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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. As soon as one pattern matches
82 (or fails to match when <b>-v</b> is used), no further patterns are considered.
83 </P>
84 <P>
85 When <b>--only-matching</b>, <b>--file-offsets</b>, or <b>--line-offsets</b>
86 is used, the output is the part of the line that matched (either shown
87 literally, or as an offset). In this case, scanning resumes immediately
88 following the match, so that further matches on the same line can be found.
89 If there are multiple patterns, they are all tried on the remainder of the
90 line. However, patterns that follow the one that matched are not tried on the
91 earlier part of the line.
92 </P>
93 <P>
94 If the <b>LC_ALL</b> or <b>LC_CTYPE</b> environment variable is set,
95 <b>pcregrep</b> uses the value to set a locale when calling the PCRE library.
96 The <b>--locale</b> option can be used to override this.
97 </P>
98 <br><a name="SEC3" href="#TOC1">SUPPORT FOR COMPRESSED FILES</a><br>
99 <P>
100 It is possible to compile <b>pcregrep</b> so that it uses <b>libz</b> or
101 <b>libbz2</b> to read files whose names end in <b>.gz</b> or <b>.bz2</b>,
102 respectively. You can find out whether your binary has support for one or both
103 of these file types by running it with the <b>--help</b> option. If the
104 appropriate support is not present, files are treated as plain text. The
105 standard input is always so treated.
106 </P>
107 <br><a name="SEC4" href="#TOC1">OPTIONS</a><br>
108 <P>
109 <b>--</b>
110 This terminate the list of options. It is useful if the next item on the
111 command line starts with a hyphen but is not an option. This allows for the
112 processing of patterns and filenames that start with hyphens.
113 </P>
114 <P>
115 <b>-A</b> <i>number</i>, <b>--after-context=</b><i>number</i>
116 Output <i>number</i> lines of context after each matching line. If filenames
117 and/or line numbers are being output, a hyphen separator is used instead of a
118 colon for the context lines. A line containing "--" is output between each
119 group of lines, unless they are in fact contiguous in the input file. The value
120 of <i>number</i> is expected to be relatively small. However, <b>pcregrep</b>
121 guarantees to have up to 8K of following text available for context output.
122 </P>
123 <P>
124 <b>-B</b> <i>number</i>, <b>--before-context=</b><i>number</i>
125 Output <i>number</i> lines of context before each matching line. If filenames
126 and/or line numbers are being output, a hyphen separator is used instead of a
127 colon for the context lines. A line containing "--" is output between each
128 group of lines, unless they are in fact contiguous in the input file. The value
129 of <i>number</i> is expected to be relatively small. However, <b>pcregrep</b>
130 guarantees to have up to 8K of preceding text available for context output.
131 </P>
132 <P>
133 <b>-C</b> <i>number</i>, <b>--context=</b><i>number</i>
134 Output <i>number</i> lines of context both before and after each matching line.
135 This is equivalent to setting both <b>-A</b> and <b>-B</b> to the same value.
136 </P>
137 <P>
138 <b>-c</b>, <b>--count</b>
139 Do not output individual lines; instead just output a count of the number of
140 lines that would otherwise have been output. If several files are given, a
141 count is output for each of them. In this mode, the <b>-A</b>, <b>-B</b>, and
142 <b>-C</b> options are ignored.
143 </P>
144 <P>
145 <b>--colour</b>, <b>--color</b>
146 If this option is given without any data, it is equivalent to "--colour=auto".
147 If data is required, it must be given in the same shell item, separated by an
148 equals sign.
149 </P>
150 <P>
151 <b>--colour=</b><i>value</i>, <b>--color=</b><i>value</i>
152 This option specifies under what circumstances the part of a line that matched
153 a pattern should be coloured in the output. The value may be "never" (the
154 default), "always", or "auto". In the latter case, colouring happens only if
155 the standard output is connected to a terminal. The colour can be specified by
156 setting the environment variable PCREGREP_COLOUR or PCREGREP_COLOR. The value
157 of this variable should be a string of two numbers, separated by a semicolon.
158 They are copied directly into the control string for setting colour on a
159 terminal, so it is your responsibility to ensure that they make sense. If
160 neither of the environment variables is set, the default is "1;31", which gives
161 red.
162 </P>
163 <P>
164 <b>-D</b> <i>action</i>, <b>--devices=</b><i>action</i>
165 If an input path is not a regular file or a directory, "action" specifies how
166 it is to be processed. Valid values are "read" (the default) or "skip"
167 (silently skip the path).
168 </P>
169 <P>
170 <b>-d</b> <i>action</i>, <b>--directories=</b><i>action</i>
171 If an input path is a directory, "action" specifies how it is to be processed.
172 Valid values are "read" (the default), "recurse" (equivalent to the <b>-r</b>
173 option), or "skip" (silently skip the path). In the default case, directories
174 are read as if they were ordinary files. In some operating systems the effect
175 of reading a directory like this is an immediate end-of-file.
176 </P>
177 <P>
178 <b>-e</b> <i>pattern</i>, <b>--regex=</b><i>pattern</i>, <b>--regexp=</b><i>pattern</i>
179 Specify a pattern to be matched. This option can be used multiple times in
180 order to specify several patterns. It can also be used as a way of specifying a
181 single pattern that starts with a hyphen. When <b>-e</b> is used, no argument
182 pattern is taken from the command line; all arguments are treated as file
183 names. There is an overall maximum of 100 patterns. They are applied to each
184 line in the order in which they are defined until one matches (or fails to
185 match if <b>-v</b> is used). If <b>-f</b> is used with <b>-e</b>, the command line
186 patterns are matched first, followed by the patterns from the file, independent
187 of the order in which these options are specified. Note that multiple use of
188 <b>-e</b> is not the same as a single pattern with alternatives. For example,
189 X|Y finds the first character in a line that is X or Y, whereas if the two
190 patterns are given separately, <b>pcregrep</b> finds X if it is present, even if
191 it follows Y in the line. It finds Y only if there is no X in the line. This
192 really matters only if you are using <b>-o</b> to show the part(s) of the line
193 that matched.
194 </P>
195 <P>
196 <b>--exclude</b>=<i>pattern</i>
197 When <b>pcregrep</b> is searching the files in a directory as a consequence of
198 the <b>-r</b> (recursive search) option, any files whose names match the pattern
199 are excluded. The pattern is a PCRE regular expression. If a file name matches
200 both <b>--include</b> and <b>--exclude</b>, it is excluded. There is no short
201 form for this option.
202 </P>
203 <P>
204 <b>-F</b>, <b>--fixed-strings</b>
205 Interpret each pattern as a list of fixed strings, separated by newlines,
206 instead of as a regular expression. The <b>-w</b> (match as a word) and <b>-x</b>
207 (match whole line) options can be used with <b>-F</b>. They apply to each of the
208 fixed strings. A line is selected if any of the fixed strings are found in it
209 (subject to <b>-w</b> or <b>-x</b>, if present).
210 </P>
211 <P>
212 <b>-f</b> <i>filename</i>, <b>--file=</b><i>filename</i>
213 Read a number of patterns from the file, one per line, and match them against
214 each line of input. A data line is output if any of the patterns match it. The
215 filename can be given as "-" to refer to the standard input. When <b>-f</b> is
216 used, patterns specified on the command line using <b>-e</b> may also be
217 present; they are tested before the file's patterns. However, no other pattern
218 is taken from the command line; all arguments are treated as file names. There
219 is an overall maximum of 100 patterns. Trailing white space is removed from
220 each line, and blank lines are ignored. An empty file contains no patterns and
221 therefore matches nothing. See also the comments about multiple patterns versus
222 a single pattern with alternatives in the description of <b>-e</b> above.
223 </P>
224 <P>
225 <b>--file-offsets</b>
226 Instead of showing lines or parts of lines that match, show each match as an
227 offset from the start of the file and a length, separated by a comma. In this
228 mode, no context is shown. That is, the <b>-A</b>, <b>-B</b>, and <b>-C</b>
229 options are ignored. If there is more than one match in a line, each of them is
230 shown separately. This option is mutually exclusive with <b>--line-offsets</b>
231 and <b>--only-matching</b>.
232 </P>
233 <P>
234 <b>-H</b>, <b>--with-filename</b>
235 Force the inclusion of the filename at the start of output lines when searching
236 a single file. By default, the filename is not shown in this case. For matching
237 lines, the filename is followed by a colon and a space; for context lines, a
238 hyphen separator is used. If a line number is also being output, it follows the
239 file name without a space.
240 </P>
241 <P>
242 <b>-h</b>, <b>--no-filename</b>
243 Suppress the output filenames when searching multiple files. By default,
244 filenames are shown when multiple files are searched. For matching lines, the
245 filename is followed by a colon and a space; for context lines, a hyphen
246 separator is used. If a line number is also being output, it follows the file
247 name without a space.
248 </P>
249 <P>
250 <b>--help</b>
251 Output a help message, giving brief details of the command options and file
252 type support, and then exit.
253 </P>
254 <P>
255 <b>-i</b>, <b>--ignore-case</b>
256 Ignore upper/lower case distinctions during comparisons.
257 </P>
258 <P>
259 <b>--include</b>=<i>pattern</i>
260 When <b>pcregrep</b> is searching the files in a directory as a consequence of
261 the <b>-r</b> (recursive search) option, only those files whose names match the
262 pattern are included. The pattern is a PCRE regular expression. If a file name
263 matches both <b>--include</b> and <b>--exclude</b>, it is excluded. There is no
264 short form for this option.
265 </P>
266 <P>
267 <b>-L</b>, <b>--files-without-match</b>
268 Instead of outputting lines from the files, just output the names of the files
269 that do not contain any lines that would have been output. Each file name is
270 output once, on a separate line.
271 </P>
272 <P>
273 <b>-l</b>, <b>--files-with-matches</b>
274 Instead of outputting lines from the files, just output the names of the files
275 containing lines that would have been output. Each file name is output
276 once, on a separate line. Searching stops as soon as a matching line is found
277 in a file.
278 </P>
279 <P>
280 <b>--label</b>=<i>name</i>
281 This option supplies a name to be used for the standard input when file names
282 are being output. If not supplied, "(standard input)" is used. There is no
283 short form for this option.
284 </P>
285 <P>
286 <b>--line-offsets</b>
287 Instead of showing lines or parts of lines that match, show each match as a
288 line number, the offset from the start of the line, and a length. The line
289 number is terminated by a colon (as usual; see the <b>-n</b> option), and the
290 offset and length are separated by a comma. In this mode, no context is shown.
291 That is, the <b>-A</b>, <b>-B</b>, and <b>-C</b> options are ignored. If there is
292 more than one match in a line, each of them is shown separately. This option is
293 mutually exclusive with <b>--file-offsets</b> and <b>--only-matching</b>.
294 </P>
295 <P>
296 <b>--locale</b>=<i>locale-name</i>
297 This option specifies a locale to be used for pattern matching. It overrides
298 the value in the <b>LC_ALL</b> or <b>LC_CTYPE</b> environment variables. If no
299 locale is specified, the PCRE library's default (usually the "C" locale) is
300 used. There is no short form for this option.
301 </P>
302 <P>
303 <b>-M</b>, <b>--multiline</b>
304 Allow patterns to match more than one line. When this option is given, patterns
305 may usefully contain literal newline characters and internal occurrences of ^
306 and $ characters. The output for any one match may consist of more than one
307 line. When this option is set, the PCRE library is called in "multiline" mode.
308 There is a limit to the number of lines that can be matched, imposed by the way
309 that <b>pcregrep</b> buffers the input file as it scans it. However,
310 <b>pcregrep</b> ensures that at least 8K characters or the rest of the document
311 (whichever is the shorter) are available for forward matching, and similarly
312 the previous 8K characters (or all the previous characters, if fewer than 8K)
313 are guaranteed to be available for lookbehind assertions.
314 </P>
315 <P>
316 <b>-N</b> <i>newline-type</i>, <b>--newline=</b><i>newline-type</i>
317 The PCRE library supports five different conventions for indicating
318 the ends of lines. They are the single-character sequences CR (carriage return)
319 and LF (linefeed), the two-character sequence CRLF, an "anycrlf" convention,
320 which recognizes any of the preceding three types, and an "any" convention, in
321 which any Unicode line ending sequence is assumed to end a line. The Unicode
322 sequences are the three just mentioned, plus VT (vertical tab, U+000B), FF
323 (formfeed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and
324 PS (paragraph separator, U+2029).
325 <br>
326 <br>
327 When the PCRE library is built, a default line-ending sequence is specified.
328 This is normally the standard sequence for the operating system. Unless
329 otherwise specified by this option, <b>pcregrep</b> uses the library's default.
330 The possible values for this option are CR, LF, CRLF, ANYCRLF, or ANY. This
331 makes it possible to use <b>pcregrep</b> on files that have come from other
332 environments without having to modify their line endings. If the data that is
333 being scanned does not agree with the convention set by this option,
334 <b>pcregrep</b> may behave in strange ways.
335 </P>
336 <P>
337 <b>-n</b>, <b>--line-number</b>
338 Precede each output line by its line number in the file, followed by a colon
339 and a space for matching lines or a hyphen and a space for context lines. If
340 the filename is also being output, it precedes the line number. This option is
341 forced if <b>--line-offsets</b> is used.
342 </P>
343 <P>
344 <b>-o</b>, <b>--only-matching</b>
345 Show only the part of the line that matched a pattern. In this mode, no
346 context is shown. That is, the <b>-A</b>, <b>-B</b>, and <b>-C</b> options are
347 ignored. If there is more than one match in a line, each of them is shown
348 separately. If <b>-o</b> is combined with <b>-v</b> (invert the sense of the
349 match to find non-matching lines), no output is generated, but the return code
350 is set appropriately. This option is mutually exclusive with
351 <b>--file-offsets</b> and <b>--line-offsets</b>.
352 </P>
353 <P>
354 <b>-q</b>, <b>--quiet</b>
355 Work quietly, that is, display nothing except error messages. The exit
356 status indicates whether or not any matches were found.
357 </P>
358 <P>
359 <b>-r</b>, <b>--recursive</b>
360 If any given path is a directory, recursively scan the files it contains,
361 taking note of any <b>--include</b> and <b>--exclude</b> settings. By default, a
362 directory is read as a normal file; in some operating systems this gives an
363 immediate end-of-file. This option is a shorthand for setting the <b>-d</b>
364 option to "recurse".
365 </P>
366 <P>
367 <b>-s</b>, <b>--no-messages</b>
368 Suppress error messages about non-existent or unreadable files. Such files are
369 quietly skipped. However, the return code is still 2, even if matches were
370 found in other files.
371 </P>
372 <P>
373 <b>-u</b>, <b>--utf-8</b>
374 Operate in UTF-8 mode. This option is available only if PCRE has been compiled
375 with UTF-8 support. Both patterns and subject lines must be valid strings of
376 UTF-8 characters.
377 </P>
378 <P>
379 <b>-V</b>, <b>--version</b>
380 Write the version numbers of <b>pcregrep</b> and the PCRE library that is being
381 used to the standard error stream.
382 </P>
383 <P>
384 <b>-v</b>, <b>--invert-match</b>
385 Invert the sense of the match, so that lines which do <i>not</i> match any of
386 the patterns are the ones that are found.
387 </P>
388 <P>
389 <b>-w</b>, <b>--word-regex</b>, <b>--word-regexp</b>
390 Force the patterns to match only whole words. This is equivalent to having \b
391 at the start and end of the pattern.
392 </P>
393 <P>
394 <b>-x</b>, <b>--line-regex</b>, <b>--line-regexp</b>
395 Force the patterns to be anchored (each must start matching at the beginning of
396 a line) and in addition, require them to match entire lines. This is
397 equivalent to having ^ and $ characters at the start and end of each
398 alternative branch in every pattern.
399 </P>
400 <br><a name="SEC5" href="#TOC1">ENVIRONMENT VARIABLES</a><br>
401 <P>
402 The environment variables <b>LC_ALL</b> and <b>LC_CTYPE</b> are examined, in that
403 order, for a locale. The first one that is set is used. This can be overridden
404 by the <b>--locale</b> option. If no locale is set, the PCRE library's default
405 (usually the "C" locale) is used.
406 </P>
407 <br><a name="SEC6" href="#TOC1">NEWLINES</a><br>
408 <P>
409 The <b>-N</b> (<b>--newline</b>) option allows <b>pcregrep</b> to scan files with
410 different newline conventions from the default. However, the setting of this
411 option does not affect the way in which <b>pcregrep</b> writes information to
412 the standard error and output streams. It uses the string "\n" in C
413 <b>printf()</b> calls to indicate newlines, relying on the C I/O library to
414 convert this to an appropriate sequence if the output is sent to a file.
415 </P>
416 <br><a name="SEC7" href="#TOC1">OPTIONS COMPATIBILITY</a><br>
417 <P>
418 The majority of short and long forms of <b>pcregrep</b>'s options are the same
419 as in the GNU <b>grep</b> program. Any long option of the form
420 <b>--xxx-regexp</b> (GNU terminology) is also available as <b>--xxx-regex</b>
421 (PCRE terminology). However, the <b>--locale</b>, <b>-M</b>, <b>--multiline</b>,
422 <b>-u</b>, and <b>--utf-8</b> options are specific to <b>pcregrep</b>.
423 </P>
424 <br><a name="SEC8" href="#TOC1">OPTIONS WITH DATA</a><br>
425 <P>
426 There are four different ways in which an option with data can be specified.
427 If a short form option is used, the data may follow immediately, or in the next
428 command line item. For example:
429 <pre>
430 -f/some/file
431 -f /some/file
432 </pre>
433 If a long form option is used, the data may appear in the same command line
434 item, separated by an equals character, or (with one exception) it may appear
435 in the next command line item. For example:
436 <pre>
437 --file=/some/file
438 --file /some/file
439 </pre>
440 Note, however, that if you want to supply a file name beginning with ~ as data
441 in a shell command, and have the shell expand ~ to a home directory, you must
442 separate the file name from the option, because the shell does not treat ~
443 specially unless it is at the start of an item.
444 </P>
445 <P>
446 The exception to the above is the <b>--colour</b> (or <b>--color</b>) option,
447 for which the data is optional. If this option does have data, it must be given
448 in the first form, using an equals character. Otherwise it will be assumed that
449 it has no data.
450 </P>
451 <br><a name="SEC9" href="#TOC1">MATCHING ERRORS</a><br>
452 <P>
453 It is possible to supply a regular expression that takes a very long time to
454 fail to match certain lines. Such patterns normally involve nested indefinite
455 repeats, for example: (a+)*\d when matched against a line of a's with no final
456 digit. The PCRE matching function has a resource limit that causes it to abort
457 in these circumstances. If this happens, <b>pcregrep</b> outputs an error
458 message and the line that caused the problem to the standard error stream. If
459 there are more than 20 such errors, <b>pcregrep</b> gives up.
460 </P>
461 <br><a name="SEC10" href="#TOC1">DIAGNOSTICS</a><br>
462 <P>
463 Exit status is 0 if any matches were found, 1 if no matches were found, and 2
464 for syntax errors and non-existent or inacessible files (even if matches were
465 found in other files) or too many matching errors. Using the <b>-s</b> option to
466 suppress error messages about inaccessble files does not affect the return
467 code.
468 </P>
469 <br><a name="SEC11" href="#TOC1">SEE ALSO</a><br>
470 <P>
471 <b>pcrepattern</b>(3), <b>pcretest</b>(1).
472 </P>
473 <br><a name="SEC12" href="#TOC1">AUTHOR</a><br>
474 <P>
475 Philip Hazel
476 <br>
477 University Computing Service
478 <br>
479 Cambridge CB2 3QH, England.
480 <br>
481 </P>
482 <br><a name="SEC13" href="#TOC1">REVISION</a><br>
483 <P>
484 Last updated: 17 December 2007
485 <br>
486 Copyright &copy; 1997-2007 University of Cambridge.
487 <br>
488 <p>
489 Return to the <a href="index.html">PCRE index page</a>.
490 </p>

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