X-Git-Url: https://git.hcoop.net/bpt/emacs.git/blobdiff_plain/06a97e7d078d1ae82083f2743d2e8a93e7c54fee..e7176868e06466fc6200fa4176c680ec88496020:/man/basic.texi diff --git a/man/basic.texi b/man/basic.texi dissimilarity index 61% index c64739c652..26b3137d63 100644 --- a/man/basic.texi +++ b/man/basic.texi @@ -1,776 +1,774 @@ -@c This is part of the Emacs manual. -@c Copyright (C) 1985, 86, 87, 93, 94, 95, 97, 2000 Free Software Foundation, Inc. -@c See file emacs.texi for copying conditions. -@node Basic, Minibuffer, Exiting, Top -@chapter Basic Editing Commands - -@kindex C-h t -@findex help-with-tutorial - We now give the basics of how to enter text, make corrections, and -save the text in a file. If this material is new to you, you might -learn it more easily by running the Emacs learn-by-doing tutorial. To -use the tutorial, run Emacs and type @kbd{Control-h t} -(@code{help-with-tutorial}). - - To clear the screen and redisplay, type @kbd{C-l} (@code{recenter}). - -@menu - -* Inserting Text:: Inserting text by simply typing it. -* Moving Point:: How to move the cursor to the place where you want to - change something. -* Erasing:: Deleting and killing text. -* Undo:: Undoing recent changes in the text. -* Files: Basic Files. Visiting, creating, and saving files. -* Help: Basic Help. Asking what a character does. -* Blank Lines:: Commands to make or delete blank lines. -* Continuation Lines:: Lines too wide for the screen. -* Position Info:: What page, line, row, or column is point on? -* Arguments:: Numeric arguments for repeating a command. -* Repeating:: A short-cut for repeating the previous command. -@end menu - -@node Inserting Text -@section Inserting Text - -@cindex insertion -@cindex graphic characters - To insert printing characters into the text you are editing, just type -them. This inserts the characters you type into the buffer at the -cursor (that is, at @dfn{point}; @pxref{Point}). The cursor moves -forward, and any text after the cursor moves forward too. If the text -in the buffer is @samp{FOOBAR}, with the cursor before the @samp{B}, -then if you type @kbd{XX}, you get @samp{FOOXXBAR}, with the cursor -still before the @samp{B}. - - To @dfn{delete} text you have just inserted, use the large key -labeled @key{DEL}, @key{BACKSPACE} or @key{DELETE} which is a short -distance above the @key{RET} or @key{ENTER} key. This is the key you -normally use for erasing the last character that you typed. -Regardless of the actual name on the key, Emacs always thinks of it as -@key{DEL}, and that's what we call it in the manual. - - The @key{DEL} key deletes the character @emph{before} the cursor. -As a consequence, the cursor and all the characters after it move -backwards. If you type a printing character and then type @key{DEL}, -they cancel out. - - Many keyboards have both a @key{BACKSPACE} key a short ways above -@key{RET} or @key{ENTER}, and a @key{DELETE} key elsewhere. In that -case, the @key{BACKSPACE} key is @key{DEL}, and the @key{DELETE} key -does something else---it deletes ``forwards,'' deleting the character -after point, the one underneath the cursor, like @kbd{C-d} (see -below). - - On a text-only terminal, Emacs cannot automatically tell which keys -it has and where they are located. If the convenient key for deletion -is @key{BACKSPACE}, you must type @kbd{M-x -delete-key-deletes-forward-mode @key{RET}} to make that key behave as -@key{DEL}. @xref{Deletion}, for more explanation of this. - -@kindex RET -@cindex newline - To end a line and start typing a new one, type @key{RET}. This -inserts a newline character in the buffer. If point is in the middle of -a line, @key{RET} splits the line. Typing @key{DEL} when the cursor is -at the beginning of a line deletes the preceding newline, thus joining -the line with the preceding line. - - Emacs can split lines automatically when they become too long, if you -turn on a special minor mode called @dfn{Auto Fill} mode. -@xref{Filling}, for how to use Auto Fill mode. - - If you prefer to have text characters replace (overwrite) existing -text rather than shove it to the right, you can enable Overwrite mode, -a minor mode. @xref{Minor Modes}. - -@cindex quoting -@kindex C-q -@findex quoted-insert - Direct insertion works for printing characters and @key{SPC}, but other -characters act as editing commands and do not insert themselves. If you -need to insert a control character or a character whose code is above 200 -octal, you must @dfn{quote} it by typing the character @kbd{Control-q} -(@code{quoted-insert}) first. (This character's name is normally written -@kbd{C-q} for short.) There are two ways to use @kbd{C-q}:@refill - -@itemize @bullet -@item -@kbd{C-q} followed by any non-graphic character (even @kbd{C-g}) -inserts that character. - -@item -@kbd{C-q} followed by a sequence of octal digits inserts the character -with the specified octal character code. You can use any number of -octal digits; any non-digit terminates the sequence. If the terminating -character is @key{RET}, it serves only to terminate the sequence; any -other non-digit is itself used as input after terminating the sequence. -(The use of octal sequences is disabled in ordinary non-binary Overwrite -mode, to give you a convenient way to insert a digit instead of -overwriting with it.) -@end itemize - -@cindex 8-bit character codes -@noindent -When multibyte characters are enabled, if you specify a code in the -range 0200 through 0377 octal, @kbd{C-q} assumes that you intend to -use some ISO 8859-@var{n} character set, and converts the specified -code to the corresponding Emacs character code. @xref{Enabling -Multibyte}. You select @emph{which} of the ISO 8859 character sets to -use through your choice of language environment (@pxref{Language -Environments}). - -@vindex read-quoted-char-radix -To use decimal or hexadecimal instead of octal, set the variable -@code{read-quoted-char-radix} to 10 or 16. If the radix is greater than -10, some letters starting with @kbd{a} serve as part of a character -code, just like digits. - -A numeric argument to @kbd{C-q} specifies how many copies of the -quoted character should be inserted (@pxref{Arguments}). - -@findex newline -@findex self-insert - Customization information: @key{DEL} in most modes runs the command -@code{delete-backward-char}; @key{RET} runs the command @code{newline}, and -self-inserting printing characters run the command @code{self-insert}, -which inserts whatever character was typed to invoke it. Some major modes -rebind @key{DEL} to other commands. - -@node Moving Point -@section Changing the Location of Point - -@cindex arrow keys -@cindex moving point -@cindex movement -@cindex cursor motion -@cindex moving the cursor - To do more than insert characters, you have to know how to move point -(@pxref{Point}). The simplest way to do this is with arrow keys, or by -clicking the left mouse button where you want to move to. - - There are also control and meta characters for cursor motion. Some -are equivalent to the arrow keys (these date back to the days before -terminals had arrow keys, and are usable on terminals which don't have -them). Others do more sophisticated things. - -@kindex C-a -@kindex C-e -@kindex C-f -@kindex C-b -@kindex C-n -@kindex C-p -@kindex M-> -@kindex M-< -@kindex M-r -@kindex LEFT -@kindex RIGHT -@kindex UP -@kindex DOWN -@findex beginning-of-line -@findex end-of-line -@findex forward-char -@findex backward-char -@findex next-line -@findex previous-line -@findex beginning-of-buffer -@findex end-of-buffer -@findex goto-char -@findex goto-line -@findex move-to-window-line -@table @kbd -@item C-a -Move to the beginning of the line (@code{beginning-of-line}). -@item C-e -Move to the end of the line (@code{end-of-line}). -@item C-f -Move forward one character (@code{forward-char}). The right-arrow key -does the same thing. -@item C-b -Move backward one character (@code{backward-char}). The left-arrow -key has the same effect. -@item M-f -Move forward one word (@code{forward-word}). -@item M-b -Move backward one word (@code{backward-word}). -@item C-n -Move down one line, vertically (@code{next-line}). This command -attempts to keep the horizontal position unchanged, so if you start in -the middle of one line, you end in the middle of the next. The -down-arrow key does the same thing. -@item C-p -Move up one line, vertically (@code{previous-line}). The up-arrow key -has the same effect. -@item M-r -Move point to left margin, vertically centered in the window -(@code{move-to-window-line}). Text does not move on the screen. - -A numeric argument says which screen line to place point on. It counts -screen lines down from the top of the window (zero for the top line). A -negative argument counts lines from the bottom (@minus{}1 for the bottom -line). -@item M-< -Move to the top of the buffer (@code{beginning-of-buffer}). With -numeric argument @var{n}, move to @var{n}/10 of the way from the top. -@xref{Arguments}, for more information on numeric arguments.@refill -@item M-> -Move to the end of the buffer (@code{end-of-buffer}). -@item C-v -Scroll the display one screen forward, and move point if necessary to put -it on the screen (@code{scroll-up}). This doesn't always -move point, but it is commonly used to do so. -If your keyboard has a @key{PAGEDOWN} key, it does the same thing. - -Scrolling commands are further described in @ref{Scrolling}. -@item M-v -Scroll one screen backward, and move point if necessary to put it on -the screen (@code{scroll-down}). This doesn't always move point, but -it is commonly used to do so. The @key{PAGEUP} key has the same -effect. -@item M-x goto-char -Read a number @var{n} and move point to buffer position @var{n}. -Position 1 is the beginning of the buffer. -@item M-x goto-line -Read a number @var{n} and move point to line number @var{n}. Line 1 -is the beginning of the buffer. -@item C-x C-n -@findex set-goal-column -@kindex C-x C-n -Use the current column of point as the @dfn{semipermanent goal column} for -@kbd{C-n} and @kbd{C-p} (@code{set-goal-column}). Henceforth, those -commands always move to this column in each line moved into, or as -close as possible given the contents of the line. This goal column remains -in effect until canceled. -@item C-u C-x C-n -Cancel the goal column. Henceforth, @kbd{C-n} and @kbd{C-p} once -again try to stick to a fixed horizontal position, as usual. -@end table - -@vindex track-eol - If you set the variable @code{track-eol} to a non-@code{nil} value, -then @kbd{C-n} and @kbd{C-p} when at the end of the starting line move -to the end of another line. Normally, @code{track-eol} is @code{nil}. -@xref{Variables}, for how to set variables such as @code{track-eol}. - -@vindex next-line-add-newlines - @kbd{C-n} normally gets an error when you use it on the last line of -the buffer (just as @kbd{C-p} gets an error on the first line). But -if you set the variable @code{next-line-add-newlines} to a -non-@code{nil} value, @kbd{C-n} on the last line of a buffer creates -an additional line at the end and moves down onto it. - -@node Erasing -@section Erasing Text - -@table @kbd -@item @key{DEL} -Delete the character before point (@code{delete-backward-char}). -@item C-d -Delete the character after point (@code{delete-char}). -@item @key{DELETE} -@itemx @key{BACKSPACE} -One of these keys, whichever is the large key above the @key{RET} or -@key{ENTER} key, deletes the character before point, like @key{DEL}. -If that is @key{BACKSPACE}, and your keyboard also has @key{DELETE}, -then @key{DELETE} deletes forwards, like @kbd{C-d}. -@item C-k -Kill to the end of the line (@code{kill-line}). -@item M-d -Kill forward to the end of the next word (@code{kill-word}). -@item M-@key{DEL} -Kill back to the beginning of the previous word -(@code{backward-kill-word}). -@end table - -@cindex killing characters and lines -@cindex deleting characters and lines -@cindex erasing characters and lines - You already know about the @key{DEL} key which deletes the character -before point (that is, before the cursor). Another key, @kbd{Control-d} -(@kbd{C-d} for short), deletes the character after point (that is, the -character that the cursor is on). This shifts the rest of the text on -the line to the left. If you type @kbd{C-d} at the end of a line, it -joins together that line and the next line. - - To erase a larger amount of text, use the @kbd{C-k} key, which kills a -line at a time. If you type @kbd{C-k} at the beginning or middle of a -line, it kills all the text up to the end of the line. If you type -@kbd{C-k} at the end of a line, it joins that line and the next line. - - @xref{Killing}, for more flexible ways of killing text. - -@node Undo -@section Undoing Changes -@cindex undo -@cindex changes, undoing - - You can undo all the recent changes in the buffer text, up to a -certain point. Each buffer records changes individually, and the undo -command always applies to the current buffer. Usually each editing -command makes a separate entry in the undo records, but some commands -such as @code{query-replace} make many entries, and very simple commands -such as self-inserting characters are often grouped to make undoing less -tedious. - -@table @kbd -@item C-x u -Undo one batch of changes---usually, one command worth (@code{undo}). -@item C-_ -The same. -@item C-u C-x u -Undo one batch of changes in the region. -@end table - -@kindex C-x u -@kindex C-_ -@findex undo - The command @kbd{C-x u} or @kbd{C-_} is how you undo. The first time -you give this command, it undoes the last change. Point moves back to -where it was before the command that made the change. - - Consecutive repetitions of @kbd{C-_} or @kbd{C-x u} undo earlier and -earlier changes, back to the limit of the undo information available. -If all recorded changes have already been undone, the undo command -prints an error message and does nothing. - - Any command other than an undo command breaks the sequence of undo -commands. Starting from that moment, the previous undo commands become -ordinary changes that you can undo. Thus, to redo changes you have -undone, type @kbd{C-f} or any other command that will harmlessly break -the sequence of undoing, then type more undo commands. - -@cindex selective undo -@kindex C-u C-x u - Ordinary undo applies to all changes made in the current buffer. You -can also perform @dfn{selective undo}, limited to the current region. -To do this, specify the region you want, then run the @code{undo} -command with a prefix argument (the value does not matter): @kbd{C-u C-x -u} or @kbd{C-u C-_}. This undoes the most recent change in the region. -To undo further changes in the same region, repeat the @code{undo} -command (no prefix argument is needed). In Transient Mark mode, any use -of @code{undo} when there is an active region performs selective undo; -you do not need a prefix argument. - - If you notice that a buffer has been modified accidentally, the -easiest way to recover is to type @kbd{C-_} repeatedly until the stars -disappear from the front of the mode line. At this time, all the -modifications you made have been canceled. Whenever an undo command -makes the stars disappear from the mode line, it means that the buffer -contents are the same as they were when the file was last read in or -saved. - - If you do not remember whether you changed the buffer deliberately, -type @kbd{C-_} once. When you see the last change you made undone, you -will see whether it was an intentional change. If it was an accident, -leave it undone. If it was deliberate, redo the change as described -above. - - Not all buffers record undo information. Buffers whose names start with -spaces don't; these buffers are used internally by Emacs and its extensions -to hold text that users don't normally look at or edit. - - You cannot undo mere cursor motion; only changes in the buffer -contents save undo information. However, some cursor motion commands -set the mark, so if you use these commands from time to time, you can -move back to the neighborhoods you have moved through by popping the -mark ring (@pxref{Mark Ring}). - -@vindex undo-limit -@vindex undo-strong-limit -@cindex undo limit - When the undo information for a buffer becomes too large, Emacs -discards the oldest undo information from time to time (during garbage -collection). You can specify how much undo information to keep by -setting two variables: @code{undo-limit} and @code{undo-strong-limit}. -Their values are expressed in units of bytes of space. - - The variable @code{undo-limit} sets a soft limit: Emacs keeps undo -data for enough commands to reach this size, and perhaps exceed it, but -does not keep data for any earlier commands beyond that. Its default -value is 20000. The variable @code{undo-strong-limit} sets a stricter -limit: the command which pushes the size past this amount is itself -forgotten. Its default value is 30000. - - Regardless of the values of those variables, the most recent change is -never discarded, so there is no danger that garbage collection occurring -right after an unintentional large change might prevent you from undoing -it. - - The reason the @code{undo} command has two keys, @kbd{C-x u} and -@kbd{C-_}, set up to run it is that it is worthy of a single-character -key, but on some keyboards it is not obvious how to type @kbd{C-_}. -@kbd{C-x u} is an alternative you can type straightforwardly on any -terminal. - -@node Basic Files -@section Files - - The commands described above are sufficient for creating and altering -text in an Emacs buffer; the more advanced Emacs commands just make -things easier. But to keep any text permanently you must put it in a -@dfn{file}. Files are named units of text which are stored by the -operating system for you to retrieve later by name. To look at or use -the contents of a file in any way, including editing the file with -Emacs, you must specify the file name. - - Consider a file named @file{/usr/rms/foo.c}. In Emacs, to begin editing -this file, type - -@example -C-x C-f /usr/rms/foo.c @key{RET} -@end example - -@noindent -Here the file name is given as an @dfn{argument} to the command @kbd{C-x -C-f} (@code{find-file}). That command uses the @dfn{minibuffer} to -read the argument, and you type @key{RET} to terminate the argument -(@pxref{Minibuffer}).@refill - - Emacs obeys the command by @dfn{visiting} the file: creating a buffer, -copying the contents of the file into the buffer, and then displaying -the buffer for you to edit. If you alter the text, you can @dfn{save} -the new text in the file by typing @kbd{C-x C-s} (@code{save-buffer}). -This makes the changes permanent by copying the altered buffer contents -back into the file @file{/usr/rms/foo.c}. Until you save, the changes -exist only inside Emacs, and the file @file{foo.c} is unaltered. - - To create a file, just visit the file with @kbd{C-x C-f} as if it -already existed. This creates an empty buffer in which you can insert -the text you want to put in the file. The file is actually created when -you save this buffer with @kbd{C-x C-s}. - - Of course, there is a lot more to learn about using files. @xref{Files}. - -@node Basic Help -@section Help - -@cindex getting help with keys - If you forget what a key does, you can find out with the Help -character, which is @kbd{C-h} (or @key{F1}, which is an alias for -@kbd{C-h}). Type @kbd{C-h k} followed by the key you want to know -about; for example, @kbd{C-h k C-n} tells you all about what @kbd{C-n} -does. @kbd{C-h} is a prefix key; @kbd{C-h k} is just one of its -subcommands (the command @code{describe-key}). The other subcommands of -@kbd{C-h} provide different kinds of help. Type @kbd{C-h} twice to get -a description of all the help facilities. @xref{Help}.@refill - -@node Blank Lines -@section Blank Lines - -@cindex inserting blank lines -@cindex deleting blank lines - Here are special commands and techniques for putting in and taking out -blank lines. - -@c widecommands -@table @kbd -@item C-o -Insert one or more blank lines after the cursor (@code{open-line}). -@item C-x C-o -Delete all but one of many consecutive blank lines -(@code{delete-blank-lines}). -@end table - -@kindex C-o -@kindex C-x C-o -@cindex blank lines -@findex open-line -@findex delete-blank-lines - When you want to insert a new line of text before an existing line, you -can do it by typing the new line of text, followed by @key{RET}. -However, it may be easier to see what you are doing if you first make a -blank line and then insert the desired text into it. This is easy to do -using the key @kbd{C-o} (@code{open-line}), which inserts a newline -after point but leaves point in front of the newline. After @kbd{C-o}, -type the text for the new line. @kbd{C-o F O O} has the same effect as -@w{@kbd{F O O @key{RET}}}, except for the final location of point. - - You can make several blank lines by typing @kbd{C-o} several times, or -by giving it a numeric argument to tell it how many blank lines to make. -@xref{Arguments}, for how. If you have a fill prefix, then @kbd{C-o} -command inserts the fill prefix on the new line, when you use it at the -beginning of a line. @xref{Fill Prefix}. - - The easy way to get rid of extra blank lines is with the command -@kbd{C-x C-o} (@code{delete-blank-lines}). @kbd{C-x C-o} in a run of -several blank lines deletes all but one of them. @kbd{C-x C-o} on a -solitary blank line deletes that blank line. When point is on a -nonblank line, @kbd{C-x C-o} deletes any blank lines following that -nonblank line. - -@node Continuation Lines -@section Continuation Lines - -@cindex continuation line -@cindex wrapping -@cindex line wrapping - If you add too many characters to one line without breaking it with -@key{RET}, the line grows to occupy two (or more) lines on the screen. -On graphical displays, Emacs indicates line wrapping with small bent -arrows in the fringes to the left and right of the window. On -text-only terminals, Emacs displays a @samp{\} character at the right -margin of a screen line if it is not the last in its text line. This -@samp{\} character says that the following screen line is not really a -distinct line in the text, just a @dfn{continuation} of a line too -long to fit the screen. Continuation is also called @dfn{line -wrapping}. - - When line wrapping occurs before a character that is wider than one -column, some columns at the end of the previous screen line may be -``empty.'' In this case, Emacs displays additional @samp{\} -characters in the ``empty'' columns, just before the @samp{\} -character that indicates continuation. - - Sometimes it is nice to have Emacs insert newlines automatically when -a line gets too long. Continuation on the screen does not do that. Use -Auto Fill mode (@pxref{Filling}) if that's what you want. - -@vindex truncate-lines -@cindex truncation - As an alternative to continuation, Emacs can display long lines by -@dfn{truncation}. This means that all the characters that do not fit -in the width of the screen or window do not appear at all. They -remain in the buffer, temporarily invisible. On terminals, @samp{$} -in the last column informs you that the line has been truncated on the -display. On window systems, a small straight arrow in the fringe to -the right of the window indicates a truncated line. - -@findex toggle-truncate-lines - Truncation instead of continuation happens whenever horizontal -scrolling is in use, and optionally in all side-by-side windows -(@pxref{Windows}). You can enable or disable truncation for a -particular buffer with the command @kbd{M-x toggle-truncate-lines}. - - @xref{Display Custom}, for additional variables that affect how text is -displayed. - -@node Position Info -@section Cursor Position Information - - Here are commands to get information about the size and position of -parts of the buffer, and to count lines. - -@table @kbd -@item M-x what-page -Display the page number of point, and the line number within the page. -@item M-x what-line -Display the line number of point in the buffer. -@item M-x line-number-mode -@itemx M-x column-number-mode -Toggle automatic display of current line number or column number. -@xref{Optional Mode Line}. -@item M-= -Display the number of lines in the current region (@code{count-lines-region}). -@xref{Mark}, for information about the region. -@item C-x = -Display the character code of character after point, character position of -point, and column of point (@code{what-cursor-position}). -@item M-x hl-line-mode -Enable or disable highlighting of the current line. -@end table - -@findex what-page -@findex what-line -@cindex line number commands -@cindex location of point -@cindex cursor location -@cindex point location - There are two commands for working with line numbers. @kbd{M-x -what-line} computes the current line number and displays it in the echo -area. To go to a given line by number, use @kbd{M-x goto-line}; it -prompts you for the number. These line numbers count from one at the -beginning of the buffer. - - You can also see the current line number in the mode line; @xref{Mode -Line}. If you narrow the buffer, then the line number in the mode line -is relative to the accessible portion (@pxref{Narrowing}). By contrast, -@code{what-line} shows both the line number relative to the narrowed -region and the line number relative to the whole buffer. - - By contrast, @kbd{M-x what-page} counts pages from the beginning of -the file, and counts lines within the page, printing both numbers. -@xref{Pages}. - -@kindex M-= -@findex count-lines-region - While on this subject, we might as well mention @kbd{M-=} (@code{count-lines-region}), -which prints the number of lines in the region (@pxref{Mark}). -@xref{Pages}, for the command @kbd{C-x l} which counts the lines in the -current page. - -@kindex C-x = -@findex what-cursor-position - The command @kbd{C-x =} (@code{what-cursor-position}) can be used to find out -the column that the cursor is in, and other miscellaneous information about -point. It prints a line in the echo area that looks like this: - -@smallexample -Char: c (0143, 99, 0x63) point=21044 of 26883(78%) column 53 -@end smallexample - -@noindent -(In fact, this is the output produced when point is before the -@samp{column} in the example.) - - The four values after @samp{Char:} describe the character that follows -point, first by showing it and then by giving its character code in -octal, decimal and hex. For a non-ASCII multibyte character, these are -followed by @samp{ext} and the character's representation, in hex, in -the buffer's coding system, if that coding system encodes the character -safely and with a single byte (@pxref{Coding Systems}). If the -character's encoding is longer than one byte, Emacs shows @samp{ext ...}. - - @samp{point=} is followed by the position of point expressed as a character -count. The front of the buffer counts as position 1, one character later -as 2, and so on. The next, larger, number is the total number of characters -in the buffer. Afterward in parentheses comes the position expressed as a -percentage of the total size. - - @samp{column} is followed by the horizontal position of point, in -columns from the left edge of the window. - - If the buffer has been narrowed, making some of the text at the -beginning and the end temporarily inaccessible, @kbd{C-x =} prints -additional text describing the currently accessible range. For example, it -might display this: - -@smallexample -Char: C (0103, 67, 0x43) point=252 of 889(28%) <231 - 599> column 0 -@end smallexample - -@noindent -where the two extra numbers give the smallest and largest character -position that point is allowed to assume. The characters between those -two positions are the accessible ones. @xref{Narrowing}. - - If point is at the end of the buffer (or the end of the accessible -part), the @w{@kbd{C-x =}} output does not describe a character after -point. The output might look like this: - -@smallexample -point=26957 of 26956(100%) column 0 -@end smallexample - - @w{@kbd{C-u C-x =}} displays additional information about a character, -in place of the buffer coordinates and column: the character set name -and the codes that identify the character within that character set; -ASCII characters are identified as belonging to the @code{ASCII} -character set. In addition, the full character encoding, even if it -takes more than a single byte, is shown after @samp{ext}. Here's an -example for a Latin-1 character A with a grave accent in a buffer whose -coding system is iso-2022-7bit@footnote{On terminals that support -Latin-1 characters, the character shown after @samp{Char:} is displayed -as the actual glyph of A with grave accent.}: - -@example -Char: @`A (04300, 2240, 0x8c0, ext ESC , A @@) (latin-iso8859-1 64) -@end example - -@node Arguments -@section Numeric Arguments -@cindex numeric arguments -@cindex prefix arguments -@cindex arguments to commands - - In mathematics and computer usage, the word @dfn{argument} means -``data provided to a function or operation.'' You can give any Emacs -command a @dfn{numeric argument} (also called a @dfn{prefix argument}). -Some commands interpret the argument as a repetition count. For -example, @kbd{C-f} with an argument of ten moves forward ten characters -instead of one. With these commands, no argument is equivalent to an -argument of one. Negative arguments tell most such commands to move or -act in the opposite direction. - -@kindex M-1 -@kindex M-@t{-} -@findex digit-argument -@findex negative-argument - If your terminal keyboard has a @key{META} key, the easiest way to -specify a numeric argument is to type digits and/or a minus sign while -holding down the @key{META} key. For example, -@example -M-5 C-n -@end example -@noindent -would move down five lines. The characters @kbd{Meta-1}, @kbd{Meta-2}, -and so on, as well as @kbd{Meta--}, do this because they are keys bound -to commands (@code{digit-argument} and @code{negative-argument}) that -are defined to contribute to an argument for the next command. Digits -and @kbd{-} modified with Control, or Control and Meta, also specify -numeric arguments. - -@kindex C-u -@findex universal-argument - Another way of specifying an argument is to use the @kbd{C-u} -(@code{universal-argument}) command followed by the digits of the -argument. With @kbd{C-u}, you can type the argument digits without -holding down modifier keys; @kbd{C-u} works on all terminals. To type a -negative argument, type a minus sign after @kbd{C-u}. Just a minus sign -without digits normally means @minus{}1. - - @kbd{C-u} followed by a character which is neither a digit nor a minus -sign has the special meaning of ``multiply by four.'' It multiplies the -argument for the next command by four. @kbd{C-u} twice multiplies it by -sixteen. Thus, @kbd{C-u C-u C-f} moves forward sixteen characters. This -is a good way to move forward ``fast,'' since it moves about 1/5 of a line -in the usual size screen. Other useful combinations are @kbd{C-u C-n}, -@kbd{C-u C-u C-n} (move down a good fraction of a screen), @kbd{C-u C-u -C-o} (make ``a lot'' of blank lines), and @kbd{C-u C-k} (kill four -lines).@refill - - Some commands care only about whether there is an argument, and not about -its value. For example, the command @kbd{M-q} (@code{fill-paragraph}) with -no argument fills text; with an argument, it justifies the text as well. -(@xref{Filling}, for more information on @kbd{M-q}.) Plain @kbd{C-u} is a -handy way of providing an argument for such commands. - - Some commands use the value of the argument as a repeat count, but do -something peculiar when there is no argument. For example, the command -@kbd{C-k} (@code{kill-line}) with argument @var{n} kills @var{n} lines, -including their terminating newlines. But @kbd{C-k} with no argument is -special: it kills the text up to the next newline, or, if point is right at -the end of the line, it kills the newline itself. Thus, two @kbd{C-k} -commands with no arguments can kill a nonblank line, just like @kbd{C-k} -with an argument of one. (@xref{Killing}, for more information on -@kbd{C-k}.)@refill - - A few commands treat a plain @kbd{C-u} differently from an ordinary -argument. A few others may treat an argument of just a minus sign -differently from an argument of @minus{}1. These unusual cases are -described when they come up; they are always for reasons of convenience -of use of the individual command. - - You can use a numeric argument to insert multiple copies of a -character. This is straightforward unless the character is a digit; for -example, @kbd{C-u 6 4 a} inserts 64 copies of the character @samp{a}. -But this does not work for inserting digits; @kbd{C-u 6 4 1} specifies -an argument of 641, rather than inserting anything. To separate the -digit to insert from the argument, type another @kbd{C-u}; for example, -@kbd{C-u 6 4 C-u 1} does insert 64 copies of the character @samp{1}. - - We use the term ``prefix argument'' as well as ``numeric argument'' to -emphasize that you type the argument before the command, and to -distinguish these arguments from minibuffer arguments that come after -the command. - -@node Repeating -@section Repeating a Command -@cindex repeating a command - -@kindex C-x z -@findex repeat - The command @kbd{C-x z} (@code{repeat}) provides another way to repeat -an Emacs command many times. This command repeats the previous Emacs -command, whatever that was. Repeating a command uses the same arguments -that were used before; it does not read new arguments each time. - - To repeat the command more than once, type additional @kbd{z}'s: each -@kbd{z} repeats the command one more time. Repetition ends when you -type a character other than @kbd{z}, or press a mouse button. - - For example, suppose you type @kbd{C-u 2 0 C-d} to delete 20 -characters. You can repeat that command (including its argument) three -additional times, to delete a total of 80 characters, by typing @kbd{C-x -z z z}. The first @kbd{C-x z} repeats the command once, and each -subsequent @kbd{z} repeats it once again. - +@c This is part of the Emacs manual. +@c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2000, 2001, +@c 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc. +@c See file emacs.texi for copying conditions. +@node Basic, Minibuffer, Exiting, Top +@chapter Basic Editing Commands + +@kindex C-h t +@findex help-with-tutorial + Here we explain the basics of how to enter text, make corrections, +and save the text in a file. If this material is new to you, we +suggest you first run the Emacs learn-by-doing tutorial, by typing +@kbd{Control-h t} inside Emacs. (@code{help-with-tutorial}). + + To clear and redisplay the screen, type @kbd{C-l} (@code{recenter}). + +@menu + +* Inserting Text:: Inserting text by simply typing it. +* Moving Point:: Moving the cursor to the place where you want to + change something. +* Erasing:: Deleting and killing text. +* Basic Undo:: Undoing recent changes in the text. +* Files: Basic Files. Visiting, creating, and saving files. +* Help: Basic Help. Asking what a character does. +* Blank Lines:: Making and deleting blank lines. +* Continuation Lines:: How Emacs displays lines too wide for the screen. +* Position Info:: What page, line, row, or column is point on? +* Arguments:: Numeric arguments for repeating a command N times. +* Repeating:: Repeating the previous command quickly. +@end menu + +@node Inserting Text +@section Inserting Text + +@cindex insertion +@cindex graphic characters + Typing printing characters inserts them into the text you are +editing. It inserts them into the buffer at the cursor; more +precisely, it inserts them at @dfn{point}, but the cursor normally +shows where point is. @xref{Point}. + + Insertion moves the cursor forward, and the following text moves +forward with the cursor. If the text in the buffer is @samp{FOOBAR}, +with the cursor before the @samp{B}, and you type @kbd{XX}, you get +@samp{FOOXXBAR}, with the cursor still before the @samp{B}. + + To @dfn{delete} text you have just inserted, use the large key +labeled @key{DEL}, @key{BACKSPACE} or @key{DELETE} which is a short +distance above the @key{RET} or @key{ENTER} key. Regardless of the +label on that key, Emacs thinks of it as @key{DEL}, and that's what we +call it in this manual. @key{DEL} is the key you normally use outside +Emacs to erase the last character that you typed. + + The @key{DEL} key deletes the character @emph{before} the cursor. +As a consequence, the cursor and all the characters after it move +backwards. If you type a printing character and then type @key{DEL}, +they cancel out. + + On most computers, Emacs sets up @key{DEL} automatically. In some +cases, especially with text-only terminals, Emacs may guess wrong. If +the key that ought to erase the last character doesn't do it in Emacs, +see @ref{DEL Does Not Delete}. + + Most PC keyboards have both a @key{BACKSPACE} key a little ways +above @key{RET} or @key{ENTER}, and a @key{DELETE} key elsewhere. On +these keyboards, Emacs tries to set up @key{BACKSPACE} as @key{DEL}. +The @key{DELETE} key deletes ``forwards'' like @kbd{C-d} (see below), +which means it deletes the character underneath the cursor (after +point). + +@kindex RET +@cindex newline + To end a line and start typing a new one, type @key{RET}. (This +key may be labeled @key{RETURN} or @key{ENTER}, but in Emacs we call +it @key{RET}.) This inserts a newline character in the buffer. If +point is at the end of the line, this creates a new blank line after +it. If point is in the middle of a line, the effect is to split that +line. Typing @key{DEL} when the cursor is at the beginning of a line +deletes the preceding newline character, thus joining the line with +the one before it. + + Emacs can split lines automatically when they become too long, if +you turn on a special minor mode called @dfn{Auto Fill} mode. +@xref{Filling}, for Auto Fill mode and other methods of @dfn{filling} +text. + + If you prefer printing characters to replace (overwrite) existing +text, rather than shove it to the right, you should enable Overwrite +mode, a minor mode. @xref{Minor Modes}. + +@cindex quoting +@kindex C-q +@findex quoted-insert + Only printing characters and @key{SPC} insert themselves in Emacs. +Other characters act as editing commands and do not insert themselves. +These include control characters, and characters with codes above 200 +octal. If you need to insert one of these characters in the buffer, +you must @dfn{quote} it by typing the character @kbd{Control-q} +(@code{quoted-insert}) first. (This character's name is normally +written @kbd{C-q} for short.) There are two ways to use +@kbd{C-q}: + +@itemize @bullet +@item +@kbd{C-q} followed by any non-graphic character (even @kbd{C-g}) +inserts that character. + +@item +@kbd{C-q} followed by a sequence of octal digits inserts the character +with the specified octal character code. You can use any number of +octal digits; any non-digit terminates the sequence. If the +terminating character is @key{RET}, it serves only to terminate the +sequence. Any other non-digit terminates the sequence and then acts +as normal input---thus, @kbd{C-q 1 0 1 B} inserts @samp{AB}. + +The use of octal sequences is disabled in ordinary non-binary +Overwrite mode, to give you a convenient way to insert a digit instead +of overwriting with it. +@end itemize + +@cindex 8-bit character codes +@noindent +When multibyte characters are enabled, if you specify a code in the +range 0200 through 0377 octal, @kbd{C-q} assumes that you intend to +use some ISO 8859-@var{n} character set, and converts the specified +code to the corresponding Emacs character code. @xref{Enabling +Multibyte}. You select @emph{which} of the ISO 8859 character sets to +use through your choice of language environment (@pxref{Language +Environments}). + +@vindex read-quoted-char-radix +To use decimal or hexadecimal instead of octal, set the variable +@code{read-quoted-char-radix} to 10 or 16. If the radix is greater than +10, some letters starting with @kbd{a} serve as part of a character +code, just like digits. + +A numeric argument tells @kbd{C-q} how many copies of the quoted +character to insert (@pxref{Arguments}). + +@findex newline +@findex self-insert + Customization information: @key{DEL} in most modes runs the command +@code{delete-backward-char}; @key{RET} runs the command +@code{newline}, and self-inserting printing characters run the command +@code{self-insert}, which inserts whatever character you typed. Some +major modes rebind @key{DEL} to other commands. + +@node Moving Point +@section Changing the Location of Point + +@cindex arrow keys +@cindex moving point +@cindex movement +@cindex cursor motion +@cindex moving the cursor + To do more than insert characters, you have to know how to move point +(@pxref{Point}). The simplest way to do this is with arrow keys, or by +clicking the left mouse button where you want to move to. + + There are also control and meta characters for cursor motion. Some +are equivalent to the arrow keys (it is faster to use these control +keys than move your hand over to the arrow keys). Others do more +sophisticated things. + +@kindex C-a +@kindex C-e +@kindex C-f +@kindex C-b +@kindex C-n +@kindex C-p +@kindex M-> +@kindex M-< +@kindex M-r +@kindex LEFT +@kindex RIGHT +@kindex UP +@kindex DOWN +@findex move-beginning-of-line +@findex move-end-of-line +@findex forward-char +@findex backward-char +@findex next-line +@findex previous-line +@findex beginning-of-buffer +@findex end-of-buffer +@findex goto-char +@findex goto-line +@findex move-to-window-line +@table @kbd +@item C-a +Move to the beginning of the line (@code{move-beginning-of-line}). +@item C-e +Move to the end of the line (@code{move-end-of-line}). +@item C-f +Move forward one character (@code{forward-char}). The right-arrow key +does the same thing. +@item C-b +Move backward one character (@code{backward-char}). The left-arrow +key has the same effect. +@item M-f +Move forward one word (@code{forward-word}). +@item M-b +Move backward one word (@code{backward-word}). +@item C-n +Move down one line vertically (@code{next-line}). This command +attempts to keep the horizontal position unchanged, so if you start in +the middle of one line, you move to the middle of the next. The +down-arrow key does the same thing. +@item C-p +Move up one line, vertically (@code{previous-line}). The up-arrow key +has the same effect. This command preserves position within the line, +like @kbd{C-n}. +@item M-r +Move point to left margin, vertically centered in the window +(@code{move-to-window-line}). Text does not move on the screen. +A numeric argument says which screen line to place point on, counting +downward from the top of the window (zero means the top line). A +negative argument counts lines up from the bottom (@minus{}1 means the +bottom line). +@item M-< +Move to the top of the buffer (@code{beginning-of-buffer}). With +numeric argument @var{n}, move to @var{n}/10 of the way from the top. +@xref{Arguments}, for more information on numeric arguments.@refill +@item M-> +Move to the end of the buffer (@code{end-of-buffer}). +@item C-v +@itemx @key{PAGEDOWN} +@itemx @key{PRIOR} +Scroll the display one screen forward, and move point if necessary to +put it on the screen (@code{scroll-up}). This doesn't always move +point, but it is commonly used to do so. If your keyboard has a +@key{PAGEDOWN} or @key{PRIOR} key, it does the same thing. + +Scrolling commands are described further in @ref{Scrolling}. +@item M-v +@itemx @key{PAGEUP} +@itemx @key{NEXT} +Scroll one screen backward, and move point if necessary to put it on +the screen (@code{scroll-down}). This doesn't always move point, but +it is commonly used to do so. If your keyboard has a @key{PAGEUP} or +@key{NEXT} key, it does the same thing. +@item M-x goto-char +Read a number @var{n} and move point to buffer position @var{n}. +Position 1 is the beginning of the buffer. +@item M-g M-g +@itemx M-g g +@itemx M-x goto-line +Read a number @var{n} and move point to the beginning of line number +@var{n}. Line 1 is the beginning of the buffer. If point is on or +just after a number in the buffer, and you type @key{RET} with the +minibuffer empty, that number is used for @var{n}. +@item C-x C-n +@findex set-goal-column +@kindex C-x C-n +Use the current column of point as the @dfn{semipermanent goal column} +for @kbd{C-n} and @kbd{C-p} (@code{set-goal-column}). When a +semipermanent goal column is in effect, those commands always try to +move to this column, or as close as possible to it, after moving +vertically. The goal column remains in effect until canceled. +@item C-u C-x C-n +Cancel the goal column. Henceforth, @kbd{C-n} and @kbd{C-p} try to +preserve the horizontal position, as usual. +@end table + +@vindex track-eol + If you set the variable @code{track-eol} to a non-@code{nil} value, +then @kbd{C-n} and @kbd{C-p}, when starting at the end of the line, move +to the end of another line. Normally, @code{track-eol} is @code{nil}. +@xref{Variables}, for how to set variables such as @code{track-eol}. + +@vindex next-line-add-newlines + @kbd{C-n} normally stops at the end of the buffer when you use it on +the last line of the buffer. However, if you set the variable +@code{next-line-add-newlines} to a non-@code{nil} value, @kbd{C-n} on +the last line of a buffer creates an additional line at the end and +moves down into it. + +@node Erasing +@section Erasing Text + +@table @kbd +@item @key{DEL} +Delete the character before point (@code{delete-backward-char}). +@item C-d +Delete the character after point (@code{delete-char}). +@item @key{DELETE} +@itemx @key{BACKSPACE} +One of these keys, whichever is the large key above the @key{RET} or +@key{ENTER} key, deletes the character before point---it is @key{DEL}. +If @key{BACKSPACE} is @key{DEL}, and your keyboard also has @key{DELETE}, +then @key{DELETE} deletes forwards, like @kbd{C-d}. +@item C-k +Kill to the end of the line (@code{kill-line}). +@item M-d +Kill forward to the end of the next word (@code{kill-word}). +@item M-@key{DEL} +Kill back to the beginning of the previous word +(@code{backward-kill-word}). +@end table + +@cindex killing characters and lines +@cindex deleting characters and lines +@cindex erasing characters and lines + You already know about the @key{DEL} key which deletes the character +before point (that is, before the cursor). Another key, @kbd{Control-d} +(@kbd{C-d} for short), deletes the character after point (that is, the +character that the cursor is on). This shifts the rest of the text on +the line to the left. If you type @kbd{C-d} at the end of a line, it +joins that line with the following line. + + To erase a larger amount of text, use the @kbd{C-k} key, which +erases (kills) a line at a time. If you type @kbd{C-k} at the +beginning or middle of a line, it kills all the text up to the end of +the line. If you type @kbd{C-k} at the end of a line, it joins that +line with the following line. + + @xref{Killing}, for more flexible ways of killing text. + +@node Basic Undo +@section Undoing Changes + + Emacs records a list of changes made in the buffer text, so you can +you can undo recent changes, as far as the records go. +Usually each editing command makes a separate entry in the undo +records, but sometimes an entry covers just part of a command, and +very simple commands may be grouped. + +@table @kbd +@item C-x u +Undo one entry of the undo records---usually, one command worth +(@code{undo}). +@item C-_ +@itemx C-/ +The same. +@end table + + The command @kbd{C-x u} (or @kbd{C-_} or @kbd{C-/}) is how you undo. +Normally this command undoes the last change, and moves point back to +where it was before the change. + + If you repeat @kbd{C-x u} (or its aliases), each repetition undoes +another, earlier change, back to the limit of the undo information +available. If all recorded changes have already been undone, the undo +command displays an error message and does nothing. + + The undo command applies only to changes in the buffer; you can't +use it to undo mere cursor motion. However, some cursor motion +commands set the mark, so if you use these commands from time to time, +you can move back to the neighborhoods you have moved through by +popping the mark ring (@pxref{Mark Ring}). + +@node Basic Files +@section Files + + Text that you insert in an Emacs buffer lasts only as long as the +Emacs session. To keep any text permanently you must put it in a +@dfn{file}. Files are named units of text which are stored by the +operating system for you to retrieve later by name. To use the +contents of a file in any way, you must specify the file name. That +includes editing the file with Emacs. + + Suppose there is a file named @file{test.emacs} in your home +directory. To begin editing this file in Emacs, type + +@example +C-x C-f test.emacs @key{RET} +@end example + +@noindent +Here the file name is given as an @dfn{argument} to the command @kbd{C-x +C-f} (@code{find-file}). That command uses the @dfn{minibuffer} to +read the argument, and you type @key{RET} to terminate the argument +(@pxref{Minibuffer}). + + Emacs obeys this command by @dfn{visiting} the file: it creates a +buffer, it copies the contents of the file into the buffer, and then +displays the buffer for editing. If you alter the text, you can +@dfn{save} the new text in the file by typing @kbd{C-x C-s} +(@code{save-buffer}). This copies the altered buffer contents back +into the file @file{test.emacs}, making them permanent. Until you +save, the changed text exists only inside Emacs, and the file +@file{test.emacs} is unaltered. + + To create a file, just visit it with @kbd{C-x C-f} as if it already +existed. This creates an empty buffer, in which you can insert the +text you want to put in the file. Emacs actually creates the file the +first time you save this buffer with @kbd{C-x C-s}. + + To learn more about using files in Emacs, see @ref{Files}. + +@node Basic Help +@section Help + +@cindex getting help with keys + If you forget what a key does, you can find out with the Help +character, which is @kbd{C-h} (or @key{F1}, which is an alias for +@kbd{C-h}). Type @kbd{C-h k} followed by the key of interest; for +example, @kbd{C-h k C-n} tells you what @kbd{C-n} does. @kbd{C-h} is +a prefix key; @kbd{C-h k} is just one of its subcommands (the command +@code{describe-key}). The other subcommands of @kbd{C-h} provide +different kinds of help. Type @kbd{C-h} twice to get a description of +all the help facilities. @xref{Help}. + +@node Blank Lines +@section Blank Lines + +@cindex inserting blank lines +@cindex deleting blank lines + Here are special commands and techniques for inserting and deleting +blank lines. + +@table @kbd +@item C-o +Insert one or more blank lines after the cursor (@code{open-line}). +@item C-x C-o +Delete all but one of many consecutive blank lines +(@code{delete-blank-lines}). +@end table + +@kindex C-o +@kindex C-x C-o +@cindex blank lines +@findex open-line +@findex delete-blank-lines + To insert a new line of text before an existing line, +type the new line of text, followed by @key{RET}. +However, it may be easier to see what you are doing if you first make a +blank line and then insert the desired text into it. This is easy to do +using the key @kbd{C-o} (@code{open-line}), which inserts a newline +after point but leaves point in front of the newline. After @kbd{C-o}, +type the text for the new line. @kbd{C-o F O O} has the same effect as +@w{@kbd{F O O @key{RET}}}, except for the final location of point. + + You can make several blank lines by typing @kbd{C-o} several times, or +by giving it a numeric argument specifying how many blank lines to make. +@xref{Arguments}, for how. If you have a fill prefix, the @kbd{C-o} +command inserts the fill prefix on the new line, if typed at the +beginning of a line. @xref{Fill Prefix}. + + The easy way to get rid of extra blank lines is with the command +@kbd{C-x C-o} (@code{delete-blank-lines}). @kbd{C-x C-o} in a run of +several blank lines deletes all but one of them. @kbd{C-x C-o} on a +lone blank line deletes that one. When point is on a nonblank line, +@kbd{C-x C-o} deletes all following blank lines (if any). + +@node Continuation Lines +@section Continuation Lines + +@cindex continuation line +@cindex wrapping +@cindex line wrapping +@cindex fringes, and continuation lines + When a text line is too long to fit in one screen line, Emacs +displays it on two or more screen lines. This is called +@dfn{continuation} or @dfn{line wrapping}. On graphical displays, +Emacs indicates line wrapping with small bent arrows in the left and +right window fringes. On text-only terminals, Emacs displays a +@samp{\} character at the right margin of a screen line if it is not +the last in its text line. This @samp{\} character says that the +following screen line is not really a new text line. + + When line wrapping occurs just before a character that is wider than one +column, some columns at the end of the previous screen line may be +``empty.'' In this case, Emacs displays additional @samp{\} +characters in the ``empty'' columns before the @samp{\} +character that indicates continuation. + + Continued lines can be difficult to read, since lines can break in +the middle of a word. If you prefer, you can make Emacs insert a +newline automatically when a line gets too long, by using Auto Fill +mode. Or enable Long Lines mode, which ensures that wrapping only +occurs between words. @xref{Filling}. + +@cindex truncation +@cindex line truncation, and fringes + Emacs can optionally @dfn{truncate} long lines---this means +displaying just one screen line worth, and the rest of the long line +does not appear at all. @samp{$} in the last column or a small +straight arrow in the window's right fringe indicates a truncated +line. + + @xref{Display Custom}, for more about line truncation, +and other variables that control how text is displayed. + +@node Position Info +@section Cursor Position Information + + Here are commands to get information about the size and position of +parts of the buffer, and to count lines. + +@table @kbd +@item M-x what-page +Display the page number of point, and the line number within that page. +@item M-x what-line +Display the line number of point in the whole buffer. +@item M-x line-number-mode +@itemx M-x column-number-mode +Toggle automatic display of the current line number or column number. +@xref{Optional Mode Line}. +@item M-= +Display the number of lines in the current region (@code{count-lines-region}). +@xref{Mark}, for information about the region. +@item C-x = +Display the character code of character after point, character position of +point, and column of point (@code{what-cursor-position}). +@item M-x hl-line-mode +Enable or disable highlighting of the current line. @xref{Cursor +Display}. +@item M-x size-indication-mode +Toggle automatic display of the size of the buffer. +@xref{Optional Mode Line}. +@end table + +@findex what-page +@findex what-line +@cindex line number commands +@cindex location of point +@cindex cursor location +@cindex point location + @kbd{M-x what-line} displays the current line number +in the echo area. You can also see the current line number in the +mode line; see @ref{Mode Line}; but if you narrow the buffer, the +line number in the mode line is relative to the accessible portion +(@pxref{Narrowing}). By contrast, @code{what-line} shows both the +line number relative to the narrowed region and the line number +relative to the whole buffer. + + @kbd{M-x what-page} counts pages from the beginning of the file, and +counts lines within the page, showing both numbers in the echo area. +@xref{Pages}. + +@kindex M-= +@findex count-lines-region + Use @kbd{M-=} (@code{count-lines-region}) to displays the number of +lines in the region (@pxref{Mark}). @xref{Pages}, for the command +@kbd{C-x l} which counts the lines in the current page. + +@kindex C-x = +@findex what-cursor-position + The command @kbd{C-x =} (@code{what-cursor-position}) shows what +cursor's column position, and other information about point and the +character after it. It displays a line in the echo area that looks +like this: + +@smallexample +Char: c (99, #o143, #x63) point=28062 of 36168 (78%) column=53 +@end smallexample + + The four values after @samp{Char:} describe the character that follows +point, first by showing it and then by giving its character code in +decimal, octal and hex. For a non-@acronym{ASCII} multibyte character, these are +followed by @samp{file} and the character's representation, in hex, in +the buffer's coding system, if that coding system encodes the character +safely and with a single byte (@pxref{Coding Systems}). If the +character's encoding is longer than one byte, Emacs shows @samp{file ...}. + + However, if the character displayed is in the range 0200 through +0377 octal, it may actually stand for an invalid UTF-8 byte read from +a file. In Emacs, that byte is represented as a sequence of 8-bit +characters, but all of them together display as the original invalid +byte, in octal code. In this case, @kbd{C-x =} shows @samp{part of +display ...} instead of @samp{file}. + + @samp{point=} is followed by the position of point expressed as a +character count. The start of the buffer is position 1, one character +later is position 2, and so on. The next, larger, number is the total +number of characters in the buffer. Afterward in parentheses comes +the position expressed as a percentage of the total size. + + @samp{column=} is followed by the horizontal position of point, in +columns from the left edge of the window. + + If the buffer has been narrowed, making some of the text at the +beginning and the end temporarily inaccessible, @kbd{C-x =} displays +additional text describing the currently accessible range. For example, it +might display this: + +@smallexample +Char: C (67, #o103, #x43) point=252 of 889 (28%) <231-599> column=0 +@end smallexample + +@noindent +where the two extra numbers give the smallest and largest character +position that point is allowed to assume. The characters between those +two positions are the accessible ones. @xref{Narrowing}. + + If point is at the end of the buffer (or the end of the accessible +part), the @w{@kbd{C-x =}} output does not describe a character after +point. The output might look like this: + +@smallexample +point=36169 of 36168 (EOB) column=0 +@end smallexample + +@cindex character set of character at point +@cindex font of character at point +@cindex text properties at point + @w{@kbd{C-u C-x =}} displays the following additional information about a +character. + +@itemize @bullet +@item +The character set name, and the codes that identify the character +within that character set; @acronym{ASCII} characters are identified +as belonging to the @code{ascii} character set. + +@item +The character's syntax and categories. + +@item +The character's encodings, both internally in the buffer, and externally +if you were to save the file. + +@item +What keys to type to input the character in the current input method +(if it supports the character). + +@item +If you are running Emacs on a graphical display, the font name and +glyph code for the character. If you are running Emacs on a text-only +terminal, the code(s) sent to the terminal. + +@item +The character's text properties (@pxref{Text Properties,,, +elisp, the Emacs Lisp Reference Manual}), and any overlays containing it +(@pxref{Overlays,,, elisp, the same manual}). +@end itemize + + Here's an example showing the Latin-1 character A with grave accent, +in a buffer whose coding system is @code{iso-latin-1}, whose +terminal coding system is @code{iso-latin-1} (so the terminal actually +displays the character as @samp{@`A}), and which has font-lock-mode +(@pxref{Font Lock}) enabled: + +@smallexample + character: @`A (2240, #o4300, #x8c0, U+00C0) + charset: latin-iso8859-1 + (Right-Hand Part of Latin Alphabet 1@dots{} + code point: #x40 + syntax: w which means: word + category: l:Latin + to input: type "`A" with latin-1-prefix +buffer code: #x81 #xC0 + file code: #xC0 (encoded by coding system iso-latin-1) + display: terminal code #xC0 + +There are text properties here: + fontified t +@end smallexample + +@node Arguments +@section Numeric Arguments +@cindex numeric arguments +@cindex prefix arguments +@cindex arguments to commands + + In mathematics and computer usage, @dfn{argument} means +``data provided to a function or operation.'' You can give any Emacs +command a @dfn{numeric argument} (also called a @dfn{prefix argument}). +Some commands interpret the argument as a repetition count. For +example, @kbd{C-f} with an argument of ten moves forward ten characters +instead of one. With these commands, no argument is equivalent to an +argument of one. Negative arguments tell most such commands to move or +act in the opposite direction. + +@kindex M-1 +@kindex M-@t{-} +@findex digit-argument +@findex negative-argument + If your terminal keyboard has a @key{META} key (labeled @key{ALT} on +PC keyboards), the easiest way to specify a numeric argument is to +type digits and/or a minus sign while holding down the @key{META} key. +For example, + +@example +M-5 C-n +@end example + +@noindent +moves down five lines. The characters @kbd{Meta-1}, @kbd{Meta-2}, +and so on, as well as @kbd{Meta--}, do this because they are keys bound +to commands (@code{digit-argument} and @code{negative-argument}) that +are defined to set up an argument for the next command. +@kbd{Meta--} without digits normally means @minus{}1. Digits and +@kbd{-} modified with Control, or Control and Meta, also specify numeric +arguments. + +@kindex C-u +@findex universal-argument + You can also specify a numeric argument by typing @kbd{C-u} +(@code{universal-argument}) followed by the digits. The advantage of +@kbd{C-u} is that you can type the digits without modifier keys; thus, +@kbd{C-u} works on all terminals. For a negative argument, type a +minus sign after @kbd{C-u}. A minus sign without digits normally +means @minus{}1. + + @kbd{C-u} alone has the special meaning of +``four times'': it multiplies the argument for the next command by +four. @kbd{C-u C-u} multiplies it by sixteen. Thus, @kbd{C-u C-u +C-f} moves forward sixteen characters. This is a good way to move +forward ``fast,'' since it moves about 1/5 of a line in the usual size +screen. Other useful combinations are @kbd{C-u C-n}, @kbd{C-u C-u +C-n} (move down a good fraction of a screen), @kbd{C-u C-u C-o} (make +``a lot'' of blank lines), and @kbd{C-u C-k} (kill four lines). + + Some commands care whether there is an argument, but ignore its +value. For example, the command @kbd{M-q} (@code{fill-paragraph}) +fills text; with an argument, it justifies the text as well. +(@xref{Filling}, for more information on @kbd{M-q}.) Plain @kbd{C-u} +is a handy way of providing an argument for such commands. + + Some commands use the value of the argument as a repeat count, but do +something peculiar when there is no argument. For example, the command +@kbd{C-k} (@code{kill-line}) with argument @var{n} kills @var{n} lines, +including their terminating newlines. But @kbd{C-k} with no argument is +special: it kills the text up to the next newline, or, if point is right at +the end of the line, it kills the newline itself. Thus, two @kbd{C-k} +commands with no arguments can kill a nonblank line, just like @kbd{C-k} +with an argument of one. (@xref{Killing}, for more information on +@kbd{C-k}.) + + A few commands treat a plain @kbd{C-u} differently from an ordinary +argument. A few others may treat an argument of just a minus sign +differently from an argument of @minus{}1. These unusual cases are +described when they come up; they exist to make an individual command +more convenient, and they are documented in that command's +documentation string. + + You can use a numeric argument before a self-inserting character to +insert multiple copies of it. This is straightforward when the +character is not a digit; for example, @kbd{C-u 6 4 a} inserts 64 +copies of the character @samp{a}. But this does not work for +inserting digits; @kbd{C-u 6 4 1} specifies an argument of 641. You +can separate the argument from the digit to insert with another +@kbd{C-u}; for example, @kbd{C-u 6 4 C-u 1} does insert 64 copies of +the character @samp{1}. + + We use the term ``prefix argument'' as well as ``numeric argument'', +to emphasize that you type these argument before the command, and to +distinguish them from minibuffer arguments that come after the +command. + +@node Repeating +@section Repeating a Command +@cindex repeating a command + + Many simple commands, such as those invoked with a single key or +with @kbd{M-x @var{command-name} @key{RET}}, can be repeated by +invoking them with a numeric argument that serves as a repeat count +(@pxref{Arguments}). However, if the command you want to repeat +prompts for input, or uses a numeric argument in another way, that +method won't work. + +@kindex C-x z +@findex repeat + The command @kbd{C-x z} (@code{repeat}) provides another way to repeat +an Emacs command many times. This command repeats the previous Emacs +command, whatever that was. Repeating a command uses the same arguments +that were used before; it does not read new arguments each time. + + To repeat the command more than once, type additional @kbd{z}'s: each +@kbd{z} repeats the command one more time. Repetition ends when you +type a character other than @kbd{z}, or press a mouse button. + + For example, suppose you type @kbd{C-u 2 0 C-d} to delete 20 +characters. You can repeat that command (including its argument) three +additional times, to delete a total of 80 characters, by typing @kbd{C-x +z z z}. The first @kbd{C-x z} repeats the command once, and each +subsequent @kbd{z} repeats it once again. + +@ignore + arch-tag: cda8952a-c439-41c1-aecf-4bc0d6482956 +@end ignore