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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">BINARY FILES</a>
20 <li><a name="TOC5" href="#SEC5">OPTIONS</a>
21 <li><a name="TOC6" href="#SEC6">ENVIRONMENT VARIABLES</a>
22 <li><a name="TOC7" href="#SEC7">NEWLINES</a>
23 <li><a name="TOC8" href="#SEC8">OPTIONS COMPATIBILITY</a>
24 <li><a name="TOC9" href="#SEC9">OPTIONS WITH DATA</a>
25 <li><a name="TOC10" href="#SEC10">MATCHING ERRORS</a>
26 <li><a name="TOC11" href="#SEC11">DIAGNOSTICS</a>
27 <li><a name="TOC12" href="#SEC12">SEE ALSO</a>
28 <li><a name="TOC13" href="#SEC13">AUTHOR</a>
29 <li><a name="TOC14" href="#SEC14">REVISION</a>
30 </ul>
31 <br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br>
32 <P>
33 <b>pcregrep [options] [long options] [pattern] [path1 path2 ...]</b>
34 </P>
35 <br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br>
36 <P>
37 <b>pcregrep</b> searches files for character patterns, in the same way as other
38 grep commands do, but it uses the PCRE regular expression library to support
39 patterns that are compatible with the regular expressions of Perl 5. See
40 <a href="pcrepattern.html"><b>pcrepattern</b>(3)</a>
41 for a full description of syntax and semantics of the regular expressions
42 that PCRE supports.
43 </P>
44 <P>
45 Patterns, whether supplied on the command line or in a separate file, are given
46 without delimiters. For example:
47 <pre>
48 pcregrep Thursday /etc/motd
49 </pre>
50 If you attempt to use delimiters (for example, by surrounding a pattern with
51 slashes, as is common in Perl scripts), they are interpreted as part of the
52 pattern. Quotes can of course be used to delimit patterns on the command line
53 because they are interpreted by the shell, and indeed quotes are required if a
54 pattern contains white space or shell metacharacters.
55 </P>
56 <P>
57 The first argument that follows any option settings is treated as the single
58 pattern to be matched when neither <b>-e</b> nor <b>-f</b> is present.
59 Conversely, when one or both of these options are used to specify patterns, all
60 arguments are treated as path names. At least one of <b>-e</b>, <b>-f</b>, or an
61 argument pattern must be provided.
62 </P>
63 <P>
64 If no files are specified, <b>pcregrep</b> reads the standard input. The
65 standard input can also be referenced by a name consisting of a single hyphen.
66 For example:
67 <pre>
68 pcregrep some-pattern /file1 - /file3
69 </pre>
70 By default, each line that matches a pattern is copied to the standard
71 output, and if there is more than one file, the file name is output at the
72 start of each line, followed by a colon. However, there are options that can
73 change how <b>pcregrep</b> behaves. In particular, the <b>-M</b> option makes it
74 possible to search for patterns that span line boundaries. What defines a line
75 boundary is controlled by the <b>-N</b> (<b>--newline</b>) option.
76 </P>
77 <P>
78 The amount of memory used for buffering files that are being scanned is
79 controlled by a parameter that can be set by the <b>--buffer-size</b> option.
80 The default value for this parameter is specified when <b>pcregrep</b> is built,
81 with the default default being 20K. A block of memory three times this size is
82 used (to allow for buffering "before" and "after" lines). An error occurs if a
83 line overflows the buffer.
84 </P>
85 <P>
86 Patterns can be no longer than 8K or BUFSIZ bytes, whichever is the greater.
87 BUFSIZ is defined in <b>&#60;stdio.h&#62;</b>. When there is more than one pattern
88 (specified by the use of <b>-e</b> and/or <b>-f</b>), each pattern is applied to
89 each line in the order in which they are defined, except that all the <b>-e</b>
90 patterns are tried before the <b>-f</b> patterns.
91 </P>
92 <P>
93 By default, as soon as one pattern matches a line, no further patterns are
94 considered. However, if <b>--colour</b> (or <b>--color</b>) is used to colour the
95 matching substrings, or if <b>--only-matching</b>, <b>--file-offsets</b>, or
96 <b>--line-offsets</b> is used to output only the part of the line that matched
97 (either shown literally, or as an offset), scanning resumes immediately
98 following the match, so that further matches on the same line can be found. If
99 there are multiple patterns, they are all tried on the remainder of the line,
100 but patterns that follow the one that matched are not tried on the earlier part
101 of the line.
102 </P>
103 <P>
104 This behaviour means that the order in which multiple patterns are specified
105 can affect the output when one of the above options is used. This is no longer
106 the same behaviour as GNU grep, which now manages to display earlier matches
107 for later patterns (as long as there is no overlap).
108 </P>
109 <P>
110 Patterns that can match an empty string are accepted, but empty string
111 matches are never recognized. An example is the pattern "(super)?(man)?", in
112 which all components are optional. This pattern finds all occurrences of both
113 "super" and "man"; the output differs from matching with "super|man" when only
114 the matching substrings are being shown.
115 </P>
116 <P>
117 If the <b>LC_ALL</b> or <b>LC_CTYPE</b> environment variable is set,
118 <b>pcregrep</b> uses the value to set a locale when calling the PCRE library.
119 The <b>--locale</b> option can be used to override this.
120 </P>
121 <br><a name="SEC3" href="#TOC1">SUPPORT FOR COMPRESSED FILES</a><br>
122 <P>
123 It is possible to compile <b>pcregrep</b> so that it uses <b>libz</b> or
124 <b>libbz2</b> to read files whose names end in <b>.gz</b> or <b>.bz2</b>,
125 respectively. You can find out whether your binary has support for one or both
126 of these file types by running it with the <b>--help</b> option. If the
127 appropriate support is not present, files are treated as plain text. The
128 standard input is always so treated.
129 </P>
130 <br><a name="SEC4" href="#TOC1">BINARY FILES</a><br>
131 <P>
132 By default, a file that contains a binary zero byte within the first 1024 bytes
133 is identified as a binary file, and is processed specially. (GNU grep also
134 identifies binary files in this manner.) See the <b>--binary-files</b> option
135 for a means of changing the way binary files are handled.
136 </P>
137 <br><a name="SEC5" href="#TOC1">OPTIONS</a><br>
138 <P>
139 The order in which some of the options appear can affect the output. For
140 example, both the <b>-h</b> and <b>-l</b> options affect the printing of file
141 names. Whichever comes later in the command line will be the one that takes
142 effect. Similarly, except where noted below, if an option is given twice, the
143 later setting is used. Numerical values for options may be followed by K or M,
144 to signify multiplication by 1024 or 1024*1024 respectively.
145 </P>
146 <P>
147 <b>--</b>
148 This terminates the list of options. It is useful if the next item on the
149 command line starts with a hyphen but is not an option. This allows for the
150 processing of patterns and filenames that start with hyphens.
151 </P>
152 <P>
153 <b>-A</b> <i>number</i>, <b>--after-context=</b><i>number</i>
154 Output <i>number</i> lines of context after each matching line. If filenames
155 and/or line numbers are being output, a hyphen separator is used instead of a
156 colon for the context lines. A line containing "--" is output between each
157 group of lines, unless they are in fact contiguous in the input file. The value
158 of <i>number</i> is expected to be relatively small. However, <b>pcregrep</b>
159 guarantees to have up to 8K of following text available for context output.
160 </P>
161 <P>
162 <b>-a</b>, <b>--text</b>
163 Treat binary files as text. This is equivalent to
164 <b>--binary-files</b>=<i>text</i>.
165 </P>
166 <P>
167 <b>-B</b> <i>number</i>, <b>--before-context=</b><i>number</i>
168 Output <i>number</i> lines of context before each matching line. If filenames
169 and/or line numbers are being output, a hyphen separator is used instead of a
170 colon for the context lines. A line containing "--" is output between each
171 group of lines, unless they are in fact contiguous in the input file. The value
172 of <i>number</i> is expected to be relatively small. However, <b>pcregrep</b>
173 guarantees to have up to 8K of preceding text available for context output.
174 </P>
175 <P>
176 <b>--binary-files=</b><i>word</i>
177 Specify how binary files are to be processed. If the word is "binary" (the
178 default), pattern matching is performed on binary files, but the only output is
179 "Binary file &#60;name&#62; matches" when a match succeeds. If the word is "text",
180 which is equivalent to the <b>-a</b> or <b>--text</b> option, binary files are
181 processed in the same way as any other file. In this case, when a match
182 succeeds, the output may be binary garbage, which can have nasty effects if
183 sent to a terminal. If the word is "without-match", which is equivalent to the
184 <b>-I</b> option, binary files are not processed at all; they are assumed not to
185 be of interest.
186 </P>
187 <P>
188 <b>--buffer-size=</b><i>number</i>
189 Set the parameter that controls how much memory is used for buffering files
190 that are being scanned.
191 </P>
192 <P>
193 <b>-C</b> <i>number</i>, <b>--context=</b><i>number</i>
194 Output <i>number</i> lines of context both before and after each matching line.
195 This is equivalent to setting both <b>-A</b> and <b>-B</b> to the same value.
196 </P>
197 <P>
198 <b>-c</b>, <b>--count</b>
199 Do not output individual lines from the files that are being scanned; instead
200 output the number of lines that would otherwise have been shown. If no lines
201 are selected, the number zero is output. If several files are are being
202 scanned, a count is output for each of them. However, if the
203 <b>--files-with-matches</b> option is also used, only those files whose counts
204 are greater than zero are listed. When <b>-c</b> is used, the <b>-A</b>,
205 <b>-B</b>, and <b>-C</b> options are ignored.
206 </P>
207 <P>
208 <b>--colour</b>, <b>--color</b>
209 If this option is given without any data, it is equivalent to "--colour=auto".
210 If data is required, it must be given in the same shell item, separated by an
211 equals sign.
212 </P>
213 <P>
214 <b>--colour=</b><i>value</i>, <b>--color=</b><i>value</i>
215 This option specifies under what circumstances the parts of a line that matched
216 a pattern should be coloured in the output. By default, the output is not
217 coloured. The value (which is optional, see above) may be "never", "always", or
218 "auto". In the latter case, colouring happens only if the standard output is
219 connected to a terminal. More resources are used when colouring is enabled,
220 because <b>pcregrep</b> has to search for all possible matches in a line, not
221 just one, in order to colour them all.
222 <br>
223 <br>
224 The colour that is used can be specified by setting the environment variable
225 PCREGREP_COLOUR or PCREGREP_COLOR. The value of this variable should be a
226 string of two numbers, separated by a semicolon. They are copied directly into
227 the control string for setting colour on a terminal, so it is your
228 responsibility to ensure that they make sense. If neither of the environment
229 variables is set, the default is "1;31", which gives red.
230 </P>
231 <P>
232 <b>-D</b> <i>action</i>, <b>--devices=</b><i>action</i>
233 If an input path is not a regular file or a directory, "action" specifies how
234 it is to be processed. Valid values are "read" (the default) or "skip"
235 (silently skip the path).
236 </P>
237 <P>
238 <b>-d</b> <i>action</i>, <b>--directories=</b><i>action</i>
239 If an input path is a directory, "action" specifies how it is to be processed.
240 Valid values are "read" (the default in non-Windows environments, for
241 compatibility with GNU grep), "recurse" (equivalent to the <b>-r</b> option), or
242 "skip" (silently skip the path, the default in Windows environments). In the
243 "read" case, directories are read as if they were ordinary files. In some
244 operating systems the effect of reading a directory like this is an immediate
245 end-of-file; in others it may provoke an error.
246 </P>
247 <P>
248 <b>-e</b> <i>pattern</i>, <b>--regex=</b><i>pattern</i>, <b>--regexp=</b><i>pattern</i>
249 Specify a pattern to be matched. This option can be used multiple times in
250 order to specify several patterns. It can also be used as a way of specifying a
251 single pattern that starts with a hyphen. When <b>-e</b> is used, no argument
252 pattern is taken from the command line; all arguments are treated as file
253 names. There is no limit to the number of patterns. They are applied to each
254 line in the order in which they are defined until one matches.
255 <br>
256 <br>
257 If <b>-f</b> is used with <b>-e</b>, the command line patterns are matched first,
258 followed by the patterns from the file(s), independent of the order in which
259 these options are specified. Note that multiple use of <b>-e</b> is not the same
260 as a single pattern with alternatives. For example, X|Y finds the first
261 character in a line that is X or Y, whereas if the two patterns are given
262 separately, with X first, <b>pcregrep</b> finds X if it is present, even if it
263 follows Y in the line. It finds Y only if there is no X in the line. This
264 matters only if you are using <b>-o</b> or <b>--colo(u)r</b> to show the part(s)
265 of the line that matched.
266 </P>
267 <P>
268 <b>--exclude</b>=<i>pattern</i>
269 Files (but not directories) whose names match the pattern are skipped without
270 being processed. This applies to all files, whether listed on the command line,
271 obtained from <b>--file-list</b>, or by scanning a directory. The pattern is a
272 PCRE regular expression, and is matched against the final component of the file
273 name, not the entire path. The <b>-F</b>, <b>-w</b>, and <b>-x</b> options do not
274 apply to this pattern. The option may be given any number of times in order to
275 specify multiple patterns. If a file name matches both an <b>--include</b>
276 and an <b>--exclude</b> pattern, it is excluded. There is no short form for this
277 option.
278 </P>
279 <P>
280 <b>--exclude-from=</b><i>filename</i>
281 Treat each non-empty line of the file as the data for an <b>--exclude</b>
282 option. What constitutes a newline when reading the file is the operating
283 system's default. The <b>--newline</b> option has no effect on this option. This
284 option may be given more than once in order to specify a number of files to
285 read.
286 </P>
287 <P>
288 <b>--exclude-dir</b>=<i>pattern</i>
289 Directories whose names match the pattern are skipped without being processed,
290 whatever the setting of the <b>--recursive</b> option. This applies to all
291 directories, whether listed on the command line, obtained from
292 <b>--file-list</b>, or by scanning a parent directory. The pattern is a PCRE
293 regular expression, and is matched against the final component of the directory
294 name, not the entire path. The <b>-F</b>, <b>-w</b>, and <b>-x</b> options do not
295 apply to this pattern. The option may be given any number of times in order to
296 specify more than one pattern. If a directory matches both <b>--include-dir</b>
297 and <b>--exclude-dir</b>, it is excluded. There is no short form for this
298 option.
299 </P>
300 <P>
301 <b>-F</b>, <b>--fixed-strings</b>
302 Interpret each data-matching pattern as a list of fixed strings, separated by
303 newlines, instead of as a regular expression. What constitutes a newline for
304 this purpose is controlled by the <b>--newline</b> option. The <b>-w</b> (match
305 as a word) and <b>-x</b> (match whole line) options can be used with <b>-F</b>.
306 They apply to each of the fixed strings. A line is selected if any of the fixed
307 strings are found in it (subject to <b>-w</b> or <b>-x</b>, if present). This
308 option applies only to the patterns that are matched against the contents of
309 files; it does not apply to patterns specified by any of the <b>--include</b> or
310 <b>--exclude</b> options.
311 </P>
312 <P>
313 <b>-f</b> <i>filename</i>, <b>--file=</b><i>filename</i>
314 Read patterns from the file, one per line, and match them against
315 each line of input. What constitutes a newline when reading the file is the
316 operating system's default. The <b>--newline</b> option has no effect on this
317 option. Trailing white space is removed from each line, and blank lines are
318 ignored. An empty file contains no patterns and therefore matches nothing. See
319 also the comments about multiple patterns versus a single pattern with
320 alternatives in the description of <b>-e</b> above.
321 <br>
322 <br>
323 If this option is given more than once, all the specified files are
324 read. A data line is output if any of the patterns match it. A filename can
325 be given as "-" to refer to the standard input. When <b>-f</b> is used, patterns
326 specified on the command line using <b>-e</b> may also be present; they are
327 tested before the file's patterns. However, no other pattern is taken from the
328 command line; all arguments are treated as the names of paths to be searched.
329 </P>
330 <P>
331 <b>--file-list</b>=<i>filename</i>
332 Read a list of files and/or directories that are to be scanned from the given
333 file, one per line. Trailing white space is removed from each line, and blank
334 lines are ignored. These paths are processed before any that are listed on the
335 command line. The filename can be given as "-" to refer to the standard input.
336 If <b>--file</b> and <b>--file-list</b> are both specified as "-", patterns are
337 read first. This is useful only when the standard input is a terminal, from
338 which further lines (the list of files) can be read after an end-of-file
339 indication. If this option is given more than once, all the specified files are
340 read.
341 </P>
342 <P>
343 <b>--file-offsets</b>
344 Instead of showing lines or parts of lines that match, show each match as an
345 offset from the start of the file and a length, separated by a comma. In this
346 mode, no context is shown. That is, the <b>-A</b>, <b>-B</b>, and <b>-C</b>
347 options are ignored. If there is more than one match in a line, each of them is
348 shown separately. This option is mutually exclusive with <b>--line-offsets</b>
349 and <b>--only-matching</b>.
350 </P>
351 <P>
352 <b>-H</b>, <b>--with-filename</b>
353 Force the inclusion of the filename at the start of output lines when searching
354 a single file. By default, the filename is not shown in this case. For matching
355 lines, the filename is followed by a colon; for context lines, a hyphen
356 separator is used. If a line number is also being output, it follows the file
357 name.
358 </P>
359 <P>
360 <b>-h</b>, <b>--no-filename</b>
361 Suppress the output filenames when searching multiple files. By default,
362 filenames are shown when multiple files are searched. For matching lines, the
363 filename is followed by a colon; for context lines, a hyphen separator is used.
364 If a line number is also being output, it follows the file name.
365 </P>
366 <P>
367 <b>--help</b>
368 Output a help message, giving brief details of the command options and file
369 type support, and then exit. Anything else on the command line is
370 ignored.
371 </P>
372 <P>
373 <b>-I</b>
374 Treat binary files as never matching. This is equivalent to
375 <b>--binary-files</b>=<i>without-match</i>.
376 </P>
377 <P>
378 <b>-i</b>, <b>--ignore-case</b>
379 Ignore upper/lower case distinctions during comparisons.
380 </P>
381 <P>
382 <b>--include</b>=<i>pattern</i>
383 If any <b>--include</b> patterns are specified, the only files that are
384 processed are those that match one of the patterns (and do not match an
385 <b>--exclude</b> pattern). This option does not affect directories, but it
386 applies to all files, whether listed on the command line, obtained from
387 <b>--file-list</b>, or by scanning a directory. The pattern is a PCRE regular
388 expression, and is matched against the final component of the file name, not
389 the entire path. The <b>-F</b>, <b>-w</b>, and <b>-x</b> options do not apply to
390 this pattern. The option may be given any number of times. If a file name
391 matches both an <b>--include</b> and an <b>--exclude</b> pattern, it is excluded.
392 There is no short form for this option.
393 </P>
394 <P>
395 <b>--include-from=</b><i>filename</i>
396 Treat each non-empty line of the file as the data for an <b>--include</b>
397 option. What constitutes a newline for this purpose is the operating system's
398 default. The <b>--newline</b> option has no effect on this option. This option
399 may be given any number of times; all the files are read.
400 </P>
401 <P>
402 <b>--include-dir</b>=<i>pattern</i>
403 If any <b>--include-dir</b> patterns are specified, the only directories that
404 are processed are those that match one of the patterns (and do not match an
405 <b>--exclude-dir</b> pattern). This applies to all directories, whether listed
406 on the command line, obtained from <b>--file-list</b>, or by scanning a parent
407 directory. The pattern is a PCRE regular expression, and is matched against the
408 final component of the directory name, not the entire path. The <b>-F</b>,
409 <b>-w</b>, and <b>-x</b> options do not apply to this pattern. The option may be
410 given any number of times. If a directory matches both <b>--include-dir</b> and
411 <b>--exclude-dir</b>, it is excluded. There is no short form for this option.
412 </P>
413 <P>
414 <b>-L</b>, <b>--files-without-match</b>
415 Instead of outputting lines from the files, just output the names of the files
416 that do not contain any lines that would have been output. Each file name is
417 output once, on a separate line.
418 </P>
419 <P>
420 <b>-l</b>, <b>--files-with-matches</b>
421 Instead of outputting lines from the files, just output the names of the files
422 containing lines that would have been output. Each file name is output
423 once, on a separate line. Searching normally stops as soon as a matching line
424 is found in a file. However, if the <b>-c</b> (count) option is also used,
425 matching continues in order to obtain the correct count, and those files that
426 have at least one match are listed along with their counts. Using this option
427 with <b>-c</b> is a way of suppressing the listing of files with no matches.
428 </P>
429 <P>
430 <b>--label</b>=<i>name</i>
431 This option supplies a name to be used for the standard input when file names
432 are being output. If not supplied, "(standard input)" is used. There is no
433 short form for this option.
434 </P>
435 <P>
436 <b>--line-buffered</b>
437 When this option is given, input is read and processed line by line, and the
438 output is flushed after each write. By default, input is read in large chunks,
439 unless <b>pcregrep</b> can determine that it is reading from a terminal (which
440 is currently possible only in Unix-like environments). Output to terminal is
441 normally automatically flushed by the operating system. This option can be
442 useful when the input or output is attached to a pipe and you do not want
443 <b>pcregrep</b> to buffer up large amounts of data. However, its use will affect
444 performance, and the <b>-M</b> (multiline) option ceases to work.
445 </P>
446 <P>
447 <b>--line-offsets</b>
448 Instead of showing lines or parts of lines that match, show each match as a
449 line number, the offset from the start of the line, and a length. The line
450 number is terminated by a colon (as usual; see the <b>-n</b> option), and the
451 offset and length are separated by a comma. In this mode, no context is shown.
452 That is, the <b>-A</b>, <b>-B</b>, and <b>-C</b> options are ignored. If there is
453 more than one match in a line, each of them is shown separately. This option is
454 mutually exclusive with <b>--file-offsets</b> and <b>--only-matching</b>.
455 </P>
456 <P>
457 <b>--locale</b>=<i>locale-name</i>
458 This option specifies a locale to be used for pattern matching. It overrides
459 the value in the <b>LC_ALL</b> or <b>LC_CTYPE</b> environment variables. If no
460 locale is specified, the PCRE library's default (usually the "C" locale) is
461 used. There is no short form for this option.
462 </P>
463 <P>
464 <b>--match-limit</b>=<i>number</i>
465 Processing some regular expression patterns can require a very large amount of
466 memory, leading in some cases to a program crash if not enough is available.
467 Other patterns may take a very long time to search for all possible matching
468 strings. The <b>pcre_exec()</b> function that is called by <b>pcregrep</b> to do
469 the matching has two parameters that can limit the resources that it uses.
470 <br>
471 <br>
472 The <b>--match-limit</b> option provides a means of limiting resource usage
473 when processing patterns that are not going to match, but which have a very
474 large number of possibilities in their search trees. The classic example is a
475 pattern that uses nested unlimited repeats. Internally, PCRE uses a function
476 called <b>match()</b> which it calls repeatedly (sometimes recursively). The
477 limit set by <b>--match-limit</b> is imposed on the number of times this
478 function is called during a match, which has the effect of limiting the amount
479 of backtracking that can take place.
480 <br>
481 <br>
482 The <b>--recursion-limit</b> option is similar to <b>--match-limit</b>, but
483 instead of limiting the total number of times that <b>match()</b> is called, it
484 limits the depth of recursive calls, which in turn limits the amount of memory
485 that can be used. The recursion depth is a smaller number than the total number
486 of calls, because not all calls to <b>match()</b> are recursive. This limit is
487 of use only if it is set smaller than <b>--match-limit</b>.
488 <br>
489 <br>
490 There are no short forms for these options. The default settings are specified
491 when the PCRE library is compiled, with the default default being 10 million.
492 </P>
493 <P>
494 <b>-M</b>, <b>--multiline</b>
495 Allow patterns to match more than one line. When this option is given, patterns
496 may usefully contain literal newline characters and internal occurrences of ^
497 and $ characters. The output for a successful match may consist of more than
498 one line, the last of which is the one in which the match ended. If the matched
499 string ends with a newline sequence the output ends at the end of that line.
500 <br>
501 <br>
502 When this option is set, the PCRE library is called in "multiline" mode.
503 There is a limit to the number of lines that can be matched, imposed by the way
504 that <b>pcregrep</b> buffers the input file as it scans it. However,
505 <b>pcregrep</b> ensures that at least 8K characters or the rest of the document
506 (whichever is the shorter) are available for forward matching, and similarly
507 the previous 8K characters (or all the previous characters, if fewer than 8K)
508 are guaranteed to be available for lookbehind assertions. This option does not
509 work when input is read line by line (see \fP--line-buffered\fP.)
510 </P>
511 <P>
512 <b>-N</b> <i>newline-type</i>, <b>--newline</b>=<i>newline-type</i>
513 The PCRE library supports five different conventions for indicating
514 the ends of lines. They are the single-character sequences CR (carriage return)
515 and LF (linefeed), the two-character sequence CRLF, an "anycrlf" convention,
516 which recognizes any of the preceding three types, and an "any" convention, in
517 which any Unicode line ending sequence is assumed to end a line. The Unicode
518 sequences are the three just mentioned, plus VT (vertical tab, U+000B), FF
519 (form feed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and
520 PS (paragraph separator, U+2029).
521 <br>
522 <br>
523 When the PCRE library is built, a default line-ending sequence is specified.
524 This is normally the standard sequence for the operating system. Unless
525 otherwise specified by this option, <b>pcregrep</b> uses the library's default.
526 The possible values for this option are CR, LF, CRLF, ANYCRLF, or ANY. This
527 makes it possible to use <b>pcregrep</b> to scan files that have come from other
528 environments without having to modify their line endings. If the data that is
529 being scanned does not agree with the convention set by this option,
530 <b>pcregrep</b> may behave in strange ways. Note that this option does not
531 apply to files specified by the <b>-f</b>, <b>--exclude-from</b>, or
532 <b>--include-from</b> options, which are expected to use the operating system's
533 standard newline sequence.
534 </P>
535 <P>
536 <b>-n</b>, <b>--line-number</b>
537 Precede each output line by its line number in the file, followed by a colon
538 for matching lines or a hyphen for context lines. If the filename is also being
539 output, it precedes the line number. This option is forced if
540 <b>--line-offsets</b> is used.
541 </P>
542 <P>
543 <b>--no-jit</b>
544 If the PCRE library is built with support for just-in-time compiling (which
545 speeds up matching), <b>pcregrep</b> automatically makes use of this, unless it
546 was explicitly disabled at build time. This option can be used to disable the
547 use of JIT at run time. It is provided for testing and working round problems.
548 It should never be needed in normal use.
549 </P>
550 <P>
551 <b>-o</b>, <b>--only-matching</b>
552 Show only the part of the line that matched a pattern instead of the whole
553 line. In this mode, no context is shown. That is, the <b>-A</b>, <b>-B</b>, and
554 <b>-C</b> options are ignored. If there is more than one match in a line, each
555 of them is shown separately. If <b>-o</b> is combined with <b>-v</b> (invert the
556 sense of the match to find non-matching lines), no output is generated, but the
557 return code is set appropriately. If the matched portion of the line is empty,
558 nothing is output unless the file name or line number are being printed, in
559 which case they are shown on an otherwise empty line. This option is mutually
560 exclusive with <b>--file-offsets</b> and <b>--line-offsets</b>.
561 </P>
562 <P>
563 <b>-o</b><i>number</i>, <b>--only-matching</b>=<i>number</i>
564 Show only the part of the line that matched the capturing parentheses of the
565 given number. Up to 32 capturing parentheses are supported, and -o0 is
566 equivalent to <b>-o</b> without a number. Because these options can be given
567 without an argument (see above), if an argument is present, it must be given in
568 the same shell item, for example, -o3 or --only-matching=2. The comments given
569 for the non-argument case above also apply to this case. If the specified
570 capturing parentheses do not exist in the pattern, or were not set in the
571 match, nothing is output unless the file name or line number are being printed.
572 <br>
573 <br>
574 If this option is given multiple times, multiple substrings are output, in the
575 order the options are given. For example, -o3 -o1 -o3 causes the substrings
576 matched by capturing parentheses 3 and 1 and then 3 again to be output. By
577 default, there is no separator (but see the next option).
578 </P>
579 <P>
580 <b>--om-separator</b>=<i>text</i>
581 Specify a separating string for multiple occurrences of <b>-o</b>. The default
582 is an empty string. Separating strings are never coloured.
583 </P>
584 <P>
585 <b>-q</b>, <b>--quiet</b>
586 Work quietly, that is, display nothing except error messages. The exit
587 status indicates whether or not any matches were found.
588 </P>
589 <P>
590 <b>-r</b>, <b>--recursive</b>
591 If any given path is a directory, recursively scan the files it contains,
592 taking note of any <b>--include</b> and <b>--exclude</b> settings. By default, a
593 directory is read as a normal file; in some operating systems this gives an
594 immediate end-of-file. This option is a shorthand for setting the <b>-d</b>
595 option to "recurse".
596 </P>
597 <P>
598 <b>--recursion-limit</b>=<i>number</i>
599 See <b>--match-limit</b> above.
600 </P>
601 <P>
602 <b>-s</b>, <b>--no-messages</b>
603 Suppress error messages about non-existent or unreadable files. Such files are
604 quietly skipped. However, the return code is still 2, even if matches were
605 found in other files.
606 </P>
607 <P>
608 <b>-u</b>, <b>--utf-8</b>
609 Operate in UTF-8 mode. This option is available only if PCRE has been compiled
610 with UTF-8 support. All patterns (including those for any <b>--exclude</b> and
611 <b>--include</b> options) and all subject lines that are scanned must be valid
612 strings of UTF-8 characters.
613 </P>
614 <P>
615 <b>-V</b>, <b>--version</b>
616 Write the version numbers of <b>pcregrep</b> and the PCRE library to the
617 standard output and then exit. Anything else on the command line is
618 ignored.
619 </P>
620 <P>
621 <b>-v</b>, <b>--invert-match</b>
622 Invert the sense of the match, so that lines which do <i>not</i> match any of
623 the patterns are the ones that are found.
624 </P>
625 <P>
626 <b>-w</b>, <b>--word-regex</b>, <b>--word-regexp</b>
627 Force the patterns to match only whole words. This is equivalent to having \b
628 at the start and end of the pattern. This option applies only to the patterns
629 that are matched against the contents of files; it does not apply to patterns
630 specified by any of the <b>--include</b> or <b>--exclude</b> options.
631 </P>
632 <P>
633 <b>-x</b>, <b>--line-regex</b>, <b>--line-regexp</b>
634 Force the patterns to be anchored (each must start matching at the beginning of
635 a line) and in addition, require them to match entire lines. This is equivalent
636 to having ^ and $ characters at the start and end of each alternative branch in
637 every pattern. This option applies only to the patterns that are matched
638 against the contents of files; it does not apply to patterns specified by any
639 of the <b>--include</b> or <b>--exclude</b> options.
640 </P>
641 <br><a name="SEC6" href="#TOC1">ENVIRONMENT VARIABLES</a><br>
642 <P>
643 The environment variables <b>LC_ALL</b> and <b>LC_CTYPE</b> are examined, in that
644 order, for a locale. The first one that is set is used. This can be overridden
645 by the <b>--locale</b> option. If no locale is set, the PCRE library's default
646 (usually the "C" locale) is used.
647 </P>
648 <br><a name="SEC7" href="#TOC1">NEWLINES</a><br>
649 <P>
650 The <b>-N</b> (<b>--newline</b>) option allows <b>pcregrep</b> to scan files with
651 different newline conventions from the default. Any parts of the input files
652 that are written to the standard output are copied identically, with whatever
653 newline sequences they have in the input. However, the setting of this option
654 does not affect the interpretation of files specified by the <b>-f</b>,
655 <b>--exclude-from</b>, or <b>--include-from</b> options, which are assumed to use
656 the operating system's standard newline sequence, nor does it affect the way in
657 which <b>pcregrep</b> writes informational messages to the standard error and
658 output streams. For these it uses the string "\n" to indicate newlines,
659 relying on the C I/O library to convert this to an appropriate sequence.
660 </P>
661 <br><a name="SEC8" href="#TOC1">OPTIONS COMPATIBILITY</a><br>
662 <P>
663 Many of the short and long forms of <b>pcregrep</b>'s options are the same
664 as in the GNU <b>grep</b> program. Any long option of the form
665 <b>--xxx-regexp</b> (GNU terminology) is also available as <b>--xxx-regex</b>
666 (PCRE terminology). However, the <b>--file-list</b>, <b>--file-offsets</b>,
667 <b>--include-dir</b>, <b>--line-offsets</b>, <b>--locale</b>, <b>--match-limit</b>,
668 <b>-M</b>, <b>--multiline</b>, <b>-N</b>, <b>--newline</b>, <b>--om-separator</b>,
669 <b>--recursion-limit</b>, <b>-u</b>, and <b>--utf-8</b> options are specific to
670 <b>pcregrep</b>, as is the use of the <b>--only-matching</b> option with a
671 capturing parentheses number.
672 </P>
673 <P>
674 Although most of the common options work the same way, a few are different in
675 <b>pcregrep</b>. For example, the <b>--include</b> option's argument is a glob
676 for GNU <b>grep</b>, but a regular expression for <b>pcregrep</b>. If both the
677 <b>-c</b> and <b>-l</b> options are given, GNU grep lists only file names,
678 without counts, but <b>pcregrep</b> gives the counts.
679 </P>
680 <br><a name="SEC9" href="#TOC1">OPTIONS WITH DATA</a><br>
681 <P>
682 There are four different ways in which an option with data can be specified.
683 If a short form option is used, the data may follow immediately, or (with one
684 exception) in the next command line item. For example:
685 <pre>
686 -f/some/file
687 -f /some/file
688 </pre>
689 The exception is the <b>-o</b> option, which may appear with or without data.
690 Because of this, if data is present, it must follow immediately in the same
691 item, for example -o3.
692 </P>
693 <P>
694 If a long form option is used, the data may appear in the same command line
695 item, separated by an equals character, or (with two exceptions) it may appear
696 in the next command line item. For example:
697 <pre>
698 --file=/some/file
699 --file /some/file
700 </pre>
701 Note, however, that if you want to supply a file name beginning with ~ as data
702 in a shell command, and have the shell expand ~ to a home directory, you must
703 separate the file name from the option, because the shell does not treat ~
704 specially unless it is at the start of an item.
705 </P>
706 <P>
707 The exceptions to the above are the <b>--colour</b> (or <b>--color</b>) and
708 <b>--only-matching</b> options, for which the data is optional. If one of these
709 options does have data, it must be given in the first form, using an equals
710 character. Otherwise <b>pcregrep</b> will assume that it has no data.
711 </P>
712 <br><a name="SEC10" href="#TOC1">MATCHING ERRORS</a><br>
713 <P>
714 It is possible to supply a regular expression that takes a very long time to
715 fail to match certain lines. Such patterns normally involve nested indefinite
716 repeats, for example: (a+)*\d when matched against a line of a's with no final
717 digit. The PCRE matching function has a resource limit that causes it to abort
718 in these circumstances. If this happens, <b>pcregrep</b> outputs an error
719 message and the line that caused the problem to the standard error stream. If
720 there are more than 20 such errors, <b>pcregrep</b> gives up.
721 </P>
722 <P>
723 The <b>--match-limit</b> option of <b>pcregrep</b> can be used to set the overall
724 resource limit; there is a second option called <b>--recursion-limit</b> that
725 sets a limit on the amount of memory (usually stack) that is used (see the
726 discussion of these options above).
727 </P>
728 <br><a name="SEC11" href="#TOC1">DIAGNOSTICS</a><br>
729 <P>
730 Exit status is 0 if any matches were found, 1 if no matches were found, and 2
731 for syntax errors, overlong lines, non-existent or inaccessible files (even if
732 matches were found in other files) or too many matching errors. Using the
733 <b>-s</b> option to suppress error messages about inaccessible files does not
734 affect the return code.
735 </P>
736 <br><a name="SEC12" href="#TOC1">SEE ALSO</a><br>
737 <P>
738 <b>pcrepattern</b>(3), <b>pcresyntax</b>(3), <b>pcretest</b>(1).
739 </P>
740 <br><a name="SEC13" href="#TOC1">AUTHOR</a><br>
741 <P>
742 Philip Hazel
743 <br>
744 University Computing Service
745 <br>
746 Cambridge CB2 3QH, England.
747 <br>
748 </P>
749 <br><a name="SEC14" href="#TOC1">REVISION</a><br>
750 <P>
751 Last updated: 13 September 2012
752 <br>
753 Copyright &copy; 1997-2012 University of Cambridge.
754 <br>
755 <p>
756 Return to the <a href="index.html">PCRE index page</a>.
757 </p>

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