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

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