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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">OPTIONS</a>
19 <li><a name="TOC4" href="#SEC4">ENVIRONMENT VARIABLES</a>
20 <li><a name="TOC5" href="#SEC5">NEWLINES</a>
21 <li><a name="TOC6" href="#SEC6">OPTIONS COMPATIBILITY</a>
22 <li><a name="TOC7" href="#SEC7">OPTIONS WITH DATA</a>
23 <li><a name="TOC8" href="#SEC8">MATCHING ERRORS</a>
24 <li><a name="TOC9" href="#SEC9">DIAGNOSTICS</a>
25 <li><a name="TOC10" href="#SEC10">AUTHOR</a>
26 </ul>
27 <br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br>
28 <P>
29 <b>pcregrep [options] [long options] [pattern] [path1 path2 ...]</b>
30 </P>
31 <br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br>
32 <P>
33 <b>pcregrep</b> searches files for character patterns, in the same way as other
34 grep commands do, but it uses the PCRE regular expression library to support
35 patterns that are compatible with the regular expressions of Perl 5. See
36 <a href="pcrepattern.html"><b>pcrepattern</b></a>
37 for a full description of syntax and semantics of the regular expressions that
38 PCRE supports.
39 </P>
40 <P>
41 Patterns, whether supplied on the command line or in a separate file, are given
42 without delimiters. For example:
43 <pre>
44 pcregrep Thursday /etc/motd
45 </pre>
46 If you attempt to use delimiters (for example, by surrounding a pattern with
47 slashes, as is common in Perl scripts), they are interpreted as part of the
48 pattern. Quotes can of course be used on the command line because they are
49 interpreted by the shell, and indeed they are required if a pattern contains
50 white space or shell metacharacters.
51 </P>
52 <P>
53 The first argument that follows any option settings is treated as the single
54 pattern to be matched when neither <b>-e</b> nor <b>-f</b> is present.
55 Conversely, when one or both of these options are used to specify patterns, all
56 arguments are treated as path names. At least one of <b>-e</b>, <b>-f</b>, or an
57 argument pattern must be provided.
58 </P>
59 <P>
60 If no files are specified, <b>pcregrep</b> reads the standard input. The
61 standard input can also be referenced by a name consisting of a single hyphen.
62 For example:
63 <pre>
64 pcregrep some-pattern /file1 - /file3
65 </pre>
66 By default, each line that matches the pattern is copied to the standard
67 output, and if there is more than one file, the file name is output at the
68 start of each line. However, there are options that can change how
69 <b>pcregrep</b> behaves. In particular, the <b>-M</b> option makes it possible to
70 search for patterns that span line boundaries. What defines a line boundary is
71 controlled by the <b>-N</b> (<b>--newline</b>) option.
72 </P>
73 <P>
74 Patterns are limited to 8K or BUFSIZ characters, whichever is the greater.
75 BUFSIZ is defined in <b>&#60;stdio.h&#62;</b>.
76 </P>
77 <P>
78 If the <b>LC_ALL</b> or <b>LC_CTYPE</b> environment variable is set,
79 <b>pcregrep</b> uses the value to set a locale when calling the PCRE library.
80 The <b>--locale</b> option can be used to override this.
81 </P>
82 <br><a name="SEC3" href="#TOC1">OPTIONS</a><br>
83 <P>
84 <b>--</b>
85 This terminate the list of options. It is useful if the next item on the
86 command line starts with a hyphen but is not an option. This allows for the
87 processing of patterns and filenames that start with hyphens.
88 </P>
89 <P>
90 <b>-A</b> <i>number</i>, <b>--after-context=</b><i>number</i>
91 Output <i>number</i> lines of context after each matching line. If filenames
92 and/or line numbers are being output, a hyphen separator is used instead of a
93 colon for the context lines. A line containing "--" is output between each
94 group of lines, unless they are in fact contiguous in the input file. The value
95 of <i>number</i> is expected to be relatively small. However, <b>pcregrep</b>
96 guarantees to have up to 8K of following text available for context output.
97 </P>
98 <P>
99 <b>-B</b> <i>number</i>, <b>--before-context=</b><i>number</i>
100 Output <i>number</i> lines of context before each matching line. If filenames
101 and/or line numbers are being output, a hyphen separator is used instead of a
102 colon for the context lines. A line containing "--" is output between each
103 group of lines, unless they are in fact contiguous in the input file. The value
104 of <i>number</i> is expected to be relatively small. However, <b>pcregrep</b>
105 guarantees to have up to 8K of preceding text available for context output.
106 </P>
107 <P>
108 <b>-C</b> <i>number</i>, <b>--context=</b><i>number</i>
109 Output <i>number</i> lines of context both before and after each matching line.
110 This is equivalent to setting both <b>-A</b> and <b>-B</b> to the same value.
111 </P>
112 <P>
113 <b>-c</b>, <b>--count</b>
114 Do not output individual lines; instead just output a count of the number of
115 lines that would otherwise have been output. If several files are given, a
116 count is output for each of them. In this mode, the <b>-A</b>, <b>-B</b>, and
117 <b>-C</b> options are ignored.
118 </P>
119 <P>
120 <b>--colour</b>, <b>--color</b>
121 If this option is given without any data, it is equivalent to "--colour=auto".
122 If data is required, it must be given in the same shell item, separated by an
123 equals sign.
124 </P>
125 <P>
126 <b>--colour=</b><i>value</i>, <b>--color=</b><i>value</i>
127 This option specifies under what circumstances the part of a line that matched
128 a pattern should be coloured in the output. The value may be "never" (the
129 default), "always", or "auto". In the latter case, colouring happens only if
130 the standard output is connected to a terminal. The colour can be specified by
131 setting the environment variable PCREGREP_COLOUR or PCREGREP_COLOR. The value
132 of this variable should be a string of two numbers, separated by a semicolon.
133 They are copied directly into the control string for setting colour on a
134 terminal, so it is your responsibility to ensure that they make sense. If
135 neither of the environment variables is set, the default is "1;31", which gives
136 red.
137 </P>
138 <P>
139 <b>-D</b> <i>action</i>, <b>--devices=</b><i>action</i>
140 If an input path is not a regular file or a directory, "action" specifies how
141 it is to be processed. Valid values are "read" (the default) or "skip"
142 (silently skip the path).
143 </P>
144 <P>
145 <b>-d</b> <i>action</i>, <b>--directories=</b><i>action</i>
146 If an input path is a directory, "action" specifies how it is to be processed.
147 Valid values are "read" (the default), "recurse" (equivalent to the <b>-r</b>
148 option), or "skip" (silently skip the path). In the default case, directories
149 are read as if they were ordinary files. In some operating systems the effect
150 of reading a directory like this is an immediate end-of-file.
151 </P>
152 <P>
153 <b>-e</b> <i>pattern</i>, <b>--regex=</b><i>pattern</i>,
154 <b>--regexp=</b><i>pattern</i> Specify a pattern to be matched. This option can
155 be used multiple times in order to specify several patterns. It can also be
156 used as a way of specifying a single pattern that starts with a hyphen. When
157 <b>-e</b> is used, no argument pattern is taken from the command line; all
158 arguments are treated as file names. There is an overall maximum of 100
159 patterns. They are applied to each line in the order in which they are defined
160 until one matches (or fails to match if <b>-v</b> is used). If <b>-f</b> is used
161 with <b>-e</b>, the command line patterns are matched first, followed by the
162 patterns from the file, independent of the order in which these options are
163 specified. Note that multiple use of <b>-e</b> is not the same as a single
164 pattern with alternatives. For example, X|Y finds the first character in a line
165 that is X or Y, whereas if the two patterns are given separately,
166 <b>pcregrep</b> finds X if it is present, even if it follows Y in the line. It
167 finds Y only if there is no X in the line. This really matters only if you are
168 using <b>-o</b> to show the portion of the line that matched.
169 </P>
170 <P>
171 <b>--exclude</b>=<i>pattern</i>
172 When <b>pcregrep</b> is searching the files in a directory as a consequence of
173 the <b>-r</b> (recursive search) option, any files whose names match the pattern
174 are excluded. The pattern is a PCRE regular expression. If a file name matches
175 both <b>--include</b> and <b>--exclude</b>, it is excluded. There is no short
176 form for this option.
177 </P>
178 <P>
179 <b>-F</b>, <b>--fixed-strings</b>
180 Interpret each pattern as a list of fixed strings, separated by newlines,
181 instead of as a regular expression. The <b>-w</b> (match as a word) and <b>-x</b>
182 (match whole line) options can be used with <b>-F</b>. They apply to each of the
183 fixed strings. A line is selected if any of the fixed strings are found in it
184 (subject to <b>-w</b> or <b>-x</b>, if present).
185 </P>
186 <P>
187 <b>-f</b> <i>filename</i>, <b>--file=</b><i>filename</i>
188 Read a number of patterns from the file, one per line, and match them against
189 each line of input. A data line is output if any of the patterns match it. The
190 filename can be given as "-" to refer to the standard input. When <b>-f</b> is
191 used, patterns specified on the command line using <b>-e</b> may also be
192 present; they are tested before the file's patterns. However, no other pattern
193 is taken from the command line; all arguments are treated as file names. There
194 is an overall maximum of 100 patterns. Trailing white space is removed from
195 each line, and blank lines are ignored. An empty file contains no patterns and
196 therefore matches nothing.
197 </P>
198 <P>
199 <b>-H</b>, <b>--with-filename</b>
200 Force the inclusion of the filename at the start of output lines when searching
201 a single file. By default, the filename is not shown in this case. For matching
202 lines, the filename is followed by a colon and a space; for context lines, a
203 hyphen separator is used. If a line number is also being output, it follows the
204 file name without a space.
205 </P>
206 <P>
207 <b>-h</b>, <b>--no-filename</b>
208 Suppress the output filenames when searching multiple files. By default,
209 filenames are shown when multiple files are searched. For matching lines, the
210 filename is followed by a colon and a space; for context lines, a hyphen
211 separator is used. If a line number is also being output, it follows the file
212 name without a space.
213 </P>
214 <P>
215 <b>--help</b>
216 Output a brief help message and exit.
217 </P>
218 <P>
219 <b>-i</b>, <b>--ignore-case</b>
220 Ignore upper/lower case distinctions during comparisons.
221 </P>
222 <P>
223 <b>--include</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, only those files whose names match the
226 pattern are included. The pattern is a PCRE regular expression. If a file name
227 matches both <b>--include</b> and <b>--exclude</b>, it is excluded. There is no
228 short form for this option.
229 </P>
230 <P>
231 <b>-L</b>, <b>--files-without-match</b>
232 Instead of outputting lines from the files, just output the names of the files
233 that do not contain any lines that would have been output. Each file name is
234 output once, on a separate line.
235 </P>
236 <P>
237 <b>-l</b>, <b>--files-with-matches</b>
238 Instead of outputting lines from the files, just output the names of the files
239 containing lines that would have been output. Each file name is output
240 once, on a separate line. Searching stops as soon as a matching line is found
241 in a file.
242 </P>
243 <P>
244 <b>--label</b>=<i>name</i>
245 This option supplies a name to be used for the standard input when file names
246 are being output. If not supplied, "(standard input)" is used. There is no
247 short form for this option.
248 </P>
249 <P>
250 <b>--locale</b>=<i>locale-name</i>
251 This option specifies a locale to be used for pattern matching. It overrides
252 the value in the <b>LC_ALL</b> or <b>LC_CTYPE</b> environment variables. If no
253 locale is specified, the PCRE library's default (usually the "C" locale) is
254 used. There is no short form for this option.
255 </P>
256 <P>
257 <b>-M</b>, <b>--multiline</b>
258 Allow patterns to match more than one line. When this option is given, patterns
259 may usefully contain literal newline characters and internal occurrences of ^
260 and $ characters. The output for any one match may consist of more than one
261 line. When this option is set, the PCRE library is called in "multiline" mode.
262 There is a limit to the number of lines that can be matched, imposed by the way
263 that <b>pcregrep</b> buffers the input file as it scans it. However,
264 <b>pcregrep</b> ensures that at least 8K characters or the rest of the document
265 (whichever is the shorter) are available for forward matching, and similarly
266 the previous 8K characters (or all the previous characters, if fewer than 8K)
267 are guaranteed to be available for lookbehind assertions.
268 </P>
269 <P>
270 <b>-N</b> <i>newline-type</i>, <b>--newline=</b><i>newline-type</i>
271 The PCRE library supports three different character sequences for indicating
272 the ends of lines. They are the single-character sequences CR (carriage return)
273 and LF (linefeed), and the two-character sequence CR, LF. When the library is
274 built, a default line-ending sequence is specified. This is normally the
275 standard sequence for the operating system. Unless otherwise specified by this
276 option, <b>pcregrep</b> uses the default. The possible values for this option
277 are CR, LF, or CRLF. This makes it possible to use <b>pcregrep</b> on files that
278 have come from other environments without having to modify their line endings.
279 If the data that is being scanned does not agree with the convention set by
280 this option, <b>pcregrep</b> may behave in strange ways.
281 </P>
282 <P>
283 <b>-n</b>, <b>--line-number</b>
284 Precede each output line by its line number in the file, followed by a colon
285 and a space for matching lines or a hyphen and a space for context lines. If
286 the filename is also being output, it precedes the line number.
287 </P>
288 <P>
289 <b>-o</b>, <b>--only-matching</b>
290 Show only the part of the line that matched a pattern. In this mode, no
291 context is shown. That is, the <b>-A</b>, <b>-B</b>, and <b>-C</b> options are
292 ignored.
293 </P>
294 <P>
295 <b>-q</b>, <b>--quiet</b>
296 Work quietly, that is, display nothing except error messages. The exit
297 status indicates whether or not any matches were found.
298 </P>
299 <P>
300 <b>-r</b>, <b>--recursive</b>
301 If any given path is a directory, recursively scan the files it contains,
302 taking note of any <b>--include</b> and <b>--exclude</b> settings. By default, a
303 directory is read as a normal file; in some operating systems this gives an
304 immediate end-of-file. This option is a shorthand for setting the <b>-d</b>
305 option to "recurse".
306 </P>
307 <P>
308 <b>-s</b>, <b>--no-messages</b>
309 Suppress error messages about non-existent or unreadable files. Such files are
310 quietly skipped. However, the return code is still 2, even if matches were
311 found in other files.
312 </P>
313 <P>
314 <b>-u</b>, <b>--utf-8</b>
315 Operate in UTF-8 mode. This option is available only if PCRE has been compiled
316 with UTF-8 support. Both patterns and subject lines must be valid strings of
317 UTF-8 characters.
318 </P>
319 <P>
320 <b>-V</b>, <b>--version</b>
321 Write the version numbers of <b>pcregrep</b> and the PCRE library that is being
322 used to the standard error stream.
323 </P>
324 <P>
325 <b>-v</b>, <b>--invert-match</b>
326 Invert the sense of the match, so that lines which do <i>not</i> match any of
327 the patterns are the ones that are found.
328 </P>
329 <P>
330 <b>-w</b>, <b>--word-regex</b>, <b>--word-regexp</b>
331 Force the patterns to match only whole words. This is equivalent to having \b
332 at the start and end of the pattern.
333 </P>
334 <P>
335 <b>-x</b>, <b>--line-regex</b>, \fP--line-regexp\fP
336 Force the patterns to be anchored (each must start matching at the beginning of
337 a line) and in addition, require them to match entire lines. This is
338 equivalent to having ^ and $ characters at the start and end of each
339 alternative branch in every pattern.
340 </P>
341 <br><a name="SEC4" href="#TOC1">ENVIRONMENT VARIABLES</a><br>
342 <P>
343 The environment variables <b>LC_ALL</b> and <b>LC_CTYPE</b> are examined, in that
344 order, for a locale. The first one that is set is used. This can be overridden
345 by the <b>--locale</b> option. If no locale is set, the PCRE library's default
346 (usually the "C" locale) is used.
347 </P>
348 <br><a name="SEC5" href="#TOC1">NEWLINES</a><br>
349 <P>
350 The <b>-N</b> (<b>--newline</b>) option allows <b>pcregrep</b> to scan files with
351 different newline conventions from the default. However, the setting of this
352 option does not affect the way in which <b>pcregrep</b> writes information to
353 the standard error and output streams. It uses the string "\n" in C
354 <b>printf()</b> calls to indicate newlines, relying on the C I/O library to
355 convert this to an appropriate sequence if the output is sent to a file.
356 </P>
357 <br><a name="SEC6" href="#TOC1">OPTIONS COMPATIBILITY</a><br>
358 <P>
359 The majority of short and long forms of <b>pcregrep</b>'s options are the same
360 as in the GNU <b>grep</b> program. Any long option of the form
361 <b>--xxx-regexp</b> (GNU terminology) is also available as <b>--xxx-regex</b>
362 (PCRE terminology). However, the <b>--locale</b>, <b>-M</b>, <b>--multiline</b>,
363 <b>-u</b>, and <b>--utf-8</b> options are specific to <b>pcregrep</b>.
364 </P>
365 <br><a name="SEC7" href="#TOC1">OPTIONS WITH DATA</a><br>
366 <P>
367 There are four different ways in which an option with data can be specified.
368 If a short form option is used, the data may follow immediately, or in the next
369 command line item. For example:
370 <pre>
371 -f/some/file
372 -f /some/file
373 </pre>
374 If a long form option is used, the data may appear in the same command line
375 item, separated by an equals character, or (with one exception) it may appear
376 in the next command line item. For example:
377 <pre>
378 --file=/some/file
379 --file /some/file
380 </pre>
381 Note, however, that if you want to supply a file name beginning with ~ as data
382 in a shell command, and have the shell expand ~ to a home directory, you must
383 separate the file name from the option, because the shell does not treat ~
384 specially unless it is at the start of an item.
385 </P>
386 <P>
387 The exception to the above is the <b>--colour</b> (or <b>--color</b>) option,
388 for which the data is optional. If this option does have data, it must be given
389 in the first form, using an equals character. Otherwise it will be assumed that
390 it has no data.
391 </P>
392 <br><a name="SEC8" href="#TOC1">MATCHING ERRORS</a><br>
393 <P>
394 It is possible to supply a regular expression that takes a very long time to
395 fail to match certain lines. Such patterns normally involve nested indefinite
396 repeats, for example: (a+)*\d when matched against a line of a's with no final
397 digit. The PCRE matching function has a resource limit that causes it to abort
398 in these circumstances. If this happens, <b>pcregrep</b> outputs an error
399 message and the line that caused the problem to the standard error stream. If
400 there are more than 20 such errors, <b>pcregrep</b> gives up.
401 </P>
402 <br><a name="SEC9" href="#TOC1">DIAGNOSTICS</a><br>
403 <P>
404 Exit status is 0 if any matches were found, 1 if no matches were found, and 2
405 for syntax errors and non-existent or inacessible files (even if matches were
406 found in other files) or too many matching errors. Using the <b>-s</b> option to
407 suppress error messages about inaccessble files does not affect the return
408 code.
409 </P>
410 <br><a name="SEC10" href="#TOC1">AUTHOR</a><br>
411 <P>
412 Philip Hazel
413 <br>
414 University Computing Service
415 <br>
416 Cambridge CB2 3QG, England.
417 </P>
418 <P>
419 Last updated: 06 June 2006
420 <br>
421 Copyright &copy; 1997-2006 University of Cambridge.
422 <p>
423 Return to the <a href="index.html">PCRE index page</a>.
424 </p>

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