@c This is part of the Emacs manual.
-@c Copyright (C) 1985, 86, 87, 93, 94, 95, 97, 2000, 2001
+@c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2000, 2001, 2004, 2005
@c Free Software Foundation, Inc.
@c See file emacs.texi for copying conditions.
@node Search, Fixit, Display, Top
asks interactively which occurrences to replace.
@menu
-* Incremental Search:: Search happens as you type the string.
-* Nonincremental Search:: Specify entire string and then search.
-* Word Search:: Search for sequence of words.
-* Regexp Search:: Search for match for a regexp.
-* Regexps:: Syntax of regular expressions.
-* Search Case:: To ignore case while searching, or not.
-* Replace:: Search, and replace some or all matches.
-* Other Repeating Search:: Operating on all matches for some regexp.
+* Incremental Search:: Search happens as you type the string.
+* Nonincremental Search:: Specify entire string and then search.
+* Word Search:: Search for sequence of words.
+* Regexp Search:: Search for match for a regexp.
+* Regexps:: Syntax of regular expressions.
+* Search Case:: To ignore case while searching, or not.
+* Replace:: Search, and replace some or all matches.
+* Other Repeating Search:: Operating on all matches for some regexp.
@end menu
-@node Incremental Search, Nonincremental Search, Search, Search
+@node Incremental Search
@section Incremental Search
-@cindex incremental search
An incremental search begins searching as soon as you type the first
character of the search string. As you type in the search string, Emacs
shows you where the string (as you have typed it so far) would be
Incremental search backward (@code{isearch-backward}).
@end table
+@menu
+* Basic Isearch:: Basic incremental search commands.
+* Repeat Isearch:: Searching for the same string again.
+* Error in Isearch:: When your string is not found.
+* Special Isearch:: Special input in incremental search.
+* Non-ASCII Isearch:: How to search for non-ASCII characters.
+* Isearch Yank:: Commands that grab text into the search string
+ or else edit the search string.
+* Highlight Isearch:: Isearch highlights the other possible matches.
+* Isearch Scroll:: Scrolling during an incremental search.
+* Slow Isearch:: Incremental search features for slow terminals.
+@end menu
+
+@node Basic Isearch
+@subsection Basics of Incremental Search
+@cindex incremental search
+
@kindex C-s
@findex isearch-forward
@kbd{C-s} starts a forward incremental search. It reads characters
@key{RET} is necessary only if the next command you want to type is a
printing character, @key{DEL}, @key{RET}, or another character that is
special within searches (@kbd{C-q}, @kbd{C-w}, @kbd{C-r}, @kbd{C-s},
-@kbd{C-y}, @kbd{M-y}, @kbd{M-r}, @kbd{M-s}, and some other
+@kbd{C-y}, @kbd{M-y}, @kbd{M-r}, @kbd{M-c}, @kbd{M-e}, and some other
meta-characters).
+ When you exit the incremental search, it sets the mark where point
+@emph{was} before the search. That is convenient for moving back
+there. In Transient Mark mode, incremental search sets the mark
+without activating it, and does so only if the mark is not already
+active.
+
+@node Repeat Isearch
+@subsection Repeating Incremental Search
+
Sometimes you search for @samp{FOO} and find one, but not the one you
expected to find. There was a second @samp{FOO} that you forgot
about, before the one you were aiming for. In this event, type
typing just @kbd{C-s C-s}: the first @kbd{C-s} is the key that invokes
incremental search, and the second @kbd{C-s} means ``search again.''
+ If a search is failing and you ask to repeat it by typing another
+@kbd{C-s}, it starts again from the beginning of the buffer.
+Repeating a failing reverse search with @kbd{C-r} starts again from
+the end. This is called @dfn{wrapping around}, and @samp{Wrapped}
+appears in the search prompt once this has happened. If you keep on
+going past the original starting point of the search, it changes to
+@samp{Overwrapped}, which means that you are revisiting matches that
+you have already seen.
+
To reuse earlier search strings, use the @dfn{search ring}. The
commands @kbd{M-p} and @kbd{M-n} move through the ring to pick a search
string to reuse. These commands leave the selected search ring element
-in the minibuffer, where you can edit it. Type @kbd{C-s} or @kbd{C-r}
+in the minibuffer, where you can edit it. To edit the current search
+string in the minibuffer without replacing it with items from the
+search ring, type @kbd{M-e}. Type @kbd{C-s} or @kbd{C-r}
to terminate editing the string and search for it.
+ You can change to searching backwards with @kbd{C-r}. If a search fails
+because the place you started was too late in the file, you should do this.
+Repeated @kbd{C-r} keeps looking for more occurrences backwards. A
+@kbd{C-s} starts going forwards again. @kbd{C-r} in a search can be canceled
+with @key{DEL}.
+
+@kindex C-r
+@findex isearch-backward
+ If you know initially that you want to search backwards, you can use
+@kbd{C-r} instead of @kbd{C-s} to start the search, because @kbd{C-r} as
+a key runs a command (@code{isearch-backward}) to search backward. A
+backward search finds matches that are entirely before the starting
+point, just as a forward search finds matches that begin after it.
+
+@node Error in Isearch
+@subsection Errors in Incremental Search
+
If your string is not found at all, the echo area says @samp{Failing
I-Search}. The cursor is after the place where Emacs found as much of your
string as it could. Thus, if you search for @samp{FOOT}, and there is no
@samp{FOOT}). A second @kbd{C-g} at that point cancels the search
entirely, returning point to where it was when the search started.
+@cindex quitting (in search)
+ The @kbd{C-g} ``quit'' character does special things during searches;
+just what it does depends on the status of the search. If the search has
+found what you specified and is waiting for input, @kbd{C-g} cancels the
+entire search. The cursor moves back to where you started the search. If
+@kbd{C-g} is typed when there are characters in the search string that have
+not been found---because Emacs is still searching for them, or because it
+has failed to find them---then the search string characters which have not
+been found are discarded from the search string. With them gone, the
+search is now successful and waiting for more input, so a second @kbd{C-g}
+will cancel the entire search.
+
+@node Special Isearch
+@subsection Special Input for Incremental Search
+
An upper-case letter in the search string makes the search
case-sensitive. If you delete the upper-case character from the search
string, it ceases to have this effect. @xref{Search Case}.
treated in the same context. You can also specify a character by its
octal code: enter @kbd{C-q} followed by a sequence of octal digits.
-@cindex searching for non-ASCII characters
+ @kbd{M-%} typed in incremental search invokes @code{query-replace}
+or @code{query-replace-regexp} (depending on search mode) with the
+current search string used as the string to replace. @xref{Query
+Replace}.
+
+ Entering @key{RET} when the search string is empty launches
+nonincremental search (@pxref{Nonincremental Search}).
+
+@vindex isearch-mode-map
+ To customize the special characters that incremental search understands,
+alter their bindings in the keymap @code{isearch-mode-map}. For a list
+of bindings, look at the documentation of @code{isearch-mode} with
+@kbd{C-h f isearch-mode @key{RET}}.
+
+@node Non-ASCII Isearch
+@subsection Isearch for Non-@acronym{ASCII} Characters
+
+@cindex searching for non-@acronym{ASCII} characters
@cindex input method, during incremental search
- To search for non-ASCII characters, you must use an input method
-(@pxref{Input Methods}). If an input method is enabled in the
-current buffer when you start the search, you can use it while you
-type the search string also. Emacs indicates that by including the
-input method mnemonic in its prompt, like this:
+
+ To enter non-@acronym{ASCII} characters in an incrementral search,
+you must use an input method (@pxref{Input Methods}). If an input
+method is enabled in the current buffer when you start the search, you
+can use it while you type the search string also. Emacs indicates
+that by including the input method mnemonic in its prompt, like this:
@example
I-search [@var{im}]:
name of the input method. The input method you enable during
incremental search remains enabled in the current buffer afterwards.
- If a search is failing and you ask to repeat it by typing another
-@kbd{C-s}, it starts again from the beginning of the buffer.
-Repeating a failing reverse search with @kbd{C-r} starts again from
-the end. This is called @dfn{wrapping around}, and @samp{Wrapped}
-appears in the search prompt once this has happened. If you keep on
-going past the original starting point of the search, it changes to
-@samp{Overwrapped}, which means that you are revisiting matches that
-you have already seen.
+@node Isearch Yank
+@subsection Isearch Yanking
-@cindex quitting (in search)
- The @kbd{C-g} ``quit'' character does special things during searches;
-just what it does depends on the status of the search. If the search has
-found what you specified and is waiting for input, @kbd{C-g} cancels the
-entire search. The cursor moves back to where you started the search. If
-@kbd{C-g} is typed when there are characters in the search string that have
-not been found---because Emacs is still searching for them, or because it
-has failed to find them---then the search string characters which have not
-been found are discarded from the search string. With them gone, the
-search is now successful and waiting for more input, so a second @kbd{C-g}
-will cancel the entire search.
-
- You can change to searching backwards with @kbd{C-r}. If a search fails
-because the place you started was too late in the file, you should do this.
-Repeated @kbd{C-r} keeps looking for more occurrences backwards. A
-@kbd{C-s} starts going forwards again. @kbd{C-r} in a search can be canceled
-with @key{DEL}.
-
-@kindex C-r
-@findex isearch-backward
- If you know initially that you want to search backwards, you can use
-@kbd{C-r} instead of @kbd{C-s} to start the search, because @kbd{C-r} as
-a key runs a command (@code{isearch-backward}) to search backward. A
-backward search finds matches that are entirely before the starting
-point, just as a forward search finds matches that begin after it.
-
- The characters @kbd{C-y} and @kbd{C-w} can be used in incremental
+ The characters @kbd{C-w} and @kbd{C-y} can be used in incremental
search to grab text from the buffer into the search string. This
makes it convenient to search for another occurrence of text at point.
@kbd{C-w} copies the character or word after point as part of the
character or word.
@kbd{C-y} is similar to @kbd{C-w} but copies all the rest of the
-current line into the search string. Both @kbd{C-y} and @kbd{C-w}
-convert the text they copy to lower case if the search is currently
-not case-sensitive; this is so the search remains case-insensitive.
+current line into the search string. If point is already at the end
+of a line, it grabs the entire next line. Both @kbd{C-y} and
+@kbd{C-w} convert the text they copy to lower case if the search is
+currently not case-sensitive; this is so the search remains
+case-insensitive.
+
+ @kbd{C-M-w} and @kbd{C-M-y} modify the search string by only one
+character at a time: @kbd{C-M-w} deletes the last character from the
+search string and @kbd{C-M-y} copies the character after point to the
+end of the search string. An alternative method to add the character
+after point into the search string is to enter the minibuffer by
+@kbd{M-e} and to type @kbd{C-f} at the end of the search string in the
+minibuffer.
The character @kbd{M-y} copies text from the kill ring into the search
string. It uses the same text that @kbd{C-y} as a command would yank.
@kbd{Mouse-2} in the echo area does the same.
@xref{Yanking}.
- When you exit the incremental search, it sets the mark to where point
-@emph{was}, before the search. That is convenient for moving back
-there. In Transient Mark mode, incremental search sets the mark without
-activating it, and does so only if the mark is not already active.
-
+@node Highlight Isearch
+@subsection Lazy Search Highlighting
@cindex lazy search highlighting
@vindex isearch-lazy-highlight
+
When you pause for a little while during incremental search, it
highlights all other possible matches for the search string. This
makes it easier to anticipate where you can get to by typing @kbd{C-s}
If you don't like this feature, you can turn it off by setting
@code{isearch-lazy-highlight} to @code{nil}.
-@vindex isearch-lazy-highlight-face
@cindex faces for highlighting search matches
You can control how this highlighting looks by customizing the faces
-@code{isearch} (used for the current match) and
-@code{isearch-lazy-highlight-face} (for all the other matches).
-
-@vindex isearch-mode-map
- To customize the special characters that incremental search understands,
-alter their bindings in the keymap @code{isearch-mode-map}. For a list
-of bindings, look at the documentation of @code{isearch-mode} with
-@kbd{C-h f isearch-mode @key{RET}}.
-
+@code{isearch} (used for the current match) and @code{lazy-highlight}
+(for all the other matches). The latter is also used for other matches
+inside @code{query-replace}.
+
+@node Isearch Scroll
+@subsection Scrolling During Incremental Search
+
+ Vertical scrolling during incremental search can be enabled by
+setting the customizable variable @code{isearch-allow-scroll} to a
+non-@code{nil} value.
+
+ You can then use the vertical scroll-bar or certain keyboard
+commands such as @kbd{@key{PRIOR}} (@code{scroll-down}),
+@kbd{@key{NEXT}} (@code{scroll-up}) and @kbd{C-l} (@code{recenter})
+within the search, thus letting you see more of the text near the
+current match. You must run these commands via their key sequences to
+stay in the search---typing M-x @var{comand-name} will always
+terminate a search.
+
+ You can give prefix arguments to these commands in the usual way.
+The current match cannot be scrolled out of the window---this is
+intentional.
+
+ Several other commands, such as @kbd{C-x 2}
+(@code{split-window-vertically}) and @kbd{C-x ^}
+(@code{enlarge-window}) which don't scroll the window, are
+nevertheless made available under this rubric, since they are likewise
+handy during a search.
+
+ You can make other commands usable within an incremental search by
+giving the command a non-@code{nil} @code{isearch-scroll} property.
+This works for commands that don't permanently change point, the
+buffer contents, the match data, the current buffer, or the selected
+window and frame. The command must not delete the current window and
+must not itself attempt an incremental search.
+
+@node Slow Isearch
@subsection Slow Terminal Incremental Search
Incremental search on a slow terminal uses a modified style of display
The number of lines to use in slow terminal search display is controlled
by the variable @code{search-slow-window-lines}. Its normal value is 1.
-@node Nonincremental Search, Word Search, Incremental Search, Search
+@node Nonincremental Search
@section Nonincremental Search
@cindex nonincremental search
historical reasons, and to avoid the need to find key sequences
for them.
-@node Word Search, Regexp Search, Nonincremental Search, Search
+@node Word Search
@section Word Search
@cindex word search
via the incremental search commands both for historical reasons and
to avoid the need to find suitable key sequences for them.
-@node Regexp Search, Regexps, Word Search, Search
+@node Regexp Search
@section Regular Expression Search
@cindex regular expression
@cindex regexp
A @dfn{regular expression} (@dfn{regexp}, for short) is a pattern
that denotes a class of alternative strings to match, possibly
infinitely many. GNU Emacs provides both incremental and
-nonincremental ways to search for a match for a regexp.
+nonincremental ways to search for a match for a regexp. The syntax of
+regular expressions is explained in the following section.
@kindex C-M-s
@findex isearch-forward-regexp
@kindex C-M-r
@findex isearch-backward-regexp
Incremental search for a regexp is done by typing @kbd{C-M-s}
-(@code{isearch-forward-regexp}), or by invoking @kbd{C-s} with a
-prefix argument (whose value does not matter). This command reads a
+(@code{isearch-forward-regexp}), by invoking @kbd{C-s} with a
+prefix argument (whose value does not matter), or by typing @kbd{M-r}
+within a forward incremental search. This command reads a
search string incrementally just like @kbd{C-s}, but it treats the
search string as a regexp rather than looking for an exact match
against the text in the buffer. Each time you add text to the search
string, you make the regexp longer, and the new regexp is searched
for. To search backward for a regexp, use @kbd{C-M-r}
-(@code{isearch-backward-regexp}), or @kbd{C-r} with a prefix argument.
+(@code{isearch-backward-regexp}), @kbd{C-r} with a prefix argument,
+or @kbd{M-r} within a backward incremental search.
All of the control characters that do special things within an
ordinary incremental search have the same function in incremental regexp
@code{isearch-forward} and @code{isearch-backward}. @xref{Incremental
Search}.
-@node Regexps, Search Case, Regexp Search, Search
+@node Regexps
@section Syntax of Regular Expressions
@cindex syntax of regexps
This manual describes regular expression features that users
typically want to use. There are additional features that are
mainly used in Lisp programs; see @ref{Regular Expressions,,,
-elisp, the same manual}.
+elisp, The Emacs Lisp Reference Manual}.
Regular expressions have a syntax in which a few characters are
special constructs and the rest are @dfn{ordinary}. An ordinary
You can also include character ranges in a character set, by writing the
starting and ending characters with a @samp{-} between them. Thus,
-@samp{[a-z]} matches any lower-case ASCII letter. Ranges may be
+@samp{[a-z]} matches any lower-case @acronym{ASCII} letter. Ranges may be
intermixed freely with individual characters, as in @samp{[a-z$%.]},
-which matches any lower-case ASCII letter or @samp{$}, @samp{%} or
+which matches any lower-case @acronym{ASCII} letter or @samp{$}, @samp{%} or
period.
Note that the usual regexp special characters are not special inside a
@item @kbd{[^ @dots{} ]}
@samp{[^} begins a @dfn{complemented character set}, which matches any
character except the ones specified. Thus, @samp{[^a-z0-9A-Z]} matches
-all characters @emph{except} ASCII letters and digits.
+all characters @emph{except} @acronym{ASCII} letters and digits.
@samp{^} is not special in a character set unless it is the first
character. The character following the @samp{^} is treated as if it
match anything. Thus, @samp{^foo} matches a @samp{foo} that occurs at
the beginning of a line.
+For historical compatibility reasons, @samp{^} can be used with this
+meaning only at the beginning of the regular expression, or after
+@samp{\(} or @samp{\|}.
+
@item @kbd{$}
is similar to @samp{^} but matches only at the end of a line. Thus,
@samp{x+$} matches a string of one @samp{x} or more at the end of a line.
+For historical compatibility reasons, @samp{$} can be used with this
+meaning only at the end of the regular expression, or before @samp{\)}
+or @samp{\|}.
+
@item @kbd{\}
has two functions: it quotes the special characters (including
@samp{\}), and it introduces additional special constructs.
@item \W
matches any character that is not a word-constituent.
+@item \_<
+matches the empty string, but only at the beginning of a symbol.
+A symbol is a sequence of one or more symbol-constituent characters.
+A symbol-constituent character is a character whose syntax is either
+@samp{w} or @samp{_}. @samp{\_<} matches at the beginning of the
+buffer only if a symbol-constituent character follows.
+
+@item \_>
+matches the empty string, but only at the end of a symbol. @samp{\_>}
+matches at the end of the buffer only if the contents end with a
+symbol-constituent character.
+
@item \s@var{c}
matches any character whose syntax is @var{c}. Here @var{c} is a
character that designates a particular syntax class: thus, @samp{w}
The constructs that pertain to words and syntax are controlled by the
setting of the syntax table (@pxref{Syntax}).
- Here is a complicated regexp, stored in @code{sentence-end} and used
-by Emacs to recognize the end of a sentence together with any
-whitespace that follows. We show its Lisp syntax to distinguish the
-spaces from the tab characters. In Lisp syntax, the string constant
-begins and ends with a double-quote. @samp{\"} stands for a
-double-quote as part of the regexp, @samp{\\} for a backslash as part
-of the regexp, @samp{\t} for a tab, and @samp{\n} for a newline.
+ Here is a complicated regexp. It is a simplified version of the
+regexp that Emacs uses, by default, to recognize the end of a sentence
+together with any whitespace that follows. We show its Lisp syntax to
+distinguish the spaces from the tab characters. In Lisp syntax, the
+string constant begins and ends with a double-quote. @samp{\"} stands
+for a double-quote as part of the regexp, @samp{\\} for a backslash as
+part of the regexp, @samp{\t} for a tab, and @samp{\n} for a newline.
@example
"[.?!][]\"')]*\\($\\| $\\|\t\\| \\)[ \t\n]*"
for matching parens.)
@end ignore
-@node Search Case, Replace, Regexps, Search
+@node Search Case
@section Searching and Case
Incremental searches in Emacs normally ignore the case of the text
effect of including an upper-case letter in the current search.
@vindex case-fold-search
+@vindex default-case-fold-search
If you set the variable @code{case-fold-search} to @code{nil}, then
all letters must match exactly, including case. This is a per-buffer
variable; altering the variable affects only the current buffer, but
-there is a default value which you can change as well. @xref{Locals}.
-This variable applies to nonincremental searches also, including those
-performed by the replace commands (@pxref{Replace}) and the minibuffer
-history matching commands (@pxref{Minibuffer History}).
+there is a default value in @code{default-case-fold-search} that you
+can also set. @xref{Locals}. This variable applies to nonincremental
+searches also, including those performed by the replace commands
+(@pxref{Replace}) and the minibuffer history matching commands
+(@pxref{Minibuffer History}).
-@node Replace, Other Repeating Search, Search Case, Search
+@node Replace
@section Replacement Commands
@cindex replacement
@cindex search-and-replace commands
Global search-and-replace operations are not needed often in Emacs,
but they are available. In addition to the simple @kbd{M-x
-replace-string} command which is like that found in most editors,
+replace-string} command which replaces all occurrences,
there is a @kbd{M-x query-replace} command which finds each occurrence
of the pattern and asks you whether to replace it.
(@pxref{Expanding Abbrevs}).
@menu
-* Unconditional Replace:: Replacing all matches for a string.
-* Regexp Replace:: Replacing all matches for a regexp.
-* Replacement and Case:: How replacements preserve case of letters.
-* Query Replace:: How to use querying.
+* Unconditional Replace:: Replacing all matches for a string.
+* Regexp Replace:: Replacing all matches for a regexp.
+* Replacement and Case:: How replacements preserve case of letters.
+* Query Replace:: How to use querying.
@end menu
@node Unconditional Replace, Regexp Replace, Replace, Replace
@subsection Unconditional Replacement
@findex replace-string
-@findex replace-regexp
@table @kbd
@item M-x replace-string @key{RET} @var{string} @key{RET} @var{newstring} @key{RET}
Replace every occurrence of @var{string} with @var{newstring}.
-@item M-x replace-regexp @key{RET} @var{regexp} @key{RET} @var{newstring} @key{RET}
-Replace every match for @var{regexp} with @var{newstring}.
@end table
To replace every instance of @samp{foo} after point with @samp{bar},
What if you want to exchange @samp{x} and @samp{y}: replace every @samp{x} with a @samp{y} and vice versa? You can do it this way:
@example
-M-x query-replace @key{RET} x @key{RET} @@TEMP@@ @key{RET}
-M-x query-replace @key{RET} y @key{RET} x @key{RET}
-M-x query-replace @key{RET} @@TEMP@@ @key{RET} y @key{RET}
+M-x replace-string @key{RET} x @key{RET} @@TEMP@@ @key{RET}
+M-< M-x replace-string @key{RET} y @key{RET} x @key{RET}
+M-< M-x replace-string @key{RET} @@TEMP@@ @key{RET} y @key{RET}
@end example
@noindent
@node Regexp Replace, Replacement and Case, Unconditional Replace, Replace
@subsection Regexp Replacement
+@findex replace-regexp
The @kbd{M-x replace-string} command replaces exact matches for a
single string. The similar command @kbd{M-x replace-regexp} replaces
any match for a specified pattern.
- In @code{replace-regexp}, the @var{newstring} need not be constant: it
-can refer to all or part of what is matched by the @var{regexp}.
-@samp{\&} in @var{newstring} stands for the entire match being replaced.
-@samp{\@var{d}} in @var{newstring}, where @var{d} is a digit, stands for
-whatever matched the @var{d}th parenthesized grouping in @var{regexp}.
-To include a @samp{\} in the text to replace with, you must enter
-@samp{\\}. For example,
+@table @kbd
+@item M-x replace-regexp @key{RET} @var{regexp} @key{RET} @var{newstring} @key{RET}
+Replace every match for @var{regexp} with @var{newstring}.
+@end table
+
+ In @code{replace-regexp}, the @var{newstring} need not be constant:
+it can refer to all or part of what is matched by the @var{regexp}.
+@samp{\&} in @var{newstring} stands for the entire match being
+replaced. @samp{\@var{d}} in @var{newstring}, where @var{d} is a
+digit, stands for whatever matched the @var{d}th parenthesized
+grouping in @var{regexp}. @samp{\#} refers to the count of
+replacements already made in this command, as a decimal number. In
+the first replacement, @samp{\#} stands for @samp{0}; in the second,
+for @samp{1}; and so on. For example,
@example
M-x replace-regexp @key{RET} c[ad]+r @key{RET} \&-safe @key{RET}
@end example
@noindent
-performs the inverse transformation.
+performs the inverse transformation. To include a @samp{\} in the
+text to replace with, you must enter @samp{\\}.
+
+ You can also use Lisp expressions to calculate parts of the
+replacement string. To do this, write @samp{\,} followed by the
+expression in the replacement string. Each replacement calculates the
+value of the expression and converts it to text without quoting (if
+it's a string, this means using the string's contents), and uses it in
+the replacement string in place of the expression itself. If the
+expression is a symbol, one space in the replacement string after the
+symbol name goes with the symbol name, so the value replaces them
+both.
+
+ Inside such an expression, you can use some special sequences.
+@samp{\&} and @samp{\@var{n}} refer here, as usual, to the entire
+match as a string, and to a submatch as a string. @var{n} may be
+multiple digits, and the value of @samp{\@var{n}} is @code{nil} if
+subexpression @var{n} did not match. You can also use @samp{\#&} and
+@samp{\#@var{n}} to refer to those matches as numbers (this is valid
+when the match or submatch has the form of a numeral). @samp{\#} here
+too stands for the number of already-completed replacements.
+
+ Repeating our example to exchange @samp{x} and @samp{y}, we can thus
+do it also this way:
+
+@example
+M-x replace-regexp @key{RET} \(x\)\|y @key{RET}
+\,(if \1 "y" "x") @key{RET}
+@end example
+
+ For computing replacement strings for @samp{\,}, the @code{format}
+function is often useful (@pxref{Formatting Strings,,, elisp, The Emacs
+Lisp Reference Manual}). For example, to add consecutively numbered
+strings like @samp{ABC00042} to columns 73 @w{to 80} (unless they are
+already occupied), you can use
+
+@example
+M-x replace-regexp @key{RET} ^.\@{0,72\@}$ @key{RET}
+\,(format "%-72sABC%05d" \& \#) @key{RET}
+@end example
+
+ If you want to enter part of the replacement string by hand each
+time, use @samp{\?} in the replacement string. Each replacement will
+ask you to edit the replacement string in the minibuffer, putting
+point where the @samp{\?} was. For example,
+
+@example
+M-x replace-regexp @key{RET} \\footnote@{ @key{RET}
+\&\\label@{fn:\#\?@} @key{RET}
+@end example
+
+@noindent
+will add labels starting with @samp{\label@{fn:0@}} to occurrences of
+@samp{\footnote@{}, but letting you edit each replacement before
+performing it. To number the labels starting at 1, use @samp{\,(1+
+\#)} instead of @samp{\#}.
@node Replacement and Case, Query Replace, Regexp Replace, Replace
@subsection Replace Commands and Case
@kindex C-M-%
@findex query-replace-regexp
@kbd{C-M-%} performs regexp search and replace (@code{query-replace-regexp}).
+It works like @code{replace-regexp} except that it queries
+like @code{query-replace}.
+
+@cindex faces for highlighting query replace
+ These commands highlight the current match using the face
+@code{query-replace}. They highlight other matches using
+@code{lazy-highlight} just like incremental search (@pxref{Incremental
+Search}).
The characters you can type when you are shown a match for the string
or regexp are:
@item ^
to go back to the position of the previous occurrence (or what used to
-be an occurrence), in case you changed it by mistake. This works by
-popping the mark ring. Only one @kbd{^} in a row is meaningful, because
-only one previous replacement position is kept during @code{query-replace}.
+be an occurrence), in case you changed it by mistake or want to
+reexamine it.
@item C-r
to enter a recursive editing level, in case the occurrence needs to be
See also @ref{Transforming File Names}, for Dired commands to rename,
copy, or link files by replacing regexp matches in file names.
-@node Other Repeating Search,, Replace, Search
+@node Other Repeating Search
@section Other Search-and-Loop Commands
Here are some other commands that find matches for a regular
@kbd{o} and @kbd{C-o} display the match in another window; @kbd{C-o}
does not select it.
+Occur mode supports the @code{next-error} functionality described in
+in @ref{Compilation Mode}.
+
@item M-x list-matching-lines
Synonym for @kbd{M-x occur}.