\C-z] 'shell) When the key sequence consists of characters, like this one, you can write it as a string or as a vector. The first format specifies the key sequence as a string, `"\C-z"'. The second format uses a vector to specify the key sequence. The square brackets (`[...]') delimit the contents of the vector. The vector in this example contains just one element, which is the integer code corresponding to `C-z'. The question mark is the Lisp syntax for a character constant; the character must follow with no intervening spaces. The single-quote before `shell' marks it as a constant symbol rather than a variable. If you omit the quote, Emacs tries to evaluate `shell' immediately as a variable. This probably causes an error; it certainly isn't what you want. Here is another example that binds a key sequence two characters long: (global-set-key "\C-xl" 'make-symbolic-link) or: (global-set-key [?\C-x ?l] 'make-symbolic-link) File: emacs, Node: Function Keys, Next: Mouse Buttons, Prev: Init Rebinding, Up: Key Bindings Rebinding Function Keys ----------------------- Key sequences can contain function keys as well as ordinary characters. Just as Lisp characters (actually integers) represent keyboard characters, Lisp symbols represent function keys. If the function key has a word as its label, then that word is also the name of the corresponding Lisp symbol. Here are the Lisp names for other function keys: `left', `up', `right', `down' Cursor arrow keys. `begin', `end', `home', `next', `prior' Other cursor repositioning keys. `select', `print', `execute', `backtab' `insert', `undo', `redo', `clearline' `insertline', `deleteline', `insertchar', `deletechar', Miscellaneous function keys. `f1' ... `f35' Numbered function keys (across the top of the keyboard). `kp-add', `kp-subtract', `kp-multiply', `kp-divide' `kp-backtab', `kp-space', `kp-tab', `kp-enter' `kp-separator', `kp-decimal', `kp-equal' Keypad keys (to the right of the regular keyboard), with names or punctuation. `kp-0', `kp-1', ... `kp-9' Keypad keys with digits. `kp-f1', `kp-f2', `kp-f3', `kp-f4' Keypad PF keys. A key sequence which contains non-characters must be a vector rather than a string. To write a vector, write square brackets containing the vector elements. Write spaces to separate the elements. If an element is a symbol, simply write the symbol's name--no delimiters or punctuation are needed. If an element is a character, write a Lisp character constant, which is `?' followed by the character as it would appear in a string. Thus, to bind function key `f1' to the command `rmail', write the following: (global-set-key [f1] 'rmail) To bind the right-arrow key to the command `forward-char', you can use this expression: (global-set-key [right] 'forward-char) using the Lisp syntax for a vector containing the symbol `right'. (This binding is present in Emacs by default.) You can mix function keys and characters in a key sequence. This example binds `C-x RIGHT' to the command `forward-page'. (global-set-key [?\C-x right] 'forward-page) where `?\C-x' is the Lisp character constant for the character `C-x'. The vector element `right' is a symbol and therefore does not take a question mark. You can use the modifier keys CTRL, META, HYPER, SUPER, ALT and SHIFT with function keys. To represent these modifiers, prepend the strings `C-', `M-', `H-', `s-', `A-' and `S-' to the symbol name. Thus, here is how to make `Hyper-Meta-RIGHT' move forward a word: (global-set-key [H-M-right] 'forward-word) File: emacs, Node: Mouse Buttons, Next: Disabling, Prev: Function Keys, Up: Key Bindings Rebinding Mouse Buttons ----------------------- Emacs uses Lisp symbols to designate mouse buttons, too. The ordinary mouse events in Emacs are "click" events; these happen when you press a button and release it without moving the mouse. You can also get "drag" events, when you move the mouse while holding the button down. Drag events happen when you finally let go of the button. The symbols for basic click events are `mouse-1' for the leftmost button, `mouse-2' for the next, and so on. Here is how you can redefine the second mouse button to split the current window: (global-set-key [mouse-2] 'split-window-vertically) The symbols for drag events are similar, but have the prefix `drag-' before the word `mouse'. For example, dragging the left button generates a `drag-mouse-1' event. You can also request events when the mouse button is pressed down. These events start with `down-' instead of `drag-'. Such events are generated only if they have key bindings. When you get a button-down event, a corresponding click or drag event will always follow. The symbols for mouse events also indicate the status of the modifier keys, with the usual prefixes `C-', `M-', `H-', `s-', `A-' and `S-'. These always follow `drag-' or `down-'. A frame includes areas that don't show text from the buffer, such as the mode line and the scroll bar. You can tell whether a mouse button comes from a special area of the screen by means of dummy "prefix keys." For example, if you click the mouse in the mode line, you get the prefix key `mode-line' before the ordinary mouse-button symbol. Thus, here is how to define the command for clicking the left button in a mode line to run `scroll-up': (global-set-key [mode-line mouse-1] 'scroll-up) Here is the complete list of these dummy prefix keys and their meanings: `mode-line' The mouse was in the mode line of a window. `vertical-line' The mouse was in the vertical line separating side-by-side windows. `vertical-scroll-bar' The mouse was in a horizontal scroll bar. This is the kind of scroll bar people normally use. `horizontal-scroll-bar' The mouse was in a horizontal scroll bar. Horizontal scroll bars do horizontal scrolling, and people don't use them often. You can put more than one mouse button in a key sequence, but it isn't usual to do so. File: emacs, Node: Disabling, Prev: Mouse Buttons, Up: Key Bindings Disabling Commands ------------------ Disabling a command marks the command as requiring confirmation before it can be executed. The purpose of disabling a command is to prevent beginning users from executing it by accident and being confused. Attempting to invoke a disabled command interactively in Emacs causes the display of a window containing the command's name, its documentation, and some instructions on what to do immediately; then Emacs asks for input saying whether to execute the command as requested, enable it and execute, or cancel it. If you decide to enable the command, you are asked whether to do this permanently or just for the current session. Enabling permanently works by automatically editing your `.emacs' file. The direct mechanism for disabling a command is to have a non-`nil' `disabled' property on the Lisp symbol for the command. Here is the Lisp program to do this: (put 'delete-region 'disabled t) If the value of the `disabled' property is a string, that string is included in the message printed when the command is used: (put 'delete-region 'disabled "Text deleted this way cannot be yanked back!\n") You can make a command disabled either by editing the `.emacs' file directly or with the command `M-x disable-command', which edits the `.emacs' file for you. Likewise, `M-x enable-command' edits `.emacs' to enable a command permanently. *Note Init File::. Whether a command is disabled is independent of what key is used to invoke it; it also applies if the command is invoked using `M-x'. Disabling a command has no effect on calling it as a function from Lisp programs. File: emacs, Node: Keyboard Translations, Next: Syntax, Prev: Key Bindings, Up: Customization Keyboard Translations ===================== Some keyboards do not make it convenient to send all the special characters that Emacs uses. The most common problem case is the DEL character. Some keyboards provide no convenient way to type this very important character--usually because they were designed to expect the character `C-h' to be used for deletion. On these keyboard, if you press the key normally used for deletion, Emacs handles the `C-h' as a prefix character and offers you a list of help options, which is not what you want. You can work around this problem within Emacs by setting up keyboard translations to turn `C-h' into DEL and DEL into `C-h', as follows: ;; Translate `C-h' to DEL. (keyboard-translate ?\C-h ?\C-?) ;; Translate DEL to `C-h'. (keyboard-translate ?\C-? ?\C-h) Keyboard translations are not the same as key bindings in keymaps (*note Keymaps::.). Emacs contains numerous keymaps that apply in different situations, but there is only one set of keyboard translations, and it applies to every character that Emacs reads from the terminal. Keyboard translations take place at the lowest level of input processing; the keys that are looked up in keymaps contain the characters that result from keyboard translation. For full information about how to use keyboard translations, see *Note Translating Input: (elisp)Translating Input. File: emacs, Node: Syntax, Next: Init File, Prev: Keyboard Translations, Up: Customization The Syntax Table ================ All the Emacs commands which parse words or balance parentheses are controlled by the "syntax table". The syntax table says which characters are opening delimiters, which are parts of words, which are string quotes, and so on. Each major mode has its own syntax table (though sometimes related major modes use the same one) which it installs in each buffer that uses that major mode. The syntax table installed in the current buffer is the one that all commands use, so we call it "the" syntax table. A syntax table is a Lisp object, a vector of length 256 whose elements are numbers. To display a description of the contents of the current syntax table, type `C-h s' (`describe-syntax'). The description of each character includes both the string you would have to give to `modify-syntax-entry' to set up that character's current syntax, and some English to explain that string if necessary. For full information on the syntax table, see *Note Syntax Table: (elisp)Syntax Table. File: emacs, Node: Init File, Prev: Syntax, Up: Customization The Init File, `~/.emacs' ========================= When Emacs is started, it normally loads a Lisp program from the file `.emacs' in your home directory. We call this file your "init file" because it specifies how to initialize Emacs for you. You can use the command line switches `-q' and `-u' to tell Emacs whether to load an init file, and which one (*note Entering Emacs::.). There can also be a "default init file", which is the library named `default.el', found via the standard search path for libraries. The Emacs distribution contains no such library; your site may create one for local customizations. If this library exists, it is loaded whenever you start Emacs (except when you specify `-q'). But your init file, if any, is loaded first; if it sets `inhibit-default-init' non-`nil', then `default' is not loaded. If you have a large amount of code in your `.emacs' file, you should move it into another file such as `~/SOMETHING.el', byte-compile it, and make your `.emacs' file load it with `(load "~/SOMETHING")'. *Note Byte Compilation: (elisp)Byte Compilation, for more information about compiling Emacs Lisp programs. * Menu: * 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. File: emacs, Node: Init Syntax, Next: Init Examples, Up: Init File Init File Syntax ---------------- The `.emacs' file contains one or more Lisp function call expressions. Each of these consists of a function name followed by arguments, all surrounded by parentheses. For example, `(setq fill-column 60)' calls the function `setq' to set the variable `fill-column' (*note Filling::.) to 60. The second argument to `setq' is an expression for the new value of the variable. This can be a constant, a variable, or a function call expression. In `.emacs', constants are used most of the time. They can be: Numbers: Numbers are written in decimal, with an optional initial minus sign. Strings: Lisp string syntax is the same as C string syntax with a few extra features. Use a double-quote character to begin and end a string constant. In a string, you can include newlines and special characters literally. But often it is cleaner to use backslash sequences for them: `\n' for newline, `\b' for backspace, `\r' for carriage return, `\t' for tab, `\f' for formfeed (control-L), `\e' for escape, `\\' for a backslash, `\"' for a double-quote, or `\OOO' for the character whose octal code is OOO. Backslash and double-quote are the only characters for which backslash sequences are mandatory. `\C-' can be used as a prefix for a control character, as in `\C-s' for ASCII control-S, and `\M-' can be used as a prefix for a Meta character, as in `\M-a' for `Meta-A' or `\M-\C-a' for `Control-Meta-A'. Characters: Lisp character constant syntax consists of a `?' followed by either a character or an escape sequence starting with `\'. Examples: `?x', `?\n', `?\"', `?\)'. Note that strings and characters are not interchangeable in Lisp; some contexts require one and some contexts require the other. True: `t' stands for `true'. False: `nil' stands for `false'. Other Lisp objects: Write a single-quote (') followed by the Lisp object you want. File: emacs, Node: Init Examples, Next: Terminal Init, Prev: Init Syntax, Up: Init File Init File Examples ------------------ Here are some examples of doing certain commonly desired things with Lisp expressions: * Make TAB in C mode just insert a tab if point is in the middle of a line. (setq c-tab-always-indent nil) Here we have a variable whose value is normally `t' for `true' and the alternative is `nil' for `false'. * Make searches case sensitive by default (in all buffers that do not override this). (setq-default case-fold-search nil) This sets the default value, which is effective in all buffers that do not have local values for the variable. Setting `case-fold-search' with `setq' affects only the current buffer's local value, which is not what you probably want to do in an init file. * Make Text mode the default mode for new buffers. (setq default-major-mode 'text-mode) Note that `text-mode' is used because it is the command for entering Text mode. The single-quote before it makes the symbol a constant; otherwise, `text-mode' would be treated as a variable name. * Turn on Auto Fill mode automatically in Text mode and related modes. (add-hook 'text-mode-hook '(lambda () (auto-fill-mode 1))) This shows how to add a hook function to a normal hook variable (*note Hooks::.). The function we supply is a list starting with `lambda', with a single-quote in front of it to make it a list constant rather than an expression. It's beyond the scope of this manual to explain Lisp functions, but for this example it is enough to know that the effect is to execute `(auto-fill-mode 1)' when Text mode is entered. You can replace it with any other expression that you like, or with several expressions in a row. Emacs comes with a function named `turn-on-auto-fill' whose definition is `(lambda () (auto-fill-mode 1))'. Thus, a simpler way to write the above example is as follows: (add-hook 'text-mode-hook 'turn-on-auto-fill) * Load the installed Lisp library named `foo' (actually a file `foo.elc' or `foo.el' in a standard Emacs directory). (load "foo") When the argument to `load' is a relative file name, not starting with `/' or `~', `load' searches the directories in `load-path' (*note Lisp Libraries::.). * Load the compiled Lisp file `foo.elc' from your home directory. (load "~/foo.elc") Here an absolute file name is used, so no searching is done. * Rebind the key `C-x l' to run the function `make-symbolic-link'. (global-set-key "\C-xl" 'make-symbolic-link) or (define-key global-map "\C-xl" 'make-symbolic-link) Note once again the single-quote used to refer to the symbol `make-symbolic-link' instead of its value as a variable. * Do the same thing for C mode only. (define-key c-mode-map "\C-xl" 'make-symbolic-link) * Redefine all keys which now run `next-line' in Fundamental mode so that they run `forward-line' instead. (substitute-key-definition 'next-line 'forward-line global-map) * Make `C-x C-v' undefined. (global-unset-key "\C-x\C-v") One reason to undefine a key is so that you can make it a prefix. Simply defining `C-x C-v ANYTHING' will make `C-x C-v' a prefix, but `C-x C-v' must first be freed of its usual non-prefix definition. * Make `$' have the syntax of punctuation in Text mode. Note the use of a character constant for `$'. (modify-syntax-entry ?\$ "." text-mode-syntax-table) * Enable the use of the command `eval-expression' without confirmation. (put 'eval-expression 'disabled nil) File: emacs, Node: Terminal Init, Next: Find Init, Prev: Init Examples, Up: Init File Terminal-specific Initialization -------------------------------- Each terminal type can have a Lisp library to be loaded into Emacs when it is run on that type of terminal. For a terminal type named TERMTYPE, the library is called `term/TERMTYPE' and it is found by searching the directories `load-path' as usual and trying the suffixes `.elc' and `.el'. Normally it appears in the subdirectory `term' of the directory where most Emacs libraries are kept. The usual purpose of the terminal-specific library is to define the escape sequences used by the terminal's function keys using the library `keypad.el'. See the file `term/vt100.el' for an example of how this is done. When the terminal type contains a hyphen, only the part of the name before the first hyphen is significant in choosing the library name. Thus, terminal types `aaa-48' and `aaa-30-rv' both use the library `term/aaa'. The code in the library can use `(getenv "TERM")' to find the full terminal type name. The library's name is constructed by concatenating the value of the variable `term-file-prefix' and the terminal type. Your `.emacs' file can prevent the loading of the terminal-specific library by setting `term-file-prefix' to `nil'. Emacs runs the hook `term-setup-hook' at the end of initialization, after both your `.emacs' file and any terminal-specific library have been read in. Add hook functions to this hook if you wish to override part of any of the terminal-specific libraries and to define initializations for terminals that do not have a library. *Note Hooks::. File: emacs, Node: Find Init, Prev: Terminal Init, Up: Init File How Emacs Finds Your Init File ------------------------------ Normally Emacs uses the environment variable `HOME' to find `.emacs'; that's what `~' means in a file name. But if you have done `su', Emacs tries to find your own `.emacs', not that of the user you are currently pretending to be. The idea is that you should get your own editor customizations even if you are running as the super user. More precisely, Emacs first determines which user's init file to use. It gets the user name from the environment variables `USER' and `LOGNAME'; if neither of those exists, it uses effective user-ID. If that user name matches the real user-ID, then Emacs uses `HOME'; otherwise, it looks up the home directory corresponding to that user name in the system's data base of users. File: emacs, Node: Quitting, Next: Lossage, Prev: Customization, Up: Top Quitting and Aborting ===================== `C-g' Quit. Cancel running or partially typed command. `C-]' Abort innermost recursive editing level and cancel the command which invoked it (`abort-recursive-edit'). `M-x top-level' Abort all recursive editing levels that are currently executing. `C-x u' Cancel an already-executed command, usually (`undo'). There are two ways of cancelling commands which are not finished executing: "quitting" with `C-g', and "aborting" with `C-]' or `M-x top-level'. Quitting cancels a partially typed command or one which is already running. Aborting exits a recursive editing level and cancels the command that invoked the recursive edit. (*Note Recursive Edit::.) Quitting with `C-g' is used for getting rid of a partially typed command, or a numeric argument that you don't want. It also stops a running command in the middle in a relatively safe way, so you can use it if you accidentally give a command which takes a long time. In particular, it is safe to quit out of killing; either your text will *all* still be in the buffer, or it will *all* be in the kill ring (or maybe both). Quitting an incremental search does special things documented under searching; in general, it may take two successive `C-g' characters to get out of a search. `C-g' works by setting the variable `quit-flag' to `t' the instant `C-g' is typed; Emacs Lisp checks this variable frequently and quits if it is non-`nil'. `C-g' is only actually executed as a command if you type it while Emacs is waiting for input. If you quit with `C-g' a second time before the first `C-g' is recognized, you activate the "emergency escape" feature and return to the shell. *Note Emergency Escape::. There may be times when you cannot quit. When Emacs is waiting for the operating system to do something, quitting is impossible unless special pains are taken for the particular system call within Emacs where the waiting occurs. We have done this for the system calls that users are likely to want to quit from, but it's possible you will find another. In one very common case--waiting for file input or output using NFS--Emacs itself knows how to quit, but most NFS implementations simply do not allow user programs to stop waiting for NFS when the NFS server is hung. Aborting with `C-]' (`abort-recursive-edit') is used to get out of a recursive editing level and cancel the command which invoked it. Quitting with `C-g' does not do this, and could not do this, because it is used to cancel a partially typed command *within* the recursive editing level. Both operations are useful. For example, if you are in a recursive edit and type `C-u 8' to enter a numeric argument, you can cancel that argument with `C-g' and remain in the recursive edit. The command `M-x top-level' is equivalent to "enough" `C-]' commands to get you out of all the levels of recursive edits that you are in. `C-]' gets you out one level at a time, but `M-x top-level' goes out all levels at once. Both `C-]' and `M-x top-level' are like all other commands, and unlike `C-g', in that they are effective only when Emacs is ready for a command. `C-]' is an ordinary key and has its meaning only because of its binding in the keymap. *Note Recursive Edit::. `C-x u' (`undo') is not strictly speaking a way of cancelling a command, but you can think of it as cancelling a command already finished executing. *Note Undo::.