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472 lines
19 KiB
Plaintext
@c This is part of the Emacs manual.
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@c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2002, 2003,
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@c 2004, 2005, 2006 Free Software Foundation, Inc.
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@c See file emacs.texi for copying conditions.
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@node Fixit, Keyboard Macros, Search, Top
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@chapter Commands for Fixing Typos
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@cindex typos, fixing
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@cindex mistakes, correcting
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In this chapter we describe the commands that are especially useful for
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the times when you catch a mistake in your text just after you have made
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it, or change your mind while composing text on the fly.
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The most fundamental command for correcting erroneous editing is the
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undo command, @kbd{C-x u} or @kbd{C-_} or @kbd{C-/}. This command
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undoes a single command (usually), a part of a command (in the case of
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@code{query-replace}), or several consecutive self-inserting
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characters. Consecutive repetitions of the undo command undo earlier
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and earlier changes, back to the limit of the undo information
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available. @xref{Undo}, for more information.
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@menu
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* Undo:: The Undo commands.
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* Kill Errors:: Commands to kill a batch of recently entered text.
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* Transpose:: Exchanging two characters, words, lines, lists...
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* Fixing Case:: Correcting case of last word entered.
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* Spelling:: Apply spelling checker to a word, or a whole file.
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@end menu
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@node Undo
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@section Undo
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@cindex undo
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@cindex changes, undoing
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The @dfn{undo} commands undo recent changes in the buffer's text.
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Each buffer records changes individually, and the undo command always
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applies to the current buffer. You can undo all the changes in a
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buffer for as far as back these records go. Usually each editing
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command makes a separate entry in the undo records, but some commands
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such as @code{query-replace} divide their changes into multiple
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entries for flexibility in undoing. Meanwhile, self-inserting
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characters are usually grouped to make undoing less tedious.
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@table @kbd
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@item C-x u
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@itemx C-_
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@itemx C-/
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Undo one entry in the current buffer's undo records (@code{undo}).
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@end table
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@kindex C-x u
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@kindex C-_
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@kindex C-/
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@findex undo
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To begin to undo, type the command @kbd{C-x u} (or its aliases,
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@kbd{C-_} or @kbd{C-/}). This undoes the most recent change in the
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buffer, and moves point back to where it was before that change.
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Consecutive repetitions of @kbd{C-x u} (or its aliases) undo earlier
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and earlier changes in the current buffer, back to the limit of the
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current buffer's undo records. If all the recorded changes have
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already been undone, the undo command just signals an error.
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If you notice that a buffer has been modified accidentally, the
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easiest way to recover is to type @kbd{C-_} repeatedly until the stars
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disappear from the front of the mode line. At this time, all the
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modifications you made have been canceled. Whenever an undo command
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makes the stars disappear from the mode line, it means that the buffer
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contents are the same as they were when the file was last read in or
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saved.
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If you do not remember whether you changed the buffer deliberately,
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type @kbd{C-_} once. When you see the last change you made undone, you
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will see whether it was an intentional change. If it was an accident,
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leave it undone. If it was deliberate, redo the change as described
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below.
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@findex undo-only
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Any command other than an undo command breaks the sequence of undo
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commands. Starting from that moment, the previous undo commands
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become ordinary changes that you can undo. Thus, to redo changes you
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have undone, type @kbd{C-f} or any other command that will harmlessly
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break the sequence of undoing, then type undo commands again. On the
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other hand, if you want to resume undoing, without redoing previous
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undo commands, use @kbd{M-x undo-only}. This is like @code{undo}, but
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will not redo changes you have just undone.
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@cindex selective undo
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@kindex C-u C-x u
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Ordinary undo applies to all changes made in the current buffer. You
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can also perform @dfn{selective undo}, limited to the region.
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To do this, specify the region you want, then run the @code{undo}
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command with a prefix argument (the value does not matter): @kbd{C-u
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C-x u} or @kbd{C-u C-_}. This undoes the most recent change in the
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region. To undo further changes in the same region, repeat the
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@code{undo} command (no prefix argument is needed). In Transient Mark
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mode (@pxref{Transient Mark}), any use of @code{undo} when there is an
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active region performs selective undo; you do not need a prefix
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argument.
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Some specialized buffers do not make undo records. Buffers
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whose names start with spaces never do; these buffers are used
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internally by Emacs and its extensions to hold text that users don't
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normally look at or edit.
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@vindex undo-limit
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@vindex undo-strong-limit
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@vindex undo-outer-limit
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@cindex undo limit
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When the undo records for a buffer becomes too large, Emacs
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discards the oldest undo records from time to time (during garbage
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collection). You can specify how much undo records to keep by
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setting three variables: @code{undo-limit}, @code{undo-strong-limit},
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and @code{undo-outer-limit}. Their values are expressed in units of
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bytes of space.
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The variable @code{undo-limit} sets a soft limit: Emacs keeps undo
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data for enough commands to reach this size, and perhaps exceed it,
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but does not keep data for any earlier commands beyond that. Its
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default value is 20000. The variable @code{undo-strong-limit} sets a
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stricter limit: a previous command (not the most recent one) which
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pushes the size past this amount is itself forgotten. The default
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value of @code{undo-strong-limit} is 30000.
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Regardless of the values of those variables, the most recent change
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is never discarded unless it gets bigger than @code{undo-outer-limit}
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(normally 3,000,000). At that point, Emacs discards the undo data and
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warns you about it. This is the only situation in which you cannot
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undo the last command. If this happens, you can increase the value of
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@code{undo-outer-limit} to make it even less likely to happen in the
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future. But if you didn't expect the command to create such large
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undo data, then it is probably a bug and you should report it.
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@xref{Bugs,, Reporting Bugs}.
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The reason the @code{undo} command has three key bindings, @kbd{C-x
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u}, @kbd{C-_} and @kbd{C-/}, is that it is worthy of a
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single-character key, but @kbd{C-x u} is more straightforward for
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beginners to remember and type. Meanwhile, @kbd{C--} on a text-only
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terminal is really @kbd{C-_}, which makes it a natural and easily
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typed binding for undoing.
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@node Kill Errors
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@section Killing Your Mistakes
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@table @kbd
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@item @key{DEL}
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Delete last character (@code{delete-backward-char}).
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@item M-@key{DEL}
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Kill last word (@code{backward-kill-word}).
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@item C-x @key{DEL}
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Kill to beginning of sentence (@code{backward-kill-sentence}).
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@end table
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The @key{DEL} character (@code{delete-backward-char}) is the most
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important correction command. It deletes the character before point.
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When @key{DEL} follows a self-inserting character command, you can think
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of it as canceling that command. However, avoid the confusion of thinking
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of @key{DEL} as a general way to cancel a command!
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When your mistake is longer than a couple of characters, it might be
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more convenient to use @kbd{M-@key{DEL}} or @kbd{C-x @key{DEL}}.
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@kbd{M-@key{DEL}} kills back to the start of the last word, and @kbd{C-x
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@key{DEL}} kills back to the start of the last sentence. @kbd{C-x
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@key{DEL}} is particularly useful when you change your mind about the
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phrasing of the text you are writing. @kbd{M-@key{DEL}} and @kbd{C-x
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@key{DEL}} save the killed text for @kbd{C-y} and @kbd{M-y} to
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retrieve. @xref{Yanking}.@refill
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@kbd{M-@key{DEL}} is often useful even when you have typed only a few
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characters wrong, if you know you are confused in your typing and aren't
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sure exactly what you typed. At such a time, you cannot correct with
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@key{DEL} except by looking at the screen to see what you did. Often it
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requires less thought to kill the whole word and start again.
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@node Transpose
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@section Transposing Text
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@table @kbd
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@item C-t
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Transpose two characters (@code{transpose-chars}).
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@item M-t
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Transpose two words (@code{transpose-words}).
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@item C-M-t
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Transpose two balanced expressions (@code{transpose-sexps}).
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@item C-x C-t
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Transpose two lines (@code{transpose-lines}).
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@end table
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@kindex C-t
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@findex transpose-chars
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The common error of transposing two characters can be fixed, when they
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are adjacent, with the @kbd{C-t} command (@code{transpose-chars}). Normally,
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@kbd{C-t} transposes the two characters on either side of point. When
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given at the end of a line, rather than transposing the last character of
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the line with the newline, which would be useless, @kbd{C-t} transposes the
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last two characters on the line. So, if you catch your transposition error
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right away, you can fix it with just a @kbd{C-t}. If you don't catch it so
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fast, you must move the cursor back between the two transposed
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characters before you type @kbd{C-t}. If you transposed a space with
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the last character of the word before it, the word motion commands are
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a good way of getting there. Otherwise, a reverse search (@kbd{C-r})
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is often the best way. @xref{Search}.
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@kindex C-x C-t
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@findex transpose-lines
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@kindex M-t
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@findex transpose-words
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@c Don't index C-M-t and transpose-sexps here, they are indexed in
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@c programs.texi, in the "List Commands" node.
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@c @kindex C-M-t
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@c @findex transpose-sexps
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@kbd{M-t} transposes the word before point with the word after point
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(@code{transpose-words}). It moves point forward over a word,
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dragging the word preceding or containing point forward as well. The
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punctuation characters between the words do not move. For example,
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@w{@samp{FOO, BAR}} transposes into @w{@samp{BAR, FOO}} rather than
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@samp{@w{BAR FOO,}}.
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@kbd{C-M-t} (@code{transpose-sexps}) is a similar command for
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transposing two expressions (@pxref{Expressions}), and @kbd{C-x C-t}
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(@code{transpose-lines}) exchanges lines. They work like @kbd{M-t}
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except as regards what units of text they transpose.
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A numeric argument to a transpose command serves as a repeat count: it
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tells the transpose command to move the character (word, expression, line)
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before or containing point across several other characters (words,
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expressions, lines). For example, @kbd{C-u 3 C-t} moves the character before
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point forward across three other characters. It would change
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@samp{f@point{}oobar} into @samp{oobf@point{}ar}. This is equivalent to
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repeating @kbd{C-t} three times. @kbd{C-u - 4 M-t} moves the word
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before point backward across four words. @kbd{C-u - C-M-t} would cancel
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the effect of plain @kbd{C-M-t}.@refill
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A numeric argument of zero is assigned a special meaning (because
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otherwise a command with a repeat count of zero would do nothing): to
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transpose the character (word, expression, line) ending after point
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with the one ending after the mark.
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@node Fixing Case
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@section Case Conversion
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@table @kbd
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@item M-- M-l
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Convert last word to lower case. Note @kbd{Meta--} is Meta-minus.
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@item M-- M-u
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Convert last word to all upper case.
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@item M-- M-c
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Convert last word to lower case with capital initial.
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@end table
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@kindex M-@t{-} M-l
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@kindex M-@t{-} M-u
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@kindex M-@t{-} M-c
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A very common error is to type words in the wrong case. Because of this,
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the word case-conversion commands @kbd{M-l}, @kbd{M-u} and @kbd{M-c} have a
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special feature when used with a negative argument: they do not move the
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cursor. As soon as you see you have mistyped the last word, you can simply
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case-convert it and go on typing. @xref{Case}.@refill
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@node Spelling
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@section Checking and Correcting Spelling
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@cindex spelling, checking and correcting
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@cindex checking spelling
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@cindex correcting spelling
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This section describes the commands to check the spelling of a single
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word or of a portion of a buffer. These commands work with the spelling
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checker programs Aspell and Ispell, which are not part of Emacs.
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@ifinfo
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@xref{Top, Aspell,, aspell, The Aspell Manual}.
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@end ifinfo
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@table @kbd
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@item M-x flyspell-mode
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Enable Flyspell mode, which highlights all misspelled words.
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@item M-x flyspell-prog-mode
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Enable Flyspell mode for comments and strings only.
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@item M-$
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Check and correct spelling of the word at point (@code{ispell-word}).
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@item M-@key{TAB}
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@itemx @key{ESC} @key{TAB}
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Complete the word before point based on the spelling dictionary
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(@code{ispell-complete-word}).
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@item M-x ispell
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Spell-check the active region or the current buffer.
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@item M-x ispell-buffer
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Check and correct spelling of each word in the buffer.
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@item M-x ispell-region
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Check and correct spelling of each word in the region.
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@item M-x ispell-message
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Check and correct spelling of each word in a draft mail message,
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excluding cited material.
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@item M-x ispell-change-dictionary @key{RET} @var{dict} @key{RET}
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Restart the Aspell or Ispell process, using @var{dict} as the dictionary.
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@item M-x ispell-kill-ispell
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Kill the Aspell or Ispell subprocess.
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@end table
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@cindex Flyspell mode
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@findex flyspell-mode
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Flyspell mode is a fully-automatic way to check spelling as you edit
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in Emacs. It operates by checking words as you change or insert them.
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When it finds a word that it does not recognize, it highlights that
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word. This does not interfere with your editing, but when you see the
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highlighted word, you can move to it and fix it. Type @kbd{M-x
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flyspell-mode} to enable or disable this mode in the current buffer.
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When Flyspell mode highlights a word as misspelled, you can click on
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it with @kbd{Mouse-2} to display a menu of possible corrections and
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actions. You can also correct the word by editing it manually in any
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way you like.
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@findex flyspell-prog-mode
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Flyspell Prog mode works just like ordinary Flyspell mode, except that
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it only checks words in comments and string constants. This feature
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is useful for editing programs. Type @kbd{M-x flyspell-prog-mode} to
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enable or disable this mode in the current buffer.
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The other Emacs spell-checking features check or look up words when
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you give an explicit command to do so.
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@kindex M-$
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@findex ispell-word
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To check the spelling of the word around or before point, and
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optionally correct it as well, use the command @kbd{M-$}
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(@code{ispell-word}). If the word is not correct, the command offers
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you various alternatives for what to do about it.
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@findex ispell-buffer
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@findex ispell-region
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To check the entire current buffer, use @kbd{M-x ispell-buffer}. Use
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@kbd{M-x ispell-region} to check just the current region. To check
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spelling in an email message you are writing, use @kbd{M-x
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ispell-message}; that command checks the whole buffer, except for
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material that is indented or appears to be cited from other messages.
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@findex ispell
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@cindex spell-checking the active region
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The @kbd{M-x ispell} command spell-checks the active region if the
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Transient Mark mode is on (@pxref{Transient Mark}), otherwise it
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spell-checks the current buffer.
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Each time these commands encounter an incorrect word, they ask you
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what to do. They display a list of alternatives, usually including
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several ``near-misses''---words that are close to the word being
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checked. Then you must type a single-character response. Here are
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the valid responses:
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@table @kbd
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@item @key{SPC}
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Skip this word---continue to consider it incorrect, but don't change it
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here.
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@item r @var{new} @key{RET}
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Replace the word (just this time) with @var{new}. (The replacement
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string will be rescanned for more spelling errors.)
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@item R @var{new} @key{RET}
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Replace the word with @var{new}, and do a @code{query-replace} so you
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can replace it elsewhere in the buffer if you wish. (The replacements
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will be rescanned for more spelling errors.)
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@item @var{digit}
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Replace the word (just this time) with one of the displayed
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near-misses. Each near-miss is listed with a digit; type that digit to
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select it.
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@item a
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Accept the incorrect word---treat it as correct, but only in this
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editing session.
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@item A
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Accept the incorrect word---treat it as correct, but only in this
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editing session and for this buffer.
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@item i
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Insert this word in your private dictionary file so that Aspell or Ispell will
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consider it correct from now on, even in future sessions.
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@item u
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Insert the lower-case version of this word in your private dic@-tion@-ary
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file.
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@item m
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Like @kbd{i}, but you can also specify dictionary completion
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information.
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@item l @var{word} @key{RET}
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Look in the dictionary for words that match @var{word}. These words
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become the new list of ``near-misses''; you can select one of them as
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the replacement by typing a digit. You can use @samp{*} in @var{word} as a
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wildcard.
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@item C-g
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Quit interactive spell checking, leaving point at the word that was
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being checked. You can restart checking again afterward with @kbd{C-u
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M-$}.
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@item X
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Same as @kbd{C-g}.
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@item x
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Quit interactive spell checking and move point back to where it was
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when you started spell checking.
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@item q
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Quit interactive spell checking and kill the Ispell subprocess.
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@item C-l
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Refresh the screen.
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@item C-z
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This key has its normal command meaning (suspend Emacs or iconify this
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frame).
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@item ?
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Show the list of options.
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@end table
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@findex ispell-complete-word
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The command @code{ispell-complete-word}, which is bound to the key
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@kbd{M-@key{TAB}} in Text mode and related modes, shows a list of
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completions based on spelling correction. Insert the beginning of a
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word, and then type @kbd{M-@key{TAB}}; the command displays a
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completion list window. (If your window manager intercepts
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@kbd{M-@key{TAB}}, type @kbd{@key{ESC} @key{TAB}} or @kbd{C-M-i}.) To
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choose one of the completions listed, click @kbd{Mouse-2} or
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@kbd{Mouse-1} fast on it, or move the cursor there in the completions
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window and type @key{RET}. @xref{Text Mode}.
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@ignore
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@findex reload-ispell
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The first time you use any of the spell checking commands, it starts
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an Ispell subprocess. The first thing the subprocess does is read your
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private dictionary, which defaults to the file @file{~/ispell.words}.
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Words that you ``insert'' with the @kbd{i} command are added to that
|
|
file, but not right away---only at the end of the interactive
|
|
replacement procedure. Use the @kbd{M-x reload-ispell} command to
|
|
reload your private dictionary if you edit the file outside of Ispell.
|
|
@end ignore
|
|
|
|
@cindex @code{ispell} program
|
|
@findex ispell-kill-ispell
|
|
Once started, the Aspell or Ispell subprocess continues to run
|
|
(waiting for something to do), so that subsequent spell checking
|
|
commands complete more quickly. If you want to get rid of the
|
|
process, use @kbd{M-x ispell-kill-ispell}. This is not usually
|
|
necessary, since the process uses no time except when you do spelling
|
|
correction.
|
|
|
|
@vindex ispell-dictionary
|
|
Ispell and Aspell use two dictionaries together for spell checking: the
|
|
standard dictionary and your private dictionary. The variable
|
|
@code{ispell-dictionary} specifies the file name to use for the
|
|
standard dictionary; a value of @code{nil} selects the default
|
|
dictionary. The command @kbd{M-x ispell-change-dictionary} sets this
|
|
variable and then restarts the subprocess, so that it will use
|
|
a different standard dictionary.
|
|
|
|
@vindex ispell-complete-word-dict
|
|
Aspell and Ispell use a separate dictionary for word completion.
|
|
The variable @code{ispell-complete-word-dict} specifies the file name
|
|
of this dictionary. The completion dictionary must be different
|
|
because it cannot use root and affix information. For some languages
|
|
there is a spell checking dictionary but no word completion
|
|
dictionary.
|
|
|
|
@ignore
|
|
arch-tag: 3359a443-96ed-448f-9f05-c8111ba8eac0
|
|
@end ignore
|