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

We now give the basics of how to enter text, make corrections, and save the text in a file.  If this material is new to you, you might learn it more easily by running the Emacs learn-by-doing tutorial.  To start the tutorial, type Control-h t (help-with-tutorial).

To clear the screen and redisplay, type C-l (recenter).

Inserting Text
==============

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 point; see Point).  The cursor moves forward, and any text after the cursor moves forward too.  If the text in the buffer is FOOBAR, with the cursor before the B, then if you type XX, you get FOOXXBAR, with the cursor still before the B.

To delete text you have just inserted, use DEL.  DEL deletes the character before the cursor (not the one that the cursor is on top of or under; that is the character AFTER the cursor).  The cursor and all characters after it move backwards.  Therefore, if you type a printing character and then type DEL, they cancel out.

To end a line and start typing a new one, type RET.  This inserts a newline character in the buffer.  If point is in the middle of a line, RET splits the line.  Typing DEL when the cursor is at the beginning of a line 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 mode called Auto Fill mode.  See Filling, for how to use Auto Fill mode.

Customization information: DEL in most modes runs the command delete-backward-char; RET runs the command newline, and self-inserting printing characters run the command self-insert, which inserts whatever character was typed to invoke it.  Some major modes rebind DEL to other commands.

Direct insertion works for printing characters and SPC, but other characters act as editing commands and do not insert themselves.  If you need to insert a control character or a character whose code is above 200 octal, you must quote it by typing the character Control-q (quoted-insert) first.  (This character's name is normally written C-q for short.)  There are two ways to use C-q:

  * C-q followed by any non-graphic character (even C-g) inserts that character.

  * C-q followed by three octal digits inserts the character with the specified character code.

A numeric argument to C-q specifies how many copies of the quoted character should be inserted (see Arguments).

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.  See Minor Modes.

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

To do more than insert characters, you have to know how to move point (see Point).  The simplest way to do this is with arrow keys or the left mouse button.

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.

C-a
     Move to the beginning of the line (beginning-of-line).

C-e
     Move to the end of the line (end-of-line).

C-f
     Move forward one character (forward-char).

C-b
     Move backward one character (backward-char).

M-f
     Move forward one word (forward-word).

M-b
     Move backward one word (backward-word).

C-n
     Move down one line, vertically (next-line).  This command attempts to keep the horizontal position unchanged, so if you start in the middle of one line, you end in the middle of the next.  When on the last line of text, C-n creates a new line and moves onto it.

C-p
     Move up one line, vertically (previous-line).

M-r
     Move point to left margin, vertically centered in the window (move-to-window-line).  Text does not move on the screen.  A numeric argument says how many screen lines down from the top of the window (zero for the top line).  A negative argument counts lines from the bottom (-1 for the bottom line).

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

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

M-x goto-char
     Read a number N and move cursor to character number N. Position 1 is the beginning of the buffer.

M-x goto-line
     Read a number N and move cursor to line number N.  Line 1 is the beginning of the buffer.

C-x C-n
     Use the current column of point as the semipermanent goal column for C-n and C-p (set-goal-column).  Henceforth, those commands always move to this column in each line moved into, or as close as possible given the contents of the line.  This goal column remains in effect until canceled.

C-u C-x C-n
     Cancel the goal column.  Henceforth, C-n and C-p once again try to avoid changing the horizontal position, as usual.

If you set the variable track-eol to a non-nil value, then C-n and C-p when at the end of the starting line move to the end of another line.  Normally, track-eol is nil. See Variables, for how to set variables such as track-eol.

Normally, C-n on the last line of a buffer appends a newline to it.  If the variable next-line-add-newlines is nil, then C-n gets an error instead (like C-p on the first line).

Erasing Text
============

DEL
     Delete the character before the cursor (delete-backward-char).

C-d
     Delete the character after the cursor (delete-char).

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

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

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

You already know about the DEL key which deletes the character before the cursor.  Another key, Control-d (C-d for short), deletes the character after the cursor, causing the rest of the text on the line to shift left.  If C-d is typed at the end of a line, that line and the next line are joined together.

To erase a larger amount of text, use the C-k key, which kills a line at a time.  If C-k is done at the beginning or middle of a line, it kills all the text up to the end of the line.  If C-k is done at the end of a line, it joins that line and the next line.

If you delete or kill text by mistake, you can use the undo command to get it back.  See Undo.

See Killing, for more flexible ways of killing text.

Files
=====

The commands 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 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 /usr/rms/foo.c.  In Emacs, to begin editing this file, type

     C-x C-f /usr/rms/foo.c RET

Here the file name is given as an argument to the command C-x C-f (find-file).  That command uses the minibuffer to read the argument, and you type RET to terminate the argument (see Minibuffer).

Emacs obeys the command by visiting the file: creating a buffer, copying the contents of the file into the buffer, and then displaying the buffer for you to edit.  Then you can make changes, and save the file by typing C-x C-s (save-buffer).  This makes the changes permanent by copying the altered contents of the buffer back into the file /usr/rms/foo.c.  Until you save, the changes exist only inside Emacs, and the file foo.c is unaltered.

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

Of course, there is a lot more to learn about using files.  See Files.

Help
====

If you forget what a key does, you can find out with the Help character, which is C-h.  Type C-h k followed by the key you want to know about; for example, C-h k C-n tells you all about what C-n does.  C-h is a prefix key; C-h k is just one of its subcommands (the command describe-key).  The other subcommands of C-h provide different kinds of help.  Type C-h three times to get a description of all the help facilities.  See Help.

Blank Lines
===========

Here are special commands and techniques for putting in and taking out blank lines.

C-o
     Insert one or more blank lines after the cursor (open-line).

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

When you want to insert a new line of text before an existing line, you can do it by typing the new line of text, followed by 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 C-o (open-line), which inserts a newline after point but leaves point in front of the newline.  After C-o, type the text for the new line.  C-o F O O has the same effect as F O O RET, except for the final location of point.

You can make several blank lines by typing C-o several times, or by giving it a numeric argument to tell it how many blank lines to make.  See Arguments, for how.

If you have a fill prefix, then C-o command inserts the fill prefix on the new line, when you use it at the beginning of a line. See Fill Prefix.

The easy way to get rid of extra blank lines is with the command C-x C-o (delete-blank-lines).  C-x C-o in a run of several blank lines deletes all but one of them.  C-x C-o on a solitary blank line deletes that blank line.  When point is on a nonblank line, C-x C-o deletes any blank lines following that nonblank line.

Continuation Lines
==================

If you add too many characters to one line, without breaking it with RET, the line will grow to occupy two (or more) lines on the screen, with a \ at the extreme right margin of all but the last of them. The \ says that the following screen line is not really a distinct line in the text, but just the continuation of a line too long to fit the screen.  Continuation is also called line wrapping.

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 (see Filling) if that's what you want.

Instead of continuation, you can display long lines by truncation.  This means that all the characters that do not fit in the width of the screen or window do not appear at all.  They remain in the buffer, temporarily invisible.  $ is used in the last column instead of \ to inform you that truncation is in effect.

You can turn off continuation for a particular buffer by setting the variable truncate-lines to non-nil in that buffer. (see Variables.)  Truncation instead of continuation also happens whenever horizontal scrolling is in use, and optionally whenever side-by-side windows are in use (see Windows).  Altering the value of truncate-lines makes it local to the current buffer; until that time, the default value is in effect.  The default is initially nil.  See Locals.

See Display Vars, for additional variables that affect how text is displayed.

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

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

M-x what-page
     Print page number of point, and line number within page.

M-x what-line
     Print line number of point in the buffer.

M-x line-number-mode
     Toggle automatic display of current line number.

M-=
     Print number of lines in the current region (count-lines-region).

C-x =
     Print character code of character after point, character position of point, and column of point (what-cursor-position).

There are two commands for printing the current line number.  M-x what-line computes the current line number and displays it in the echo area.  M-x line-number-mode enables display of the current line number in the mode line; once you turn this on, the number updates as you move point, so it remains valid all the time.  See Mode Line.

Line numbers count from one at the beginning of the buffer.  To go to a given line by number, use M-x goto-line; it prompts you for the line number.

By contrast, M-x what-page counts pages from the beginning of the file, and counts lines within the page, printing both numbers. See Pages.

While on this subject, we might as well mention M-= (count-lines-region), which prints the number of lines in the region (see Mark). See Pages, for the command C-x l which counts the lines in the current page.

The command C-x = (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:

     Char: x (0170)  point=65986 of 563027(12%)  x=44

(In fact, this is the output produced when point is before the x=44 in the example.)

The two values after Char: describe the character following point, first by showing it and second by giving its octal character code.

point= is followed by the position of point expressed as a character count.  The front of the buffer counts as position 1, one character later as 2, and so on.  The next, larger number is the total number of characters in the buffer.  Afterward in parentheses comes the position expressed as a percentage of the total size.

x= is followed by the horizontal position of point, in columns from the left edge of the window.

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

     Char: x (0170)  point=65986 of 563025(12%) <65102 - 68533>  x=44

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

If point is at the end of the buffer (or the end of the accessible part), C-x = omits any description of the character after point. The output looks like this:

     point=563026 of 563025(100%)  x=0

Numeric Arguments
=================

Any Emacs command can be given a numeric argument (also called a prefix argument).  Some commands interpret the argument as a repetition count.  For example, giving an argument of ten to the key C-f 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.

If your terminal keyboard has a META key, the easiest way to specify a numeric argument is to type digits and/or a minus sign while holding down the the META key.  For example,

     M-5 C-n

would move down five lines.  The characters Meta-1, Meta-2, and so on, as well as Meta--, do this because they are keys bound to commands (digit-argument and negative-argument) that are defined to contribute to an argument for the next command.

Another way of specifying an argument is to use the C-u (universal-argument) command followed by the digits of the argument. With C-u, you can type the argument digits without holding down shift keys.  To type a negative argument, start with a minus sign. Just a minus sign normally means -1.  C-u works on all terminals.

C-u followed by a character which is neither a digit nor a minus sign has the special meaning of ``multiply by four''.  It multiplies the argument for the next command by four.  C-u twice multiplies it by sixteen.  Thus, C-u C-u C-f moves forward sixteen characters.  This is a good way to move forward ``fast'', since it moves about 1/5 of a line in the usual size screen.  Other useful combinations are C-u C-n, C-u C-u C-n (move down a good fraction of a screen), C-u C-u C-o (make ``a lot'' of blank lines), and C-u C-k (kill four lines).

Some commands care only about whether there is an argument, and not about its value.  For example, the command M-q (fill-paragraph) with no argument fills text; with an argument, it justifies the text as well. (see Filling, for more information on M-q.)  Just C-u is a handy way of providing an argument for such commands.

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

A few commands treat a plain C-u differently from an ordinary argument.  A few others may treat an argument of just a minus sign differently from an argument of -1.  These unusual cases will be described when they come up; they are always for reasons of convenience of use of the individual command.

You can use a numeric argument to insert multiple copies of a character.  This is straightforward unless the character is a digit.  To prevent the digit from becoming part of the argument, type another C-u.  That terminates the argument.  If you then type another digit, then the digit acts as a self-inserting character and uses the argument as a repeat count.

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.