/[pcre]/code/trunk/doc/html/pcregrep.html
ViewVC logotype

Contents of /code/trunk/doc/html/pcregrep.html

Parent Directory Parent Directory | Revision Log Revision Log


Revision 392 - (show annotations)
Tue Mar 17 21:30:30 2009 UTC (10 years, 6 months ago) by ph10
File MIME type: text/html
File size: 25558 byte(s)
Error occurred while calculating annotation data.
Update after detrailing for a test release.
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 not 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 <b>--</b>
123 This terminate the list of options. It is useful if the next item on the
124 command line starts with a hyphen but is not an option. This allows for the
125 processing of patterns and filenames that start with hyphens.
126 </P>
127 <P>
128 <b>-A</b> <i>number</i>, <b>--after-context=</b><i>number</i>
129 Output <i>number</i> lines of context after each matching line. If filenames
130 and/or line numbers are being output, a hyphen separator is used instead of a
131 colon for the context lines. A line containing "--" is output between each
132 group of lines, unless they are in fact contiguous in the input file. The value
133 of <i>number</i> is expected to be relatively small. However, <b>pcregrep</b>
134 guarantees to have up to 8K of following text available for context output.
135 </P>
136 <P>
137 <b>-B</b> <i>number</i>, <b>--before-context=</b><i>number</i>
138 Output <i>number</i> lines of context before each matching line. If filenames
139 and/or line numbers are being output, a hyphen separator is used instead of a
140 colon for the context lines. A line containing "--" is output between each
141 group of lines, unless they are in fact contiguous in the input file. The value
142 of <i>number</i> is expected to be relatively small. However, <b>pcregrep</b>
143 guarantees to have up to 8K of preceding text available for context output.
144 </P>
145 <P>
146 <b>-C</b> <i>number</i>, <b>--context=</b><i>number</i>
147 Output <i>number</i> lines of context both before and after each matching line.
148 This is equivalent to setting both <b>-A</b> and <b>-B</b> to the same value.
149 </P>
150 <P>
151 <b>-c</b>, <b>--count</b>
152 Do not output individual lines; instead just output a count of the number of
153 lines that would otherwise have been output. If several files are given, a
154 count is output for each of them. In this mode, the <b>-A</b>, <b>-B</b>, and
155 <b>-C</b> options are ignored.
156 </P>
157 <P>
158 <b>--colour</b>, <b>--color</b>
159 If this option is given without any data, it is equivalent to "--colour=auto".
160 If data is required, it must be given in the same shell item, separated by an
161 equals sign.
162 </P>
163 <P>
164 <b>--colour=</b><i>value</i>, <b>--color=</b><i>value</i>
165 This option specifies under what circumstances the parts of a line that matched
166 a pattern should be coloured in the output. By default, the output is not
167 coloured. The value (which is optional, see above) may be "never", "always", or
168 "auto". In the latter case, colouring happens only if the standard output is
169 connected to a terminal. More resources are used when colouring is enabled,
170 because <b>pcregrep</b> has to search for all possible matches in a line, not
171 just one, in order to colour them all.
172 </P>
173 <P>
174 The colour that is used can be specified by setting the environment variable
175 PCREGREP_COLOUR or PCREGREP_COLOR. The value of this variable should be a
176 string of two numbers, separated by a semicolon. They are copied directly into
177 the control string for setting colour on a terminal, so it is your
178 responsibility to ensure that they make sense. If neither of the environment
179 variables is set, the default is "1;31", which gives red.
180 </P>
181 <P>
182 <b>-D</b> <i>action</i>, <b>--devices=</b><i>action</i>
183 If an input path is not a regular file or a directory, "action" specifies how
184 it is to be processed. Valid values are "read" (the default) or "skip"
185 (silently skip the path).
186 </P>
187 <P>
188 <b>-d</b> <i>action</i>, <b>--directories=</b><i>action</i>
189 If an input path is a directory, "action" specifies how it is to be processed.
190 Valid values are "read" (the default), "recurse" (equivalent to the <b>-r</b>
191 option), or "skip" (silently skip the path). In the default case, directories
192 are read as if they were ordinary files. In some operating systems the effect
193 of reading a directory like this is an immediate end-of-file.
194 </P>
195 <P>
196 <b>-e</b> <i>pattern</i>, <b>--regex=</b><i>pattern</i>, <b>--regexp=</b><i>pattern</i>
197 Specify a pattern to be matched. This option can be used multiple times in
198 order to specify several patterns. It can also be used as a way of specifying a
199 single pattern that starts with a hyphen. When <b>-e</b> is used, no argument
200 pattern is taken from the command line; all arguments are treated as file
201 names. There is an overall maximum of 100 patterns. They are applied to each
202 line in the order in which they are defined until one matches (or fails to
203 match if <b>-v</b> is used). If <b>-f</b> is used with <b>-e</b>, the command line
204 patterns are matched first, followed by the patterns from the file, independent
205 of the order in which these options are specified. Note that multiple use of
206 <b>-e</b> is not the same as a single pattern with alternatives. For example,
207 X|Y finds the first character in a line that is X or Y, whereas if the two
208 patterns are given separately, <b>pcregrep</b> finds X if it is present, even if
209 it follows Y in the line. It finds Y only if there is no X in the line. This
210 really matters only if you are using <b>-o</b> to show the part(s) of the line
211 that matched.
212 </P>
213 <P>
214 <b>--exclude</b>=<i>pattern</i>
215 When <b>pcregrep</b> is searching the files in a directory as a consequence of
216 the <b>-r</b> (recursive search) option, any regular files whose names match the
217 pattern are excluded. Subdirectories are not excluded by this option; they are
218 searched recursively, subject to the <b>--exclude_dir</b> and
219 <b>--include_dir</b> options. The pattern is a PCRE regular expression, and is
220 matched against the final component of the file name (not the entire path). If
221 a file name matches both <b>--include</b> and <b>--exclude</b>, it is excluded.
222 There is no short form for this option.
223 </P>
224 <P>
225 <b>--exclude_dir</b>=<i>pattern</i>
226 When <b>pcregrep</b> is searching the contents of a directory as a consequence
227 of the <b>-r</b> (recursive search) option, any subdirectories whose names match
228 the pattern are excluded. (Note that the \fP--exclude\fP option does not affect
229 subdirectories.) The pattern is a PCRE regular expression, and is matched
230 against the final component of the name (not the entire path). If a
231 subdirectory name matches both <b>--include_dir</b> and <b>--exclude_dir</b>, it
232 is excluded. There is no short form for this option.
233 </P>
234 <P>
235 <b>-F</b>, <b>--fixed-strings</b>
236 Interpret each pattern as a list of fixed strings, separated by newlines,
237 instead of as a regular expression. The <b>-w</b> (match as a word) and <b>-x</b>
238 (match whole line) options can be used with <b>-F</b>. They apply to each of the
239 fixed strings. A line is selected if any of the fixed strings are found in it
240 (subject to <b>-w</b> or <b>-x</b>, if present).
241 </P>
242 <P>
243 <b>-f</b> <i>filename</i>, <b>--file=</b><i>filename</i>
244 Read a number of patterns from the file, one per line, and match them against
245 each line of input. A data line is output if any of the patterns match it. The
246 filename can be given as "-" to refer to the standard input. When <b>-f</b> is
247 used, patterns specified on the command line using <b>-e</b> may also be
248 present; they are tested before the file's patterns. However, no other pattern
249 is taken from the command line; all arguments are treated as file names. There
250 is an overall maximum of 100 patterns. Trailing white space is removed from
251 each line, and blank lines are ignored. An empty file contains no patterns and
252 therefore matches nothing. See also the comments about multiple patterns versus
253 a single pattern with alternatives in the description of <b>-e</b> above.
254 </P>
255 <P>
256 <b>--file-offsets</b>
257 Instead of showing lines or parts of lines that match, show each match as an
258 offset from the start of the file and a length, separated by a comma. In this
259 mode, no context is shown. That is, the <b>-A</b>, <b>-B</b>, and <b>-C</b>
260 options are ignored. If there is more than one match in a line, each of them is
261 shown separately. This option is mutually exclusive with <b>--line-offsets</b>
262 and <b>--only-matching</b>.
263 </P>
264 <P>
265 <b>-H</b>, <b>--with-filename</b>
266 Force the inclusion of the filename at the start of output lines when searching
267 a single file. By default, the filename is not shown in this case. For matching
268 lines, the filename is followed by a colon; for context lines, a hyphen
269 separator is used. If a line number is also being output, it follows the file
270 name.
271 </P>
272 <P>
273 <b>-h</b>, <b>--no-filename</b>
274 Suppress the output filenames when searching multiple files. By default,
275 filenames are shown when multiple files are searched. For matching lines, the
276 filename is followed by a colon; for context lines, a hyphen separator is used.
277 If a line number is also being output, it follows the file name.
278 </P>
279 <P>
280 <b>--help</b>
281 Output a help message, giving brief details of the command options and file
282 type support, and then exit.
283 </P>
284 <P>
285 <b>-i</b>, <b>--ignore-case</b>
286 Ignore upper/lower case distinctions during comparisons.
287 </P>
288 <P>
289 <b>--include</b>=<i>pattern</i>
290 When <b>pcregrep</b> is searching the files in a directory as a consequence of
291 the <b>-r</b> (recursive search) option, only those regular files whose names
292 match the pattern are included. Subdirectories are always included and searched
293 recursively, subject to the \fP--include_dir\fP and <b>--exclude_dir</b>
294 options. The pattern is a PCRE regular expression, and is matched against the
295 final component of the file name (not the entire path). If a file name matches
296 both <b>--include</b> and <b>--exclude</b>, it is excluded. There is no short
297 form for this option.
298 </P>
299 <P>
300 <b>--include_dir</b>=<i>pattern</i>
301 When <b>pcregrep</b> is searching the contents of a directory as a consequence
302 of the <b>-r</b> (recursive search) option, only those subdirectories whose
303 names match the pattern are included. (Note that the <b>--include</b> option
304 does not affect subdirectories.) The pattern is a PCRE regular expression, and
305 is matched against the final component of the name (not the entire path). If a
306 subdirectory name matches both <b>--include_dir</b> and <b>--exclude_dir</b>, it
307 is excluded. There is no short form for this option.
308 </P>
309 <P>
310 <b>-L</b>, <b>--files-without-match</b>
311 Instead of outputting lines from the files, just output the names of the files
312 that do not contain any lines that would have been output. Each file name is
313 output once, on a separate line.
314 </P>
315 <P>
316 <b>-l</b>, <b>--files-with-matches</b>
317 Instead of outputting lines from the files, just output the names of the files
318 containing lines that would have been output. Each file name is output
319 once, on a separate line. Searching stops as soon as a matching line is found
320 in a file.
321 </P>
322 <P>
323 <b>--label</b>=<i>name</i>
324 This option supplies a name to be used for the standard input when file names
325 are being output. If not supplied, "(standard input)" is used. There is no
326 short form for this option.
327 </P>
328 <P>
329 <b>--line-offsets</b>
330 Instead of showing lines or parts of lines that match, show each match as a
331 line number, the offset from the start of the line, and a length. The line
332 number is terminated by a colon (as usual; see the <b>-n</b> option), and the
333 offset and length are separated by a comma. In this mode, no context is shown.
334 That is, the <b>-A</b>, <b>-B</b>, and <b>-C</b> options are ignored. If there is
335 more than one match in a line, each of them is shown separately. This option is
336 mutually exclusive with <b>--file-offsets</b> and <b>--only-matching</b>.
337 </P>
338 <P>
339 <b>--locale</b>=<i>locale-name</i>
340 This option specifies a locale to be used for pattern matching. It overrides
341 the value in the <b>LC_ALL</b> or <b>LC_CTYPE</b> environment variables. If no
342 locale is specified, the PCRE library's default (usually the "C" locale) is
343 used. There is no short form for this option.
344 </P>
345 <P>
346 <b>-M</b>, <b>--multiline</b>
347 Allow patterns to match more than one line. When this option is given, patterns
348 may usefully contain literal newline characters and internal occurrences of ^
349 and $ characters. The output for any one match may consist of more than one
350 line. When this option is set, the PCRE library is called in "multiline" mode.
351 There is a limit to the number of lines that can be matched, imposed by the way
352 that <b>pcregrep</b> buffers the input file as it scans it. However,
353 <b>pcregrep</b> ensures that at least 8K characters or the rest of the document
354 (whichever is the shorter) are available for forward matching, and similarly
355 the previous 8K characters (or all the previous characters, if fewer than 8K)
356 are guaranteed to be available for lookbehind assertions.
357 </P>
358 <P>
359 <b>-N</b> <i>newline-type</i>, <b>--newline=</b><i>newline-type</i>
360 The PCRE library supports five different conventions for indicating
361 the ends of lines. They are the single-character sequences CR (carriage return)
362 and LF (linefeed), the two-character sequence CRLF, an "anycrlf" convention,
363 which recognizes any of the preceding three types, and an "any" convention, in
364 which any Unicode line ending sequence is assumed to end a line. The Unicode
365 sequences are the three just mentioned, plus VT (vertical tab, U+000B), FF
366 (formfeed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and
367 PS (paragraph separator, U+2029).
368 <br>
369 <br>
370 When the PCRE library is built, a default line-ending sequence is specified.
371 This is normally the standard sequence for the operating system. Unless
372 otherwise specified by this option, <b>pcregrep</b> uses the library's default.
373 The possible values for this option are CR, LF, CRLF, ANYCRLF, or ANY. This
374 makes it possible to use <b>pcregrep</b> on files that have come from other
375 environments without having to modify their line endings. If the data that is
376 being scanned does not agree with the convention set by this option,
377 <b>pcregrep</b> may behave in strange ways.
378 </P>
379 <P>
380 <b>-n</b>, <b>--line-number</b>
381 Precede each output line by its line number in the file, followed by a colon
382 for matching lines or a hyphen for context lines. If the filename is also being
383 output, it precedes the line number. This option is forced if
384 <b>--line-offsets</b> is used.
385 </P>
386 <P>
387 <b>-o</b>, <b>--only-matching</b>
388 Show only the part of the line that matched a pattern. In this mode, no
389 context is shown. That is, the <b>-A</b>, <b>-B</b>, and <b>-C</b> options are
390 ignored. If there is more than one match in a line, each of them is shown
391 separately. If <b>-o</b> is combined with <b>-v</b> (invert the sense of the
392 match to find non-matching lines), no output is generated, but the return code
393 is set appropriately. This option is mutually exclusive with
394 <b>--file-offsets</b> and <b>--line-offsets</b>.
395 </P>
396 <P>
397 <b>-q</b>, <b>--quiet</b>
398 Work quietly, that is, display nothing except error messages. The exit
399 status indicates whether or not any matches were found.
400 </P>
401 <P>
402 <b>-r</b>, <b>--recursive</b>
403 If any given path is a directory, recursively scan the files it contains,
404 taking note of any <b>--include</b> and <b>--exclude</b> settings. By default, a
405 directory is read as a normal file; in some operating systems this gives an
406 immediate end-of-file. This option is a shorthand for setting the <b>-d</b>
407 option to "recurse".
408 </P>
409 <P>
410 <b>-s</b>, <b>--no-messages</b>
411 Suppress error messages about non-existent or unreadable files. Such files are
412 quietly skipped. However, the return code is still 2, even if matches were
413 found in other files.
414 </P>
415 <P>
416 <b>-u</b>, <b>--utf-8</b>
417 Operate in UTF-8 mode. This option is available only if PCRE has been compiled
418 with UTF-8 support. Both patterns and subject lines must be valid strings of
419 UTF-8 characters.
420 </P>
421 <P>
422 <b>-V</b>, <b>--version</b>
423 Write the version numbers of <b>pcregrep</b> and the PCRE library that is being
424 used to the standard error stream.
425 </P>
426 <P>
427 <b>-v</b>, <b>--invert-match</b>
428 Invert the sense of the match, so that lines which do <i>not</i> match any of
429 the patterns are the ones that are found.
430 </P>
431 <P>
432 <b>-w</b>, <b>--word-regex</b>, <b>--word-regexp</b>
433 Force the patterns to match only whole words. This is equivalent to having \b
434 at the start and end of the pattern.
435 </P>
436 <P>
437 <b>-x</b>, <b>--line-regex</b>, <b>--line-regexp</b>
438 Force the patterns to be anchored (each must start matching at the beginning of
439 a line) and in addition, require them to match entire lines. This is
440 equivalent to having ^ and $ characters at the start and end of each
441 alternative branch in every pattern.
442 </P>
443 <br><a name="SEC5" href="#TOC1">ENVIRONMENT VARIABLES</a><br>
444 <P>
445 The environment variables <b>LC_ALL</b> and <b>LC_CTYPE</b> are examined, in that
446 order, for a locale. The first one that is set is used. This can be overridden
447 by the <b>--locale</b> option. If no locale is set, the PCRE library's default
448 (usually the "C" locale) is used.
449 </P>
450 <br><a name="SEC6" href="#TOC1">NEWLINES</a><br>
451 <P>
452 The <b>-N</b> (<b>--newline</b>) option allows <b>pcregrep</b> to scan files with
453 different newline conventions from the default. However, the setting of this
454 option does not affect the way in which <b>pcregrep</b> writes information to
455 the standard error and output streams. It uses the string "\n" in C
456 <b>printf()</b> calls to indicate newlines, relying on the C I/O library to
457 convert this to an appropriate sequence if the output is sent to a file.
458 </P>
459 <br><a name="SEC7" href="#TOC1">OPTIONS COMPATIBILITY</a><br>
460 <P>
461 The majority of short and long forms of <b>pcregrep</b>'s options are the same
462 as in the GNU <b>grep</b> program. Any long option of the form
463 <b>--xxx-regexp</b> (GNU terminology) is also available as <b>--xxx-regex</b>
464 (PCRE terminology). However, the <b>--locale</b>, <b>-M</b>, <b>--multiline</b>,
465 <b>-u</b>, and <b>--utf-8</b> options are specific to <b>pcregrep</b>.
466 </P>
467 <br><a name="SEC8" href="#TOC1">OPTIONS WITH DATA</a><br>
468 <P>
469 There are four different ways in which an option with data can be specified.
470 If a short form option is used, the data may follow immediately, or in the next
471 command line item. For example:
472 <pre>
473 -f/some/file
474 -f /some/file
475 </pre>
476 If a long form option is used, the data may appear in the same command line
477 item, separated by an equals character, or (with one exception) it may appear
478 in the next command line item. For example:
479 <pre>
480 --file=/some/file
481 --file /some/file
482 </pre>
483 Note, however, that if you want to supply a file name beginning with ~ as data
484 in a shell command, and have the shell expand ~ to a home directory, you must
485 separate the file name from the option, because the shell does not treat ~
486 specially unless it is at the start of an item.
487 </P>
488 <P>
489 The exception to the above is the <b>--colour</b> (or <b>--color</b>) option,
490 for which the data is optional. If this option does have data, it must be given
491 in the first form, using an equals character. Otherwise it will be assumed that
492 it has no data.
493 </P>
494 <br><a name="SEC9" href="#TOC1">MATCHING ERRORS</a><br>
495 <P>
496 It is possible to supply a regular expression that takes a very long time to
497 fail to match certain lines. Such patterns normally involve nested indefinite
498 repeats, for example: (a+)*\d when matched against a line of a's with no final
499 digit. The PCRE matching function has a resource limit that causes it to abort
500 in these circumstances. If this happens, <b>pcregrep</b> outputs an error
501 message and the line that caused the problem to the standard error stream. If
502 there are more than 20 such errors, <b>pcregrep</b> gives up.
503 </P>
504 <br><a name="SEC10" href="#TOC1">DIAGNOSTICS</a><br>
505 <P>
506 Exit status is 0 if any matches were found, 1 if no matches were found, and 2
507 for syntax errors and non-existent or inacessible files (even if matches were
508 found in other files) or too many matching errors. Using the <b>-s</b> option to
509 suppress error messages about inaccessble files does not affect the return
510 code.
511 </P>
512 <br><a name="SEC11" href="#TOC1">SEE ALSO</a><br>
513 <P>
514 <b>pcrepattern</b>(3), <b>pcretest</b>(1).
515 </P>
516 <br><a name="SEC12" href="#TOC1">AUTHOR</a><br>
517 <P>
518 Philip Hazel
519 <br>
520 University Computing Service
521 <br>
522 Cambridge CB2 3QH, England.
523 <br>
524 </P>
525 <br><a name="SEC13" href="#TOC1">REVISION</a><br>
526 <P>
527 Last updated: 01 March 2009
528 <br>
529 Copyright &copy; 1997-2009 University of Cambridge.
530 <br>
531 <p>
532 Return to the <a href="index.html">PCRE index page</a>.
533 </p>

Properties

Name Value
svn:eol-style native
svn:keywords "Author Date Id Revision Url"

  ViewVC Help
Powered by ViewVC 1.1.5