VIM: pattern

## PATTERN

    *pattern.txt*   For Vim version 6.1.  Last change: 2002 Feb 27

    		  VIM REFERENCE MANUAL    by Bram Moolenaar

    Patterns and search commands				*pattern-searches*

    The very basics can be found in section |03.9| of the user manual.  A few more
    explanations are in chapter 27 |usr_27|.

    1. Search commands		|search-commands|
    2. The definition of a pattern	|search-pattern|
    3. Highlighting matches		|match-highlight|

    1. Search commands					*search-commands*

    							*/*
    /{pattern}[/]<CR>	Search forward for the [count]'th occurrence of
    			{pattern} (exclusive).

    /{pattern}/{offset}<CR>	Search forward for the [count]'th occurrence of
    			{pattern} and go |{offset}| lines up or down.
    			(linewise).

    							*/<CR>*
    /<CR>			Search forward for the [count]'th latest used
    			pattern |last-pattern| with latest used |{offset}|.

    //{offset}<CR>		Search forward for the [count]'th latest used
    			pattern |last-pattern| with new |{offset}|.  If
    			{offset} is empty no offset is used.

    							*?*
    ?{pattern}[?]<CR>	Search backward for the [count]'th previous
    			occurrence of {pattern} (exclusive).

    ?{pattern}?{offset}<CR>	Search backward for the [count]'th previous
    			occurrence of {pattern} and go |{offset}| lines up or
    			down (linewise).

    							*?<CR>*
    ?<CR>			Search backward for the [count]'th latest used
    			pattern |last-pattern| with latest used |{offset}|.

    ??{offset}<CR>		Search backward for the [count]'th latest used
    			pattern |last-pattern| with new |{offset}|.  If
    			{offset} is empty no offset is used.

    							*n*
    n			Repeat the latest "/" or "?" [count] times.
    			|last-pattern| {Vi: no count}

    							*N*
    N			Repeat the latest "/" or "?" [count] times in
    			opposite direction. |last-pattern| {Vi: no count}

    							*star* *E348* *E349*
    *			Search forward for the [count]'th occurrence of the
    			word nearest to the cursor.  The word used for the
    			search is the first of:
    				1. the keyword under the cursor |'iskeyword'|
    				2. the first keyword after the cursor, in the
    				   current line
    				3. the non-blank word under the cursor
    				4. the first non-blank word after the cursor,
    				   in the current line
    			Only whole keywords are searched for, like with the
    			command "/\<keyword\>".  (exclusive)  {not in Vi}
    			'ignorecase' is used, 'smartcase' is not.

    							*#*
    #			Same as "*", but search backward.  The pound sign
    			(character 163) also works.  If the "#" key works as
    			backspace, try using "stty erase <BS>" before starting
    			Vim (<BS> is CTRL-H or a real backspace).  {not in Vi}

    							*gstar*
    g*			Like "*", but don't put "\<" and "\>" around the word.
    			This makes the search also find matches that are not a
    			whole word.  {not in Vi}

    							*g#*
    g#			Like "#", but don't put "\<" and "\>" around the word.
    			This makes the search also find matches that are not a
    			whole word.  {not in Vi}

    							*gd*
    gd			Goto local Declaration.  When the cursor is on a local
    			variable, this command will jump to its declaration.
    			First Vim searches for the start of the current
    			function, just like "[[".  If it is not found the
    			search stops in line 1.  If it is found, Vim goes back
    			until a blank line is found.  From this position Vim
    			searches for the keyword under the cursor, like with
    			"*", but lines that look like a comment are ignored
    			(see 'comments' option).
    			Note that this is not guaranteed to work, Vim does not
    			really check the syntax, it only searches for a match
    			with the keyword.  If included files also need to be
    			searched use the commands listed in |include-search|.
    			After this command |n| searches forward for the next
    			match (not backward).
    			{not in Vi}

    							*gD*
    gD			Goto global Declaration.  When the cursor is on a
    			global variable that is defined in the file, this
    			command will jump to its declaration.  This works just
    			like "gd", except that the search for the keyword
    			always starts in line 1.  {not in Vi}

    							*CTRL-C*
    CTRL-C			Interrupt current (search) command.  Use CTRL-Break on
    			MS-DOS |dos-CTRL-Break|.
    			In Normal mode, any pending command is aborted.

    							*:noh* *:nohlsearch*
    :noh[lsearch]		Stop the highlighting for the 'hlsearch' option.  It
    			is automatically turned back on when using a search
    			command, or setting the 'hlsearch' option.
    			This command doesn't work in an autocommand, because
    			the highlighting state is saved and restored when
    			executing autocommands |autocmd-searchpat|.

    While typing the search pattern the current match will be shown if the
    'incsearch' option is on.  Remember that you still have to finish the search
    command with <CR> to actually position the cursor at the displayed match.  Or
    use <Esc> to abandon the search.

    All matches for the last used search pattern will be highlighted if you set
    the 'hlsearch' option.  This can be suspended with the |:nohlsearch| command.

    					*search-offset* *{offset}*
    These commands search for the specified pattern.  With "/" and "?" an
    additional offset may be given.  There are two types of offsets: line offsets
    and character offsets.  {the character offsets are not in Vi}

    The offset gives the cursor position relative to the found match:
        [num]	[num] lines downwards, in column 1
        +[num]	[num] lines downwards, in column 1
        -[num]	[num] lines upwards, in column 1
        e[+num]	[num] characters to the right of the end of the match
        e[-num]	[num] characters to the left of the end of the match
        s[+num]	[num] characters to the right of the start of the match
        s[-num]	[num] characters to the left of the start of the match
        b[+num]	[num] characters to the right of the start (begin) of the match
        b[-num]	[num] characters to the left of the start (begin) of the match

    If a '-' or '+' is given but [num] is omitted, a count of one will be used.
    When including an offset with 'e', the search becomes inclusive (the
    character the cursor lands on is included in operations).

    Examples:

    pattern			cursor position
    /test/+1		one line below "test", in column 1
    /test/e			on the last t of "test"
    /test/s+2		on the 's' of "test"
    /test/b-3		three characters before "test"

    If one of these commands is used after an operator, the characters between
    the cursor position before and after the search is affected.  However, if a
    line offset is given, the whole lines between the two cursor positions are
    affected.

    An example of how to search for matches with a pattern and change the match
    with another word:
    	/foo<CR>	find "foo"
    	c//e		change until end of match
    	bar<Esc>	type replacement
    	//<CR>		go to start of next match
    	c//e		change until end of match
    	beep<Esc>	type another replacement
    			etc.

    							*//;* *E386*
    A very special offset is ';' followed by another search command.  For example:

       /test 1/;/test
       /test.*/+1;?ing?

    The first one first finds the next occurrence of "test 1", and then the first
    occurrence of "test" after that.

    This is like executing two search commands after each other, except that:
    - It can be used as a single motion command after an operator.
    - The direction for a following "n" or "N" command comes from the first
      search command.
    - When an error occurs the cursor is not moved at all.

    							*last-pattern*
    The last used pattern and offset are remembered.  They can be used to repeat
    the search, possibly in another direction or with another count.  Note that
    two patterns are remembered: One for 'normal' search commands and one for the
    substitute command ":s".  Each time an empty pattern is given, the previously
    used pattern is used.

    The 'magic' option sticks with the last used pattern.  If you change 'magic',
    this will not change how the last used pattern will be interpreted.
    The 'ignorecase' option does not do this.  When 'ignorecase' is changed, it
    will result in the pattern to match other text.

    All matches for the last used search pattern will be highlighted if you set
    the 'hlsearch' option.

    To clear the last used search pattern:
    	:let @/ = ""
    This will not set the pattern to an empty string, because that would match
    everywhere.  The pattern is really cleared, like when starting Vim.

    In Vi the ":tag" command sets the last search pattern when the tag is searched
    for.  In Vim this is not done, the previous search pattern is still remembered,
    unless the 't' flag is present in 'cpoptions'.  The search pattern is always
    put in the search history.

    If the 'wrapscan' option is on (which is the default), searches wrap around
    the end of the buffer.  If 'wrapscan' is not set, the backward search stops
    at the beginning and the forward search stops at the end of the buffer.  If
    'wrapscan' is set and the pattern was not found the error message "pattern
    not found" is given, and the cursor will not be moved.  If 'wrapscan' is not
    set the message becomes "search hit BOTTOM without match" when searching
    forward, or "search hit TOP without match" when searching backward.  If
    wrapscan is set and the search wraps around the end of the file the message
    "search hit TOP, continuing at BOTTOM" or "search hit BOTTOM, continuing at
    TOP" is given when searching backwards or forwards respectively.  This can be
    switched off by setting the 's' flag in the 'shortmess' option.  The highlight
    method 'w' is used for this message (default: standout).

    							*search-range*
    You cannot limit the search command "/" to a certain range of lines.  A trick
    to do this anyway is to use the ":substitute" command with the 'c' flag.
    Example:
       :.,300s/Pattern//gc
    This command will search from the cursor position until line 300 for
    "Pattern".  At the match, you will be asked to type a character.  Type 'q' to
    stop at this match, type 'n' to find the next match.

    The "*", "#", "g*" and "g#" commands look for a word near the cursor in this
    order, the first one that is found is used:
    - The keyword currently under the cursor.
    - The first keyword to the right of the cursor, in the same line.
    - The WORD currently under the cursor.
    - The first WORD to the right of the cursor, in the same line.
    The keyword may only contain letters and characters in 'iskeyword'.
    The WORD may contain any non-blanks (<Tab>s and/or <Space>s).
    Note that if you type with ten fingers, the characters are easy to remember:
    the "#" is under your left hand middle finger (search to the left and up) and
    the "*" is under your right hand middle finger (search to the right and down).
    (this depends on your keyboard layout though).

    2. The definition of a pattern		*search-pattern* *pattern* *[pattern]*
    					*regular-expression* *regexp* *Pattern*
    					*E76* *E361* *E363* *E383*

    For starters, read chapter 27 of the user manual |usr_27|.

    						*/bar* */\bar* */pattern*
    1. A pattern is one or more branches, separated by "\|".  It matches anything
       that matches one of the branches.  Example: "foo\|beep" matches "foo" and
       matches "beep".  If more than one branch matches, the first one is used.

       pattern ::=	    branch
    		or  branch \| branch
    		or  branch \| branch \| branch
    		etc.

    						*/branch* */\&*
    2. A branch is one or more concats, separated by "\&".  It matches the last
       concat, but only if all the preceding concats also match at the same
       position.  Example: "foobeep\&..." matches "foo" in "foobeep".

       branch ::=	    concat
    		or  concat \& concat
    		or  concat \& concat \& concat
    		etc.

    						*/concat*
    3. A concat is one or more pieces, concatenated.  It matches a match for the
       first piece, followed by a match for the second piece, etc.  Example:
       "f[0-9]b", first matches "f", then a digit and then "b".

       concat  ::=	    piece
    		or  piece piece
    		or  piece piece piece
    		etc.

    						*/piece*
    4. A piece is an atom, possibly followed by a multi, an indication of how many
       times the atom can be matched.  Example: "a*" matches any sequence of "a"
       characters: "", "a", "aa", etc.  See |/multi|.

       piece   ::=	    atom
    		or  atom  multi

    						*/atom*
    5. An atom can be one of a long list of items.  Each atom matches a certain
       character.  It is often an ordinary character or a character class.  Braces
       can be used to make a pattern into an atom.  The "\z(\)" construct is only
       for syntax highlighting.

       atom    ::=	    ordinary-atom		|/ordinary-atom|
    		or  \( pattern \)		|/\(|
    		or  \%( pattern \)		|/\%(|
    		or  \z( pattern \)		|/\z(|

    Overview of multi items.				*/multi* *E61* *E62*
    More explanation and examples below, follow the links.			*E64*

    	  multi
         'magic' 'nomagic'	matches of the preceding atom
    |/star|	*	\*	0 or more	as many as possible
    |/\+|	\+	\+	1 or more	as many as possible (*)
    |/\=|	\=	\=	0 or 1		as many as possible (*)
    |/\?|	\?	\?	0 or 1		as many as possible (*)

    |/\{|	\{n,m}	\{n,m}	n to m		as many as possible (*)
    	\{n}	\{n}	n		exactly (*)
    	\{n,}	\{n,}	at least n	as many as possible (*)
    	\{,m}	\{,m}	0 to m		as many as possible (*)
    	\{}	\{}	0 or more	as many as possible (same as *) (*)

    |/\{-|	\{-n,m}	\{-n,m}	n to m		as few as possible (*)
    	\{-n}	\{-n}	n		exactly (*)
    	\{-n,}	\{-n,}	at least n	as few as possible (*)
    	\{-,m}	\{-,m}	0 to m		as few as possible (*)
    	\{-}	\{-}	0 or more	as few as possible (*)

    							*E59*
    |/\@>|	\@>	\@>	1, like matching a whole pattern (*)
    |/\@=|	\@=	\@=	nothing, requires a match |/zero-width| (*)
    |/\@!|	\@!	\@!	nothing, requires NO match |/zero-width| (*)
    |/\@<=|	\@<=	\@<=	nothing, requires a match behind |/zero-width| (*)
    |/\@<!|	\@<!	\@<!	nothing, requires NO match behind |/zero-width| (*)

    (*) {not in Vi}

    Overview of ordinary atoms.				*/ordinary-atom*
    More explanation and examples below, follow the links.

          ordinary atom
          magic   nomagic	matches
    |/^|	^	^	start-of-line (at start of pattern) |/zero-width|
    |/\^|	\^	\^	literal '^'
    |/\_^|	\_^	\_^	start-of-line (used anywhere) |/zero-width|
    |/$|	$	$	end-of-line (at end of pattern) |/zero-width|
    |/\$|	\$	\$	literal '$'
    |/\_$|	\_$	\_$	end-of-line (used anywhere) |/zero-width|
    |/.|	.	\.	any single character (not an end-of-line)
    |/\_.|	\_.	\_.	any single character or end-of-line
    |/\<|	\<	\<	beginning of a word |/zero-width|
    |/\>|	\>	\>	end of a word |/zero-width|
    |/\zs|	\zs	\zs	anything, sets start of match
    |/\ze|	\ze	\ze	anything, sets end of match
    |/\%^|	\%^	\%^	beginning of file |/zero-width|		*E71*
    |/\%$|	\%$	\%$	end of file |/zero-width|
    |/\%#|	\%#	\%#	cursor position |/zero-width|
    |/\%l|	\%23l	\%23l	in line 23 |/zero-width|
    |/\%c|	\%23c	\%23c	in column 23 |/zero-width|
    |/\%v|	\%23v	\%23v	in virtual column 23 |/zero-width|

    Character classes {not in Vi}:
    |/\i|	\i	\i	identifier character (see 'isident' option)
    |/\I|	\I	\I	like "\i", but excluding digits
    |/\k|	\k	\k	keyword character (see 'iskeyword' option)
    |/\K|	\K	\K	like "\k", but excluding digits
    |/\f|	\f	\f	file name character (see 'isfname' option)
    |/\F|	\F	\F	like "\f", but excluding digits
    |/\p|	\p	\p	printable character (see 'isprint' option)
    |/\P|	\P	\P	like "\p", but excluding digits
    |/\s|	\s	\s	whitespace character: <Space> and <Tab>
    |/\S|	\S	\S	non-whitespace character; opposite of \s
    |/\d|	\d	\d	digit:				[0-9]
    |/\D|	\D	\D	non-digit:			[^0-9]
    |/\x|	\x	\x	hex digit:			[0-9A-Fa-f]
    |/\X|	\X	\X	non-hex digit:			[^0-9A-Fa-f]
    |/\o|	\o	\o	octal digit:			[0-7]
    |/\O|	\O	\O	non-octal digit:		[^0-7]
    |/\w|	\w	\w	word character:			[0-9A-Za-z_]
    |/\W|	\W	\W	non-word character:		[^0-9A-Za-z_]
    |/\h|	\h	\h	head of word character:		[A-Za-z_]
    |/\H|	\H	\H	non-head of word character:	[^A-Za-z_]
    |/\a|	\a	\a	alphabetic character:		[A-Za-z]
    |/\A|	\A	\A	non-alphabetic character:	[^A-Za-z]
    |/\l|	\l	\l	lowercase character:		[a-z]
    |/\L|	\L	\L	non-lowercase character:	[^a-z]
    |/\u|	\u	\u	uppercase character:		[A-Z]
    |/\U|	\U	\U	non-uppercase character		[^A-Z]
    |/\_|	\_x	\_x	where x is any of the characters above: character
    			class with end-of-line included
    (end of character classes)

    |/\e|	\e	\e	<Esc>
    |/\t|	\t	\t	<Tab>
    |/\r|	\r	\r	<CR>
    |/\b|	\b	\b	<BS>
    |/\n|	\n	\n	end-of-line
    |/~|	~	\~	last given substitute string
    |/\1|	\1	\1	same string as matched by first \(\) {not in Vi}
    |/\2|	\2	\2	Like "\1", but uses second \(\)
    	   ...
    |/\9|	\9	\9	Like "\1", but uses ninth \(\)
    								*E68*
    |/\z1|	\z1	\z1	only for syntax highlighting, see |:syn-ext-match|
    	   ...
    |/\z1|	\z9	\z9	only for syntax highlighting, see |:syn-ext-match|

    	x	x	a character with no special meaning matches itself

    |/[]|	[]	\[]	any character specified inside the []
    |/\%[]| \%[]	\%[]	a list of optionally matched atoms

    |/\c|	\c	\c	ignore case
    |/\C|	\C	\C	match case
    |/\m|	\m	\m	'magic' on for the following chars in the pattern
    |/\M|	\M	\M	'magic' off for the following chars in the pattern
    |/\v|	\v	\v	the following chars in the pattern are "very magic"
    |/\V|	\V	\V	the following chars in the pattern are "very nomagic"

    Example			matches
    \<\I\i*		or
    \<\h\w*
    \<[a-zA-Z_][a-zA-Z0-9_]*
    			An identifier (e.g., in a C program).

    \(\.$\|\. \)		A period followed by <EOL> or a space.

    [.!?][])"']*\($\|[ ]\)	A search pattern that finds the end of a sentence,
    			with almost the same definition as the ")" command.

    Magic							*/magic*

    Some characters in the pattern are taken literally.  They match with the same
    character in the text.  When preceded with a backslash however, these
    characters get a special meaning.

    Other characters have a special meaning without a backslash.  They need to be
    preceded with a backslash to match literally.

    If a character is taken literally or not depends on the 'magic' option and the
    items mentioned next.
    							*/\m* */\M*
    Use of "\m" makes the pattern after it be interpreted as if 'magic' is set,
    ignoring the actual value of the 'magic' option.
    Use of "\M" makes the pattern after it be interpreted as if 'nomagic' is used.
    							*/\v* */\V*
    Use of "\v" means that in the pattern after it all ASCII characters except
    '0'-'9', 'a'-'z', 'A'-'Z' and '_' have a special meaning.  "very magic"

    Use of "\V" means that in the pattern after it only the backslash has a
    special meaning.  "very nomagic"

    Examples:
    after:	  \v	   \m	    \M	     \V		matches
    		'magic' 'nomagic'
    	  $	   $	    $	     \$		matches end-of-line
    	  .	   .	    \.	     \.		matches any character
    	  *	   *	    \*	     \*		any number of the previous atom
    	  ()	   \(\)     \(\)     \(\)	grouping into an atom
    	  |	   \|	    \|	     \|		separating alternatives
    	  \a	   \a	    \a	     \a		alphabetic character
    	  \\	   \\	    \\	     \\		literal backslash
    	  \.	   \.	    .	     .		literal dot
    	  \{	   {	    {	     {		literal '{'
    	  a	   a	    a	     a		literal 'a'

    {only Vim supports \m, \M, \v and \V}

    It is recommended to always keep the 'magic' option at the default setting,
    which is 'magic'.  This avoids portability problems.  To make a pattern immune
    to the 'magic' option being set or not, put "\m" or "\M" at the start of the
    pattern.

    Multi items

    An atom can be followed by an indication of how many times the atom can be
    matched and in what way.  This is called a multi.  See |/multi| for an
    overview.

    It is not possible to use a multi that can match more than one time after an
    atom that can match an empty string.  That's because this could result in an
    endless loop.  If you try it, you will get this error message:
    	*, \+ or \{ operand could be empty

    						*/star* */\star* *E56*
    *	(use \* with 'nomagic')
    	Matches 0 or more of the preceding atom, as many as possible.
    	Example  'nomagic'	matches
    	a*	   a\*		"", "a", "aa", "aaa", etc.
    	.*	   \.\*		anything, also an empty string, no end-of-line
    	\_.*	   \_.\*	everything up to the end of the buffer
    	\_.*END	   \_.\*END	everything up to and including the last "END"
    				in the buffer

    	Be aware that repeating "\_." can match a lot of text and take a long
    	time.  For example, "\_.*END" matches all text from the current
    	position to the last occurrence of "END" in the file.  Since the "*"
    	will match as many as possible, this first skips over all lines until
    	the end of the file and then tries matching "END", backing up one
    	character at a time.

    							*/\+* *E57*
    \+	Matches 1 or more of the preceding atom, as many as possible. {not in
    	Vi}
    	Example		matches
    	^.\+$		any non-empty line
    	\s\+		white space of at least one character

    							*/\=*
    \=	Matches 0 or 1 of the preceding atom, as many as possible. {not in Vi}
    	Example		matches
    	foo\=		"fo" and "foo"

    							*/\?*
    \?	Just like \=.  Cannot be used when searching backwards with the "?"
    	command. {not in Vi}

    							*/\{* *E58* *E60*
    \{n,m}	Matches n to m of the preceding atom, as many as possible
    \{n}	Matches n of the preceding atom
    \{n,}	Matches at least n of the preceding atom, as many as possible
    \{,m}	Matches 0 to m of the preceding atom, as many as possible
    \{}	Matches 0 or more of the preceding atom, as many as possible (like *)
    							*/\{-*
    \{-n,m}	matches n to m of the preceding atom, as few as possible
    \{-n}	matches n of the preceding atom
    \{-n,}	matches at least n of the preceding atom, as few as possible
    \{-,m}	matches 0 to m of the preceding atom, as few as possible
    \{-}	matches 0 or more of the preceding atom, as few as possible
    	{Vi does not have any of these}

    	n and m are positive decimal numbers

    	If a "-" appears immediately after the "{", then a shortest match
    	first algorithm is used (see example below).  In particular, "\{-}" is
    	the same as "*" but uses the shortest match first algorithm.  BUT: A
    	match that starts earlier is preferred over a shorter match: "a\{-}b"
    	matches "aaab" in "xaaab".

    	Example			matches
    	ab\{2,3}c		"abbc" or "abbbc"
    	a\{5}			"aaaaa".
    	ab\{2,}c		"abbc", "abbbc", "abbbbc", etc
    	ab\{,3}c		"ac", "abc", "abbc" or "abbbc".
    	a[bc]\{3}d		"abbbd", "abbcd", "acbcd", "acccd", etc.
    	a\(bc\)\{1,2}d		"abcd" or "abcbcd"
    	a[bc]\{-}[cd]		"abc" in "abcd"
    	a[bc]*[cd]		"abcd" in "abcd"

    	The } may optionally be preceded with a backslash: \{n,m\}.

    							*/\@=*
    \@=	Matches the preceding atom with zero width. {not in Vi}
    	Like '(?=pattern)" in Perl.
    	Example			matches
    	foo\(bar\)\@=		"foo" in "foobar"
    	foo\(bar\)\@=foo	nothing
    							*/zero-width*
    	When using "\@=" (or "^", "$", "\<", "\>") no characters are included
    	in the match.  These items are only used to check if a match can be
    	made.  This can be tricky, because a match with following items will
    	be done in the same position.  The last example above will not match
    	"foobarfoo", because it tries match "foo" in the same position where
    	"bar" matched.

    	Note that using "\&" works the same as using "\@=": "foo\&.." is the
    	same as "\(foo\)\@=..".  But using "\&" is easier, you don't need the
    	braces.

    							*/\@!*
    \@!	Matches with zero width if the preceding atom does NOT match at the
    	current position |/zero-width| {not in Vi}
    	Like '(?!pattern)" in Perl.
    	Example			matches
    	foo\(bar\)\@!		any "foo" not followed by "bar"
    	a.\{-}p\@!		"a", "ap", "app", etc. not followed by a "p"

    	Using "\@!" is tricky, because there are many places where a pattern
    	does not match.  "a.*p\@!" will match from an "a" to the end of the
    	line, because ".*" can match all characters in the line and the "p"
    	doesn't match at the end of the line.  "a.\{-}p\@!" will match any
    	"a", "ap", "aap", etc. that isn't followed by a "p", because the "."
    	can match a "p" and "p\@!" doesn't match after that.

    	You can't use "\@!" to look for a non-match before the matching
    	position: "\(foo\)\@!bar" will match "bar" in "foobar", because at the
    	position where "bar" matches, "foo" does not match.  To avoid matching
    	"foobar" you could use "\(foo\)\@!...bar", but that doesn't match a
    	bar at the start of a line. Use "\(foo\)\@<!bar".

    							*/\@<=*
    \@<=	Matches with zero width if the preceding atom matches just before what
    	follows. |/zero-width| {not in Vi}
    	Like '(?<=pattern)" in Perl, but Vim allows non-fixed-width patterns.
    	Example			matches
    	\(an\_s\+\)\@<=file	"file" after "an" and white space or an
    				end-of-line
    	For speed it's often much better to avoid this multi.  Try using "\zs"
    	instead |/\zs|.  To match the same as the above example:
    		an\_s\+\zsfile

    	"\@<=" and "\@<!" check for matches just before what follows.
    	Theoretically these matches could start anywhere before this position.
    	But to limit the time needed, only the line where what follows matches
    	is searched, and one line before that (if there is one).  This should
    	be sufficient to match most things and not be too slow.
    	The part of the pattern after "\@<=" and "\@<!" are checked for a
    	match first, thus things like "\1" don't work to reference \(\) inside
    	the preceding atom.  It does work the other way around:
    	Example			matches
    	\1\@<=,\([a-z]\+\)	",abc" in "abc,abc"

    							*/\@<!*
    \@<!	Matches with zero width if the preceding atom does NOT match just
    	before what follows.  Thus this matches if there is no position in the
    	current or previous line where the atom matches such that it ends just
    	before what follows.  |/zero-width| {not in Vi}
    	Like '(?<!pattern)" in Perl, but Vim allows non-fixed-width patterns.
    	The match with the preceding atom is made to end just before the match
    	with what follows, thus an atom that ends in ".*" will work.
    	Warning: This can be slow (because many positions need to be checked
    	for a match).
    	Example			matches
    	\(foo\)\@<!bar		any "bar" that's not in "foobar"
    	\(\/\/.*\)\@\<!in	"in" which is not after "//"

    							*/\@>*
    \@>	Matches the preceding atom like matching a whole pattern. {not in Vi}
    	Like '(?>pattern)" in Perl.
    	Example		matches
    	\(a*\)\@>a	nothing (the "a*" takes all the "a"'s, there can't be
    			another one following)

    	This matches the preceding atom as if it was a pattern by itself.  If
    	it doesn't match, there is no retry with shorter sub-matches or
    	anything.  Observe this difference: "a*b" and "a*ab" both match
    	"aaab", but in the second case the "a*" matches only the first two
    	"a"s.  "\(a*\)\@>ab" will not match "aaab", because the "a*" matches
    	the "aaa" (as many "a"s as possible), thus the "ab" can't match.

    An ordinary atom can be:

    							*/^*
    ^	At beginning of pattern or after "\|", "\(", "\%(" or "\n": matches
    	start-of-line; at other positions, matches literal '^'. |/zero-width|
    	Example		matches
    	^beep(		the start of the C function "beep" (probably).

    							*/\^*
    \^	At any position, matches literal '^'.

    							*/\_^*
    \_^	At any position, matches start-of-line. |/zero-width|
    	Example		matches
    	\_s*\_^foo	white space and blank lines and then "foo" at
    			start-of-line

    							*/$*
    $	At end of pattern or in front of "\|" or "\)" ("|" or ")" after "\v"):
    	matches end-of-line <EOL>; at other positions, matches literal '$'.
    	|/zero-width|

    							*/\$*
    \$	At any position, matches literal '$'.

    							*/\_$*
    \_$	At any position, matches end-of-line. |/zero-width|
    	Example		matches
    	foo\_$\_s*	"foo" at end-of-line and following white space and
    			blank lines

    .	(with 'nomagic': \.)				*/.* */\.*
    	Matches any single character, but not an end-of-line.

    							*/\_.*
    \_.	Matches any single character or end-of-line.
    	Careful: "\_.*" matches all text to the end of the buffer!

    							*/\<*
    \<	Matches the beginning of a word: The next char is the first char of a
    	word.  The 'iskeyword' option specifies what is a word character.
    	|/zero-width|

    							*/\>*
    \>	Matches the end of a word: The previous char is the last char of a
    	word. The 'iskeyword' option specifies what is a word character.
    	|/zero-width|

    							*/\zs*
    \zs	Matches at any position, and sets the start of the match there: The
    	next char is the first char of the whole match. |/zero-width|
    	Can be used multiple times, the last one encountered in a matching
    	branch is used.
    	Example: "^\s*\zsif" matches an "if" at the start of a line, ignoring
    	white space.
    	{not in Vi} {not available when compiled without the +syntax feature}
    							*/\ze*
    \ze	Matches at any position, and sets the end of the match there: The
    	previous char is the last char of the whole match. |/zero-width|
    	Can be used multiple times, the last one encountered in a matching
    	branch is used.
    	Example: "end\ze\(if\|for\)" matches the "end" in "endif" and
    	"endfor".
    	{not in Vi} {not available when compiled without the +syntax feature}

    						*/\%^* *start-of-file*
    \%^	Matches start of the file.  When matching with a string, matches the
    	start of the string. {not in Vi}
    	For example, to find the first "VIM" in a file:
    		/\%^\_.\{-}\zsVIM

    						*/\%$* *end-of-file*
    \%$	Matches end of the file.  When matching with a string, matches the
    	end of the string. {not in Vi}
    	Note that this does NOT find the last "VIM" in a file:
    		/VIM\_.\{-}\%$
    	It will find the next VIM, because the part after it will always
    	match.  This one will find the last "VIM" in the file:
    		/VIM\ze\(\(VIM\)\@!\_.\)*\%$
    	This uses |/\@!| to ascertain that "VIM" does NOT match in any
    	position after the first "VIM".
    	Searching from the end of the file backwards is easier!

    						*/\%#* *cursor-position*
    \%#	Matches with the cursor position.  Only works when matching in a
    	buffer displayed in a window. {not in Vi}
    	WARNING: When the cursor is moved after the pattern was used, the
    	result becomes invalid.  Vim doesn't automatically update the matches.
    	This is especially relevant for syntax highlighting and 'hlsearch'.
    	In other words: When the cursor moves the display isn't updated for
    	this change.  An update is done for lines which are changed (the whole
    	line is updated) or when using the |CTRL-L| command (the whole screen
    	is updated).  Example, to highlight the word under the cursor:
    		/\k*\%#\k*
    	When 'hlsearch' is set and you move the cursor around and make changes
    	this will clearly show when the match is updated or not.

    						*/\%l* */\%>l* */\%<l*
    \%23l	Matches in a specific line.
    \%<23l	Matches above a specific line.
    \%>23l	Matches below a specific line.
    	These three can be used to match specific lines in a buffer.  The "23"
    	can be any line number.  The first line is 1. {not in Vi}
    	WARNING: When inserting or deleting lines Vim does not automatically
    	update the matches.  This means Syntax highlighting quickly becomes
    	wrong.
    	Example, to highlight the line where the cursor currently is:
    		:exe '/\%' . line(".") . 'l.*'
    	When 'hlsearch' is set and you move the cursor around and make changes
    	this will clearly show when the match is updated or not.

    						*/\%c* */\%>c* */\%<c*
    \%23c	Matches in a specific column.
    \%<23c	Matches before a specific column.
    \%>23c	Matches after a specific column.
    	These three can be used to match specific columns in a buffer or
    	string.  The "23" can be any column number.  The first column is 1.
    	Actually, the column is the byte number (thus it's not exactly right
    	for multi-byte characters).  {not in Vi}
    	WARNING: When inserting or deleting text Vim does not automatically
    	update the matches.  This means Syntax highlighting quickly becomes
    	wrong.
    	Example, to highlight the column where the cursor currently is:
    		:exe '/\%' . col(".") . 'c'
    	When 'hlsearch' is set and you move the cursor around and make changes
    	this will clearly show when the match is updated or not.

    						*/\%v* */\%>v* */\%<v*
    \%23v	Matches in a specific virtual column.
    \%<23v	Matches before a specific virtual column.
    \%>23v	Matches after a specific virtual column.
    	These three can be used to match specific virtual columns in a buffer
    	or string.  When not matching with a buffer in a window, the option
    	values of the current window are used (e.g., 'tabstop').
    	The "23" can be any column number.  The first column is 1.
    	Note that some virtual column positions will never match, because they
    	are halfway a Tab or other character that occupies more than one
    	screen character.  {not in Vi}
    	WARNING: When inserting or deleting text Vim does not automatically
    	update the matches.  This means Syntax highlighting quickly becomes
    	wrong.
    	Example, to highlight the all characters after virtual column 72:
    		/\%>72v.*
    	When 'hlsearch' is set and you move the cursor around and make changes
    	this will clearly show when the match is updated or not.
    	To match the text up to column 17:
    		/.*\%17v
    	Column 17 is not included, because that's where the "\%17v" matches,
    	and since this is a |/zero-width| match, column 17 isn't included in
    	the match.  This does the same:
    		/.*\%<18v

    Character classes: {not in Vi}
    \i	identifier character (see 'isident' option)	*/\i*
    \I	like "\i", but excluding digits			*/\I*
    \k	keyword character (see 'iskeyword' option)	*/\k*
    \K	like "\k", but excluding digits			*/\K*
    \f	file name character (see 'isfname' option)	*/\f*
    \F	like "\f", but excluding digits			*/\F*
    \p	printable character (see 'isprint' option)	*/\p*
    \P	like "\p", but excluding digits			*/\P*

    NOTE: the above also work for multi-byte characters.  The ones below only
    match ASCII characters, as indicated by the range.

    						*whitespace* *white-space*
    \s	whitespace character: <Space> and <Tab>		*/\s*
    \S	non-whitespace character; opposite of \s	*/\S*
    \d	digit:				[0-9]		*/\d*
    \D	non-digit:			[^0-9]		*/\D*
    \x	hex digit:			[0-9A-Fa-f]	*/\x*
    \X	non-hex digit:			[^0-9A-Fa-f]	*/\X*
    \o	octal digit:			[0-7]		*/\o*
    \O	non-octal digit:		[^0-7]		*/\O*
    \w	word character:			[0-9A-Za-z_]	*/\w*
    \W	non-word character:		[^0-9A-Za-z_]	*/\W*
    \h	head of word character:		[A-Za-z_]	*/\h*
    \H	non-head of word character:	[^A-Za-z_]	*/\H*
    \a	alphabetic character:		[A-Za-z]	*/\a*
    \A	non-alphabetic character:	[^A-Za-z]	*/\A*
    \l	lowercase character:		[a-z]		*/\l*
    \L	non-lowercase character:	[^a-z]		*/\L*
    \u	uppercase character:		[A-Z]		*/\u*
    \U	non-uppercase character		[^A-Z]		*/\U*

    	NOTE: Using the atom is faster than the [] form.

    	NOTE: 'ignorecase', "\c" and "\C" are not used by character classes.

    							*/\_* *E63*
    \_x	Where "x" is any of the characters above: The character class with
    	end-of-line added
    (end of character classes)

    \e	matches <Esc>					*/\e*
    \t	matches <Tab>					*/\t*
    \r	matches <CR>					*/\r*
    \b	matches <BS>					*/\b*
    \n	matches a end-of-line				*/\n*

    ~	matches the last given substitute string	*/~* */\~*

    \(\)	A pattern enclosed by escaped parentheses	*/\(* */\(\)* */\)*
    	(e.g., "\(^a\)") matches 'a' at the start of a line.  *E51* *E54* *E55*

    \1      Matches the same string that was matched by	*/\1* *E65*
    	the first sub-expression in \( and \). {not in Vi}
    	Example: "\([a-z]\).\1" matches "ata", "ehe", "tot", etc.
    \2      Like "\1", but uses second sub-expression,	*/\2*
       ...							*/\3*
    \9      Like "\1", but uses ninth sub-expression.	*/\9*
    	Note: The numbering of groups is done based on which "\(" comes first
    	in the pattern (going left to right), NOT based on what is matched
    	first.

    \%(\)	A pattern enclosed by escaped parentheses.	*/\%(\)* */\%(* *E53*
    	Just like \(\), but without counting it as a sub-expression
    	{not in Vi}

    x	A single character, with no special meaning, matches itself

    							*/\* */\\*
    \x	A backslash followed by a single character, with no special meaning,
    	is reserved for future expansions

    []	(with 'nomagic': \[])		*/[]* */\[]* */\_[]* */collection*
    \_[]
    	A collection. This is a sequence of characters enclosed in brackets.
    	It matches any single character in the collection.
    	Example		matches
    	[xyz]		any 'x', 'y' or 'z'
    	[a-zA-Z]$	any alphabetic character at the end of a line
    	\c[a-z]$	same

    	With "\_" prepended the collection also includes the end-of-line.
    	The same can be done by including "\n" in the collection.  The
    	end-of-line is also matched when the collection starts with "^"!  Thus
    	"\_[^ab]" matches the end-of-line and any character but "a" and "b".
    	This makes it Vi compatible: Without the "\_" or "\n" the collection
    	does not match an end-of-line.

    	If the sequence begins with "^", it matches any single character NOT
    	in the collection: "[^xyz]" matches anything but 'x', 'y' and 'z'.
    	- If two characters in the sequence are separated by '-', this is
    	  shorthand for the full list of ASCII characters between them.  E.g.,
    	  "[0-9]" matches any decimal digit.
    	- A character class expression is evaluated to the set of characters
    	  belonging to that character class.  The following character classes
    	  are supported:
    			  Name		Contents
    *[:alnum:]*		  [:alnum:]     letters and digits
    *[:alpha:]*		  [:alpha:]     letters
    *[:blank:]*		  [:blank:]     space and tab characters
    *[:cntrl:]*		  [:cntrl:]     control characters
    *[:digit:]*		  [:digit:]     decimal digits
    *[:graph:]*		  [:graph:]     printable characters excluding space
    *[:lower:]*		  [:lower:]     lowercase letters (all letters when
    					'ignorecase' is used)
    *[:print:]*		  [:print:]     printable characters including space
    *[:punct:]*		  [:punct:]     punctuation characters
    *[:space:]*		  [:space:]     whitespace characters
    *[:upper:]*		  [:upper:]     uppercase letters (all letters when
    					'ignorecase' is used)
    *[:xdigit:]*		  [:xdigit:]    hexadecimal digits
    *[:return:]*		  [:return:]	the <CR> character
    *[:tab:]*		  [:tab:]	the <Tab> character
    *[:escape:]*		  [:escape:]	the <Esc> character
    *[:backspace:]*		  [:backspace:]	the <BS> character
    	  The brackets in character class expressions are additional to the
    	  brackets delimiting a collection.  For example, the following is a
    	  plausible pattern for a UNIX filename: "[-./[:alnum:]_~]\+" That is,
    	  a list of at least one character, each of which is either '-', '.',
    	  '/', alphabetic, numeric, '_' or '~'.
    	  These items only work for 8-bit characters.
    							  */\]*
    	- To include a literal ']', '^', '-' or '\' in the collection, put a
    	  backslash before it: "[xyz\]]", "[\^xyz]", "[xy\-z]" and "[xyz\\]".
    	  (Note: POSIX does not support the use of a backslash this way).  For
    	  ']' you can also make it the first character (following a possible
    	  "^"):  "[]xyz]" or "[^]xyz]" {not in Vi}.
    	  For '-' you can also make it the first or last character: "[-xyz]",
    	  "[^-xyz]" or "[xyz-]".  For '\' you can also let it be followed by
    	  any character that's not in "^]-\bertn".  "[\xyz]" matches '\', 'x',
    	  'y' and 'z'.  It's better to use "\\" though, future expansions may
    	  use other characters after '\'.
    	- The following translations are accepted when the 'l' flag is not
    	  included in 'cpoptions' {not in Vi}:
    		\e	<Esc>
    		\t	<Tab>
    		\r	<CR>	(NOT end-of-line!)
    		\b	<BS>
    	  NOTE: The other backslash codes mentioned above do not work inside
    	  []!
    	- Matching with a collection can be slow, because each character in
    	  the text has to be compared with each character in the collection.
    	  Use one of the other atoms above when possible.  Example: "\d" is
    	  much faster than "[0-9]" and matches the same characters.

    						*/\%[]* *E69* *E70* *E369*
    \%[]	A list of optionally matched atoms.  This always matches.
    	It matches as much of the list of atoms it contains as possible.  Thus
    	it stops at the first atom that doesn't match.  For example:
    		/r\%[ead]
    	matches "r", "re", "rea" or "read".  The longest that matches is used.
    	To match the Ex command "function", where "fu" is required and
    	"nction" is optional, this would work:
    		/\<fu\%[nction]\>
    	The end-of-word atom "\>" is used to avoid matching "fu" in "full".
    	It gets more complicated when the atoms are not ordinary characters.
    	You don't often have to use it, but it is possible.  Example:
    		/\<r\%[[eo]ad]\>
    	Matches the words "r", "re", "ro", "rea", "roa", "read" and "road".
    	{not available when compiled without the +syntax feature}

    Ignoring case in a pattern					*/ignorecase*

    If the 'ignorecase' option is on, the case of normal letters is ignored.
    'smartcase' can be set to ignore case when the pattern contains lowercase
    letters only.
    							*/\c* */\C*
    When "\c" appears anywhere in the pattern, the whole pattern is handled like
    'ignorecase' is on.  The actual value of 'ignorecase' and 'smartcase' is
    ignored.  "\C" does the opposite: Force matching case for the whole pattern.
    {only Vim supports \c and \C}
    Note that 'ignorecase', "\c" and "\C" are not used for the character classes.

    Examples:
          pattern	'ignorecase'  'smartcase'	matches
    	foo	  off		-		foo
    	foo	  on		-		foo Foo FOO
    	Foo	  on		off		foo Foo FOO
    	Foo	  on		on		    Foo
    	\cfoo	  -		-		foo Foo FOO
    	foo\C	  -		-		foo

    Technical detail:				*NL-used-for-Nul*
    <Nul> characters in the file are stored as <NL> in memory.  In the display
    they are shown as "^@".  The translation is done when reading and writing
    files.  To match a <Nul> with a search pattern you can just enter CTRL-@ or
    "CTRL-V 000".  This is probably just what you expect.  Internally the
    character is replaced with a <NL> in the search pattern.  What is unusual is
    that typing CTRL-V CTRL-J also inserts a <NL>, thus also searches for a <Nul>
    in the file.  {Vi cannot handle <Nul> characters in the file at all}

    						*CR-used-for-NL*
    When 'fileformat' is "mac", <NL> characters in the file are stored as <CR>
    characters internally.  In the display they are shown as "^M".  Otherwise this
    works similar to the usage of <NL> for a <Nul>.

    When working with expression evaluation, a <NL> character in the pattern
    matches a <NL> in the string.  The use of "\n" (backslash n) to match a <NL>
    doesn't work there, it only works to match text in the buffer.

    3. Highlighting matches					*match-highlight*

    							*:mat* *:match*
    :mat[ch] {group} /{pattern}/
    		Define a pattern to highlight in the current window.  It will
    		be highlighted with {group}.  Example:
    			:highlight MyGroup ctermbg=green guibg=green
    			:match MyGroup /TODO/
    		Instead of // any character can be used to mark the start and
    		end of the {pattern}.
    		{group} must exist at the moment this command is executed.
    		The match overrides the 'hlsearch' highlighting.
    		'ignorecase' does not apply, use |/\c| in the pattern to
    		ignore case.  Otherwise case is not ignored.
    		Note that highlighting the last used search pattern with
    		'hlsearch' is used in all windows, while the pattern defined
    		with ":match" only exists in the current window.  It is kept
    		when switching to another buffer.
    		Another example, which highlights all characters in virtual
    		column 72 and more:
    			:highlight rightMargin term=bold ctermfg=blue guifg=blue
    			:match rightMargin /.\%>72v/
    <		To highlight all character that are in virtual column 7:
    			:highlight col8 ctermbg=grey guibg=grey
    			:match col8 /\%<8v.\%>7v/
    		Note the use of two items to also match a character that
    		occupies more than one virtual column, such as a TAB.

    :mat[ch]
    :mat[ch] none
    		Clear a previously defined match pattern.

     vim:tw=78:ts=8:ft=help:norl:

Generated by vim2html on Tue Apr 16 08:10:03 UTC 2002