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Info file ../info/emacs, produced by Makeinfo, -*- Text -*- from input file lemacs.tex. 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: emacs, Node: Minibuffer, Next: M-x, Prev: Undo, Up: Top The Minibuffer ************** Emacs commands use the "minibuffer" to read arguments more complicated than a single number. Minibuffer arguments can be file names, buffer names, Lisp function names, Emacs command names, Lisp expressions, and many other things, depending on the command reading the argument. To edit the argument in the minibuffer, you can use Emacs editing commands. When the minibuffer is in use, it appears in the echo area, and the cursor moves there. The beginning of the minibuffer line displays a "prompt" indicating what kind of input you should supply and how it will be used. The prompt is often derived from the name of the command the argument is for. The prompt normally ends with a colon. Sometimes a "default argument" appears in parentheses after the colon; it too is part of the prompt. The default is used as the argument value if you enter an empty argument (e.g., just type RET). For example, commands that read buffer names always show a default, which is the name of the buffer that will be used if you type just RET. The simplest way to give a minibuffer argument is to type the text you want, terminated by RET to exit the minibuffer. To get out of the minibuffer and cancel the command that it was for, type `C-g'. Since the minibuffer uses the screen space of the echo area, it can conflict with other ways Emacs customarily uses the echo area. Here is how Emacs handles such conflicts: * If a command gets an error while you are in the minibuffer, this does not cancel the minibuffer. However, the echo area is needed for the error message and therefore the minibuffer itself is hidden for a while. It comes back after a few seconds, or as soon as you type anything. * If you use a command in the minibuffer whose purpose is to print a message in the echo area (for example `C-x =') the message is displayed normally, and the minibuffer is hidden for a while. It comes back after a few seconds, or as soon as you type anything. * Echoing of keystrokes does not take place while the minibuffer is in use. * Menu: * File: Minibuffer File. Entering file names with the minibuffer. * Edit: Minibuffer Edit. How to edit in the minibuffer. * Completion:: An abbreviation facility for minibuffer input. * Repetition:: Re-executing commands that used the minibuffer. File: emacs, Node: Minibuffer File, Next: Minibuffer Edit, Prev: Minibuffer, Up: Minibuffer Minibuffers for File Names ========================== Sometimes the minibuffer starts out with text in it. For example, when you are supposed to give a file name, the minibuffer starts out containing the "default directory", which ends with a slash. This informs you in which directory the file will be found if you do not specify one. For example, the minibuffer might start out with Find File: /u2/emacs/src/ where `Find File: ' is the prompt. Typing `buffer.c' specifies the file `/u2/emacs/src/buffer.c'. To find files in nearby directories, use `..'; thus, if you type `../lisp/simple.el', the file that you visit will be the one named `/u2/emacs/lisp/simple.el'. Alternatively, you can use `M-DEL' to kill directory names you don't want (*note Words::.). You can also type an absolute file name, one starting with a slash or a tilde, ignoring the default directory. For example, to find the file `/etc/termcap', just type the name, giving Find File: /u2/emacs/src//etc/termcap Two slashes in a row are not normally meaningful in Unix file names, but they are allowed in GNU Emacs. They mean, "ignore everything before the second slash in the pair." Thus, `/u2/emacs/src/' is ignored, and you get the file `/etc/termcap'. If you set `insert-default-directory' to `nil', the default directory is not inserted in the minibuffer. This way, the minibuffer starts out empty. But the name you type, if relative, is still interpreted with respect to the same default directory. File: emacs, Node: Minibuffer Edit, Next: Completion, Prev: Minibuffer File, Up: Minibuffer Editing in the Minibuffer ========================= The minibuffer is an Emacs buffer (albeit a peculiar one), and the usual Emacs commands are available for editing the text of an argument you are entering. Since RET in the minibuffer is defined to exit the minibuffer, you must use `C-o' or `C-q LFD' to insert a newline into the minibuffer. (Recall that a newline is really the LFD character.) The minibuffer has its own window which always has space on the screen but acts as if it were not there when the minibuffer is not in use. When the minibuffer is in use. The minibuffer window is just like the others; you can switch to another window with `C-x o', edit text in other windows and perhaps even visit more files, before returning to the minibuffer to submit the argument. You can kill text in another window, return to the minibuffer window, and then yank the text to use it in the argument. *Note Windows::. There are, however, some restrictions on the use of the minibuffer window. You cannot switch buffers in it--the minibuffer and its window are permanently attached. You also cannot split or kill the minibuffer window, but you can make it taller with `C-x ^'. If you are in the minibuffer and issue a command that displays help text in another window, that window will be scrolled if you type `C-M-v' while in the minibuffer until you exit the minibuffer. This feature is helpful if a completing minibuffer gives you a long list of possible completions. If the variable `minibuffer-confirm-incomplete' is `true', you are asked for confirmation if there is no known completion for the text you typed. For example, if you attempted to visit a non-existent file, the minibuffer might read: Find File:chocolate_bar.c [no completions, confirm] If you press `Return' again, that confirms the filename. Otherwise, you can continue editing it. Emacs supports recursive use of the minibuffer. However, it is easy to do this by accident (because of autorepeating keyboards, for example) and get confused. Therefore, most Emacs commands that use the minibuffer refuse to operate if the minibuffer window is selected. If the minibuffer is active but you have switched to a different window, recursive use of the minibuffer is allowed--if you know enough to try to do this, you probably will not get confused. If you set the variable `enable-recursive-minibuffers' to be non-`nil', recursive use of the minibuffer is always allowed. File: emacs, Node: Completion, Next: Repetition, Prev: Minibuffer Edit, Up: Minibuffer Completion ========== When appropriate, the minibuffer provides a "completion" facility. You type the beginning of an argument and one of the completion keys, and Emacs visibly fills in the rest, depending on what you have already typed. When completion is available, certain keys--TAB, RET, and SPC--are redefined to complete an abbreviation present in the minibuffer into a longer string that it stands for, by matching it against a set of "completion alternatives" provided by the command reading the argument. `?' is defined to display a list of possible completions of what you have inserted. For example, when the minibuffer is being used by `Meta-x' to read the name of a command, it is given a list of all available Emacs command names to complete against. The completion keys match the text in the minibuffer against all the command names, find any additional characters of the name that are implied by the ones already present in the minibuffer, and add those characters to the ones you have given. Case is normally significant in completion, because it is significant in most of the names that you can complete (buffer names, file names and command names). Thus, `fo' will not complete to `Foo'. When you are completing a name in which case does not matter, case may be ignored for completion's sake if specified by program. When a completion list is displayed, the completions will highlight as you move the mouse over them. Clicking middle on any highlighted completion will "select" it just as if you had typed it in and hit RET. Completion Example ------------------ Consider the following example. If you type `Meta-x au TAB', TAB looks for alternatives (in this case, command names) that start with `au'. There are only two commands: `auto-fill-mode' and `auto-save-mode'. They are the same as far as `auto-', so the `au' in the minibuffer changes to `auto-'. If you type TAB again immediately, there are multiple possibilities for the very next character--it could be `s' or `f'--so no more characters are added; but a list of all possible completions is displayed in another window. If you go on to type `f TAB', this TAB sees `auto-f'. The only command name starting this way is `auto-fill-mode', so completion inserts the rest of that command. You now have `auto-fill-mode' in the minibuffer after typing just `au TAB f TAB'. Note that TAB has this effect because in the minibuffer it is bound to the function `minibuffer-complete' when completion is supposed to be done. Completion Commands ------------------- Here is a list of all the completion commands defined in the minibuffer when completion is available. `TAB' Complete the text in the minibuffer as much as possible (`minibuffer-complete'). `SPC' Complete the text in the minibuffer but don't add or fill out more than one word (`minibuffer-complete-word'). `RET' Submit the text in the minibuffer as the argument, possibly completing first as described below (`minibuffer-complete-and-exit'). `?' Print a list of all possible completions of the text in the minibuffer (`minibuffer-list-completions'). `button2' Select the highlighted text under the mouse as a minibuffer response. When the minibuffer is being used to prompt the user for a completion, any valid completions which are visible on the screen will highlight when the mouse moves over them. Clicking button2 will select the highlighted completion and exit the minibuffer. (`minibuf-select-highlighted-completion'). SPC completes similar to TAB, but never goes beyond the next hyphen or space. If you have `auto-f' in the minibuffer and type SPC, it finds that the completion is `auto-fill-mode', but it stops completing after `fill-'. The result is `auto-fill-'. Another SPC at this point completes all the way to `auto-fill-mode'. SPC in the minibuffer runs the function `minibuffer-complete-word' when completion is available. There are three different ways that RET can work in completing minibuffers, depending on how the argument will be used. * "Strict" completion is used when it is meaningless to give any argument except one of the known alternatives. For example, when `C-x k' reads the name of a buffer to kill, it is meaningless to give anything but the name of an existing buffer. In strict completion, RET refuses to exit if the text in the minibuffer does not complete to an exact match. * "Cautious" completion is similar to strict completion, except that RET exits only if the text was an exact match already, not needing completion. If the text is not an exact match, RET does not exit, but it does complete the text. If it completes to an exact match, a second RET will exit. Cautious completion is used for reading file names for files that must already exist. * "Permissive" completion is used when any string is meaningful, and the list of completion alternatives is just a guide. For example, when `C-x C-f' reads the name of a file to visit, any file name is allowed, in case you want to create a file. In permissive completion, RET takes the text in the minibuffer exactly as given, without completing it. The completion commands display a list of all possible completions in a window whenever there is more than one possibility for the very next character. Typing `?' explicitly requests such a list. The list of completions counts as help text, so `C-M-v' typed in the minibuffer scrolls the list. When completion is done on file names, certain file names are usually ignored. The variable `completion-ignored-extensions' contains a list of strings; a file whose name ends in any of those strings is ignored as a possible completion. The standard value of this variable has several elements including `".o"', `".elc"', `".dvi"' and `"~"'. The effect is that, for example, `foo' completes to `foo.c' even though `foo.o' exists as well. If the only possible completions are files that end in "ignored" strings, they are not ignored. If a completion command finds the next character is undetermined, it automatically displays a list of all possible completions. If the variable `completion-auto-help' is set to `nil', this does not happen, and you must type `?' to display the possible completions. If the variable `minibuffer-confirm-incomplete' is set to true, then in contexts where `completing-read' allows answers that are not valid completions, an extra RET must be typed to confirm the response. This is helpful for catching typos, etc. File: emacs, Node: Repetition, Prev: Completion, Up: Minibuffer Repeating Minibuffer Commands ============================= Every command that uses the minibuffer at least once is recorded on a special history list, together with the values of the minibuffer arguments, so that you can repeat the command easily. In particular, every use of `Meta-x' is recorded, since `M-x' uses the minibuffer to read the command name. `C-x ESC' Re-execute a recent minibuffer command (`repeat-complex-command'). `M-p' Within `C-x ESC', move to previous recorded command (`previous-complex-command'). `M-n' Within `C-x ESC', move to the next (more recent) recorded command (`next-complex-command'). `M-x list-command-history' Display the entire command history, showing all the commands `C-x ESC' can repeat, most recent first. `C-x ESC' is used to re-execute a recent command that used the minibuffer. With no argument, it repeats the last command. A numeric argument specifies which command to repeat; 1 means the last one, and larger numbers specify earlier commands. `C-x ESC' works by turning the previous command into a Lisp expression and then entering a minibuffer initialized with the text for that expression. If you type just RET, the command is repeated as before. You can also change the command by editing the Lisp expression. The expression you finally submit will be executed. The repeated command is added to the front of the command history unless it is identical to the most recently executed command already there. Even if you don't understand Lisp syntax, it will probably be obvious which command is displayed for repetition. If you do not change the text, you can be sure the command will repeat exactly as before. If you are in the minibuffer for `C-x ESC' and the command shown to you is not the one you want to repeat, you can move around the list of previous commands using `M-n' and `M-p'. `M-p' replaces the contents of the minibuffer with the next earlier recorded command, and `M-n' replaces it with the next later command. After finding the desired previous command, you can edit its expression and then resubmit it by typing RET. Any editing you have done on the command to be repeated is lost if you use `M-n' or `M-p'. `M-n' and `M-p' are specially defined within `C-x ESC' to run the commands `previous-complex-command' and `next-complex-command'. The list of previous commands using the minibuffer is stored as a Lisp list in the variable `command-history'. Each element of the list is a Lisp expression which describes one command and its arguments. Lisp programs can reexecute a command by feeding the corresponding `command-history' element to `eval'. File: emacs, Node: M-x, Next: Help, Prev: Minibuffer, Up: Top Running Commands by Name ************************ The Emacs commands that are used often or that must be quick to type are bound to keys--short sequences of characters--for convenient use. Other Emacs commands that are used more rarely are not bound to keys; to run them, you must refer to them by name. A command name consists, by convention, of one or more words, separated by hyphens; for example, `auto-fill-mode' or `manual-entry'. The use of English words makes the command name easier to remember than a key made up of obscure characters, even though it results in more characters to type. You can run any command by name, even if it can be run by keys as well. To run a command by name, to start with `M-x', then type the command name, and finish with RET. `M-x' uses the minibuffer to read the command name. RET exits the minibuffer and runs the command. Emacs uses the minibuffer for reading input for many different purposes; on this occasion, the string `M-x' is displayed at the beginning of the minibuffer as a "prompt" to remind you that your input should be the name of a command to be run. *Note Minibuffer::, for full information on the features of the minibuffer. You can use completion to enter a command name. For example, to invoke the command `forward-char', type: M-x forward-char RET or M-x fo TAB c RET Note that `forward-char' is the same command that you invoke with the key `C-f'. You can call any command (interactively callable function) defined in Emacs by its name using `M-x' whether or not any keys are bound to it. If you type `C-g' while Emacs reads the command name, you cancel the `M-x' command and get out of the minibuffer, ending up at top level. To pass a numeric argument to a command you are invoking with `M-x', specify the numeric argument before the `M-x'. `M-x' passes the argument along to the function that it calls. The argument value appears in the prompt while the command name is being read. You can use the command `M-x interactive' to specify a way of parsing arguments for interactive use of a function. For example, write (defun foo (arg) "Doc string" (interactive "p") ...use arg...) to make ARG be the prefix argument when `foo' is called as a command. The call to `interactive' is actually a declaration rather than a function; it tells `call-interactively' how to read arguments to pass to the function. When actually called, `interactive' returns `nil'. The argument of INTERACTIVE is usually a string containing a code letter followed by a prompt. Some code letters do not use I/O to get the argument and do not need prompts. To prompt for multiple arguments, you must provide a code letter, its prompt, a newline, and another code letter, etc. If the argument is not a string, it is evaluated to get a list of arguments to pass to the function. If you do not provide an argument to `interactive', no arguments are passed when calling interactively. Available code letters are: `a' Function name: symbol with a function definition. `b' Name of existing buffer. `B' Name of buffer, possibly nonexistent. `c' Character. `C' Command name: symbol with interactive function definition. `d' Value of point as number. Does not do I/O. `D' Directory name. `e' Last mouse event. `f' Existing file name. `F' Possibly nonexistent file name. `k' Key sequence (string). `m' Value of mark as number. Does not do I/O. `n' Number read using minibuffer. `N' Prefix arg converted to number, or if none, do like code `n'. `p' Prefix arg converted to number. Does not do I/O. `P' Prefix arg in raw form. Does not do I/O. `r' Region: point and mark as two numeric arguments, smallest first. Does not do I/O. `s' Any string. `S' Any symbol. `v' Variable name: symbol that is `user-variable-p'. `x' Lisp expression read but not evaluated. `X' Lisp expression read and evaluated. In addition, if the string begins with `*', an error is signaled if the buffer is read-only. This happens before reading any arguments. If the string begins with `@', the window the mouse is over is selected before anything else is done. You may use both `@' and `*'; they are processed in the order that they appear. Normally, when describing a command that is run by name, we omit the RET that is needed to terminate the name. Thus we may refer to `M-x auto-fill-mode' rather than `M-x auto-fill-mode' RET. We mention the RET only when it it necessary to emphasize its presence, for example, when describing a sequence of input that contains a command name and arguments that follow it. `M-x' is defined to run the command `execute-extended-command', which is responsible for reading the name of another command and invoking it. File: emacs, Node: Help, Next: Mark, Prev: M-x, Up: Top Help **** Emacs provides extensive help features which revolve around a single character, `C-h'. `C-h' is a prefix key that is used only for documentation-printing commands. The characters you can type after `C-h' are called "help options". One help option is `C-h'; you use it to ask for help about using `C-h'. `C-h C-h' prints a list of the possible help options, and then asks you to type the desired option. It prompts with a string A, B, C, F, I, K, L, M, N, S, T, V, W, C-c, C-d, C-n, C-w or C-h for more help: You should type one of those characters. Typing a third `C-h' displays a description of what the options mean; Emacs still waits for you to type an option. To cancel, type `C-g'. Here is a summary of the defined help commands. `C-h a STRING RET' Display list of commands whose names contain STRING (`command- apropos'). `C-h b' Display a table of all key bindings in effect now; local bindings of the current major mode first, followed by all global bindings (`describe-bindings'). `C-h c KEY' Print the name of the command that KEY runs (`describe-key- briefly'). `c' is for `character'. For more extensive information on KEY, use `C-h k'. `C-h f FUNCTION RET' Display documentation on the Lisp function named FUNCTION (`describe-function'). Note that commands are Lisp functions, so a command name may be used. `C-h i' Run Info, the program for browsing documentation files (`info'). The complete Emacs manual is available on-line in Info. `C-h k KEY' Display name and documentation of the command KEY runs (`describe-key'). `C-h l' Display a description of the last 100 characters you typed (`view-lossage'). `C-h m' Display documentation of the current major mode (`describe-mode'). `C-h n' Display documentation of Emacs changes, most recent first (`view-emacs-news'). `C-h p' Display a table of all mouse bindings in effect now; local bindings of the current major mode first, followed by all global bindings (`describe-pointer'). `C-h s' Display current contents of the syntax table, plus an explanation of what they mean (`describe-syntax'). `C-h t' Display the Emacs tutorial (`help-with-tutorial'). `C-h v VAR RET' Display the documentation of the Lisp variable VAR (`describe- variable'). `C-h w COMMAND RET' Print which keys run the command named COMMAND (`where-is'). Documentation for a Key ======================= The most basic `C-h' options are `C-h c' (`describe-key-briefly') and `C-h k' (`describe-key'). `C-h c KEY' prints the name of the command that KEY is bound to in the echo area. For example, `C-h c C-f' prints `forward-char'. Since command names are chosen to describe what the command does, using this option is a good way to get a somewhat cryptic description of what KEY does. `C-h k KEY' is similar to `C-h c' but gives more information. It displays the documentation string of the function KEY is bound to as well as its name. KEY is a string or vector of events. When called interactvely, KEY may also be a menu selection. This information does not usually fit into the echo area, so a window is used for the display. Help by Command or Variable Name ================================ `C-h f' (`describe-function') reads the name of a Lisp function using the minibuffer, then displays that function's documentation string in a window. Since commands are Lisp functions, you can use the argument FUNCTION to get the documentation of a command that you know by name. For example, C-h f auto-fill-mode RET displays the documentation for `auto-fill-mode'. Using `C-h f' is the only way to see the documentation of a command that is not bound to any key, that is, a command you would normally call using `M-x'. If the variable `describe-function-show-arglist' is `t', `describe-function' shows its arglist if the FUNCTION is not an autoload function. `C-h f' is also useful for Lisp functions you are planning to use in a Lisp program. For example, if you have just written the code `(make-vector len)' and want to make sure you are using `make-vector' properly, type `C-h f make-vector RET'. Because `C-h f' allows all function names, not just command names, you may find that some of your favorite abbreviations that work in `M-x' don't work in `C-h f'. An abbreviation may be unique among command names, yet fail to be unique when other function names are allowed. If you type RET, leaving the minibuffer empty, `C-h f' by default describes the function called by the innermost Lisp expression in the buffer around point, provided that is a valid, defined Lisp function name. For example, if point is located following the text `(make-vector (car x)', the innermost list containing point is the one starting with `(make-vector', so the default is to describe the function `make-vector'. `C-h f' is often useful just to verify that you have the right spelling for the function name. If `C-h f' mentions a default in the prompt, you have typed the name of a defined Lisp function. If that is what you wanted to know, just type `C-g' to cancel the `C-h f' command and continue editing. `C-h w COMMAND RET' tells you what keys are bound to COMMAND. It prints a list of the keys in the echo area. Alternatively, it informs you that a command is not bound to any keys, which implies that you must use `M-x' to call the command. `C-h v' (`describe-variable') is like `C-h f' but describes Lisp variables instead of Lisp functions. Its default is the Lisp symbol around or before point, if that is the name of a known Lisp variable. *Note Variables::. Apropos ======= It is possible to ask a question like, "What are the commands for working with files?" To do this, type `C-h a file RET', which displays a list of all command names that contain `file', such as `copy-file', `find-file', and so on. With each command name a brief description of its use and information on the keys you can use to invoke it is displayed. For example, you would be informed that you can invoke `find-file' by typing `C-x C-f'. The `a' in `C-h a' stands for `Apropos'; `C-h a' runs the Lisp function `command-apropos'. Because `C-h a' looks only for functions whose names contain the string you specify, you must use ingenuity in choosing the string. If you are looking for commands for killing backwards and `C-h a kill-backwards RET' doesn't reveal any commands, don't give up. Try just `kill', or just `backwards', or just `back'. Be persistent. Pretend you are playing Adventure. Also note that you can use a regular expression as the argument (*note Regexps::.). Here is a set of arguments to give to `C-h a' that covers many classes of Emacs commands, since there are strong conventions for naming standard Emacs commands. By giving you a feeling for the naming conventions, this set of arguments can also help you develop a technique for picking `apropos' strings. char, line, word, sentence, paragraph, region, page, sexp, list, defun, buffer, screen, window, file, dir, register, mode, beginning, end, forward, backward, next, previous, up, down, search, goto, kill, delete, mark, insert, yank, fill, indent, case, change, set, what, list, find, view, describe. To list all Lisp symbols that contain a match for a regexp, not just the ones that are defined as commands, use the command `M-x apropos' instead of `C-h a'. Other Help Commands =================== `C-h i' (`info') runs the Info program, which is used for browsing through structured documentation files. The entire Emacs manual is available within Info. Eventually all the documentation of the GNU system will be available. Type `h' after entering Info to run a tutorial on using Info. If something surprising happens, and you are not sure what commands you typed, use `C-h l' (`view-lossage'). `C-h l' prints the last 100 command characters you typed. If you see commands you don't know, use `C-h c' to find out what they do. Emacs has several major modes. Each mode redefines a few keys and makes a few other changes in how editing works. `C-h m' (`describe-mode') prints documentation on the current major mode, which normally describes all the commands that are changed in this mode. `C-h b' (`describe-bindings') and `C-h s' (`describe-syntax') present information about the current Emacs mode that is not covered by `C-h m'. `C-h b' displays a list of all key bindings now in effect; the local bindings of the current major mode first, followed by the global bindings (*note Key Bindings::.). `C-h s' displays the contents of the syntax table, with explanations of each character's syntax (*note Syntax::.). The other `C-h' options display various files of useful information. `C-h C-w' displays details on the complete absence of warranty for GNU Emacs. `C-h n' (`view-emacs-news') displays the file `emacs/etc/NEWS', which contains documentation on Emacs changes arranged chronologically. `C-h t' (`help-with-tutorial') displays the learn-by-doing Emacs tutorial. `C-h C-c' (`describe-copying') displays the file `emacs/etc/COPYING', which tells you the conditions you must obey in distributing copies of Emacs. `C-h C-d' (`describe-distribution') displays another file named `emacs/etc/DISTRIB', which tells you how you can order a copy of the latest version of Emacs. File: emacs, Node: Mark, Next: Killing, Prev: Help, Up: Top Selecting Text ************** Many Emacs commands operate on an arbitrary contiguous part of the current buffer. You can select text in two ways: * You use special keys to select text by defining a region between point and the mark. * If you are running Lucid GNU Emacs under X, you can also select text with the mouse. The Mark and the Region ======================= To specify the text for a command to operate on, set "the mark" at one end of it, and move point to the other end. The text between point and the mark is called "the region". You can move point or the mark to adjust the boundaries of the region. It doesn't matter which one is set first chronologically, or which one comes earlier in the text. Once the mark has been set, it remains until it is set again at another place. The mark remains fixed with respect to the preceding character if text is inserted or deleted in a buffer. Each Emacs buffer has its own mark; when you return to a buffer that had been selected previously, it has the same mark it had before. Many commands that insert text, such as `C-y' (`yank') and `M-x insert-buffer', position the mark at one end of the inserted text--the opposite end from where point is positioned, so that the region contains the text just inserted. Aside from delimiting the region, the mark is useful for marking a spot that you may want to go back to. To make this feature more useful, Emacs remembers 16 previous locations of the mark in the `mark ring'. * Menu: * Setting Mark:: Commands to set the mark. * Using Region:: Summary of ways to operate on contents of the region. * Marking Objects:: Commands to put region around textual units. * Mark Ring:: Previous mark positions saved so you can go back there. * Using X Selections:: Using the mouse to mark a region if running under X. File: emacs, Node: Setting Mark, Next: Using Region, Prev: Mark, Up: Mark Setting the Mark ---------------- Here are some commands for setting the mark: `C-SPC' Set the mark where point is (`set-mark-command'). `C-@' The same. `C-x C-x' Interchange mark and point (`exchange-point-and-mark'). `C-<' Pushes a mark at the beginning of the buffer. `C->' Pushes a mark at the end of the buffer. For example, to convert part of the buffer to all upper-case, you can use the `C-x C-u' (`upcase-region') command, which operates on the text in the region. First go to the beginning of the text you want to capitalize and type `C-SPC' to put the mark there, then move to the end, and then type `C-x C-u' to capitalize the selected region. You can also set the mark at the end of the text, move to the beginning, and then type `C-x C-u'. Most commands that operate on the text in the region have the word `region' in their names. The most common way to set the mark is with the `C-SPC' command (`set-mark-command'). This command sets the mark where point is. You can then move point away, leaving the mark behind. It is actually incorrect to speak of the character `C-SPC'; there is no such character. When you type SPC while holding down CTRL, you get the character `C-@' on most terminals. This character is actually bound to `set-mark-command'. But unless you are unlucky enough to have a terminal where typing `C-SPC' does not produce `C-@', you should think of this character as `C-SPC'. Since terminals have only one cursor, Emacs cannot show you where the mark is located. Most people use the mark soon after they set it, before they forget where it is. But you can see where the mark is with the command `C-x C-x' (`exchange-point-and-mark') which puts the mark where point was and point where the mark was. The extent of the region is unchanged, but the cursor and point are now at the previous location of the mark. Another way to set the mark is to push the mark to the beginning of a buffer while leaving point at its original location. If you supply an argument to `C-<' (`mark-bob'), the mark is pushed N/10 of the way from the true beginning of the buffer. You can also set the mark at the end of a buffer with `C->' (`mark-eob'). It pushes the mark to the end of the buffer, leaving point alone. Supplying an argument to the command, pushes the mark N/10 of the way from the true end of the buffer. If you are using Lucid GNU Emacs under the X window system, you can set the variable `zmacs-regions' to `t'. This makes the current region (defined by point and mark) highlight and makes it available as the X clipboard selection, which means you can use the menu bar items on it. *Note Active Regions:: for more information. `C-x C-x' is also useful when you are satisfied with the location of point but want to move the mark; do `C-x C-x' to put point there and then you can move it. A second use of `C-x C-x', if necessary, puts the mark at the new location with point back at its original location. * Menu: * Active Regions:: Having the region highlight while working under X. File: emacs, Node: Using Region, Next: Marking Objects, Prev: Setting Mark, Up: Mark Operating on the Region ----------------------- Once you have created an active region, you can do many things to the text in it: * Kill it with `C-w' (*note Killing::.). * Save it in a register with `C-x x' (*note Registers::.). * Save it in a buffer or a file (*note Accumulating Text::.). * Convert case with `C-x C-l' or `C-x C-u' (*note Case::.). * Evaluate it as Lisp code with `M-x eval-region' (*note Lisp Eval::.). * Fill it as text with `M-g' (*note Filling::.). * Print hardcopy with `M-x print-region' (*note Hardcopy::.). * Indent it with `C-x TAB' or `C-M-\' (*note Indentation::.). File: emacs, Node: Marking Objects, Next: Mark Ring, Prev: Using Region, Up: Mark Commands to Mark Textual Objects -------------------------------- There are commands for placing point and the mark around a textual object such as a word, list, paragraph or page. `M-@' Set mark after end of next word (`mark-word'). This command and the following one do not move point. `C-M-@' Set mark after end of next Lisp expression (`mark-sexp'). `M-h' Put region around current paragraph (`mark-paragraph'). `C-M-h' Put region around current Lisp defun (`mark-defun'). `C-x h' Put region around entire buffer (`mark-whole-buffer'). `C-x C-p' Put region around current page (`mark-page'). `M-@' (`mark-word') puts the mark at the end of the next word, while `C-M-@' (`mark-sexp') puts it at the end of the next Lisp expression. These characters sometimes save you some typing. A number of commands are available that set both point and mark and thus delimit an object in the buffer. `M-h' (`mark-paragraph') moves point to the beginning of the paragraph that surrounds or follows point, and puts the mark at the end of that paragraph (*note Paragraphs::.). You can then indent, case-convert, or kill the whole paragraph. In the same fashion, `C-M-h' (`mark-defun') puts point before and the mark after the current or following defun (*note Defuns::.). `C-x C-p' (`mark-page') puts point before the current page (or the next or previous, depending on the argument), and mark at the end (*note Pages::.). The mark goes after the terminating page delimiter (to include it), while point goes after the preceding page delimiter (to exclude it). Finally, `C-x h' (`mark-whole-buffer') sets up the entire buffer as the region by putting point at the beginning and the mark at the end. File: emacs, Node: Mark Ring, Prev: Marking Objects, Up: Mark The Mark Ring ------------- Aside from delimiting the region, the mark is also useful for marking a spot that you may want to go back to. To make this feature more useful, Emacs remembers 16 previous locations of the mark in the "mark ring". Most commands that set the mark push the old mark onto this ring. To return to a marked location, use `C-u C-SPC' (or `C-u C-@'); this is the command `set-mark-command' given a numeric argument. The command moves point to where the mark was, and restores the mark from the ring of former marks. Repeated use of this command moves point to all the old marks on the ring, one by one. The marks you have seen go to the end of the ring, so no marks are lost. Each buffer has its own mark ring. All editing commands use the current buffer's mark ring. In particular, `C-u C-SPC' always stays in the same buffer. Many commands that can move long distances, such as `M-<' (`beginning-of-buffer'), start by setting the mark and saving the old mark on the mark ring. This makes it easier for you to move back later. Searches set the mark, unless they do not actually move point. When a command sets the mark, `Mark Set' is printed in the echo area. The variable `mark-ring-max' is the maximum number of entries to keep in the mark ring. If that many entries exist and another entry is added, the last entry in the list is discarded. Repeating `C-u C-SPC' circulates through the entries that are currently in the ring. The variable `mark-ring' holds the mark ring itself, as a list of marker objects in the order most recent first. This variable is local in every buffer. File: emacs, Node: Mouse Selection, Next: Entering Emacs, Prev: Pull-Down Menus, Up: Top Selecting Text with the Mouse ============================= If you are using Lucid GNU Emacs under X, you can use the mouse cursor to select text. There are two mouse cursor shapes: * When the mouse cursor is over text, it appears as an I-beam, the same cursor that `xterm' uses. * When the mouse cursor is not over text, it appears as a plus sign (+). You can set the value of the variable `x-mode-pointer-shape' to determine the shape of the mouse pointer when it is over the modeline. If the value is `nil', the variable `x-nontext-pointer-shape' or the variable `x-pointer-shape' is used. If you want to get fancy, you can set the foreground and background colors of the mouse pointer with the variables `x-pointer-background-color' and `x-pointer-foreground-color'. There are two ways to select a region of text with the mouse: To select a word in text, double click with the left mouse button while the mouse cursor is over the word. The word is highlighted when selected. On monochrome monitors, a stipled background indicates that a region of text has been highlighted. On color monitors, a color background indicates highlighted text. You can triple-click to select whole lines. To select an arbitrary region of text: 1. Move the mouse cursor over the character at the beginning of the region of text you want to select. 2. Press and hold the left mouse button. 3. While holding the left mouse button down, drag the cursor to the character at the end of the region of text you want to select. 4. Release the left mouse button. The selected region of text is highlighted. Once a region of text is selected, it becomes the primary X selection (*note Using X Selections::.) as well as the Emacs selected region. You can paste it into other X applications and use the options from the Edit pull-down menu on it. Since it is also the Emacs region, you can use Emacs region commands on it. Additional Mouse Operations --------------------------- Lucid GNU Emacs also provides the following mouse functions. Most of these are not bound to mouse gestures by default, but they are provided for your customization pleasure. For example, if you wanted `shift-left' (that is, holding down the shift key and clicking the left button) to delete the character at which you are pointing, then you could do this: (global-set-key '(shift button1) 'mouse-del-char) `mouse-del-char' Delete the character pointed to by the mouse. `mouse-delete-window' Delete the Emacs window that the mouse is on. `mouse-keep-one-window' Select the Emacs window that the mouse is on, then delete all other windows on this screen. `mouse-kill-line' Kill the line pointed to by the mouse. `mouse-line-length' Print the length of the line indicated by the pointer. `mouse-scroll' Scroll point to the mouse position. `mouse-select' Select the Emacs window the mouse is on. `mouse-select-and-split' Select the Emacs window mouse is on, then split it vertically in half. `mouse-set-mark' Select the Emacs window the mouse is on and set the mark at the mouse position. Display the cursor at that position for a second. `mouse-set-point' Select the Emacs window that the mouse is on and move point to the mouse position. `mouse-track' Make a selection with the mouse. This is the default binding of the left mouse button (button1). `mouse-track-adjust' Extend the existing selection. This is the default binding of shift-button1. `mouse-track-and-copy-to-cutbuffer' Make a selection like `mouse-track', but also copy it to the cut buffer. `mouse-track-delete-and-insert' Make a selection with the mouse and insert it at point. This is the default binding of control-shift-button1. `mouse-track-insert' Make a selection with the mouse and insert it at point. This is the default binding of control-button1. `mouse-window-to-region' Narrow a window to the region between the cursor and the mouse pointer. The `M-x mouse-track' command should be bound to a mouse button. If you click-and-drag, the selection is set to the region between the point of the initial click and the point at which you release the button. These positions do not need to be ordered. If you click-and-release without moving the mouse, the point is moved, and the selection is disowned (there will be no selection owner.) The mark will be set to the previous position of point. If you double-click, the selection will extend by symbols instead of by characters. If you triple-click, the selection will extend by lines. If you drag the mouse off the top or bottom of the window, you can select pieces of text that are larger than the visible part of the buffer; the buffer will scroll as necessary. The selected text becomes the current X selection, and is also copied to the top of the kill ring. Point will be left at the position at which you released the button and the mark will be left at the initial click position. Bind a mouse click to `mouse-track-and-copy-to-cutbuffer' to copy selections to the cut buffer. See also the `mouse-track-adjust' command, on `Sh-button1'. The `M-x mouse-track-adjust' command should be bound to a mouse button. The selection will be enlarged or shrunk so that the point of the mouse click is one of its endpoints. This is only meaningful after the `mouse-track' command (button1) has been executed. The `M-x mouse-track-delete-and-insert' command is exactly the same as the `mouse-track' command on button1, except that point is not moved; the selected text is immediately inserted after being selected; and the text of the selection is deleted. The `M-x mouse-track-insert' command is exactly the same as the `mouse-track' command on button1, except that point is not moved; the selected text is immediately inserted after being selected; and the selection is immediately disowned afterwards.