xref: /vim-8.2.3635/runtime/doc/pattern.txt (revision bc93cebb)
1*pattern.txt*   For Vim version 8.2.  Last change: 2019 Dec 07
2
3
4		  VIM REFERENCE MANUAL    by Bram Moolenaar
5
6
7Patterns and search commands				*pattern-searches*
8
9The very basics can be found in section |03.9| of the user manual.  A few more
10explanations are in chapter 27 |usr_27.txt|.
11
121. Search commands		|search-commands|
132. The definition of a pattern	|search-pattern|
143. Magic			|/magic|
154. Overview of pattern items	|pattern-overview|
165. Multi items			|pattern-multi-items|
176. Ordinary atoms		|pattern-atoms|
187. Ignoring case in a pattern	|/ignorecase|
198. Composing characters		|patterns-composing|
209. Compare with Perl patterns	|perl-patterns|
2110. Highlighting matches	|match-highlight|
22
23==============================================================================
241. Search commands				*search-commands*
25
26							*/*
27/{pattern}[/]<CR>	Search forward for the [count]'th occurrence of
28			{pattern} |exclusive|.
29
30/{pattern}/{offset}<CR>	Search forward for the [count]'th occurrence of
31			{pattern} and go |{offset}| lines up or down.
32			|linewise|.
33
34							*/<CR>*
35/<CR>			Search forward for the [count]'th occurrence of the
36			latest used pattern |last-pattern| with latest used
37			|{offset}|.
38
39//{offset}<CR>		Search forward for the [count]'th occurrence of the
40			latest used pattern |last-pattern| with new
41			|{offset}|.  If {offset} is empty no offset is used.
42
43							*?*
44?{pattern}[?]<CR>	Search backward for the [count]'th previous
45			occurrence of {pattern} |exclusive|.
46
47?{pattern}?{offset}<CR>	Search backward for the [count]'th previous
48			occurrence of {pattern} and go |{offset}| lines up or
49			down |linewise|.
50
51							*?<CR>*
52?<CR>			Search backward for the [count]'th occurrence of the
53			latest used pattern |last-pattern| with latest used
54			|{offset}|.
55
56??{offset}<CR>		Search backward for the [count]'th occurrence of the
57			latest used pattern |last-pattern| with new
58			|{offset}|.  If {offset} is empty no offset is used.
59
60							*n*
61n			Repeat the latest "/" or "?" [count] times.
62			If the cursor doesn't move the search is repeated with
63			count + 1.
64			|last-pattern|
65
66							*N*
67N			Repeat the latest "/" or "?" [count] times in
68			opposite direction. |last-pattern|
69
70							*star* *E348* *E349*
71*			Search forward for the [count]'th occurrence of the
72			word nearest to the cursor.  The word used for the
73			search is the first of:
74				1. the keyword under the cursor |'iskeyword'|
75				2. the first keyword after the cursor, in the
76				   current line
77				3. the non-blank word under the cursor
78				4. the first non-blank word after the cursor,
79				   in the current line
80			Only whole keywords are searched for, like with the
81			command "/\<keyword\>".  |exclusive|
82			'ignorecase' is used, 'smartcase' is not.
83
84							*#*
85#			Same as "*", but search backward.  The pound sign
86			(character 163) also works.  If the "#" key works as
87			backspace, try using "stty erase <BS>" before starting
88			Vim (<BS> is CTRL-H or a real backspace).
89
90							*gstar*
91g*			Like "*", but don't put "\<" and "\>" around the word.
92			This makes the search also find matches that are not a
93			whole word.
94
95							*g#*
96g#			Like "#", but don't put "\<" and "\>" around the word.
97			This makes the search also find matches that are not a
98			whole word.
99
100							*gd*
101gd			Goto local Declaration.  When the cursor is on a local
102			variable, this command will jump to its declaration.
103			First Vim searches for the start of the current
104			function, just like "[[".  If it is not found the
105			search stops in line 1.  If it is found, Vim goes back
106			until a blank line is found.  From this position Vim
107			searches for the keyword under the cursor, like with
108			"*", but lines that look like a comment are ignored
109			(see 'comments' option).
110			Note that this is not guaranteed to work, Vim does not
111			really check the syntax, it only searches for a match
112			with the keyword.  If included files also need to be
113			searched use the commands listed in |include-search|.
114			After this command |n| searches forward for the next
115			match (not backward).
116
117							*gD*
118gD			Goto global Declaration.  When the cursor is on a
119			global variable that is defined in the file, this
120			command will jump to its declaration.  This works just
121			like "gd", except that the search for the keyword
122			always starts in line 1.
123
124							*1gd*
1251gd			Like "gd", but ignore matches inside a {} block that
126			ends before the cursor position.
127
128							*1gD*
1291gD			Like "gD", but ignore matches inside a {} block that
130			ends before the cursor position.
131
132							*CTRL-C*
133CTRL-C			Interrupt current (search) command.  Use CTRL-Break on
134			MS-Windows |dos-CTRL-Break|.
135			In Normal mode, any pending command is aborted.
136
137							*:noh* *:nohlsearch*
138:noh[lsearch]		Stop the highlighting for the 'hlsearch' option.  It
139			is automatically turned back on when using a search
140			command, or setting the 'hlsearch' option.
141			This command doesn't work in an autocommand, because
142			the highlighting state is saved and restored when
143			executing autocommands |autocmd-searchpat|.
144			Same thing for when invoking a user function.
145
146While typing the search pattern the current match will be shown if the
147'incsearch' option is on.  Remember that you still have to finish the search
148command with <CR> to actually position the cursor at the displayed match.  Or
149use <Esc> to abandon the search.
150
151All matches for the last used search pattern will be highlighted if you set
152the 'hlsearch' option.  This can be suspended with the |:nohlsearch| command.
153
154When 'shortmess' does not include the "S" flag, Vim will automatically show an
155index, on which the cursor is. This can look like this: >
156
157  [1/5]		Cursor is on first of 5 matches.
158  [1/>99]	Cursor is on first of more than 99 matches.
159  [>99/>99]	Cursor is after 99 match of more than 99 matches.
160  [?/??]	Unknown how many matches exists, generating the
161		statistics was aborted because of search timeout.
162
163Note: the count does not take offset into account.
164
165When no match is found you get the error: *E486* Pattern not found
166Note that for the |:global| command this behaves like a normal message, for Vi
167compatibility.  For the |:s| command the "e" flag can be used to avoid the
168error message |:s_flags|.
169
170					*search-offset* *{offset}*
171These commands search for the specified pattern.  With "/" and "?" an
172additional offset may be given.  There are two types of offsets: line offsets
173and character offsets.
174
175The offset gives the cursor position relative to the found match:
176    [num]	[num] lines downwards, in column 1
177    +[num]	[num] lines downwards, in column 1
178    -[num]	[num] lines upwards, in column 1
179    e[+num]	[num] characters to the right of the end of the match
180    e[-num]	[num] characters to the left of the end of the match
181    s[+num]	[num] characters to the right of the start of the match
182    s[-num]	[num] characters to the left of the start of the match
183    b[+num]	[num] identical to s[+num] above (mnemonic: begin)
184    b[-num]	[num] identical to s[-num] above (mnemonic: begin)
185    ;{pattern}  perform another search, see |//;|
186
187If a '-' or '+' is given but [num] is omitted, a count of one will be used.
188When including an offset with 'e', the search becomes inclusive (the
189character the cursor lands on is included in operations).
190
191Examples:
192
193pattern			cursor position	~
194/test/+1		one line below "test", in column 1
195/test/e			on the last t of "test"
196/test/s+2		on the 's' of "test"
197/test/b-3		three characters before "test"
198
199If one of these commands is used after an operator, the characters between
200the cursor position before and after the search is affected.  However, if a
201line offset is given, the whole lines between the two cursor positions are
202affected.
203
204An example of how to search for matches with a pattern and change the match
205with another word: >
206	/foo<CR>	find "foo"
207	c//e<CR>	change until end of match
208	bar<Esc>	type replacement
209	//<CR>		go to start of next match
210	c//e<CR>	change until end of match
211	beep<Esc>	type another replacement
212			etc.
213<
214							*//;* *E386*
215A very special offset is ';' followed by another search command.  For example: >
216
217   /test 1/;/test
218   /test.*/+1;?ing?
219
220The first one first finds the next occurrence of "test 1", and then the first
221occurrence of "test" after that.
222
223This is like executing two search commands after each other, except that:
224- It can be used as a single motion command after an operator.
225- The direction for a following "n" or "N" command comes from the first
226  search command.
227- When an error occurs the cursor is not moved at all.
228
229							*last-pattern*
230The last used pattern and offset are remembered.  They can be used to repeat
231the search, possibly in another direction or with another count.  Note that
232two patterns are remembered: One for 'normal' search commands and one for the
233substitute command ":s".  Each time an empty pattern is given, the previously
234used pattern is used.  However, if there is no previous search command, a
235previous substitute pattern is used, if possible.
236
237The 'magic' option sticks with the last used pattern.  If you change 'magic',
238this will not change how the last used pattern will be interpreted.
239The 'ignorecase' option does not do this.  When 'ignorecase' is changed, it
240will result in the pattern to match other text.
241
242All matches for the last used search pattern will be highlighted if you set
243the 'hlsearch' option.
244
245To clear the last used search pattern: >
246	:let @/ = ""
247This will not set the pattern to an empty string, because that would match
248everywhere.  The pattern is really cleared, like when starting Vim.
249
250The search usually skips matches that don't move the cursor.  Whether the next
251match is found at the next character or after the skipped match depends on the
252'c' flag in 'cpoptions'.  See |cpo-c|.
253	   with 'c' flag:   "/..." advances 1 to 3 characters
254	without 'c' flag:   "/..." advances 1 character
255The unpredictability with the 'c' flag is caused by starting the search in the
256first column, skipping matches until one is found past the cursor position.
257
258When searching backwards, searching starts at the start of the line, using the
259'c' flag in 'cpoptions' as described above.  Then the last match before the
260cursor position is used.
261
262In Vi the ":tag" command sets the last search pattern when the tag is searched
263for.  In Vim this is not done, the previous search pattern is still remembered,
264unless the 't' flag is present in 'cpoptions'.  The search pattern is always
265put in the search history.
266
267If the 'wrapscan' option is on (which is the default), searches wrap around
268the end of the buffer.  If 'wrapscan' is not set, the backward search stops
269at the beginning and the forward search stops at the end of the buffer.  If
270'wrapscan' is set and the pattern was not found the error message "pattern
271not found" is given, and the cursor will not be moved.  If 'wrapscan' is not
272set the message becomes "search hit BOTTOM without match" when searching
273forward, or "search hit TOP without match" when searching backward.  If
274wrapscan is set and the search wraps around the end of the file the message
275"search hit TOP, continuing at BOTTOM" or "search hit BOTTOM, continuing at
276TOP" is given when searching backwards or forwards respectively.  This can be
277switched off by setting the 's' flag in the 'shortmess' option.  The highlight
278method 'w' is used for this message (default: standout).
279
280							*search-range*
281You can limit the search command "/" to a certain range of lines by including
282\%>l items.  For example, to match the word "limit" below line 199 and above
283line 300: >
284	/\%>199l\%<300llimit
285Also see |/\%>l|.
286
287Another way is to use the ":substitute" command with the 'c' flag.  Example: >
288   :.,300s/Pattern//gc
289This command will search from the cursor position until line 300 for
290"Pattern".  At the match, you will be asked to type a character.  Type 'q' to
291stop at this match, type 'n' to find the next match.
292
293The "*", "#", "g*" and "g#" commands look for a word near the cursor in this
294order, the first one that is found is used:
295- The keyword currently under the cursor.
296- The first keyword to the right of the cursor, in the same line.
297- The WORD currently under the cursor.
298- The first WORD to the right of the cursor, in the same line.
299The keyword may only contain letters and characters in 'iskeyword'.
300The WORD may contain any non-blanks (<Tab>s and/or <Space>s).
301Note that if you type with ten fingers, the characters are easy to remember:
302the "#" is under your left hand middle finger (search to the left and up) and
303the "*" is under your right hand middle finger (search to the right and down).
304(this depends on your keyboard layout though).
305
306								*E956*
307In very rare cases a regular expression is used recursively.  This can happen
308when executing a pattern takes a long time and when checking for messages on
309channels a callback is invoked that also uses a pattern or an autocommand is
310triggered.  In most cases this should be fine, but if a pattern is in use when
311it's used again it fails.  Usually this means there is something wrong with
312the pattern.
313
314==============================================================================
3152. The definition of a pattern		*search-pattern* *pattern* *[pattern]*
316					*regular-expression* *regexp* *Pattern*
317					*E76* *E383* *E476*
318
319For starters, read chapter 27 of the user manual |usr_27.txt|.
320
321						*/bar* */\bar* */pattern*
3221. A pattern is one or more branches, separated by "\|".  It matches anything
323   that matches one of the branches.  Example: "foo\|beep" matches "foo" and
324   matches "beep".  If more than one branch matches, the first one is used.
325
326   pattern ::=	    branch
327		or  branch \| branch
328		or  branch \| branch \| branch
329		etc.
330
331						*/branch* */\&*
3322. A branch is one or more concats, separated by "\&".  It matches the last
333   concat, but only if all the preceding concats also match at the same
334   position.  Examples:
335	"foobeep\&..." matches "foo" in "foobeep".
336	".*Peter\&.*Bob" matches in a line containing both "Peter" and "Bob"
337
338   branch ::=	    concat
339		or  concat \& concat
340		or  concat \& concat \& concat
341		etc.
342
343						*/concat*
3443. A concat is one or more pieces, concatenated.  It matches a match for the
345   first piece, followed by a match for the second piece, etc.  Example:
346   "f[0-9]b", first matches "f", then a digit and then "b".
347
348   concat  ::=	    piece
349		or  piece piece
350		or  piece piece piece
351		etc.
352
353						*/piece*
3544. A piece is an atom, possibly followed by a multi, an indication of how many
355   times the atom can be matched.  Example: "a*" matches any sequence of "a"
356   characters: "", "a", "aa", etc.  See |/multi|.
357
358   piece   ::=	    atom
359		or  atom  multi
360
361						*/atom*
3625. An atom can be one of a long list of items.  Many atoms match one character
363   in the text.  It is often an ordinary character or a character class.
364   Braces can be used to make a pattern into an atom.  The "\z(\)" construct
365   is only for syntax highlighting.
366
367   atom    ::=	    ordinary-atom		|/ordinary-atom|
368		or  \( pattern \)		|/\(|
369		or  \%( pattern \)		|/\%(|
370		or  \z( pattern \)		|/\z(|
371
372
373				*/\%#=* *two-engines* *NFA*
374Vim includes two regexp engines:
3751. An old, backtracking engine that supports everything.
3762. A new, NFA engine that works much faster on some patterns, possibly slower
377   on some patterns.
378
379Vim will automatically select the right engine for you.  However, if you run
380into a problem or want to specifically select one engine or the other, you can
381prepend one of the following to the pattern:
382
383	\%#=0	Force automatic selection.  Only has an effect when
384	        'regexpengine' has been set to a non-zero value.
385	\%#=1	Force using the old engine.
386	\%#=2	Force using the NFA engine.
387
388You can also use the 'regexpengine' option to change the default.
389
390			 *E864* *E868* *E874* *E875* *E876* *E877* *E878*
391If selecting the NFA engine and it runs into something that is not implemented
392the pattern will not match.  This is only useful when debugging Vim.
393
394==============================================================================
3953. Magic							*/magic*
396
397Some characters in the pattern are taken literally.  They match with the same
398character in the text.  When preceded with a backslash however, these
399characters get a special meaning.
400
401Other characters have a special meaning without a backslash.  They need to be
402preceded with a backslash to match literally.
403
404If a character is taken literally or not depends on the 'magic' option and the
405items mentioned next.
406							*/\m* */\M*
407Use of "\m" makes the pattern after it be interpreted as if 'magic' is set,
408ignoring the actual value of the 'magic' option.
409Use of "\M" makes the pattern after it be interpreted as if 'nomagic' is used.
410							*/\v* */\V*
411Use of "\v" means that after it, all ASCII characters except '0'-'9', 'a'-'z',
412'A'-'Z' and '_' have special meaning: "very magic"
413
414Use of "\V" means that after it, only a backslash and terminating character
415(usually / or ?) have special meaning: "very nomagic"
416
417Examples:
418after:	  \v	   \m	    \M	     \V		matches ~
419		'magic' 'nomagic'
420	  $	   $	    $	     \$		matches end-of-line
421	  .	   .	    \.	     \.		matches any character
422	  *	   *	    \*	     \*		any number of the previous atom
423	  ~	   ~	    \~	     \~		latest substitute string
424	  ()	   \(\)     \(\)     \(\)	grouping into an atom
425	  |	   \|	    \|	     \|		separating alternatives
426	  \a	   \a	    \a	     \a		alphabetic character
427	  \\	   \\	    \\	     \\		literal backslash
428	  \.	   \.	    .	     .		literal dot
429	  \{	   {	    {	     {		literal '{'
430	  a	   a	    a	     a		literal 'a'
431
432{only Vim supports \m, \M, \v and \V}
433
434It is recommended to always keep the 'magic' option at the default setting,
435which is 'magic'.  This avoids portability problems.  To make a pattern immune
436to the 'magic' option being set or not, put "\m" or "\M" at the start of the
437pattern.
438
439==============================================================================
4404. Overview of pattern items				*pattern-overview*
441						*E865* *E866* *E867* *E869*
442
443Overview of multi items.				*/multi* *E61* *E62*
444More explanation and examples below, follow the links.		*E64* *E871*
445
446	  multi ~
447     'magic' 'nomagic'	matches of the preceding atom ~
448|/star|	*	\*	0 or more	as many as possible
449|/\+|	\+	\+	1 or more	as many as possible
450|/\=|	\=	\=	0 or 1		as many as possible
451|/\?|	\?	\?	0 or 1		as many as possible
452
453|/\{|	\{n,m}	\{n,m}	n to m		as many as possible
454	\{n}	\{n}	n		exactly
455	\{n,}	\{n,}	at least n	as many as possible
456	\{,m}	\{,m}	0 to m		as many as possible
457	\{}	\{}	0 or more	as many as possible (same as *)
458
459|/\{-|	\{-n,m}	\{-n,m}	n to m		as few as possible
460	\{-n}	\{-n}	n		exactly
461	\{-n,}	\{-n,}	at least n	as few as possible
462	\{-,m}	\{-,m}	0 to m		as few as possible
463	\{-}	\{-}	0 or more	as few as possible
464
465							*E59*
466|/\@>|	\@>	\@>	1, like matching a whole pattern
467|/\@=|	\@=	\@=	nothing, requires a match |/zero-width|
468|/\@!|	\@!	\@!	nothing, requires NO match |/zero-width|
469|/\@<=|	\@<=	\@<=	nothing, requires a match behind |/zero-width|
470|/\@<!|	\@<!	\@<!	nothing, requires NO match behind |/zero-width|
471
472
473Overview of ordinary atoms.				*/ordinary-atom*
474More explanation and examples below, follow the links.
475
476      ordinary atom ~
477      magic   nomagic	matches ~
478|/^|	^	^	start-of-line (at start of pattern) |/zero-width|
479|/\^|	\^	\^	literal '^'
480|/\_^|	\_^	\_^	start-of-line (used anywhere) |/zero-width|
481|/$|	$	$	end-of-line (at end of pattern) |/zero-width|
482|/\$|	\$	\$	literal '$'
483|/\_$|	\_$	\_$	end-of-line (used anywhere) |/zero-width|
484|/.|	.	\.	any single character (not an end-of-line)
485|/\_.|	\_.	\_.	any single character or end-of-line
486|/\<|	\<	\<	beginning of a word |/zero-width|
487|/\>|	\>	\>	end of a word |/zero-width|
488|/\zs|	\zs	\zs	anything, sets start of match
489|/\ze|	\ze	\ze	anything, sets end of match
490|/\%^|	\%^	\%^	beginning of file |/zero-width|		*E71*
491|/\%$|	\%$	\%$	end of file |/zero-width|
492|/\%V|	\%V	\%V	inside Visual area |/zero-width|
493|/\%#|	\%#	\%#	cursor position |/zero-width|
494|/\%'m|	\%'m	\%'m	mark m position |/zero-width|
495|/\%l|	\%23l	\%23l	in line 23 |/zero-width|
496|/\%c|	\%23c	\%23c	in column 23 |/zero-width|
497|/\%v|	\%23v	\%23v	in virtual column 23 |/zero-width|
498
499Character classes:					*/character-classes*
500      magic   nomagic	matches ~
501|/\i|	\i	\i	identifier character (see 'isident' option)
502|/\I|	\I	\I	like "\i", but excluding digits
503|/\k|	\k	\k	keyword character (see 'iskeyword' option)
504|/\K|	\K	\K	like "\k", but excluding digits
505|/\f|	\f	\f	file name character (see 'isfname' option)
506|/\F|	\F	\F	like "\f", but excluding digits
507|/\p|	\p	\p	printable character (see 'isprint' option)
508|/\P|	\P	\P	like "\p", but excluding digits
509|/\s|	\s	\s	whitespace character: <Space> and <Tab>
510|/\S|	\S	\S	non-whitespace character; opposite of \s
511|/\d|	\d	\d	digit:				[0-9]
512|/\D|	\D	\D	non-digit:			[^0-9]
513|/\x|	\x	\x	hex digit:			[0-9A-Fa-f]
514|/\X|	\X	\X	non-hex digit:			[^0-9A-Fa-f]
515|/\o|	\o	\o	octal digit:			[0-7]
516|/\O|	\O	\O	non-octal digit:		[^0-7]
517|/\w|	\w	\w	word character:			[0-9A-Za-z_]
518|/\W|	\W	\W	non-word character:		[^0-9A-Za-z_]
519|/\h|	\h	\h	head of word character:		[A-Za-z_]
520|/\H|	\H	\H	non-head of word character:	[^A-Za-z_]
521|/\a|	\a	\a	alphabetic character:		[A-Za-z]
522|/\A|	\A	\A	non-alphabetic character:	[^A-Za-z]
523|/\l|	\l	\l	lowercase character:		[a-z]
524|/\L|	\L	\L	non-lowercase character:	[^a-z]
525|/\u|	\u	\u	uppercase character:		[A-Z]
526|/\U|	\U	\U	non-uppercase character		[^A-Z]
527|/\_|	\_x	\_x	where x is any of the characters above: character
528			class with end-of-line included
529(end of character classes)
530
531      magic   nomagic	matches ~
532|/\e|	\e	\e	<Esc>
533|/\t|	\t	\t	<Tab>
534|/\r|	\r	\r	<CR>
535|/\b|	\b	\b	<BS>
536|/\n|	\n	\n	end-of-line
537|/~|	~	\~	last given substitute string
538|/\1|	\1	\1	same string as matched by first \(\)
539|/\2|	\2	\2	Like "\1", but uses second \(\)
540	   ...
541|/\9|	\9	\9	Like "\1", but uses ninth \(\)
542								*E68*
543|/\z1|	\z1	\z1	only for syntax highlighting, see |:syn-ext-match|
544	   ...
545|/\z1|	\z9	\z9	only for syntax highlighting, see |:syn-ext-match|
546
547	x	x	a character with no special meaning matches itself
548
549|/[]|	[]	\[]	any character specified inside the []
550|/\%[]|	\%[]	\%[]	a sequence of optionally matched atoms
551
552|/\c|	\c	\c	ignore case, do not use the 'ignorecase' option
553|/\C|	\C	\C	match case, do not use the 'ignorecase' option
554|/\Z|	\Z	\Z	ignore differences in Unicode "combining characters".
555			Useful when searching voweled Hebrew or Arabic text.
556
557      magic   nomagic	matches ~
558|/\m|	\m	\m	'magic' on for the following chars in the pattern
559|/\M|	\M	\M	'magic' off for the following chars in the pattern
560|/\v|	\v	\v	the following chars in the pattern are "very magic"
561|/\V|	\V	\V	the following chars in the pattern are "very nomagic"
562|/\%#=|   \%#=1   \%#=1   select regexp engine |/zero-width|
563
564|/\%d|	\%d	\%d	match specified decimal character (eg \%d123)
565|/\%x|	\%x	\%x	match specified hex character (eg \%x2a)
566|/\%o|	\%o	\%o	match specified octal character (eg \%o040)
567|/\%u|	\%u	\%u	match specified multibyte character (eg \%u20ac)
568|/\%U|	\%U	\%U	match specified large multibyte character (eg
569			\%U12345678)
570|/\%C|	\%C	\%C	match any composing characters
571
572Example			matches ~
573\<\I\i*		or
574\<\h\w*
575\<[a-zA-Z_][a-zA-Z0-9_]*
576			An identifier (e.g., in a C program).
577
578\(\.$\|\. \)		A period followed by <EOL> or a space.
579
580[.!?][])"']*\($\|[ ]\)	A search pattern that finds the end of a sentence,
581			with almost the same definition as the ")" command.
582
583cat\Z			Both "cat" and "càt" ("a" followed by 0x0300)
584			Does not match "càt" (character 0x00e0), even
585			though it may look the same.
586
587
588==============================================================================
5895. Multi items						*pattern-multi-items*
590
591An atom can be followed by an indication of how many times the atom can be
592matched and in what way.  This is called a multi.  See |/multi| for an
593overview.
594
595							*/star* */\star*
596*	(use \* when 'magic' is not set)
597	Matches 0 or more of the preceding atom, as many as possible.
598	Example  'nomagic'	matches ~
599	a*	   a\*		"", "a", "aa", "aaa", etc.
600	.*	   \.\*		anything, also an empty string, no end-of-line
601	\_.*	   \_.\*	everything up to the end of the buffer
602	\_.*END	   \_.\*END	everything up to and including the last "END"
603				in the buffer
604
605	Exception: When "*" is used at the start of the pattern or just after
606	"^" it matches the star character.
607
608	Be aware that repeating "\_." can match a lot of text and take a long
609	time.  For example, "\_.*END" matches all text from the current
610	position to the last occurrence of "END" in the file.  Since the "*"
611	will match as many as possible, this first skips over all lines until
612	the end of the file and then tries matching "END", backing up one
613	character at a time.
614
615							*/\+*
616\+	Matches 1 or more of the preceding atom, as many as possible.
617	Example		matches ~
618	^.\+$		any non-empty line
619	\s\+		white space of at least one character
620
621							*/\=*
622\=	Matches 0 or 1 of the preceding atom, as many as possible.
623	Example		matches ~
624	foo\=		"fo" and "foo"
625
626							*/\?*
627\?	Just like \=.  Cannot be used when searching backwards with the "?"
628	command.
629
630					*/\{* *E60* *E554* *E870*
631\{n,m}	Matches n to m of the preceding atom, as many as possible
632\{n}	Matches n of the preceding atom
633\{n,}	Matches at least n of the preceding atom, as many as possible
634\{,m}	Matches 0 to m of the preceding atom, as many as possible
635\{}	Matches 0 or more of the preceding atom, as many as possible (like *)
636							*/\{-*
637\{-n,m}	matches n to m of the preceding atom, as few as possible
638\{-n}	matches n of the preceding atom
639\{-n,}	matches at least n of the preceding atom, as few as possible
640\{-,m}	matches 0 to m of the preceding atom, as few as possible
641\{-}	matches 0 or more of the preceding atom, as few as possible
642
643	n and m are positive decimal numbers or zero
644								*non-greedy*
645	If a "-" appears immediately after the "{", then a shortest match
646	first algorithm is used (see example below).  In particular, "\{-}" is
647	the same as "*" but uses the shortest match first algorithm.  BUT: A
648	match that starts earlier is preferred over a shorter match: "a\{-}b"
649	matches "aaab" in "xaaab".
650
651	Example			matches ~
652	ab\{2,3}c		"abbc" or "abbbc"
653	a\{5}			"aaaaa"
654	ab\{2,}c		"abbc", "abbbc", "abbbbc", etc.
655	ab\{,3}c		"ac", "abc", "abbc" or "abbbc"
656	a[bc]\{3}d		"abbbd", "abbcd", "acbcd", "acccd", etc.
657	a\(bc\)\{1,2}d		"abcd" or "abcbcd"
658	a[bc]\{-}[cd]		"abc" in "abcd"
659	a[bc]*[cd]		"abcd" in "abcd"
660
661	The } may optionally be preceded with a backslash: \{n,m\}.
662
663							*/\@=*
664\@=	Matches the preceding atom with zero width.
665	Like "(?=pattern)" in Perl.
666	Example			matches ~
667	foo\(bar\)\@=		"foo" in "foobar"
668	foo\(bar\)\@=foo	nothing
669							*/zero-width*
670	When using "\@=" (or "^", "$", "\<", "\>") no characters are included
671	in the match.  These items are only used to check if a match can be
672	made.  This can be tricky, because a match with following items will
673	be done in the same position.  The last example above will not match
674	"foobarfoo", because it tries match "foo" in the same position where
675	"bar" matched.
676
677	Note that using "\&" works the same as using "\@=": "foo\&.." is the
678	same as "\(foo\)\@=..".  But using "\&" is easier, you don't need the
679	braces.
680
681
682							*/\@!*
683\@!	Matches with zero width if the preceding atom does NOT match at the
684	current position. |/zero-width|
685	Like "(?!pattern)" in Perl.
686	Example			matches ~
687	foo\(bar\)\@!		any "foo" not followed by "bar"
688	a.\{-}p\@!		"a", "ap", "app", "appp", etc. not immediately
689				followed by a "p"
690	if \(\(then\)\@!.\)*$	"if " not followed by "then"
691
692	Using "\@!" is tricky, because there are many places where a pattern
693	does not match.  "a.*p\@!" will match from an "a" to the end of the
694	line, because ".*" can match all characters in the line and the "p"
695	doesn't match at the end of the line.  "a.\{-}p\@!" will match any
696	"a", "ap", "app", etc. that isn't followed by a "p", because the "."
697	can match a "p" and "p\@!" doesn't match after that.
698
699	You can't use "\@!" to look for a non-match before the matching
700	position: "\(foo\)\@!bar" will match "bar" in "foobar", because at the
701	position where "bar" matches, "foo" does not match.  To avoid matching
702	"foobar" you could use "\(foo\)\@!...bar", but that doesn't match a
703	bar at the start of a line.  Use "\(foo\)\@<!bar".
704
705	Useful example: to find "foo" in a line that does not contain "bar": >
706		/^\%(.*bar\)\@!.*\zsfoo
707<	This pattern first checks that there is not a single position in the
708	line where "bar" matches.  If ".*bar" matches somewhere the \@! will
709	reject the pattern.  When there is no match any "foo" will be found.
710	The "\zs" is to have the match start just before "foo".
711
712							*/\@<=*
713\@<=	Matches with zero width if the preceding atom matches just before what
714	follows. |/zero-width|
715	Like "(?<=pattern)" in Perl, but Vim allows non-fixed-width patterns.
716	Example			matches ~
717	\(an\_s\+\)\@<=file	"file" after "an" and white space or an
718				end-of-line
719	For speed it's often much better to avoid this multi.  Try using "\zs"
720	instead |/\zs|.  To match the same as the above example:
721		an\_s\+\zsfile
722	At least set a limit for the look-behind, see below.
723
724	"\@<=" and "\@<!" check for matches just before what follows.
725	Theoretically these matches could start anywhere before this position.
726	But to limit the time needed, only the line where what follows matches
727	is searched, and one line before that (if there is one).  This should
728	be sufficient to match most things and not be too slow.
729
730	In the old regexp engine the part of the pattern after "\@<=" and
731	"\@<!" are checked for a match first, thus things like "\1" don't work
732	to reference \(\) inside the preceding atom.  It does work the other
733	way around:
734	Bad example			matches ~
735	\%#=1\1\@<=,\([a-z]\+\)		",abc" in "abc,abc"
736
737	However, the new regexp engine works differently, it is better to not
738	rely on this behavior, do not use \@<= if it can be avoided:
739	Example				matches ~
740	\([a-z]\+\)\zs,\1		",abc" in "abc,abc"
741
742\@123<=
743	Like "\@<=" but only look back 123 bytes. This avoids trying lots
744	of matches that are known to fail and make executing the pattern very
745	slow.  Example, check if there is a "<" just before "span":
746		/<\@1<=span
747	This will try matching "<" only one byte before "span", which is the
748	only place that works anyway.
749	After crossing a line boundary, the limit is relative to the end of
750	the line.  Thus the characters at the start of the line with the match
751	are not counted (this is just to keep it simple).
752	The number zero is the same as no limit.
753
754							*/\@<!*
755\@<!	Matches with zero width if the preceding atom does NOT match just
756	before what follows.  Thus this matches if there is no position in the
757	current or previous line where the atom matches such that it ends just
758	before what follows.  |/zero-width|
759	Like "(?<!pattern)" in Perl, but Vim allows non-fixed-width patterns.
760	The match with the preceding atom is made to end just before the match
761	with what follows, thus an atom that ends in ".*" will work.
762	Warning: This can be slow (because many positions need to be checked
763	for a match).  Use a limit if you can, see below.
764	Example			matches ~
765	\(foo\)\@<!bar		any "bar" that's not in "foobar"
766	\(\/\/.*\)\@<!in	"in" which is not after "//"
767
768\@123<!
769	Like "\@<!" but only look back 123 bytes. This avoids trying lots of
770	matches that are known to fail and make executing the pattern very
771	slow.
772
773							*/\@>*
774\@>	Matches the preceding atom like matching a whole pattern.
775	Like "(?>pattern)" in Perl.
776	Example		matches ~
777	\(a*\)\@>a	nothing (the "a*" takes all the "a"'s, there can't be
778			another one following)
779
780	This matches the preceding atom as if it was a pattern by itself.  If
781	it doesn't match, there is no retry with shorter sub-matches or
782	anything.  Observe this difference: "a*b" and "a*ab" both match
783	"aaab", but in the second case the "a*" matches only the first two
784	"a"s.  "\(a*\)\@>ab" will not match "aaab", because the "a*" matches
785	the "aaa" (as many "a"s as possible), thus the "ab" can't match.
786
787
788==============================================================================
7896.  Ordinary atoms					*pattern-atoms*
790
791An ordinary atom can be:
792
793							*/^*
794^	At beginning of pattern or after "\|", "\(", "\%(" or "\n": matches
795	start-of-line; at other positions, matches literal '^'. |/zero-width|
796	Example		matches ~
797	^beep(		the start of the C function "beep" (probably).
798
799							*/\^*
800\^	Matches literal '^'.  Can be used at any position in the pattern.
801
802							*/\_^*
803\_^	Matches start-of-line. |/zero-width|  Can be used at any position in
804	the pattern.
805	Example		matches ~
806	\_s*\_^foo	white space and blank lines and then "foo" at
807			start-of-line
808
809							*/$*
810$	At end of pattern or in front of "\|", "\)" or "\n" ('magic' on):
811	matches end-of-line <EOL>; at other positions, matches literal '$'.
812	|/zero-width|
813
814							*/\$*
815\$	Matches literal '$'.  Can be used at any position in the pattern.
816
817							*/\_$*
818\_$	Matches end-of-line. |/zero-width|  Can be used at any position in the
819	pattern.  Note that "a\_$b" never matches, since "b" cannot match an
820	end-of-line.  Use "a\nb" instead |/\n|.
821	Example		matches ~
822	foo\_$\_s*	"foo" at end-of-line and following white space and
823			blank lines
824
825.	(with 'nomagic': \.)				*/.* */\.*
826	Matches any single character, but not an end-of-line.
827
828							*/\_.*
829\_.	Matches any single character or end-of-line.
830	Careful: "\_.*" matches all text to the end of the buffer!
831
832							*/\<*
833\<	Matches the beginning of a word: The next char is the first char of a
834	word.  The 'iskeyword' option specifies what is a word character.
835	|/zero-width|
836
837							*/\>*
838\>	Matches the end of a word: The previous char is the last char of a
839	word.  The 'iskeyword' option specifies what is a word character.
840	|/zero-width|
841
842							*/\zs*
843\zs	Matches at any position, and sets the start of the match there: The
844	next char is the first char of the whole match. |/zero-width|
845	Example: >
846		/^\s*\zsif
847<	matches an "if" at the start of a line, ignoring white space.
848	Can be used multiple times, the last one encountered in a matching
849	branch is used.  Example: >
850		/\(.\{-}\zsFab\)\{3}
851<	Finds the third occurrence of "Fab".
852	This cannot be followed by a multi. *E888*
853	{not available when compiled without the |+syntax| feature}
854							*/\ze*
855\ze	Matches at any position, and sets the end of the match there: The
856	previous char is the last char of the whole match. |/zero-width|
857	Can be used multiple times, the last one encountered in a matching
858	branch is used.
859	Example: "end\ze\(if\|for\)" matches the "end" in "endif" and
860	"endfor".
861	This cannot be followed by a multi. |E888|
862	{not available when compiled without the |+syntax| feature}
863
864						*/\%^* *start-of-file*
865\%^	Matches start of the file.  When matching with a string, matches the
866	start of the string.
867	For example, to find the first "VIM" in a file: >
868		/\%^\_.\{-}\zsVIM
869<
870						*/\%$* *end-of-file*
871\%$	Matches end of the file.  When matching with a string, matches the
872	end of the string.
873	Note that this does NOT find the last "VIM" in a file: >
874		/VIM\_.\{-}\%$
875<	It will find the next VIM, because the part after it will always
876	match.  This one will find the last "VIM" in the file: >
877		/VIM\ze\(\(VIM\)\@!\_.\)*\%$
878<	This uses |/\@!| to ascertain that "VIM" does NOT match in any
879	position after the first "VIM".
880	Searching from the end of the file backwards is easier!
881
882						*/\%V*
883\%V	Match inside the Visual area.  When Visual mode has already been
884	stopped match in the area that |gv| would reselect.
885	This is a |/zero-width| match.  To make sure the whole pattern is
886	inside the Visual area put it at the start and just before the end of
887	the pattern, e.g.: >
888		/\%Vfoo.*ba\%Vr
889<	This also works if only "foo bar" was Visually selected. This: >
890		/\%Vfoo.*bar\%V
891<	would match "foo bar" if the Visual selection continues after the "r".
892	Only works for the current buffer.
893
894						*/\%#* *cursor-position*
895\%#	Matches with the cursor position.  Only works when matching in a
896	buffer displayed in a window.
897	WARNING: When the cursor is moved after the pattern was used, the
898	result becomes invalid.  Vim doesn't automatically update the matches.
899	This is especially relevant for syntax highlighting and 'hlsearch'.
900	In other words: When the cursor moves the display isn't updated for
901	this change.  An update is done for lines which are changed (the whole
902	line is updated) or when using the |CTRL-L| command (the whole screen
903	is updated).  Example, to highlight the word under the cursor: >
904		/\k*\%#\k*
905<	When 'hlsearch' is set and you move the cursor around and make changes
906	this will clearly show when the match is updated or not.
907
908						*/\%'m* */\%<'m* */\%>'m*
909\%'m	Matches with the position of mark m.
910\%<'m	Matches before the position of mark m.
911\%>'m	Matches after the position of mark m.
912	Example, to highlight the text from mark 's to 'e: >
913		/.\%>'s.*\%<'e..
914<	Note that two dots are required to include mark 'e in the match.  That
915	is because "\%<'e" matches at the character before the 'e mark, and
916	since it's a |/zero-width| match it doesn't include that character.
917	WARNING: When the mark is moved after the pattern was used, the result
918	becomes invalid.  Vim doesn't automatically update the matches.
919	Similar to moving the cursor for "\%#" |/\%#|.
920
921						*/\%l* */\%>l* */\%<l* *E951*
922\%23l	Matches in a specific line.
923\%<23l	Matches above a specific line (lower line number).
924\%>23l	Matches below a specific line (higher line number).
925	These three can be used to match specific lines in a buffer.  The "23"
926	can be any line number.  The first line is 1.
927	WARNING: When inserting or deleting lines Vim does not automatically
928	update the matches.  This means Syntax highlighting quickly becomes
929	wrong.
930	Example, to highlight the line where the cursor currently is: >
931		:exe '/\%' . line(".") . 'l.*'
932<	When 'hlsearch' is set and you move the cursor around and make changes
933	this will clearly show when the match is updated or not.
934
935						*/\%c* */\%>c* */\%<c*
936\%23c	Matches in a specific column.
937\%<23c	Matches before a specific column.
938\%>23c	Matches after a specific column.
939	These three can be used to match specific columns in a buffer or
940	string.  The "23" can be any column number.  The first column is 1.
941	Actually, the column is the byte number (thus it's not exactly right
942	for multi-byte characters).
943	WARNING: When inserting or deleting text Vim does not automatically
944	update the matches.  This means Syntax highlighting quickly becomes
945	wrong.
946	Example, to highlight the column where the cursor currently is: >
947		:exe '/\%' . col(".") . 'c'
948<	When 'hlsearch' is set and you move the cursor around and make changes
949	this will clearly show when the match is updated or not.
950	Example for matching a single byte in column 44: >
951		/\%>43c.\%<46c
952<	Note that "\%<46c" matches in column 45 when the "." matches a byte in
953	column 44.
954						*/\%v* */\%>v* */\%<v*
955\%23v	Matches in a specific virtual column.
956\%<23v	Matches before a specific virtual column.
957\%>23v	Matches after a specific virtual column.
958	These three can be used to match specific virtual columns in a buffer
959	or string.  When not matching with a buffer in a window, the option
960	values of the current window are used (e.g., 'tabstop').
961	The "23" can be any column number.  The first column is 1.
962	Note that some virtual column positions will never match, because they
963	are halfway through a tab or other character that occupies more than
964	one screen character.
965	WARNING: When inserting or deleting text Vim does not automatically
966	update highlighted matches.  This means Syntax highlighting quickly
967	becomes wrong.
968	Example, to highlight all the characters after virtual column 72: >
969		/\%>72v.*
970<	When 'hlsearch' is set and you move the cursor around and make changes
971	this will clearly show when the match is updated or not.
972	To match the text up to column 17: >
973		/^.*\%17v
974<	Column 17 is not included, because this is a |/zero-width| match. To
975	include the column use: >
976		/^.*\%17v.
977<	This command does the same thing, but also matches when there is no
978	character in column 17: >
979		/^.*\%<18v.
980<	Note that without the "^" to anchor the match in the first column,
981	this will also highlight column 17: >
982		/.*\%17v
983<	Column 17 is highlighted by 'hlsearch' because there is another match
984	where ".*" matches zero characters.
985<
986
987Character classes:
988\i	identifier character (see 'isident' option)	*/\i*
989\I	like "\i", but excluding digits			*/\I*
990\k	keyword character (see 'iskeyword' option)	*/\k*
991\K	like "\k", but excluding digits			*/\K*
992\f	file name character (see 'isfname' option)	*/\f*
993\F	like "\f", but excluding digits			*/\F*
994\p	printable character (see 'isprint' option)	*/\p*
995\P	like "\p", but excluding digits			*/\P*
996
997NOTE: the above also work for multi-byte characters.  The ones below only
998match ASCII characters, as indicated by the range.
999
1000						*whitespace* *white-space*
1001\s	whitespace character: <Space> and <Tab>		*/\s*
1002\S	non-whitespace character; opposite of \s	*/\S*
1003\d	digit:				[0-9]		*/\d*
1004\D	non-digit:			[^0-9]		*/\D*
1005\x	hex digit:			[0-9A-Fa-f]	*/\x*
1006\X	non-hex digit:			[^0-9A-Fa-f]	*/\X*
1007\o	octal digit:			[0-7]		*/\o*
1008\O	non-octal digit:		[^0-7]		*/\O*
1009\w	word character:			[0-9A-Za-z_]	*/\w*
1010\W	non-word character:		[^0-9A-Za-z_]	*/\W*
1011\h	head of word character:		[A-Za-z_]	*/\h*
1012\H	non-head of word character:	[^A-Za-z_]	*/\H*
1013\a	alphabetic character:		[A-Za-z]	*/\a*
1014\A	non-alphabetic character:	[^A-Za-z]	*/\A*
1015\l	lowercase character:		[a-z]		*/\l*
1016\L	non-lowercase character:	[^a-z]		*/\L*
1017\u	uppercase character:		[A-Z]		*/\u*
1018\U	non-uppercase character:	[^A-Z]		*/\U*
1019
1020	NOTE: Using the atom is faster than the [] form.
1021
1022	NOTE: 'ignorecase', "\c" and "\C" are not used by character classes.
1023
1024			*/\_* *E63* */\_i* */\_I* */\_k* */\_K* */\_f* */\_F*
1025			*/\_p* */\_P* */\_s* */\_S* */\_d* */\_D* */\_x* */\_X*
1026			*/\_o* */\_O* */\_w* */\_W* */\_h* */\_H* */\_a* */\_A*
1027			*/\_l* */\_L* */\_u* */\_U*
1028\_x	Where "x" is any of the characters above: The character class with
1029	end-of-line added
1030(end of character classes)
1031
1032\e	matches <Esc>					*/\e*
1033\t	matches <Tab>					*/\t*
1034\r	matches <CR>					*/\r*
1035\b	matches <BS>					*/\b*
1036\n	matches an end-of-line				*/\n*
1037	When matching in a string instead of buffer text a literal newline
1038	character is matched.
1039
1040~	matches the last given substitute string	*/~* */\~*
1041
1042\(\)	A pattern enclosed by escaped parentheses.	*/\(* */\(\)* */\)*
1043	E.g., "\(^a\)" matches 'a' at the start of a line.
1044	*E51* *E54* *E55* *E872* *E873*
1045
1046\1      Matches the same string that was matched by	*/\1* *E65*
1047	the first sub-expression in \( and \).
1048	Example: "\([a-z]\).\1" matches "ata", "ehe", "tot", etc.
1049\2      Like "\1", but uses second sub-expression,	*/\2*
1050   ...							*/\3*
1051\9      Like "\1", but uses ninth sub-expression.	*/\9*
1052	Note: The numbering of groups is done based on which "\(" comes first
1053	in the pattern (going left to right), NOT based on what is matched
1054	first.
1055
1056\%(\)	A pattern enclosed by escaped parentheses.	*/\%(\)* */\%(* *E53*
1057	Just like \(\), but without counting it as a sub-expression.  This
1058	allows using more groups and it's a little bit faster.
1059
1060x	A single character, with no special meaning, matches itself
1061
1062							*/\* */\\*
1063\x	A backslash followed by a single character, with no special meaning,
1064	is reserved for future expansions
1065
1066[]	(with 'nomagic': \[])		*/[]* */\[]* */\_[]* */collection*
1067\_[]
1068	A collection.  This is a sequence of characters enclosed in brackets.
1069	It matches any single character in the collection.
1070	Example		matches ~
1071	[xyz]		any 'x', 'y' or 'z'
1072	[a-zA-Z]$	any alphabetic character at the end of a line
1073	\c[a-z]$	same
1074	[А-яЁё]		Russian alphabet (with utf-8 and cp1251)
1075
1076								*/[\n]*
1077	With "\_" prepended the collection also includes the end-of-line.
1078	The same can be done by including "\n" in the collection.  The
1079	end-of-line is also matched when the collection starts with "^"!  Thus
1080	"\_[^ab]" matches the end-of-line and any character but "a" and "b".
1081	This makes it Vi compatible: Without the "\_" or "\n" the collection
1082	does not match an end-of-line.
1083								*E769*
1084	When the ']' is not there Vim will not give an error message but
1085	assume no collection is used.  Useful to search for '['.  However, you
1086	do get E769 for internal searching.  And be aware that in a
1087	`:substitute` command the whole command becomes the pattern.  E.g.
1088	":s/[/x/" searches for "[/x" and replaces it with nothing.  It does
1089	not search for "[" and replaces it with "x"!
1090
1091								*E944* *E945*
1092	If the sequence begins with "^", it matches any single character NOT
1093	in the collection: "[^xyz]" matches anything but 'x', 'y' and 'z'.
1094	- If two characters in the sequence are separated by '-', this is
1095	  shorthand for the full list of ASCII characters between them.  E.g.,
1096	  "[0-9]" matches any decimal digit. If the starting character exceeds
1097	  the ending character, e.g. [c-a], E944 occurs. Non-ASCII characters
1098	  can be used, but the character values must not be more than 256 apart
1099	  in the old regexp engine. For example, searching by [\u3000-\u4000]
1100	  after setting re=1 emits a E945 error. Prepending \%#=2 will fix it.
1101	- A character class expression is evaluated to the set of characters
1102	  belonging to that character class.  The following character classes
1103	  are supported:
1104		  Name	      Func	Contents ~
1105*[:alnum:]*	  [:alnum:]   isalnum	ASCII letters and digits
1106*[:alpha:]*	  [:alpha:]   isalpha  	ASCII letters
1107*[:blank:]*	  [:blank:]     	space and tab
1108*[:cntrl:]*	  [:cntrl:]   iscntrl 	ASCII control characters
1109*[:digit:]*	  [:digit:]     	decimal digits '0' to '9'
1110*[:graph:]*	  [:graph:]   isgraph	ASCII printable characters excluding
1111					space
1112*[:lower:]*	  [:lower:]   (1)	lowercase letters (all letters when
1113					'ignorecase' is used)
1114*[:print:]*	  [:print:]   (2) 	printable characters including space
1115*[:punct:]*	  [:punct:]   ispunct	ASCII punctuation characters
1116*[:space:]*	  [:space:]     	whitespace characters: space, tab, CR,
1117					NL, vertical tab, form feed
1118*[:upper:]*	  [:upper:]   (3)	uppercase letters (all letters when
1119					'ignorecase' is used)
1120*[:xdigit:]*	  [:xdigit:]    	hexadecimal digits: 0-9, a-f, A-F
1121*[:return:]*	  [:return:]		the <CR> character
1122*[:tab:]*	  [:tab:]		the <Tab> character
1123*[:escape:]*	  [:escape:]		the <Esc> character
1124*[:backspace:]*	  [:backspace:]		the <BS> character
1125*[:ident:]*	  [:ident:]		identifier character (same as "\i")
1126*[:keyword:]*	  [:keyword:]		keyword character (same as "\k")
1127*[:fname:]*	  [:fname:]		file name character (same as "\f")
1128	  The brackets in character class expressions are additional to the
1129	  brackets delimiting a collection.  For example, the following is a
1130	  plausible pattern for a UNIX filename: "[-./[:alnum:]_~]\+" That is,
1131	  a list of at least one character, each of which is either '-', '.',
1132	  '/', alphabetic, numeric, '_' or '~'.
1133	  These items only work for 8-bit characters, except [:lower:] and
1134	  [:upper:] also work for multi-byte characters when using the new
1135	  regexp engine.  See |two-engines|.  In the future these items may
1136	  work for multi-byte characters.  For now, to get all "alpha"
1137	  characters you can use: [[:lower:][:upper:]].
1138
1139	  The "Func" column shows what library function is used.  The
1140	  implementation depends on the system.  Otherwise:
1141	  (1) Uses islower() for ASCII and Vim builtin rules for other
1142	  characters.
1143	  (2) Uses Vim builtin rules
1144	  (3) As with (1) but using isupper()
1145							*/[[=* *[==]*
1146	- An equivalence class.  This means that characters are matched that
1147	  have almost the same meaning, e.g., when ignoring accents.  This
1148	  only works for Unicode, latin1 and latin9.  The form is:
1149		[=a=]
1150							*/[[.* *[..]*
1151	- A collation element.  This currently simply accepts a single
1152	  character in the form:
1153		[.a.]
1154							  */\]*
1155	- To include a literal ']', '^', '-' or '\' in the collection, put a
1156	  backslash before it: "[xyz\]]", "[\^xyz]", "[xy\-z]" and "[xyz\\]".
1157	  (Note: POSIX does not support the use of a backslash this way).  For
1158	  ']' you can also make it the first character (following a possible
1159	  "^"):  "[]xyz]" or "[^]xyz]".
1160	  For '-' you can also make it the first or last character: "[-xyz]",
1161	  "[^-xyz]" or "[xyz-]".  For '\' you can also let it be followed by
1162	  any character that's not in "^]-\bdertnoUux".  "[\xyz]" matches '\',
1163	  'x', 'y' and 'z'.  It's better to use "\\" though, future expansions
1164	  may use other characters after '\'.
1165	- Omitting the trailing ] is not considered an error. "[]" works like
1166	  "[]]", it matches the ']' character.
1167	- The following translations are accepted when the 'l' flag is not
1168	  included in 'cpoptions':
1169		\e	<Esc>
1170		\t	<Tab>
1171		\r	<CR>	(NOT end-of-line!)
1172		\b	<BS>
1173		\n	line break, see above |/[\n]|
1174		\d123	decimal number of character
1175		\o40	octal number of character up to 0377
1176		\x20	hexadecimal number of character up to 0xff
1177		\u20AC	hex. number of multibyte character up to 0xffff
1178		\U1234	hex. number of multibyte character up to 0xffffffff
1179	  NOTE: The other backslash codes mentioned above do not work inside
1180	  []!
1181	- Matching with a collection can be slow, because each character in
1182	  the text has to be compared with each character in the collection.
1183	  Use one of the other atoms above when possible.  Example: "\d" is
1184	  much faster than "[0-9]" and matches the same characters.  However,
1185	  the new |NFA| regexp engine deals with this better than the old one.
1186
1187						*/\%[]* *E69* *E70* *E369*
1188\%[]	A sequence of optionally matched atoms.  This always matches.
1189	It matches as much of the list of atoms it contains as possible.  Thus
1190	it stops at the first atom that doesn't match.  For example: >
1191		/r\%[ead]
1192<	matches "r", "re", "rea" or "read".  The longest that matches is used.
1193	To match the Ex command "function", where "fu" is required and
1194	"nction" is optional, this would work: >
1195		/\<fu\%[nction]\>
1196<	The end-of-word atom "\>" is used to avoid matching "fu" in "full".
1197	It gets more complicated when the atoms are not ordinary characters.
1198	You don't often have to use it, but it is possible.  Example: >
1199		/\<r\%[[eo]ad]\>
1200<	Matches the words "r", "re", "ro", "rea", "roa", "read" and "road".
1201	There can be no \(\), \%(\) or \z(\) items inside the [] and \%[] does
1202	not nest.
1203	To include a "[" use "[[]" and for "]" use []]", e.g.,: >
1204		/index\%[[[]0[]]]
1205<	matches "index" "index[", "index[0" and "index[0]".
1206	{not available when compiled without the |+syntax| feature}
1207
1208				*/\%d* */\%x* */\%o* */\%u* */\%U* *E678*
1209
1210\%d123	Matches the character specified with a decimal number.  Must be
1211	followed by a non-digit.
1212\%o40	Matches the character specified with an octal number up to 0377.
1213	Numbers below 040 must be followed by a non-octal digit or a non-digit.
1214\%x2a	Matches the character specified with up to two hexadecimal characters.
1215\%u20AC	Matches the character specified with up to four hexadecimal
1216	characters.
1217\%U1234abcd	Matches the character specified with up to eight hexadecimal
1218	characters, up to 0x7fffffff
1219
1220==============================================================================
12217. Ignoring case in a pattern					*/ignorecase*
1222
1223If the 'ignorecase' option is on, the case of normal letters is ignored.
1224'smartcase' can be set to ignore case when the pattern contains lowercase
1225letters only.
1226							*/\c* */\C*
1227When "\c" appears anywhere in the pattern, the whole pattern is handled like
1228'ignorecase' is on.  The actual value of 'ignorecase' and 'smartcase' is
1229ignored.  "\C" does the opposite: Force matching case for the whole pattern.
1230{only Vim supports \c and \C}
1231Note that 'ignorecase', "\c" and "\C" are not used for the character classes.
1232
1233Examples:
1234      pattern	'ignorecase'  'smartcase'	matches ~
1235	foo	  off		-		foo
1236	foo	  on		-		foo Foo FOO
1237	Foo	  on		off		foo Foo FOO
1238	Foo	  on		on		    Foo
1239	\cfoo	  -		-		foo Foo FOO
1240	foo\C	  -		-		foo
1241
1242Technical detail:				*NL-used-for-Nul*
1243<Nul> characters in the file are stored as <NL> in memory.  In the display
1244they are shown as "^@".  The translation is done when reading and writing
1245files.  To match a <Nul> with a search pattern you can just enter CTRL-@ or
1246"CTRL-V 000".  This is probably just what you expect.  Internally the
1247character is replaced with a <NL> in the search pattern.  What is unusual is
1248that typing CTRL-V CTRL-J also inserts a <NL>, thus also searches for a <Nul>
1249in the file.
1250
1251						*CR-used-for-NL*
1252When 'fileformat' is "mac", <NL> characters in the file are stored as <CR>
1253characters internally.  In the text they are shown as "^J".  Otherwise this
1254works similar to the usage of <NL> for a <Nul>.
1255
1256When working with expression evaluation, a <NL> character in the pattern
1257matches a <NL> in the string.  The use of "\n" (backslash n) to match a <NL>
1258doesn't work there, it only works to match text in the buffer.
1259
1260						*pattern-multi-byte*
1261Patterns will also work with multi-byte characters, mostly as you would
1262expect.  But invalid bytes may cause trouble, a pattern with an invalid byte
1263will probably never match.
1264
1265==============================================================================
12668. Composing characters					*patterns-composing*
1267
1268							*/\Z*
1269When "\Z" appears anywhere in the pattern, all composing characters are
1270ignored.  Thus only the base characters need to match, the composing
1271characters may be different and the number of composing characters may differ.
1272Only relevant when 'encoding' is "utf-8".
1273Exception: If the pattern starts with one or more composing characters, these
1274must match.
1275							*/\%C*
1276Use "\%C" to skip any composing characters.  For example, the pattern "a" does
1277not match in "càt" (where the a has the composing character 0x0300), but
1278"a\%C" does.  Note that this does not match "cát" (where the á is character
12790xe1, it does not have a compositing character).  It does match "cat" (where
1280the a is just an a).
1281
1282When a composing character appears at the start of the pattern of after an
1283item that doesn't include the composing character, a match is found at any
1284character that includes this composing character.
1285
1286When using a dot and a composing character, this works the same as the
1287composing character by itself, except that it doesn't matter what comes before
1288this.
1289
1290The order of composing characters does not matter.  Also, the text may have
1291more composing characters than the pattern, it still matches.  But all
1292composing characters in the pattern must be found in the text.
1293
1294Suppose B is a base character and x and y are composing characters:
1295	pattern		text		match ~
1296	Bxy		Bxy		yes (perfect match)
1297	Bxy		Byx		yes (order ignored)
1298	Bxy		By		no (x missing)
1299	Bxy		Bx		no (y missing)
1300	Bx		Bx		yes (perfect match)
1301	Bx		By		no (x missing)
1302	Bx		Bxy		yes (extra y ignored)
1303	Bx		Byx		yes (extra y ignored)
1304
1305==============================================================================
13069. Compare with Perl patterns				*perl-patterns*
1307
1308Vim's regexes are most similar to Perl's, in terms of what you can do.  The
1309difference between them is mostly just notation;  here's a summary of where
1310they differ:
1311
1312Capability			in Vimspeak	in Perlspeak ~
1313----------------------------------------------------------------
1314force case insensitivity	\c		(?i)
1315force case sensitivity		\C		(?-i)
1316backref-less grouping		\%(atom\)	(?:atom)
1317conservative quantifiers	\{-n,m}		*?, +?, ??, {}?
13180-width match			atom\@=		(?=atom)
13190-width non-match		atom\@!		(?!atom)
13200-width preceding match		atom\@<=	(?<=atom)
13210-width preceding non-match	atom\@<!	(?<!atom)
1322match without retry		atom\@>		(?>atom)
1323
1324Vim and Perl handle newline characters inside a string a bit differently:
1325
1326In Perl, ^ and $ only match at the very beginning and end of the text,
1327by default, but you can set the 'm' flag, which lets them match at
1328embedded newlines as well.  You can also set the 's' flag, which causes
1329a . to match newlines as well.  (Both these flags can be changed inside
1330a pattern using the same syntax used for the i flag above, BTW.)
1331
1332On the other hand, Vim's ^ and $ always match at embedded newlines, and
1333you get two separate atoms, \%^ and \%$, which only match at the very
1334start and end of the text, respectively.  Vim solves the second problem
1335by giving you the \_ "modifier":  put it in front of a . or a character
1336class, and they will match newlines as well.
1337
1338Finally, these constructs are unique to Perl:
1339- execution of arbitrary code in the regex:  (?{perl code})
1340- conditional expressions:  (?(condition)true-expr|false-expr)
1341
1342...and these are unique to Vim:
1343- changing the magic-ness of a pattern:  \v \V \m \M
1344   (very useful for avoiding backslashitis)
1345- sequence of optionally matching atoms:  \%[atoms]
1346- \& (which is to \| what "and" is to "or";  it forces several branches
1347   to match at one spot)
1348- matching lines/columns by number:  \%5l \%5c \%5v
1349- setting the start and end of the match:  \zs \ze
1350
1351==============================================================================
135210. Highlighting matches				*match-highlight*
1353
1354							*:mat* *:match*
1355:mat[ch] {group} /{pattern}/
1356		Define a pattern to highlight in the current window.  It will
1357		be highlighted with {group}.  Example: >
1358			:highlight MyGroup ctermbg=green guibg=green
1359			:match MyGroup /TODO/
1360<		Instead of // any character can be used to mark the start and
1361		end of the {pattern}.  Watch out for using special characters,
1362		such as '"' and '|'.
1363
1364		{group} must exist at the moment this command is executed.
1365
1366		The {group} highlighting still applies when a character is
1367		to be highlighted for 'hlsearch', as the highlighting for
1368		matches is given higher priority than that of 'hlsearch'.
1369		Syntax highlighting (see 'syntax') is also overruled by
1370		matches.
1371
1372		Note that highlighting the last used search pattern with
1373		'hlsearch' is used in all windows, while the pattern defined
1374		with ":match" only exists in the current window.  It is kept
1375		when switching to another buffer.
1376
1377		'ignorecase' does not apply, use |/\c| in the pattern to
1378		ignore case.  Otherwise case is not ignored.
1379
1380		'redrawtime' defines the maximum time searched for pattern
1381		matches.
1382
1383		When matching end-of-line and Vim redraws only part of the
1384		display you may get unexpected results.  That is because Vim
1385		looks for a match in the line where redrawing starts.
1386
1387		Also see |matcharg()| and |getmatches()|. The former returns
1388		the highlight group and pattern of a previous |:match|
1389		command.  The latter returns a list with highlight groups and
1390		patterns defined by both |matchadd()| and |:match|.
1391
1392		Highlighting matches using |:match| are limited to three
1393		matches (aside from |:match|, |:2match| and |:3match| are
1394		available). |matchadd()| does not have this limitation and in
1395		addition makes it possible to prioritize matches.
1396
1397		Another example, which highlights all characters in virtual
1398		column 72 and more: >
1399			:highlight rightMargin term=bold ctermfg=blue guifg=blue
1400			:match rightMargin /.\%>72v/
1401<		To highlight all character that are in virtual column 7: >
1402			:highlight col8 ctermbg=grey guibg=grey
1403			:match col8 /\%<8v.\%>7v/
1404<		Note the use of two items to also match a character that
1405		occupies more than one virtual column, such as a TAB.
1406
1407:mat[ch]
1408:mat[ch] none
1409		Clear a previously defined match pattern.
1410
1411
1412:2mat[ch] {group} /{pattern}/					*:2match*
1413:2mat[ch]
1414:2mat[ch] none
1415:3mat[ch] {group} /{pattern}/					*:3match*
1416:3mat[ch]
1417:3mat[ch] none
1418		Just like |:match| above, but set a separate match.  Thus
1419		there can be three matches active at the same time.  The match
1420		with the lowest number has priority if several match at the
1421		same position.
1422		The ":3match" command is used by the |matchparen| plugin.  You
1423		are suggested to use ":match" for manual matching and
1424		":2match" for another plugin.
1425
1426
1427 vim:tw=78:ts=8:noet:ft=help:norl:
1428