/[pcre]/code/trunk/doc/pcregrep.1
ViewVC logotype

Contents of /code/trunk/doc/pcregrep.1

Parent Directory Parent Directory | Revision Log Revision Log


Revision 286 - (show annotations) (download)
Mon Dec 17 14:46:11 2007 UTC (7 years ago) by ph10
File size: 21155 byte(s)
Add .gz and .bz2 optional support to pcregrep.

1 .TH PCREGREP 1
2 .SH NAME
3 pcregrep - a grep with Perl-compatible regular expressions.
4 .SH SYNOPSIS
5 .B pcregrep [options] [long options] [pattern] [path1 path2 ...]
6 .
7 .SH DESCRIPTION
8 .rs
9 .sp
10 \fBpcregrep\fP searches files for character patterns, in the same way as other
11 grep commands do, but it uses the PCRE regular expression library to support
12 patterns that are compatible with the regular expressions of Perl 5. See
13 .\" HREF
14 \fBpcrepattern\fP(3)
15 .\"
16 for a full description of syntax and semantics of the regular expressions
17 that PCRE supports.
18 .P
19 Patterns, whether supplied on the command line or in a separate file, are given
20 without delimiters. For example:
21 .sp
22 pcregrep Thursday /etc/motd
23 .sp
24 If you attempt to use delimiters (for example, by surrounding a pattern with
25 slashes, as is common in Perl scripts), they are interpreted as part of the
26 pattern. Quotes can of course be used to delimit patterns on the command line
27 because they are interpreted by the shell, and indeed they are required if a
28 pattern contains white space or shell metacharacters.
29 .P
30 The first argument that follows any option settings is treated as the single
31 pattern to be matched when neither \fB-e\fP nor \fB-f\fP is present.
32 Conversely, when one or both of these options are used to specify patterns, all
33 arguments are treated as path names. At least one of \fB-e\fP, \fB-f\fP, or an
34 argument pattern must be provided.
35 .P
36 If no files are specified, \fBpcregrep\fP reads the standard input. The
37 standard input can also be referenced by a name consisting of a single hyphen.
38 For example:
39 .sp
40 pcregrep some-pattern /file1 - /file3
41 .sp
42 By default, each line that matches a pattern is copied to the standard
43 output, and if there is more than one file, the file name is output at the
44 start of each line, followed by a colon. However, there are options that can
45 change how \fBpcregrep\fP behaves. In particular, the \fB-M\fP option makes it
46 possible to search for patterns that span line boundaries. What defines a line
47 boundary is controlled by the \fB-N\fP (\fB--newline\fP) option.
48 .P
49 Patterns are limited to 8K or BUFSIZ characters, whichever is the greater.
50 BUFSIZ is defined in \fB<stdio.h>\fP. When there is more than one pattern
51 (specified by the use of \fB-e\fP and/or \fB-f\fP), each pattern is applied to
52 each line in the order in which they are defined, except that all the \fB-e\fP
53 patterns are tried before the \fB-f\fP patterns. As soon as one pattern matches
54 (or fails to match when \fB-v\fP is used), no further patterns are considered.
55 .P
56 When \fB--only-matching\fP, \fB--file-offsets\fP, or \fB--line-offsets\fP
57 is used, the output is the part of the line that matched (either shown
58 literally, or as an offset). In this case, scanning resumes immediately
59 following the match, so that further matches on the same line can be found.
60 If there are multiple patterns, they are all tried on the remainder of the
61 line. However, patterns that follow the one that matched are not tried on the
62 earlier part of the line.
63 .P
64 If the \fBLC_ALL\fP or \fBLC_CTYPE\fP environment variable is set,
65 \fBpcregrep\fP uses the value to set a locale when calling the PCRE library.
66 The \fB--locale\fP option can be used to override this.
67 .
68 .SH "SUPPORT FOR COMPRESSED FILES"
69 .rs
70 .sp
71 It is possible to compile \fBpcregrep\fP so that it uses \fBlibz\fP or
72 \fBlibbz2\fP to read files whose names end in \fB.gz\fP or \fB.bz2\fP,
73 respectively. You can find out whether your binary has support for one or both
74 of these file types by running it with the \fB--help\fP option. If the
75 appropriate support is not present, files are treated as plain text. The
76 standard input is always so treated.
77 .
78 .SH OPTIONS
79 .rs
80 .TP 10
81 \fB--\fP
82 This terminate the list of options. It is useful if the next item on the
83 command line starts with a hyphen but is not an option. This allows for the
84 processing of patterns and filenames that start with hyphens.
85 .TP
86 \fB-A\fP \fInumber\fP, \fB--after-context=\fP\fInumber\fP
87 Output \fInumber\fP lines of context after each matching line. If filenames
88 and/or line numbers are being output, a hyphen separator is used instead of a
89 colon for the context lines. A line containing "--" is output between each
90 group of lines, unless they are in fact contiguous in the input file. The value
91 of \fInumber\fP is expected to be relatively small. However, \fBpcregrep\fP
92 guarantees to have up to 8K of following text available for context output.
93 .TP
94 \fB-B\fP \fInumber\fP, \fB--before-context=\fP\fInumber\fP
95 Output \fInumber\fP lines of context before each matching line. If filenames
96 and/or line numbers are being output, a hyphen separator is used instead of a
97 colon for the context lines. A line containing "--" is output between each
98 group of lines, unless they are in fact contiguous in the input file. The value
99 of \fInumber\fP is expected to be relatively small. However, \fBpcregrep\fP
100 guarantees to have up to 8K of preceding text available for context output.
101 .TP
102 \fB-C\fP \fInumber\fP, \fB--context=\fP\fInumber\fP
103 Output \fInumber\fP lines of context both before and after each matching line.
104 This is equivalent to setting both \fB-A\fP and \fB-B\fP to the same value.
105 .TP
106 \fB-c\fP, \fB--count\fP
107 Do not output individual lines; instead just output a count of the number of
108 lines that would otherwise have been output. If several files are given, a
109 count is output for each of them. In this mode, the \fB-A\fP, \fB-B\fP, and
110 \fB-C\fP options are ignored.
111 .TP
112 \fB--colour\fP, \fB--color\fP
113 If this option is given without any data, it is equivalent to "--colour=auto".
114 If data is required, it must be given in the same shell item, separated by an
115 equals sign.
116 .TP
117 \fB--colour=\fP\fIvalue\fP, \fB--color=\fP\fIvalue\fP
118 This option specifies under what circumstances the part of a line that matched
119 a pattern should be coloured in the output. The value may be "never" (the
120 default), "always", or "auto". In the latter case, colouring happens only if
121 the standard output is connected to a terminal. The colour can be specified by
122 setting the environment variable PCREGREP_COLOUR or PCREGREP_COLOR. The value
123 of this variable should be a string of two numbers, separated by a semicolon.
124 They are copied directly into the control string for setting colour on a
125 terminal, so it is your responsibility to ensure that they make sense. If
126 neither of the environment variables is set, the default is "1;31", which gives
127 red.
128 .TP
129 \fB-D\fP \fIaction\fP, \fB--devices=\fP\fIaction\fP
130 If an input path is not a regular file or a directory, "action" specifies how
131 it is to be processed. Valid values are "read" (the default) or "skip"
132 (silently skip the path).
133 .TP
134 \fB-d\fP \fIaction\fP, \fB--directories=\fP\fIaction\fP
135 If an input path is a directory, "action" specifies how it is to be processed.
136 Valid values are "read" (the default), "recurse" (equivalent to the \fB-r\fP
137 option), or "skip" (silently skip the path). In the default case, directories
138 are read as if they were ordinary files. In some operating systems the effect
139 of reading a directory like this is an immediate end-of-file.
140 .TP
141 \fB-e\fP \fIpattern\fP, \fB--regex=\fP\fIpattern\fP, \fB--regexp=\fP\fIpattern\fP
142 Specify a pattern to be matched. This option can be used multiple times in
143 order to specify several patterns. It can also be used as a way of specifying a
144 single pattern that starts with a hyphen. When \fB-e\fP is used, no argument
145 pattern is taken from the command line; all arguments are treated as file
146 names. There is an overall maximum of 100 patterns. They are applied to each
147 line in the order in which they are defined until one matches (or fails to
148 match if \fB-v\fP is used). If \fB-f\fP is used with \fB-e\fP, the command line
149 patterns are matched first, followed by the patterns from the file, independent
150 of the order in which these options are specified. Note that multiple use of
151 \fB-e\fP is not the same as a single pattern with alternatives. For example,
152 X|Y finds the first character in a line that is X or Y, whereas if the two
153 patterns are given separately, \fBpcregrep\fP finds X if it is present, even if
154 it follows Y in the line. It finds Y only if there is no X in the line. This
155 really matters only if you are using \fB-o\fP to show the part(s) of the line
156 that matched.
157 .TP
158 \fB--exclude\fP=\fIpattern\fP
159 When \fBpcregrep\fP is searching the files in a directory as a consequence of
160 the \fB-r\fP (recursive search) option, any files whose names match the pattern
161 are excluded. The pattern is a PCRE regular expression. If a file name matches
162 both \fB--include\fP and \fB--exclude\fP, it is excluded. There is no short
163 form for this option.
164 .TP
165 \fB-F\fP, \fB--fixed-strings\fP
166 Interpret each pattern as a list of fixed strings, separated by newlines,
167 instead of as a regular expression. The \fB-w\fP (match as a word) and \fB-x\fP
168 (match whole line) options can be used with \fB-F\fP. They apply to each of the
169 fixed strings. A line is selected if any of the fixed strings are found in it
170 (subject to \fB-w\fP or \fB-x\fP, if present).
171 .TP
172 \fB-f\fP \fIfilename\fP, \fB--file=\fP\fIfilename\fP
173 Read a number of patterns from the file, one per line, and match them against
174 each line of input. A data line is output if any of the patterns match it. The
175 filename can be given as "-" to refer to the standard input. When \fB-f\fP is
176 used, patterns specified on the command line using \fB-e\fP may also be
177 present; they are tested before the file's patterns. However, no other pattern
178 is taken from the command line; all arguments are treated as file names. There
179 is an overall maximum of 100 patterns. Trailing white space is removed from
180 each line, and blank lines are ignored. An empty file contains no patterns and
181 therefore matches nothing. See also the comments about multiple patterns versus
182 a single pattern with alternatives in the description of \fB-e\fP above.
183 .TP
184 \fB--file-offsets\fP
185 Instead of showing lines or parts of lines that match, show each match as an
186 offset from the start of the file and a length, separated by a comma. In this
187 mode, no context is shown. That is, the \fB-A\fP, \fB-B\fP, and \fB-C\fP
188 options are ignored. If there is more than one match in a line, each of them is
189 shown separately. This option is mutually exclusive with \fB--line-offsets\fP
190 and \fB--only-matching\fP.
191 .TP
192 \fB-H\fP, \fB--with-filename\fP
193 Force the inclusion of the filename at the start of output lines when searching
194 a single file. By default, the filename is not shown in this case. For matching
195 lines, the filename is followed by a colon and a space; for context lines, a
196 hyphen separator is used. If a line number is also being output, it follows the
197 file name without a space.
198 .TP
199 \fB-h\fP, \fB--no-filename\fP
200 Suppress the output filenames when searching multiple files. By default,
201 filenames are shown when multiple files are searched. For matching lines, the
202 filename is followed by a colon and a space; for context lines, a hyphen
203 separator is used. If a line number is also being output, it follows the file
204 name without a space.
205 .TP
206 \fB--help\fP
207 Output a help message, giving brief details of the command options and file
208 type support, and then exit.
209 .TP
210 \fB-i\fP, \fB--ignore-case\fP
211 Ignore upper/lower case distinctions during comparisons.
212 .TP
213 \fB--include\fP=\fIpattern\fP
214 When \fBpcregrep\fP is searching the files in a directory as a consequence of
215 the \fB-r\fP (recursive search) option, only those files whose names match the
216 pattern are included. The pattern is a PCRE regular expression. If a file name
217 matches both \fB--include\fP and \fB--exclude\fP, it is excluded. There is no
218 short form for this option.
219 .TP
220 \fB-L\fP, \fB--files-without-match\fP
221 Instead of outputting lines from the files, just output the names of the files
222 that do not contain any lines that would have been output. Each file name is
223 output once, on a separate line.
224 .TP
225 \fB-l\fP, \fB--files-with-matches\fP
226 Instead of outputting lines from the files, just output the names of the files
227 containing lines that would have been output. Each file name is output
228 once, on a separate line. Searching stops as soon as a matching line is found
229 in a file.
230 .TP
231 \fB--label\fP=\fIname\fP
232 This option supplies a name to be used for the standard input when file names
233 are being output. If not supplied, "(standard input)" is used. There is no
234 short form for this option.
235 .TP
236 \fB--line-offsets\fP
237 Instead of showing lines or parts of lines that match, show each match as a
238 line number, the offset from the start of the line, and a length. The line
239 number is terminated by a colon (as usual; see the \fB-n\fP option), and the
240 offset and length are separated by a comma. In this mode, no context is shown.
241 That is, the \fB-A\fP, \fB-B\fP, and \fB-C\fP options are ignored. If there is
242 more than one match in a line, each of them is shown separately. This option is
243 mutually exclusive with \fB--file-offsets\fP and \fB--only-matching\fP.
244 .TP
245 \fB--locale\fP=\fIlocale-name\fP
246 This option specifies a locale to be used for pattern matching. It overrides
247 the value in the \fBLC_ALL\fP or \fBLC_CTYPE\fP environment variables. If no
248 locale is specified, the PCRE library's default (usually the "C" locale) is
249 used. There is no short form for this option.
250 .TP
251 \fB-M\fP, \fB--multiline\fP
252 Allow patterns to match more than one line. When this option is given, patterns
253 may usefully contain literal newline characters and internal occurrences of ^
254 and $ characters. The output for any one match may consist of more than one
255 line. When this option is set, the PCRE library is called in "multiline" mode.
256 There is a limit to the number of lines that can be matched, imposed by the way
257 that \fBpcregrep\fP buffers the input file as it scans it. However,
258 \fBpcregrep\fP ensures that at least 8K characters or the rest of the document
259 (whichever is the shorter) are available for forward matching, and similarly
260 the previous 8K characters (or all the previous characters, if fewer than 8K)
261 are guaranteed to be available for lookbehind assertions.
262 .TP
263 \fB-N\fP \fInewline-type\fP, \fB--newline=\fP\fInewline-type\fP
264 The PCRE library supports five different conventions for indicating
265 the ends of lines. They are the single-character sequences CR (carriage return)
266 and LF (linefeed), the two-character sequence CRLF, an "anycrlf" convention,
267 which recognizes any of the preceding three types, and an "any" convention, in
268 which any Unicode line ending sequence is assumed to end a line. The Unicode
269 sequences are the three just mentioned, plus VT (vertical tab, U+000B), FF
270 (formfeed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and
271 PS (paragraph separator, U+2029).
272 .sp
273 When the PCRE library is built, a default line-ending sequence is specified.
274 This is normally the standard sequence for the operating system. Unless
275 otherwise specified by this option, \fBpcregrep\fP uses the library's default.
276 The possible values for this option are CR, LF, CRLF, ANYCRLF, or ANY. This
277 makes it possible to use \fBpcregrep\fP on files that have come from other
278 environments without having to modify their line endings. If the data that is
279 being scanned does not agree with the convention set by this option,
280 \fBpcregrep\fP may behave in strange ways.
281 .TP
282 \fB-n\fP, \fB--line-number\fP
283 Precede each output line by its line number in the file, followed by a colon
284 and a space for matching lines or a hyphen and a space for context lines. If
285 the filename is also being output, it precedes the line number. This option is
286 forced if \fB--line-offsets\fP is used.
287 .TP
288 \fB-o\fP, \fB--only-matching\fP
289 Show only the part of the line that matched a pattern. In this mode, no
290 context is shown. That is, the \fB-A\fP, \fB-B\fP, and \fB-C\fP options are
291 ignored. If there is more than one match in a line, each of them is shown
292 separately. If \fB-o\fP is combined with \fB-v\fP (invert the sense of the
293 match to find non-matching lines), no output is generated, but the return code
294 is set appropriately. This option is mutually exclusive with
295 \fB--file-offsets\fP and \fB--line-offsets\fP.
296 .TP
297 \fB-q\fP, \fB--quiet\fP
298 Work quietly, that is, display nothing except error messages. The exit
299 status indicates whether or not any matches were found.
300 .TP
301 \fB-r\fP, \fB--recursive\fP
302 If any given path is a directory, recursively scan the files it contains,
303 taking note of any \fB--include\fP and \fB--exclude\fP settings. By default, a
304 directory is read as a normal file; in some operating systems this gives an
305 immediate end-of-file. This option is a shorthand for setting the \fB-d\fP
306 option to "recurse".
307 .TP
308 \fB-s\fP, \fB--no-messages\fP
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 .TP
313 \fB-u\fP, \fB--utf-8\fP
314 Operate in UTF-8 mode. This option is available only if PCRE has been compiled
315 with UTF-8 support. Both patterns and subject lines must be valid strings of
316 UTF-8 characters.
317 .TP
318 \fB-V\fP, \fB--version\fP
319 Write the version numbers of \fBpcregrep\fP and the PCRE library that is being
320 used to the standard error stream.
321 .TP
322 \fB-v\fP, \fB--invert-match\fP
323 Invert the sense of the match, so that lines which do \fInot\fP match any of
324 the patterns are the ones that are found.
325 .TP
326 \fB-w\fP, \fB--word-regex\fP, \fB--word-regexp\fP
327 Force the patterns to match only whole words. This is equivalent to having \eb
328 at the start and end of the pattern.
329 .TP
330 \fB-x\fP, \fB--line-regex\fP, \fB--line-regexp\fP
331 Force the patterns to be anchored (each must start matching at the beginning of
332 a line) and in addition, require them to match entire lines. This is
333 equivalent to having ^ and $ characters at the start and end of each
334 alternative branch in every pattern.
335 .
336 .
337 .SH "ENVIRONMENT VARIABLES"
338 .rs
339 .sp
340 The environment variables \fBLC_ALL\fP and \fBLC_CTYPE\fP are examined, in that
341 order, for a locale. The first one that is set is used. This can be overridden
342 by the \fB--locale\fP option. If no locale is set, the PCRE library's default
343 (usually the "C" locale) is used.
344 .
345 .
346 .SH "NEWLINES"
347 .rs
348 .sp
349 The \fB-N\fP (\fB--newline\fP) option allows \fBpcregrep\fP to scan files with
350 different newline conventions from the default. However, the setting of this
351 option does not affect the way in which \fBpcregrep\fP writes information to
352 the standard error and output streams. It uses the string "\en" in C
353 \fBprintf()\fP calls to indicate newlines, relying on the C I/O library to
354 convert this to an appropriate sequence if the output is sent to a file.
355 .
356 .
357 .SH "OPTIONS COMPATIBILITY"
358 .rs
359 .sp
360 The majority of short and long forms of \fBpcregrep\fP's options are the same
361 as in the GNU \fBgrep\fP program. Any long option of the form
362 \fB--xxx-regexp\fP (GNU terminology) is also available as \fB--xxx-regex\fP
363 (PCRE terminology). However, the \fB--locale\fP, \fB-M\fP, \fB--multiline\fP,
364 \fB-u\fP, and \fB--utf-8\fP options are specific to \fBpcregrep\fP.
365 .
366 .
367 .SH "OPTIONS WITH DATA"
368 .rs
369 .sp
370 There are four different ways in which an option with data can be specified.
371 If a short form option is used, the data may follow immediately, or in the next
372 command line item. For example:
373 .sp
374 -f/some/file
375 -f /some/file
376 .sp
377 If a long form option is used, the data may appear in the same command line
378 item, separated by an equals character, or (with one exception) it may appear
379 in the next command line item. For example:
380 .sp
381 --file=/some/file
382 --file /some/file
383 .sp
384 Note, however, that if you want to supply a file name beginning with ~ as data
385 in a shell command, and have the shell expand ~ to a home directory, you must
386 separate the file name from the option, because the shell does not treat ~
387 specially unless it is at the start of an item.
388 .P
389 The exception to the above is the \fB--colour\fP (or \fB--color\fP) option,
390 for which the data is optional. If this option does have data, it must be given
391 in the first form, using an equals character. Otherwise it will be assumed that
392 it has no data.
393 .
394 .
395 .SH "MATCHING ERRORS"
396 .rs
397 .sp
398 It is possible to supply a regular expression that takes a very long time to
399 fail to match certain lines. Such patterns normally involve nested indefinite
400 repeats, for example: (a+)*\ed when matched against a line of a's with no final
401 digit. The PCRE matching function has a resource limit that causes it to abort
402 in these circumstances. If this happens, \fBpcregrep\fP outputs an error
403 message and the line that caused the problem to the standard error stream. If
404 there are more than 20 such errors, \fBpcregrep\fP gives up.
405 .
406 .
407 .SH DIAGNOSTICS
408 .rs
409 .sp
410 Exit status is 0 if any matches were found, 1 if no matches were found, and 2
411 for syntax errors and non-existent or inacessible files (even if matches were
412 found in other files) or too many matching errors. Using the \fB-s\fP option to
413 suppress error messages about inaccessble files does not affect the return
414 code.
415 .
416 .
417 .SH "SEE ALSO"
418 .rs
419 .sp
420 \fBpcrepattern\fP(3), \fBpcretest\fP(1).
421 .
422 .
423 .SH AUTHOR
424 .rs
425 .sp
426 .nf
427 Philip Hazel
428 University Computing Service
429 Cambridge CB2 3QH, England.
430 .fi
431 .
432 .
433 .SH REVISION
434 .rs
435 .sp
436 .nf
437 Last updated: 17 December 2007
438 Copyright (c) 1997-2007 University of Cambridge.
439 .fi

Properties

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

webmaster@exim.org
ViewVC Help
Powered by ViewVC 1.1.12