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1 <html>
2 <head>
3 <title>pcregrep specification</title>
4 </head>
5 <body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
6 <h1>pcregrep man page</h1>
7 <p>
8 Return to the <a href="index.html">PCRE index page</a>.
9 </p>
10 <p>
11 This page is part of the PCRE HTML documentation. It was generated automatically
12 from the original man page. If there is any nonsense in it, please consult the
13 man page, in case the conversion went wrong.
14 <br>
15 <ul>
16 <li><a name="TOC1" href="#SEC1">SYNOPSIS</a>
17 <li><a name="TOC2" href="#SEC2">DESCRIPTION</a>
18 <li><a name="TOC3" href="#SEC3">SUPPORT FOR COMPRESSED FILES</a>
19 <li><a name="TOC4" href="#SEC4">OPTIONS</a>
20 <li><a name="TOC5" href="#SEC5">ENVIRONMENT VARIABLES</a>
21 <li><a name="TOC6" href="#SEC6">NEWLINES</a>
22 <li><a name="TOC7" href="#SEC7">OPTIONS COMPATIBILITY</a>
23 <li><a name="TOC8" href="#SEC8">OPTIONS WITH DATA</a>
24 <li><a name="TOC9" href="#SEC9">MATCHING ERRORS</a>
25 <li><a name="TOC10" href="#SEC10">DIAGNOSTICS</a>
26 <li><a name="TOC11" href="#SEC11">SEE ALSO</a>
27 <li><a name="TOC12" href="#SEC12">AUTHOR</a>
28 <li><a name="TOC13" href="#SEC13">REVISION</a>
29 </ul>
30 <br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br>
31 <P>
32 <b>pcregrep [options] [long options] [pattern] [path1 path2 ...]</b>
33 </P>
34 <br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br>
35 <P>
36 <b>pcregrep</b> searches files for character patterns, in the same way as other
37 grep commands do, but it uses the PCRE regular expression library to support
38 patterns that are compatible with the regular expressions of Perl 5. See
39 <a href="pcrepattern.html"><b>pcrepattern</b>(3)</a>
40 for a full description of syntax and semantics of the regular expressions
41 that PCRE supports.
42 </P>
43 <P>
44 Patterns, whether supplied on the command line or in a separate file, are given
45 without delimiters. For example:
46 <pre>
47 pcregrep Thursday /etc/motd
48 </pre>
49 If you attempt to use delimiters (for example, by surrounding a pattern with
50 slashes, as is common in Perl scripts), they are interpreted as part of the
51 pattern. Quotes can of course be used to delimit patterns on the command line
52 because they are interpreted by the shell, and indeed they are required if a
53 pattern contains white space or shell metacharacters.
54 </P>
55 <P>
56 The first argument that follows any option settings is treated as the single
57 pattern to be matched when neither <b>-e</b> nor <b>-f</b> is present.
58 Conversely, when one or both of these options are used to specify patterns, all
59 arguments are treated as path names. At least one of <b>-e</b>, <b>-f</b>, or an
60 argument pattern must be provided.
61 </P>
62 <P>
63 If no files are specified, <b>pcregrep</b> reads the standard input. The
64 standard input can also be referenced by a name consisting of a single hyphen.
65 For example:
66 <pre>
67 pcregrep some-pattern /file1 - /file3
68 </pre>
69 By default, each line that matches a pattern is copied to the standard
70 output, and if there is more than one file, the file name is output at the
71 start of each line, followed by a colon. However, there are options that can
72 change how <b>pcregrep</b> behaves. In particular, the <b>-M</b> option makes it
73 possible to search for patterns that span line boundaries. What defines a line
74 boundary is controlled by the <b>-N</b> (<b>--newline</b>) option.
75 </P>
76 <P>
77 Patterns are limited to 8K or BUFSIZ characters, whichever is the greater.
78 BUFSIZ is defined in <b>&#60;stdio.h&#62;</b>. When there is more than one pattern
79 (specified by the use of <b>-e</b> and/or <b>-f</b>), each pattern is applied to
80 each line in the order in which they are defined, except that all the <b>-e</b>
81 patterns are tried before the <b>-f</b> patterns.
82 </P>
83 <P>
84 By default, as soon as one pattern matches (or fails to match when <b>-v</b> is
85 used), no further patterns are considered. However, if <b>--colour</b> (or
86 <b>--color</b>) is used to colour the matching substrings, or if
87 <b>--only-matching</b>, <b>--file-offsets</b>, or <b>--line-offsets</b> is used to
88 output only the part of the line that matched (either shown literally, or as an
89 offset), scanning resumes immediately following the match, so that further
90 matches on the same line can be found. If there are multiple patterns, they are
91 all tried on the remainder of the line, but patterns that follow the one that
92 matched are not tried on the earlier part of the line.
93 </P>
94 <P>
95 This is the same behaviour as GNU grep, but it does mean that the order in
96 which multiple patterns are specified can affect the output when one of the
97 above options is used.
98 </P>
99 <P>
100 Patterns that can match an empty string are accepted, but empty string
101 matches are never recognized. An example is the pattern "(super)?(man)?", in
102 which all components are optional. This pattern finds all occurrences of both
103 "super" and "man"; the output differs from matching with "super|man" when only
104 the matching substrings are being shown.
105 </P>
106 <P>
107 If the <b>LC_ALL</b> or <b>LC_CTYPE</b> environment variable is set,
108 <b>pcregrep</b> uses the value to set a locale when calling the PCRE library.
109 The <b>--locale</b> option can be used to override this.
110 </P>
111 <br><a name="SEC3" href="#TOC1">SUPPORT FOR COMPRESSED FILES</a><br>
112 <P>
113 It is possible to compile <b>pcregrep</b> so that it uses <b>libz</b> or
114 <b>libbz2</b> to read files whose names end in <b>.gz</b> or <b>.bz2</b>,
115 respectively. You can find out whether your binary has support for one or both
116 of these file types by running it with the <b>--help</b> option. If the
117 appropriate support is not present, files are treated as plain text. The
118 standard input is always so treated.
119 </P>
120 <br><a name="SEC4" href="#TOC1">OPTIONS</a><br>
121 <P>
122 The order in which some of the options appear can affect the output. For
123 example, both the <b>-h</b> and <b>-l</b> options affect the printing of file
124 names. Whichever comes later in the command line will be the one that takes
125 effect.
126 </P>
127 <P>
128 <b>--</b>
129 This terminate the list of options. It is useful if the next item on the
130 command line starts with a hyphen but is not an option. This allows for the
131 processing of patterns and filenames that start with hyphens.
132 </P>
133 <P>
134 <b>-A</b> <i>number</i>, <b>--after-context=</b><i>number</i>
135 Output <i>number</i> lines of context after each matching line. If filenames
136 and/or line numbers are being output, a hyphen separator is used instead of a
137 colon for the context lines. A line containing "--" is output between each
138 group of lines, unless they are in fact contiguous in the input file. The value
139 of <i>number</i> is expected to be relatively small. However, <b>pcregrep</b>
140 guarantees to have up to 8K of following text available for context output.
141 </P>
142 <P>
143 <b>-B</b> <i>number</i>, <b>--before-context=</b><i>number</i>
144 Output <i>number</i> lines of context before each matching line. If filenames
145 and/or line numbers are being output, a hyphen separator is used instead of a
146 colon for the context lines. A line containing "--" is output between each
147 group of lines, unless they are in fact contiguous in the input file. The value
148 of <i>number</i> is expected to be relatively small. However, <b>pcregrep</b>
149 guarantees to have up to 8K of preceding text available for context output.
150 </P>
151 <P>
152 <b>-C</b> <i>number</i>, <b>--context=</b><i>number</i>
153 Output <i>number</i> lines of context both before and after each matching line.
154 This is equivalent to setting both <b>-A</b> and <b>-B</b> to the same value.
155 </P>
156 <P>
157 <b>-c</b>, <b>--count</b>
158 Do not output individual lines from the files that are being scanned; instead
159 output the number of lines that would otherwise have been shown. If no lines
160 are selected, the number zero is output. If several files are are being
161 scanned, a count is output for each of them. However, if the
162 <b>--files-with-matches</b> option is also used, only those files whose counts
163 are greater than zero are listed. When <b>-c</b> is used, the <b>-A</b>,
164 <b>-B</b>, and <b>-C</b> options are ignored.
165 </P>
166 <P>
167 <b>--colour</b>, <b>--color</b>
168 If this option is given without any data, it is equivalent to "--colour=auto".
169 If data is required, it must be given in the same shell item, separated by an
170 equals sign.
171 </P>
172 <P>
173 <b>--colour=</b><i>value</i>, <b>--color=</b><i>value</i>
174 This option specifies under what circumstances the parts of a line that matched
175 a pattern should be coloured in the output. By default, the output is not
176 coloured. The value (which is optional, see above) may be "never", "always", or
177 "auto". In the latter case, colouring happens only if the standard output is
178 connected to a terminal. More resources are used when colouring is enabled,
179 because <b>pcregrep</b> has to search for all possible matches in a line, not
180 just one, in order to colour them all.
181 <br>
182 <br>
183 The colour that is used can be specified by setting the environment variable
184 PCREGREP_COLOUR or PCREGREP_COLOR. The value of this variable should be a
185 string of two numbers, separated by a semicolon. They are copied directly into
186 the control string for setting colour on a terminal, so it is your
187 responsibility to ensure that they make sense. If neither of the environment
188 variables is set, the default is "1;31", which gives red.
189 </P>
190 <P>
191 <b>-D</b> <i>action</i>, <b>--devices=</b><i>action</i>
192 If an input path is not a regular file or a directory, "action" specifies how
193 it is to be processed. Valid values are "read" (the default) or "skip"
194 (silently skip the path).
195 </P>
196 <P>
197 <b>-d</b> <i>action</i>, <b>--directories=</b><i>action</i>
198 If an input path is a directory, "action" specifies how it is to be processed.
199 Valid values are "read" (the default), "recurse" (equivalent to the <b>-r</b>
200 option), or "skip" (silently skip the path). In the default case, directories
201 are read as if they were ordinary files. In some operating systems the effect
202 of reading a directory like this is an immediate end-of-file.
203 </P>
204 <P>
205 <b>-e</b> <i>pattern</i>, <b>--regex=</b><i>pattern</i>, <b>--regexp=</b><i>pattern</i>
206 Specify a pattern to be matched. This option can be used multiple times in
207 order to specify several patterns. It can also be used as a way of specifying a
208 single pattern that starts with a hyphen. When <b>-e</b> is used, no argument
209 pattern is taken from the command line; all arguments are treated as file
210 names. There is an overall maximum of 100 patterns. They are applied to each
211 line in the order in which they are defined until one matches (or fails to
212 match if <b>-v</b> is used). If <b>-f</b> is used with <b>-e</b>, the command line
213 patterns are matched first, followed by the patterns from the file, independent
214 of the order in which these options are specified. Note that multiple use of
215 <b>-e</b> is not the same as a single pattern with alternatives. For example,
216 X|Y finds the first character in a line that is X or Y, whereas if the two
217 patterns are given separately, <b>pcregrep</b> finds X if it is present, even if
218 it follows Y in the line. It finds Y only if there is no X in the line. This
219 really matters only if you are using <b>-o</b> to show the part(s) of the line
220 that matched.
221 </P>
222 <P>
223 <b>--exclude</b>=<i>pattern</i>
224 When <b>pcregrep</b> is searching the files in a directory as a consequence of
225 the <b>-r</b> (recursive search) option, any regular files whose names match the
226 pattern are excluded. Subdirectories are not excluded by this option; they are
227 searched recursively, subject to the <b>--exclude-dir</b> and
228 <b>--include_dir</b> options. The pattern is a PCRE regular expression, and is
229 matched against the final component of the file name (not the entire path). If
230 a file name matches both <b>--include</b> and <b>--exclude</b>, it is excluded.
231 There is no short form for this option.
232 </P>
233 <P>
234 <b>--exclude-dir</b>=<i>pattern</i>
235 When <b>pcregrep</b> is searching the contents of a directory as a consequence
236 of the <b>-r</b> (recursive search) option, any subdirectories whose names match
237 the pattern are excluded. (Note that the \fP--exclude\fP option does not affect
238 subdirectories.) The pattern is a PCRE regular expression, and is matched
239 against the final component of the name (not the entire path). If a
240 subdirectory name matches both <b>--include-dir</b> and <b>--exclude-dir</b>, it
241 is excluded. There is no short form for this option.
242 </P>
243 <P>
244 <b>-F</b>, <b>--fixed-strings</b>
245 Interpret each pattern as a list of fixed strings, separated by newlines,
246 instead of as a regular expression. The <b>-w</b> (match as a word) and <b>-x</b>
247 (match whole line) options can be used with <b>-F</b>. They apply to each of the
248 fixed strings. A line is selected if any of the fixed strings are found in it
249 (subject to <b>-w</b> or <b>-x</b>, if present).
250 </P>
251 <P>
252 <b>-f</b> <i>filename</i>, <b>--file=</b><i>filename</i>
253 Read a number of patterns from the file, one per line, and match them against
254 each line of input. A data line is output if any of the patterns match it. The
255 filename can be given as "-" to refer to the standard input. When <b>-f</b> is
256 used, patterns specified on the command line using <b>-e</b> may also be
257 present; they are tested before the file's patterns. However, no other pattern
258 is taken from the command line; all arguments are treated as file names. There
259 is an overall maximum of 100 patterns. Trailing white space is removed from
260 each line, and blank lines are ignored. An empty file contains no patterns and
261 therefore matches nothing. See also the comments about multiple patterns versus
262 a single pattern with alternatives in the description of <b>-e</b> above.
263 </P>
264 <P>
265 <b>--file-offsets</b>
266 Instead of showing lines or parts of lines that match, show each match as an
267 offset from the start of the file and a length, separated by a comma. In this
268 mode, no context is shown. That is, the <b>-A</b>, <b>-B</b>, and <b>-C</b>
269 options are ignored. If there is more than one match in a line, each of them is
270 shown separately. This option is mutually exclusive with <b>--line-offsets</b>
271 and <b>--only-matching</b>.
272 </P>
273 <P>
274 <b>-H</b>, <b>--with-filename</b>
275 Force the inclusion of the filename at the start of output lines when searching
276 a single file. By default, the filename is not shown in this case. For matching
277 lines, the filename is followed by a colon; for context lines, a hyphen
278 separator is used. If a line number is also being output, it follows the file
279 name.
280 </P>
281 <P>
282 <b>-h</b>, <b>--no-filename</b>
283 Suppress the output filenames when searching multiple files. By default,
284 filenames are shown when multiple files are searched. For matching lines, the
285 filename is followed by a colon; for context lines, a hyphen separator is used.
286 If a line number is also being output, it follows the file name.
287 </P>
288 <P>
289 <b>--help</b>
290 Output a help message, giving brief details of the command options and file
291 type support, and then exit.
292 </P>
293 <P>
294 <b>-i</b>, <b>--ignore-case</b>
295 Ignore upper/lower case distinctions during comparisons.
296 </P>
297 <P>
298 <b>--include</b>=<i>pattern</i>
299 When <b>pcregrep</b> is searching the files in a directory as a consequence of
300 the <b>-r</b> (recursive search) option, only those regular files whose names
301 match the pattern are included. Subdirectories are always included and searched
302 recursively, subject to the \fP--include-dir\fP and <b>--exclude-dir</b>
303 options. The pattern is a PCRE regular expression, and is matched against the
304 final component of the file name (not the entire path). If a file name matches
305 both <b>--include</b> and <b>--exclude</b>, it is excluded. There is no short
306 form for this option.
307 </P>
308 <P>
309 <b>--include-dir</b>=<i>pattern</i>
310 When <b>pcregrep</b> is searching the contents of a directory as a consequence
311 of the <b>-r</b> (recursive search) option, only those subdirectories whose
312 names match the pattern are included. (Note that the <b>--include</b> option
313 does not affect subdirectories.) The pattern is a PCRE regular expression, and
314 is matched against the final component of the name (not the entire path). If a
315 subdirectory name matches both <b>--include-dir</b> and <b>--exclude-dir</b>, it
316 is excluded. There is no short form for this option.
317 </P>
318 <P>
319 <b>-L</b>, <b>--files-without-match</b>
320 Instead of outputting lines from the files, just output the names of the files
321 that do not contain any lines that would have been output. Each file name is
322 output once, on a separate line.
323 </P>
324 <P>
325 <b>-l</b>, <b>--files-with-matches</b>
326 Instead of outputting lines from the files, just output the names of the files
327 containing lines that would have been output. Each file name is output
328 once, on a separate line. Searching normally stops as soon as a matching line
329 is found in a file. However, if the <b>-c</b> (count) option is also used,
330 matching continues in order to obtain the correct count, and those files that
331 have at least one match are listed along with their counts. Using this option
332 with <b>-c</b> is a way of suppressing the listing of files with no matches.
333 </P>
334 <P>
335 <b>--label</b>=<i>name</i>
336 This option supplies a name to be used for the standard input when file names
337 are being output. If not supplied, "(standard input)" is used. There is no
338 short form for this option.
339 </P>
340 <P>
341 <b>--line-buffered</b>
342 When this option is given, input is read and processed line by line, and the
343 output is flushed after each write. By default, input is read in large chunks,
344 unless <b>pcregrep</b> can determine that it is reading from a terminal (which
345 is currently possible only in Unix environments). Output to terminal is
346 normally automatically flushed by the operating system. This option can be
347 useful when the input or output is attached to a pipe and you do not want
348 <b>pcregrep</b> to buffer up large amounts of data. However, its use will affect
349 performance, and the <b>-M</b> (multiline) option ceases to work.
350 </P>
351 <P>
352 <b>--line-offsets</b>
353 Instead of showing lines or parts of lines that match, show each match as a
354 line number, the offset from the start of the line, and a length. The line
355 number is terminated by a colon (as usual; see the <b>-n</b> option), and the
356 offset and length are separated by a comma. In this mode, no context is shown.
357 That is, the <b>-A</b>, <b>-B</b>, and <b>-C</b> options are ignored. If there is
358 more than one match in a line, each of them is shown separately. This option is
359 mutually exclusive with <b>--file-offsets</b> and <b>--only-matching</b>.
360 </P>
361 <P>
362 <b>--locale</b>=<i>locale-name</i>
363 This option specifies a locale to be used for pattern matching. It overrides
364 the value in the <b>LC_ALL</b> or <b>LC_CTYPE</b> environment variables. If no
365 locale is specified, the PCRE library's default (usually the "C" locale) is
366 used. There is no short form for this option.
367 </P>
368 <P>
369 <b>--match-limit</b>=<i>number</i>
370 Processing some regular expression patterns can require a very large amount of
371 memory, leading in some cases to a program crash if not enough is available.
372 Other patterns may take a very long time to search for all possible matching
373 strings. The <b>pcre_exec()</b> function that is called by <b>pcregrep</b> to do
374 the matching has two parameters that can limit the resources that it uses.
375 <br>
376 <br>
377 The <b>--match-limit</b> option provides a means of limiting resource usage
378 when processing patterns that are not going to match, but which have a very
379 large number of possibilities in their search trees. The classic example is a
380 pattern that uses nested unlimited repeats. Internally, PCRE uses a function
381 called <b>match()</b> which it calls repeatedly (sometimes recursively). The
382 limit set by \fb--match-limit\fP is imposed on the number of times this
383 function is called during a match, which has the effect of limiting the amount
384 of backtracking that can take place.
385 <br>
386 <br>
387 The <b>--recursion-limit</b> option is similar to <b>--match-limit</b>, but
388 instead of limiting the total number of times that <b>match()</b> is called, it
389 limits the depth of recursive calls, which in turn limits the amount of memory
390 that can be used. The recursion depth is a smaller number than the total number
391 of calls, because not all calls to <b>match()</b> are recursive. This limit is
392 of use only if it is set smaller than <b>--match-limit</b>.
393 <br>
394 <br>
395 There are no short forms for these options. The default settings are specified
396 when the PCRE library is compiled, with the default default being 10 million.
397 </P>
398 <P>
399 <b>-M</b>, <b>--multiline</b>
400 Allow patterns to match more than one line. When this option is given, patterns
401 may usefully contain literal newline characters and internal occurrences of ^
402 and $ characters. The output for any one match may consist of more than one
403 line. When this option is set, the PCRE library is called in "multiline" mode.
404 There is a limit to the number of lines that can be matched, imposed by the way
405 that <b>pcregrep</b> buffers the input file as it scans it. However,
406 <b>pcregrep</b> ensures that at least 8K characters or the rest of the document
407 (whichever is the shorter) are available for forward matching, and similarly
408 the previous 8K characters (or all the previous characters, if fewer than 8K)
409 are guaranteed to be available for lookbehind assertions. This option does not
410 work when input is read line by line (see \fP--line-buffered\fP.)
411 </P>
412 <P>
413 <b>-N</b> <i>newline-type</i>, <b>--newline</b>=<i>newline-type</i>
414 The PCRE library supports five different conventions for indicating
415 the ends of lines. They are the single-character sequences CR (carriage return)
416 and LF (linefeed), the two-character sequence CRLF, an "anycrlf" convention,
417 which recognizes any of the preceding three types, and an "any" convention, in
418 which any Unicode line ending sequence is assumed to end a line. The Unicode
419 sequences are the three just mentioned, plus VT (vertical tab, U+000B), FF
420 (formfeed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and
421 PS (paragraph separator, U+2029).
422 <br>
423 <br>
424 When the PCRE library is built, a default line-ending sequence is specified.
425 This is normally the standard sequence for the operating system. Unless
426 otherwise specified by this option, <b>pcregrep</b> uses the library's default.
427 The possible values for this option are CR, LF, CRLF, ANYCRLF, or ANY. This
428 makes it possible to use <b>pcregrep</b> on files that have come from other
429 environments without having to modify their line endings. If the data that is
430 being scanned does not agree with the convention set by this option,
431 <b>pcregrep</b> may behave in strange ways.
432 </P>
433 <P>
434 <b>-n</b>, <b>--line-number</b>
435 Precede each output line by its line number in the file, followed by a colon
436 for matching lines or a hyphen for context lines. If the filename is also being
437 output, it precedes the line number. This option is forced if
438 <b>--line-offsets</b> is used.
439 </P>
440 <P>
441 <b>-o</b>, <b>--only-matching</b>
442 Show only the part of the line that matched a pattern instead of the whole
443 line. In this mode, no context is shown. That is, the <b>-A</b>, <b>-B</b>, and
444 <b>-C</b> options are ignored. If there is more than one match in a line, each
445 of them is shown separately. If <b>-o</b> is combined with <b>-v</b> (invert the
446 sense of the match to find non-matching lines), no output is generated, but the
447 return code is set appropriately. If the matched portion of the line is empty,
448 nothing is output unless the file name or line number are being printed, in
449 which case they are shown on an otherwise empty line. This option is mutually
450 exclusive with <b>--file-offsets</b> and <b>--line-offsets</b>.
451 </P>
452 <P>
453 <b>-o</b><i>number</i>, <b>--only-matching</b>=<i>number</i>
454 Show only the part of the line that matched the capturing parentheses of the
455 given number. Up to 32 capturing parentheses are supported. Because these
456 options can be given without an argument (see above), if an argument is
457 present, it must be given in the same shell item, for example, -o3 or
458 --only-matching=2. The comments given for the non-argument case above also
459 apply to this case. If the specified capturing parentheses do not exist in the
460 pattern, or were not set in the match, nothing is output unless the file name
461 or line number are being printed.
462 </P>
463 <P>
464 <b>-q</b>, <b>--quiet</b>
465 Work quietly, that is, display nothing except error messages. The exit
466 status indicates whether or not any matches were found.
467 </P>
468 <P>
469 <b>-r</b>, <b>--recursive</b>
470 If any given path is a directory, recursively scan the files it contains,
471 taking note of any <b>--include</b> and <b>--exclude</b> settings. By default, a
472 directory is read as a normal file; in some operating systems this gives an
473 immediate end-of-file. This option is a shorthand for setting the <b>-d</b>
474 option to "recurse".
475 </P>
476 <P>
477 <b>--recursion-limit</b>=<i>number</i>
478 See <b>--match-limit</b> above.
479 </P>
480 <P>
481 <b>-s</b>, <b>--no-messages</b>
482 Suppress error messages about non-existent or unreadable files. Such files are
483 quietly skipped. However, the return code is still 2, even if matches were
484 found in other files.
485 </P>
486 <P>
487 <b>-u</b>, <b>--utf-8</b>
488 Operate in UTF-8 mode. This option is available only if PCRE has been compiled
489 with UTF-8 support. Both patterns and subject lines must be valid strings of
490 UTF-8 characters.
491 </P>
492 <P>
493 <b>-V</b>, <b>--version</b>
494 Write the version numbers of <b>pcregrep</b> and the PCRE library that is being
495 used to the standard error stream.
496 </P>
497 <P>
498 <b>-v</b>, <b>--invert-match</b>
499 Invert the sense of the match, so that lines which do <i>not</i> match any of
500 the patterns are the ones that are found.
501 </P>
502 <P>
503 <b>-w</b>, <b>--word-regex</b>, <b>--word-regexp</b>
504 Force the patterns to match only whole words. This is equivalent to having \b
505 at the start and end of the pattern.
506 </P>
507 <P>
508 <b>-x</b>, <b>--line-regex</b>, <b>--line-regexp</b>
509 Force the patterns to be anchored (each must start matching at the beginning of
510 a line) and in addition, require them to match entire lines. This is
511 equivalent to having ^ and $ characters at the start and end of each
512 alternative branch in every pattern.
513 </P>
514 <br><a name="SEC5" href="#TOC1">ENVIRONMENT VARIABLES</a><br>
515 <P>
516 The environment variables <b>LC_ALL</b> and <b>LC_CTYPE</b> are examined, in that
517 order, for a locale. The first one that is set is used. This can be overridden
518 by the <b>--locale</b> option. If no locale is set, the PCRE library's default
519 (usually the "C" locale) is used.
520 </P>
521 <br><a name="SEC6" href="#TOC1">NEWLINES</a><br>
522 <P>
523 The <b>-N</b> (<b>--newline</b>) option allows <b>pcregrep</b> to scan files with
524 different newline conventions from the default. However, the setting of this
525 option does not affect the way in which <b>pcregrep</b> writes information to
526 the standard error and output streams. It uses the string "\n" in C
527 <b>printf()</b> calls to indicate newlines, relying on the C I/O library to
528 convert this to an appropriate sequence if the output is sent to a file.
529 </P>
530 <br><a name="SEC7" href="#TOC1">OPTIONS COMPATIBILITY</a><br>
531 <P>
532 Many of the short and long forms of <b>pcregrep</b>'s options are the same
533 as in the GNU <b>grep</b> program (version 2.5.4). Any long option of the form
534 <b>--xxx-regexp</b> (GNU terminology) is also available as <b>--xxx-regex</b>
535 (PCRE terminology). However, the <b>--file-offsets</b>, <b>--include-dir</b>,
536 <b>--line-offsets</b>, <b>--locale</b>, <b>--match-limit</b>, <b>-M</b>,
537 <b>--multiline</b>, <b>-N</b>, <b>--newline</b>, <b>--recursion-limit</b>,
538 <b>-u</b>, and <b>--utf-8</b> options are specific to <b>pcregrep</b>, as is the
539 use of the <b>--only-matching</b> option with a capturing parentheses number.
540 </P>
541 <P>
542 Although most of the common options work the same way, a few are different in
543 <b>pcregrep</b>. For example, the <b>--include</b> option's argument is a glob
544 for GNU <b>grep</b>, but a regular expression for <b>pcregrep</b>. If both the
545 <b>-c</b> and <b>-l</b> options are given, GNU grep lists only file names,
546 without counts, but <b>pcregrep</b> gives the counts.
547 </P>
548 <br><a name="SEC8" href="#TOC1">OPTIONS WITH DATA</a><br>
549 <P>
550 There are four different ways in which an option with data can be specified.
551 If a short form option is used, the data may follow immediately, or (with one
552 exception) in the next command line item. For example:
553 <pre>
554 -f/some/file
555 -f /some/file
556 </pre>
557 The exception is the <b>-o</b> option, which may appear with or without data.
558 Because of this, if data is present, it must follow immediately in the same
559 item, for example -o3.
560 </P>
561 <P>
562 If a long form option is used, the data may appear in the same command line
563 item, separated by an equals character, or (with two exceptions) it may appear
564 in the next command line item. For example:
565 <pre>
566 --file=/some/file
567 --file /some/file
568 </pre>
569 Note, however, that if you want to supply a file name beginning with ~ as data
570 in a shell command, and have the shell expand ~ to a home directory, you must
571 separate the file name from the option, because the shell does not treat ~
572 specially unless it is at the start of an item.
573 </P>
574 <P>
575 The exceptions to the above are the <b>--colour</b> (or <b>--color</b>) and
576 <b>--only-matching</b> options, for which the data is optional. If one of these
577 options does have data, it must be given in the first form, using an equals
578 character. Otherwise <b>pcregrep</b> will assume that it has no data.
579 </P>
580 <br><a name="SEC9" href="#TOC1">MATCHING ERRORS</a><br>
581 <P>
582 It is possible to supply a regular expression that takes a very long time to
583 fail to match certain lines. Such patterns normally involve nested indefinite
584 repeats, for example: (a+)*\d when matched against a line of a's with no final
585 digit. The PCRE matching function has a resource limit that causes it to abort
586 in these circumstances. If this happens, <b>pcregrep</b> outputs an error
587 message and the line that caused the problem to the standard error stream. If
588 there are more than 20 such errors, <b>pcregrep</b> gives up.
589 </P>
590 <P>
591 The <b>--match-limit</b> option of <b>pcregrep</b> can be used to set the overall
592 resource limit; there is a second option called <b>--recursion-limit</b> that
593 sets a limit on the amount of memory (usually stack) that is used (see the
594 discussion of these options above).
595 </P>
596 <br><a name="SEC10" href="#TOC1">DIAGNOSTICS</a><br>
597 <P>
598 Exit status is 0 if any matches were found, 1 if no matches were found, and 2
599 for syntax errors and non-existent or inacessible files (even if matches were
600 found in other files) or too many matching errors. Using the <b>-s</b> option to
601 suppress error messages about inaccessble files does not affect the return
602 code.
603 </P>
604 <br><a name="SEC11" href="#TOC1">SEE ALSO</a><br>
605 <P>
606 <b>pcrepattern</b>(3), <b>pcretest</b>(1).
607 </P>
608 <br><a name="SEC12" href="#TOC1">AUTHOR</a><br>
609 <P>
610 Philip Hazel
611 <br>
612 University Computing Service
613 <br>
614 Cambridge CB2 3QH, England.
615 <br>
616 </P>
617 <br><a name="SEC13" href="#TOC1">REVISION</a><br>
618 <P>
619 Last updated: 16 November 2010
620 <br>
621 Copyright &copy; 1997-2010 University of Cambridge.
622 <br>
623 <p>
624 Return to the <a href="index.html">PCRE index page</a>.
625 </p>

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