@c This is part of the Emacs manual.
-@c Copyright (C) 1985, 86, 87, 93-95, 97, 2000 Free Software Foundation, Inc.
+@c Copyright (C) 1985, 86, 87, 93, 94, 95, 97, 2000, 2001
+@c Free Software Foundation, Inc.
@c See file emacs.texi for copying conditions.
@node Search, Fixit, Display, Top
@chapter Searching and Replacement
those of other editors.
Besides the usual @code{replace-string} command that finds all
-occurrences of one string and replaces them with another, Emacs has a fancy
-replacement command called @code{query-replace} which asks interactively
-which occurrences to replace.
+occurrences of one string and replaces them with another, Emacs has a
+more flexible replacement command called @code{query-replace}, which
+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.
+* Configuring Scrolling:: Scrolling within incremental search.
+* 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
@kindex C-s
@findex isearch-forward
- @kbd{C-s} starts an incremental search. @kbd{C-s} reads characters from
-the keyboard and positions the cursor at the first occurrence of the
-characters that you have typed. If you type @kbd{C-s} and then @kbd{F},
-the cursor moves right after the first @samp{F}. Type an @kbd{O}, and see
-the cursor move to after the first @samp{FO}. After another @kbd{O}, the
-cursor is after the first @samp{FOO} after the place where you started the
-search. At each step, the buffer text that matches the search string is
-highlighted, if the terminal can do that; at each step, the current search
-string is updated in the echo area.
+ @kbd{C-s} starts a forward incremental search. It reads characters
+from the keyboard, and moves point past the next occurrence of those
+characters. If you type @kbd{C-s} and then @kbd{F}, that puts the
+cursor after the first @samp{F} (the first following the starting point, since
+this is a forward search). Then if you type an @kbd{O}, you will see
+the cursor move just after the first @samp{FO} (the @samp{F} in that
+@samp{FO} may or may not be the first @samp{F}). After another
+@kbd{O}, the cursor moves after the first @samp{FOO} after the place
+where you started the search. At each step, the buffer text that
+matches the search string is highlighted, if the terminal can do that;
+the current search string is always displayed in the echo area.
If you make a mistake in typing the search string, you can cancel
characters with @key{DEL}. Each @key{DEL} cancels the last character of
When you are satisfied with the place you have reached, you can type
@key{RET}, which stops searching, leaving the cursor where the search
brought it. Also, any command not specially meaningful in searches
-stops the searching and is then executed. Thus, typing @kbd{C-a} would
-exit the search and then move to the beginning of the line. @key{RET}
-is necessary only if the next command you want to type is a printing
-character, @key{DEL}, @key{RET}, or another control character that is
+stops the searching and is then executed. Thus, typing @kbd{C-a}
+would exit the search and then move to the beginning of the line.
+@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}, or @kbd{M-s}).
+@kbd{C-y}, @kbd{M-y}, @kbd{M-r}, @kbd{M-s}, and some other
+meta-characters).
- Sometimes you search for @samp{FOO} and find it, 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 another @kbd{C-s}
-to move to the next occurrence of the search string. This can be done any
-number of times. If you overshoot, you can cancel some @kbd{C-s}
-characters with @key{DEL}.
+ 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
+another @kbd{C-s} to move to the next occurrence of the search string.
+You can repeat this any number of times. If you overshoot, you can
+cancel some @kbd{C-s} characters with @key{DEL}.
After you exit a search, you can search for the same string again by
typing just @kbd{C-s C-s}: the first @kbd{C-s} is the key that invokes
At this point there are several things you can do. If your string was
mistyped, you can rub some of it out and correct it. If you like the place
you have found, you can type @key{RET} or some other Emacs command to
-``accept what the search offered.'' Or you can type @kbd{C-g}, which
+remain there. Or you can type @kbd{C-g}, which
removes from the search string the characters that could not be found (the
@samp{T} in @samp{FOOT}), leaving those that were found (the @samp{FOO} in
@samp{FOOT}). A second @kbd{C-g} at that point cancels the search
case-sensitive. If you delete the upper-case character from the search
string, it ceases to have this effect. @xref{Search Case}.
+ To search for a newline, type @kbd{C-j}. To search for another
+control character, such as control-S or carriage return, you must quote
+it by typing @kbd{C-q} first. This function of @kbd{C-q} is analogous
+to its use for insertion (@pxref{Inserting Text}): it causes the
+following character to be treated the way any ``ordinary'' character is
+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-@acronym{ASCII} characters
+@cindex input method, during incremental search
+ To search for non-@acronym{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:
+
+@example
+I-search [@var{im}]:
+@end example
+
+@noindent
+@findex isearch-toggle-input-method
+@findex isearch-toggle-specified-input-method
+where @var{im} is the mnemonic of the active input method. You can
+toggle (enable or disable) the input method while you type the search
+string with @kbd{C-\} (@code{isearch-toggle-input-method}). You can
+turn on a certain (non-default) input method with @kbd{C-^}
+(@code{isearch-toggle-specified-input-method}), which prompts for the
+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}. @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.
+@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.
@cindex quitting (in search)
The @kbd{C-g} ``quit'' character does special things during searches;
search is now successful and waiting for more input, so a second @kbd{C-g}
will cancel the entire search.
- To search for a newline, type @kbd{C-j}. To search for another
-control character, such as control-S or carriage return, you must quote
-it by typing @kbd{C-q} first. This function of @kbd{C-q} is analogous
-to its use for insertion (@pxref{Inserting Text}): it causes the
-following character to be treated the way any ``ordinary'' character is
-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.
-
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
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
-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 word after point as part of the search string,
-advancing point over that word. Another @kbd{C-s} to repeat the search
-will then search for a string including that 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.
+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
+search string, advancing point over it. (The decision, whether to
+copy a character or a word, is heuristic.) Another @kbd{C-s} to
+repeat the search will then search for a string including that
+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.
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.
+@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
activating it, and does so only if the mark is not already active.
@cindex lazy search highlighting
- By default, Isearch uses @dfn{lazy highlighting}. All matches for
-the current search string in the buffer after the point where searching
-starts are highlighted. The extra highlighting makes it easier to
-anticipate where the cursor will end up each time you press @kbd{C-s} or
-@kbd{C-r} to repeat a pending search. Highlighting of these additional
-matches happens in a deferred fashion so as not to rob Isearch of its
-usual snappy response.
-@vindex isearch-lazy-highlight-cleanup
-By default the highlighting of matches is cleared when you end the
-search. Customize the variable @code{isearch-lazy-highlight-cleanup} to
-avoid cleaning up automatically. The command @kbd{M-x
-isearch-lazy-highlight-cleanup} can be used to clean up manually.
@vindex isearch-lazy-highlight
-Customize the variable @code{isearch-lazy-highlight} to turn off this
-feature.
+ 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}
+or @kbd{C-r} to repeat the search. The short delay before highlighting
+other matches helps indicate which match is the current one.
+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,
of bindings, look at the documentation of @code{isearch-mode} with
@kbd{C-h f isearch-mode @key{RET}}.
+@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-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.
+
+ For a list of commands which are configured as scrolling commands by
+default and instructions on how thus to configure other commands, see
+@ref{Configuring Scrolling}.
+
@subsection Slow Terminal Incremental Search
Incremental search on a slow terminal uses a modified style of display
that is designed to take less time. Instead of redisplaying the buffer at
each place the search gets to, it creates a new single-line window and uses
that to display the line that the search has found. The single-line window
-comes into play as soon as point gets outside of the text that is already
+comes into play as soon as point moves outside of the text that is already
on the screen.
When you terminate the search, the single-line window is removed.
-Then Emacs redisplays the window in which the search was done, to show
+Emacs then redisplays the window in which the search was done, to show
its new position of point.
-@ignore
- The three dots at the end of the search string, normally used to indicate
-that searching is going on, are not displayed in slow style display.
-@end ignore
-
@vindex search-slow-speed
The slow terminal style of display is used when the terminal baud rate is
less than or equal to the value of the variable @code{search-slow-speed},
-initially 1200.
+initially 1200. See @code{baud-rate} in @ref{Display Custom}.
@vindex search-slow-window-lines
The number of lines to use in slow terminal search display is controlled
To do a nonincremental search, first type @kbd{C-s @key{RET}}. This
enters the minibuffer to read the search string; terminate the string
with @key{RET}, and then the search takes place. If the string is not
-found, the search command gets an error.
-
- The way @kbd{C-s @key{RET}} works is that the @kbd{C-s} invokes
-incremental search, which is specially programmed to invoke nonincremental
-search if the argument you give it is empty. (Such an empty argument would
-otherwise be useless.) @kbd{C-r @key{RET}} also works this way.
-
- However, nonincremental searches performed using @kbd{C-s @key{RET}} do
-not call @code{search-forward} right away. The first thing done is to see
-if the next character is @kbd{C-w}, which requests a word search.
+found, the search command signals an error.
+
+ When you type @kbd{C-s @key{RET}}, the @kbd{C-s} invokes incremental
+search as usual. That command is specially programmed to invoke
+nonincremental search, @code{search-forward}, if the string you
+specify is empty. (Such an empty argument would otherwise be
+useless.) But it does not call @code{search-forward} right away. First
+it checks the next input character to see if is @kbd{C-w},
+which specifies a word search.
@ifinfo
@xref{Word Search}.
@end ifinfo
+@kbd{C-r @key{RET}} does likewise, for a reverse incremental search.
@findex search-forward
@findex search-backward
commands @code{search-forward} and @code{search-backward}. These
commands may be bound to keys in the usual manner. The feature that you
can get to them via the incremental search commands exists for
-historical reasons, and to avoid the need to find suitable key sequences
+historical reasons, and to avoid the need to find key sequences
for them.
@node Word Search, Regexp Search, Nonincremental Search, Search
Word search searches for a sequence of words without regard to how the
words are separated. More precisely, you type a string of many words,
-using single spaces to separate them, and the string can be found even if
-there are multiple spaces, newlines or other punctuation between the words.
+using single spaces to separate them, and the string can be found even
+if there are multiple spaces, newlines, or other punctuation characters
+between these words.
Word search is useful for editing a printed document made with a text
formatter. If you edit while looking at the printed, formatted version,
@findex word-search-backward
Forward and backward word searches are implemented by the commands
@code{word-search-forward} and @code{word-search-backward}. These
-commands may be bound to keys in the usual manner. The feature that you
-can get to them via the incremental search commands exists for historical
-reasons, and to avoid the need to find suitable key sequences for them.
+commands may be bound to keys in the usual manner. They are available
+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
@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. In GNU Emacs, you can search for the next match for a regexp
-either incrementally or not.
+ 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.
@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}). 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. Invoking @kbd{C-s}
-with a prefix argument (its value does not matter) is another way to do
-a forward incremental regexp search. 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-forward-regexp}), or by invoking @kbd{C-s} with a
+prefix argument (whose value does not matter). 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.
All of the control characters that do special things within an
ordinary incremental search have the same function in incremental regexp
@node Regexps, Search Case, Regexp Search, Search
@section Syntax of Regular Expressions
-@cindex regexp syntax
+@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}.
Regular expressions have a syntax in which a few characters are
special constructs and the rest are @dfn{ordinary}. An ordinary
character and nothing else. The special characters are @samp{$},
@samp{^}, @samp{.}, @samp{*}, @samp{+}, @samp{?}, @samp{[}, @samp{]} and
@samp{\}. Any other character appearing in a regular expression is
-ordinary, unless a @samp{\} precedes it.
+ordinary, unless a @samp{\} precedes it. (When you use regular
+expressions in a Lisp program, each @samp{\} must be doubled, see the
+example near the end of this section.)
For example, @samp{f} is not a special character, so it is ordinary, and
therefore @samp{f} is a regular expression that matches the string
the string @samp{fo}. Still trivial. To do something nontrivial, you
need to use one of the special characters. Here is a list of them.
-@table @kbd
-@item .@: @r{(Period)}
+@table @asis
+@item @kbd{.}@: @r{(Period)}
is a special character that matches any single character except a newline.
Using concatenation, we can make regular expressions like @samp{a.b}, which
matches any three-character string that begins with @samp{a} and ends with
@samp{b}.@refill
-@item *
+@item @kbd{*}
is not a construct by itself; it is a postfix operator that means to
match the preceding regular expression repetitively as many times as
possible. Thus, @samp{o*} matches any number of @samp{o}s (including no
The next alternative is for @samp{a*} to match only two @samp{a}s.
With this choice, the rest of the regexp matches successfully.@refill
-@item +
+@item @kbd{+}
is a postfix operator, similar to @samp{*} except that it must match
the preceding expression at least once. So, for example, @samp{ca+r}
matches the strings @samp{car} and @samp{caaaar} but not the string
@samp{cr}, whereas @samp{ca*r} matches all three strings.
-@item ?
+@item @kbd{?}
is a postfix operator, similar to @samp{*} except that it can match the
preceding expression either once or not at all. For example,
@samp{ca?r} matches @samp{car} or @samp{cr}; nothing else.
-@item *?, +?, ??
+@item @kbd{*?}, @kbd{+?}, @kbd{??}
@cindex non-greedy regexp matching
are non-greedy variants of the operators above. The normal operators
-@samp{*}, @samp{+}, @samp{?} are @dfn{greedy} in that they match as much
-as they can, while if you append a @samp{?} after them, it makes them
-non-greedy: they will match as little as possible.
-
-@item \@{@var{n},@var{m}\@}
-is another postfix operator that specifies an interval of iteration:
-the preceding regular expression must match between @var{n} and
-@var{m} times. If @var{m} is omitted, then there is no upper bound
-and if @var{,m} is omitted, then the regular expression must match
-exactly @var{n} times. @*
-@samp{\@{0,1\@}} is equivalent to @samp{?}. @*
-@samp{\@{0,\@}} is equivalent to @samp{*}. @*
-@samp{\@{1,\@}} is equivalent to @samp{+}. @*
-@samp{\@{@var{n}\@}} is equivalent to @samp{\@{@var{n},@var{n}\@}}.
-
-@item [ @dots{} ]
+@samp{*}, @samp{+}, @samp{?} are @dfn{greedy} in that they match as
+much as they can, as long as the overall regexp can still match. With
+a following @samp{?}, they are non-greedy: they will match as little
+as possible.
+
+Thus, both @samp{ab*} and @samp{ab*?} can match the string @samp{a}
+and the string @samp{abbbb}; but if you try to match them both against
+the text @samp{abbb}, @samp{ab*} will match it all (the longest valid
+match), while @samp{ab*?} will match just @samp{a} (the shortest
+valid match).
+
+Non-greedy operators match the shortest possible string starting at a
+given starting point; in a forward search, though, the earliest
+possible starting point for match is always the one chosen. Thus, if
+you search for @samp{a.*?$} against the text @samp{abbab} followed by
+a newline, it matches the whole string. Since it @emph{can} match
+starting at the first @samp{a}, it does.
+
+@item @kbd{\@{@var{n}\@}}
+is a postfix operator that specifies repetition @var{n} times---that
+is, the preceding regular expression must match exactly @var{n} times
+in a row. For example, @samp{x\@{4\@}} matches the string @samp{xxxx}
+and nothing else.
+
+@item @kbd{\@{@var{n},@var{m}\@}}
+is a postfix operator that specifies repetition between @var{n} and
+@var{m} times---that is, the preceding regular expression must match
+at least @var{n} times, but no more than @var{m} times. If @var{m} is
+omitted, then there is no upper limit, but the preceding regular
+expression must match at least @var{n} times.@* @samp{\@{0,1\@}} is
+equivalent to @samp{?}. @* @samp{\@{0,\@}} is equivalent to
+@samp{*}. @* @samp{\@{1,\@}} is equivalent to @samp{+}.
+
+@item @kbd{[ @dots{} ]}
is a @dfn{character set}, which begins with @samp{[} and is terminated
by @samp{]}. In the simplest case, the characters between the two
brackets are what this set can match.
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
and @samp{-}.
To include @samp{^} in a set, put it anywhere but at the beginning of
-the set.
+the set. (At the beginning, it complements the set---see below.)
When you use a range in case-insensitive search, you should write both
ends of the range in upper case, or both in lower case, or both should
be non-letters. The behavior of a mixed-case range such as @samp{A-z}
is somewhat ill-defined, and it may change in future Emacs versions.
-@item [^ @dots{} ]
+@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} 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
mentioned as one of the characters not to match. This is in contrast to
the handling of regexps in programs such as @code{grep}.
-@item ^
+@item @kbd{^}
is a special character that matches the empty string, but only at the
beginning of a line in the text being matched. Otherwise it fails to
match anything. Thus, @samp{^foo} matches a @samp{foo} that occurs at
the beginning of a line.
-@item $
+For historical compatibility reasons, @samp{^} can be used with this
+meaning only at the beginning of the regular expression, or after
+@samp{\(} or @samp{\|}.
+
+@item @kbd{$}
is similar to @samp{^} but matches only at the end of a line. Thus,
@samp{x+$} matches a string of one @samp{x} or more at the end of a line.
-@item \
+For historical compatibility reasons, @samp{$} can be used with this
+meaning only at the end of the regular expression, or before @samp{\)}
+or @samp{\|}.
+
+@item @kbd{\}
has two functions: it quotes the special characters (including
@samp{\}), and it introduces additional special constructs.
This last application is not a consequence of the idea of a
parenthetical grouping; it is a separate feature that is assigned as a
second meaning to the same @samp{\( @dots{} \)} construct. In practice
-there is almost no conflict between the two meanings.
+there is usually no conflict between the two meanings; when there is
+a conflict, you can use a ``shy'' group.
@item \(?: @dots{} \)
-is another grouping construct (often called ``shy'') that serves the same
-first two purposes, but not the third:
-it cannot be referred to later on by number. This is only useful
-for mechanically constructed regular expressions where grouping
-constructs need to be introduced implicitly and hence risk changing the
-numbering of subsequent groups.
+@cindex shy group, in regexp
+specifies a ``shy'' group that does not record the matched substring;
+you can't refer back to it with @samp{\@var{d}}. This is useful
+in mechanically combining regular expressions, so that you
+can add groups for syntactic purposes without interfering with
+the numbering of the groups that were written by the user.
@item \@var{d}
matches the same text that matched the @var{d}th occurrence of a
match is recorded.
@item \`
-matches the empty string, but only at the beginning
-of the buffer or string being matched against.
+matches the empty string, but only at the beginning of the string or
+buffer (or its accessible portion) being matched against.
@item \'
-matches the empty string, but only at the end of
-the buffer or string being matched against.
+matches the empty string, but only at the end of the string or buffer
+(or its accessible portion) being matched against.
@item \=
matches the empty string, but only at point.
@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 word or symbol constituent
+characters. @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. A symbol
+is a sequence of one or more word or symbol constituent characters.
+@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 represents a syntax code: thus, @samp{w} for word
-constituent, @samp{-} for whitespace, @samp{(} for open parenthesis,
-etc. Represent a character of whitespace (which can be a newline) by
-either @samp{-} or a space character.
+character that designates a particular syntax class: thus, @samp{w}
+for word constituent, @samp{-} or @samp{ } for whitespace, @samp{.}
+for ordinary punctuation, etc. @xref{Syntax}.
@item \S@var{c}
matches any character whose syntax is not @var{c}.
+
+@cindex categories of characters
+@cindex characters which belong to a specific language
+@findex describe-categories
+@item \c@var{c}
+matches any character that belongs to the category @var{c}. For
+example, @samp{\cc} matches Chinese characters, @samp{\cg} matches
+Greek characters, etc. For the description of the known categories,
+type @kbd{M-x describe-categories @key{RET}}.
+
+@item \C@var{c}
+matches any character that does @emph{not} belong to category
+@var{c}.
@end table
The constructs that pertain to words and syntax are controlled by the
setting of the syntax table (@pxref{Syntax}).
- Here is a complicated regexp, used by Emacs to recognize the end of a
-sentence together with any whitespace that follows. It is given in Lisp
-syntax to enable you 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, 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.
@example
-"[.?!][]\"')]*\\($\\|\t\\| \\)[ \t\n]*"
+"[.?!][]\"')]*\\($\\| $\\|\t\\| \\)[ \t\n]*"
@end example
@noindent
-This contains four parts in succession: a character set matching period,
-@samp{?}, or @samp{!}; a character set matching close-brackets, quotes,
-or parentheses, repeated any number of times; an alternative in
-backslash-parentheses that matches end-of-line, a tab, or two spaces;
-and a character set matching whitespace characters, repeated any number
-of times.
-
- To enter the same regexp interactively, you would type @key{TAB} to
-enter a tab, and @kbd{C-j} to enter a newline. You would also type
-single backslashes as themselves, instead of doubling them for Lisp syntax.
-
-@node Search Case, Replace, Regexps, Search
+This contains four parts in succession: a character set matching
+period, @samp{?}, or @samp{!}; a character set matching
+close-brackets, quotes, or parentheses, repeated zero or more times; a
+set of alternatives within backslash-parentheses that matches either
+end-of-line, a space at the end of a line, a tab, or two spaces; and a
+character set matching whitespace characters, repeated any number of
+times.
+
+ To enter the same regexp in incremental search, you would type
+@key{TAB} to enter a tab, and @kbd{C-j} to enter a newline. You would
+also type single backslashes as themselves, instead of doubling them
+for Lisp syntax. In commands that use ordinary minibuffer input to
+read a regexp, you would quote the @kbd{C-j} by preceding it with a
+@kbd{C-q} to prevent @kbd{C-j} from exiting the minibuffer.
+
+@ignore
+@c I commented this out because it is missing vital information
+@c and therefore useless. For instance, what do you do to *use* the
+@c regular expression when it is finished? What jobs is this good for?
+@c -- rms
+
+@findex re-builder
+@cindex authoring regular expressions
+ For convenient interactive development of regular expressions, you
+can use the @kbd{M-x re-builder} command. It provides a convenient
+interface for creating regular expressions, by giving immediate visual
+feedback. The buffer from which @code{re-builder} was invoked becomes
+the target for the regexp editor, which pops in a separate window. At
+all times, all the matches in the target buffer for the current
+regular expression are highlighted. Each parenthesized sub-expression
+of the regexp is shown in a distinct face, which makes it easier to
+verify even very complex regexps. (On displays that don't support
+colors, Emacs blinks the cursor around the matched text, as it does
+for matching parens.)
+@end ignore
+
+@node Search Case, Configuring Scrolling, Regexps, Search
@section Searching and Case
-@vindex case-fold-search
Incremental searches in Emacs normally ignore the case of the text
they are searching through, if you specify the text in lower case.
Thus, if you specify searching for @samp{foo}, then @samp{Foo} and
well as to string search. The effect ceases if you delete the
upper-case letter from the search string.
+ Typing @kbd{M-c} within an incremental search toggles the case
+sensitivity of that search. The effect does not extend beyond the
+current incremental search to the next one, but it does override the
+effect of including an upper-case letter in the current search.
+
+@vindex 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
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 Configuring Scrolling, Replace, Search Case, Search
+@section Configuring Scrolling
+@cindex scrolling in incremental search
+@vindex isearch-allow-scroll
+
+Scrolling, etc., during incremental search is enabled by setting the
+customizable variable @code{isearch-allow-scroll} to a non-nil value.
+
+@c See Subject: Info file: How do I get an itemized list without blank lines?
+@c Date: Sat, 12 Apr 2003 09:45:31 +0000 in gnu.emacs.help
+@subsection Standard scrolling commands
+Here is the list of commands which are configured by default to be
+``scrolling'' commands in an incremental search, together with their
+usual bindings:
+@subsubsection Commands which scroll the window:
+@table @asis
+@item @code{scroll-bar-toolkit-scroll} (@kbd{@key{vertical-scroll-bar}@key{mouse-1}} in X-Windows)
+@itemx @code{mac-handle-scroll-bar-event} (@kbd{@key{vertical-scroll-bar}@key{mouse-1}} on a Mac)
+@itemx @code{w32-handle-scroll-bar-event} (@kbd{@key{vertical-scroll-bar}@key{mouse-1}} in MS-Windows)
+@item @code{recenter} (@kbd{C-l}) @xref{Scrolling}.
+@itemx @code{reposition-window} (@kbd{C-M-l}) @xref{Scrolling}.
+@itemx @code{scroll-up} (@kbd{@key{NEXT}}) @xref{Scrolling}.
+@itemx @code{scroll-down} (@kbd{@key{PRIOR}}) @xref{Scrolling}.
+@end table
+
+@subsubsection Commands which act on the other window:
+@table @asis
+@item @code{list-buffers} (@kbd{C-x C-b}) @xref{List Buffers}.
+@itemx @code{scroll-other-window} (@kbd{C-M-v}) @xref{Other Window}.
+@itemx @code{scroll-other-window-down} (@kbd{C-M-S-v}) @xref{Other Window}.
+@itemx @code{beginning-of-buffer-other-window} (@kbd{M-@key{home}})
+@itemx @code{end-of-buffer-other-window} (@kbd{M-@key{end}})
+@end table
+
+@subsubsection Commands which change the window layout:
+@table @asis
+@item @code{delete-other-windows} (@kbd{C-x 1}) @xref{Change Window}.
+@itemx @code{balance-windows} (@kbd{C-x +}) @xref{Change Window}.
+@itemx @code{split-window-vertically} (@kbd{C-x 2}) @xref{Split Window}.
+@itemx @code{enlarge-window} (@kbd{C-x ^}) @xref{Change Window}.
+@end table
+
+@subsection Configuring other commands as scrolling commands
+To do this, set a command's isearch-scroll property to the value t.
+For example:
+
+@example
+@code{(put 'my-command 'isearch-scroll t)}
+@end example
+
+You should only thus configure commands which are ``safe'': i.e., they
+won't leave emacs in an inconsistent state when executed within a
+search - that is to say, the following things may be changed by a
+command only temporarily, and must be restored before the command
+finishes:
+
+@enumerate
+@item
+Point.
+@item
+The buffer contents.
+@item
+The selected window and selected frame.
+@item
+The current match-data @xref{Match Data,,,elisp}.
+@end enumerate
+
+Additionally, the command must not delete the current window and must
+not itself attempt an incremental search. It may, however, change the
+window's size, or create or delete other windows and frames.
+
+Note that an attempt by a command to scroll the text
+@emph{horizontally} won't work, although it will do no harm - any such
+scrolling will be overriden and nullified by the display code.
+
+@node Replace, Other Repeating Search, Configuring Scrolling, Search
@section Replacement Commands
@cindex replacement
@cindex search-and-replace commands
@cindex string substitution
@cindex global substitution
- Global search-and-replace operations are not needed as often in Emacs
-as they are in other editors@footnote{In some editors,
-search-and-replace operations are the only convenient way to make a
-single change in the text.}, but they are available. In addition to the
-simple @kbd{M-x replace-string} command which is like that found in most
-editors, there is a @kbd{M-x query-replace} command which asks you, for
-each occurrence of the pattern, whether to replace it.
+ 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,
+there is a @kbd{M-x query-replace} command which finds each occurrence
+of the pattern and asks you whether to replace it.
The replace commands normally operate on the text from point to the
-end of the buffer; however, in Transient Mark mode, when the mark is
-active, they operate on the region. The replace commands all replace
-one string (or regexp) with one replacement string. It is possible to
-perform several replacements in parallel using the command
-@code{expand-region-abbrevs} (@pxref{Expanding Abbrevs}).
+end of the buffer; however, in Transient Mark mode (@pxref{Transient
+Mark}), when the mark is active, they operate on the region. The
+replace commands all replace one string (or regexp) with one
+replacement string. It is possible to perform several replacements in
+parallel using the command @code{expand-region-abbrevs}
+(@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
A numeric argument restricts replacement to matches that are surrounded
by word boundaries. The argument's value doesn't matter.
+ 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 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
+This works provided the string @samp{@@TEMP@@} does not appear
+in your text.
+
@node Regexp Replace, Replacement and Case, Unconditional Replace, Replace
@subsection Regexp Replacement
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,
+ 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, which ought to be a string, 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 counts as part of the symbol name, so the value replaces
+them both.
+
+ Inside such an expression, @samp{\&} and @samp{\@var{n}} used as
+subexpressions refer respectively to the entire match as a string, and
+to a submatch as a string. @var{n} may exceed 9 here, 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}} refer to
+those matches converted to numbers (this is valid when the match or
+submatch has the form of a number). @samp{\#} 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
+
+ The @code{format} function (@pxref{Formatting Strings,,,elisp, GNU
+Emacs Lisp Reference Manual}) comes in handy for computing replacement
+strings for @samp{\,}. 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
+enter a recursive edit, with point at the position 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 occurences 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
If the first argument of a replace command is all lower case, the
-commands ignores case while searching for occurrences to
+command ignores case while searching for occurrences to
replace---provided @code{case-fold-search} is non-@code{nil}. If
@code{case-fold-search} is set to @code{nil}, case is always significant
in all searches.
@samp{bar}, not all of them, then you cannot use an ordinary
@code{replace-string}. Instead, use @kbd{M-%} (@code{query-replace}).
This command finds occurrences of @samp{foo} one by one, displays each
-occurrence and asks you whether to replace it. A numeric argument to
-@code{query-replace} tells it to consider only occurrences that are
-bounded by word-delimiter characters. This preserves case, just like
-@code{replace-string}, provided @code{case-replace} is non-@code{nil},
-as it normally is.
+occurrence and asks you whether to replace it. Aside from querying,
+@code{query-replace} works just like @code{replace-string}. It
+preserves case, like @code{replace-string}, provided
+@code{case-replace} is non-@code{nil}, as it normally is. A numeric
+argument means consider only occurrences that are bounded by
+word-delimiter characters.
@kindex C-M-%
@findex query-replace-regexp
- Aside from querying, @code{query-replace} works just like
-@code{replace-string}, and @code{query-replace-regexp} works just like
-@code{replace-regexp}. This command is run by @kbd{C-M-%}.
+ @kbd{C-M-%} performs regexp search and replace (@code{query-replace-regexp}).
- The things you can type when you are shown an occurrence of @var{string}
-or a match for @var{regexp} are:
+ The characters you can type when you are shown a match for the string
+or regexp are:
@ignore @c Not worth it.
@kindex SPC @r{(query-replace)}
@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
occurrence of @var{string}. When done, exit the recursive editing level
with @kbd{C-M-c} to proceed to the next occurrence.
+@item e
+to edit the replacement string in the minibuffer. When you exit the
+minibuffer by typing @key{RET}, the minibuffer contents replace the
+current occurrence of the pattern. They also become the new
+replacement string for any further occurrences.
+
@item C-l
to redisplay the screen. Then you must type another character to
specify what to do with this occurrence.
@section Other Search-and-Loop Commands
Here are some other commands that find matches for a regular
-expression. They all operate from point to the end of the buffer, and
-all ignore case in matching, if the pattern contains no upper-case
-letters and @code{case-fold-search} is non-@code{nil}.
+expression. They all ignore case in matching, if the pattern contains
+no upper-case letters and @code{case-fold-search} is non-@code{nil}.
+Aside from @code{occur} and its variants, all operate on the text from
+point to the end of the buffer, or on the active region in Transient
+Mark mode.
@findex list-matching-lines
@findex occur
-@findex count-matches
+@findex multi-occur
+@findex multi-occur-by-filename-regexp
+@findex how-many
@findex delete-non-matching-lines
@findex delete-matching-lines
@findex flush-lines
@table @kbd
@item M-x occur @key{RET} @var{regexp} @key{RET}
-Display a list showing each line in the buffer that contains a match for
-@var{regexp}. A numeric argument specifies the number of context lines
-to print before and after each matching line; the default is none.
-To limit the search to part of the buffer, narrow to that part
-(@pxref{Narrowing}).
+Display a list showing each line in the buffer that contains a match
+for @var{regexp}. To limit the search to part of the buffer, narrow
+to that part (@pxref{Narrowing}). A numeric argument @var{n}
+specifies that @var{n} lines of context are to be displayed before and
+after each matching line.
@kindex RET @r{(Occur mode)}
+@kindex o @r{(Occur mode)}
+@kindex C-o @r{(Occur mode)}
The buffer @samp{*Occur*} containing the output serves as a menu for
-finding the occurrences in their original context. Click @kbd{Mouse-2}
-on an occurrence listed in @samp{*Occur*}, or position point there and
-type @key{RET}; this switches to the buffer that was searched and
-moves point to the original of the chosen occurrence.
+finding the occurrences in their original context. Click
+@kbd{Mouse-2} on an occurrence listed in @samp{*Occur*}, or position
+point there and type @key{RET}; this switches to the buffer that was
+searched and moves point to the original of the chosen occurrence.
+@kbd{o} and @kbd{C-o} display the match in another window; @kbd{C-o}
+does not select it.
@item M-x list-matching-lines
Synonym for @kbd{M-x occur}.
-@item M-x count-matches @key{RET} @var{regexp} @key{RET}
-Print the number of matches for @var{regexp} after point.
+@item M-x multi-occur @key{RET} @var{buffers} @key{RET} @var{regexp} @key{RET}
+This function is just like @code{occur}, except it is able to search
+through multiple buffers.
+
+@item M-x multi-occur-by-filename-regexp @key{RET} @var{bufregexp} @key{RET} @var{regexp} @key{RET}
+This function is similar to @code{multi-occur}, except the buffers to
+search are specified by a regexp on their filename.
+
+@item M-x how-many @key{RET} @var{regexp} @key{RET}
+Print the number of matches for @var{regexp} that exist in the buffer
+after point. In Transient Mark mode, if the region is active, the
+command operates on the region instead.
@item M-x flush-lines @key{RET} @var{regexp} @key{RET}
-Delete each line that follows point and contains a match for
-@var{regexp}.
+Delete each line that contains a match for @var{regexp}, operating on
+the text after point. In Transient Mark mode, if the region is
+active, the command operates on the region instead.
@item M-x keep-lines @key{RET} @var{regexp} @key{RET}
-Delete each line that follows point and @emph{does not} contain a match
-for @var{regexp}.
+Delete each line that @emph{does not} contain a match for
+@var{regexp}, operating on the text after point. In Transient Mark
+mode, if the region is active, the command operates on the region
+instead.
@end table
- In addition, you can use @code{grep} from Emacs to search a collection
-of files for matches for a regular expression, then visit the matches
-either sequentially or in arbitrary order. @xref{Grep Searching}.
+ You can also search multiple files under control of a tags table
+(@pxref{Tags Search}) or through Dired @kbd{A} command
+(@pxref{Operating on Files}), or ask the @code{grep} program to do it
+(@pxref{Grep Searching}).
+
+@ignore
+ arch-tag: fd9d8e77-66af-491c-b212-d80999613e3e
+@end ignore
HCoop / bpt / emacs.git / blobdiff