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Allow multiple -o in pcregrep, and add --om-separator.
1 .TH PCREGREP 1 "13 September 2012" "PCRE 8.32"
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 quotes 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 The amount of memory used for buffering files that are being scanned is
50 controlled by a parameter that can be set by the \fB--buffer-size\fP option.
51 The default value for this parameter is specified when \fBpcregrep\fP is built,
52 with the default default being 20K. A block of memory three times this size is
53 used (to allow for buffering "before" and "after" lines). An error occurs if a
54 line overflows the buffer.
55 .P
56 Patterns can be no longer than 8K or BUFSIZ bytes, whichever is the greater.
57 BUFSIZ is defined in \fB<stdio.h>\fP. When there is more than one pattern
58 (specified by the use of \fB-e\fP and/or \fB-f\fP), each pattern is applied to
59 each line in the order in which they are defined, except that all the \fB-e\fP
60 patterns are tried before the \fB-f\fP patterns.
61 .P
62 By default, as soon as one pattern matches a line, no further patterns are
63 considered. However, if \fB--colour\fP (or \fB--color\fP) is used to colour the
64 matching substrings, or if \fB--only-matching\fP, \fB--file-offsets\fP, or
65 \fB--line-offsets\fP is used to output only the part of the line that matched
66 (either shown literally, or as an offset), scanning resumes immediately
67 following the match, so that further matches on the same line can be found. If
68 there are multiple patterns, they are all tried on the remainder of the line,
69 but patterns that follow the one that matched are not tried on the earlier part
70 of the line.
71 .P
72 This behaviour means that the order in which multiple patterns are specified
73 can affect the output when one of the above options is used. This is no longer
74 the same behaviour as GNU grep, which now manages to display earlier matches
75 for later patterns (as long as there is no overlap).
76 .P
77 Patterns that can match an empty string are accepted, but empty string
78 matches are never recognized. An example is the pattern "(super)?(man)?", in
79 which all components are optional. This pattern finds all occurrences of both
80 "super" and "man"; the output differs from matching with "super|man" when only
81 the matching substrings are being shown.
82 .P
83 If the \fBLC_ALL\fP or \fBLC_CTYPE\fP environment variable is set,
84 \fBpcregrep\fP uses the value to set a locale when calling the PCRE library.
85 The \fB--locale\fP option can be used to override this.
86 .
87 .
88 .SH "SUPPORT FOR COMPRESSED FILES"
89 .rs
90 .sp
91 It is possible to compile \fBpcregrep\fP so that it uses \fBlibz\fP or
92 \fBlibbz2\fP to read files whose names end in \fB.gz\fP or \fB.bz2\fP,
93 respectively. You can find out whether your binary has support for one or both
94 of these file types by running it with the \fB--help\fP option. If the
95 appropriate support is not present, files are treated as plain text. The
96 standard input is always so treated.
97 .
98 .
99 .SH "BINARY FILES"
100 .rs
101 .sp
102 By default, a file that contains a binary zero byte within the first 1024 bytes
103 is identified as a binary file, and is processed specially. (GNU grep also
104 identifies binary files in this manner.) See the \fB--binary-files\fP option
105 for a means of changing the way binary files are handled.
106 .
107 .
108 .SH OPTIONS
109 .rs
110 .sp
111 The order in which some of the options appear can affect the output. For
112 example, both the \fB-h\fP and \fB-l\fP options affect the printing of file
113 names. Whichever comes later in the command line will be the one that takes
114 effect. Similarly, except where noted below, if an option is given twice, the
115 later setting is used. Numerical values for options may be followed by K or M,
116 to signify multiplication by 1024 or 1024*1024 respectively.
117 .TP 10
118 \fB--\fP
119 This terminates the list of options. It is useful if the next item on the
120 command line starts with a hyphen but is not an option. This allows for the
121 processing of patterns and filenames that start with hyphens.
122 .TP
123 \fB-A\fP \fInumber\fP, \fB--after-context=\fP\fInumber\fP
124 Output \fInumber\fP lines of context after each matching line. If filenames
125 and/or line numbers are being output, a hyphen separator is used instead of a
126 colon for the context lines. A line containing "--" is output between each
127 group of lines, unless they are in fact contiguous in the input file. The value
128 of \fInumber\fP is expected to be relatively small. However, \fBpcregrep\fP
129 guarantees to have up to 8K of following text available for context output.
130 .TP
131 \fB-a\fP, \fB--text\fP
132 Treat binary files as text. This is equivalent to
133 \fB--binary-files\fP=\fItext\fP.
134 .TP
135 \fB-B\fP \fInumber\fP, \fB--before-context=\fP\fInumber\fP
136 Output \fInumber\fP lines of context before each matching line. If filenames
137 and/or line numbers are being output, a hyphen separator is used instead of a
138 colon for the context lines. A line containing "--" is output between each
139 group of lines, unless they are in fact contiguous in the input file. The value
140 of \fInumber\fP is expected to be relatively small. However, \fBpcregrep\fP
141 guarantees to have up to 8K of preceding text available for context output.
142 .TP
143 \fB--binary-files=\fP\fIword\fP
144 Specify how binary files are to be processed. If the word is "binary" (the
145 default), pattern matching is performed on binary files, but the only output is
146 "Binary file <name> matches" when a match succeeds. If the word is "text",
147 which is equivalent to the \fB-a\fP or \fB--text\fP option, binary files are
148 processed in the same way as any other file. In this case, when a match
149 succeeds, the output may be binary garbage, which can have nasty effects if
150 sent to a terminal. If the word is "without-match", which is equivalent to the
151 \fB-I\fP option, binary files are not processed at all; they are assumed not to
152 be of interest.
153 .TP
154 \fB--buffer-size=\fP\fInumber\fP
155 Set the parameter that controls how much memory is used for buffering files
156 that are being scanned.
157 .TP
158 \fB-C\fP \fInumber\fP, \fB--context=\fP\fInumber\fP
159 Output \fInumber\fP lines of context both before and after each matching line.
160 This is equivalent to setting both \fB-A\fP and \fB-B\fP to the same value.
161 .TP
162 \fB-c\fP, \fB--count\fP
163 Do not output individual lines from the files that are being scanned; instead
164 output the number of lines that would otherwise have been shown. If no lines
165 are selected, the number zero is output. If several files are are being
166 scanned, a count is output for each of them. However, if the
167 \fB--files-with-matches\fP option is also used, only those files whose counts
168 are greater than zero are listed. When \fB-c\fP is used, the \fB-A\fP,
169 \fB-B\fP, and \fB-C\fP options are ignored.
170 .TP
171 \fB--colour\fP, \fB--color\fP
172 If this option is given without any data, it is equivalent to "--colour=auto".
173 If data is required, it must be given in the same shell item, separated by an
174 equals sign.
175 .TP
176 \fB--colour=\fP\fIvalue\fP, \fB--color=\fP\fIvalue\fP
177 This option specifies under what circumstances the parts of a line that matched
178 a pattern should be coloured in the output. By default, the output is not
179 coloured. The value (which is optional, see above) may be "never", "always", or
180 "auto". In the latter case, colouring happens only if the standard output is
181 connected to a terminal. More resources are used when colouring is enabled,
182 because \fBpcregrep\fP has to search for all possible matches in a line, not
183 just one, in order to colour them all.
184 .sp
185 The colour that is used can be specified by setting the environment variable
186 PCREGREP_COLOUR or PCREGREP_COLOR. The value of this variable should be a
187 string of two numbers, separated by a semicolon. They are copied directly into
188 the control string for setting colour on a terminal, so it is your
189 responsibility to ensure that they make sense. If neither of the environment
190 variables is set, the default is "1;31", which gives red.
191 .TP
192 \fB-D\fP \fIaction\fP, \fB--devices=\fP\fIaction\fP
193 If an input path is not a regular file or a directory, "action" specifies how
194 it is to be processed. Valid values are "read" (the default) or "skip"
195 (silently skip the path).
196 .TP
197 \fB-d\fP \fIaction\fP, \fB--directories=\fP\fIaction\fP
198 If an input path is a directory, "action" specifies how it is to be processed.
199 Valid values are "read" (the default in non-Windows environments, for
200 compatibility with GNU grep), "recurse" (equivalent to the \fB-r\fP option), or
201 "skip" (silently skip the path, the default in Windows environments). In the
202 "read" case, directories are read as if they were ordinary files. In some
203 operating systems the effect of reading a directory like this is an immediate
204 end-of-file; in others it may provoke an error.
205 .TP
206 \fB-e\fP \fIpattern\fP, \fB--regex=\fP\fIpattern\fP, \fB--regexp=\fP\fIpattern\fP
207 Specify a pattern to be matched. This option can be used multiple times in
208 order to specify several patterns. It can also be used as a way of specifying a
209 single pattern that starts with a hyphen. When \fB-e\fP is used, no argument
210 pattern is taken from the command line; all arguments are treated as file
211 names. There is no limit to the number of patterns. They are applied to each
212 line in the order in which they are defined until one matches.
213 .sp
214 If \fB-f\fP is used with \fB-e\fP, the command line patterns are matched first,
215 followed by the patterns from the file(s), independent of the order in which
216 these options are specified. Note that multiple use of \fB-e\fP is not the same
217 as a single pattern with alternatives. For example, X|Y finds the first
218 character in a line that is X or Y, whereas if the two patterns are given
219 separately, with X first, \fBpcregrep\fP finds X if it is present, even if it
220 follows Y in the line. It finds Y only if there is no X in the line. This
221 matters only if you are using \fB-o\fP or \fB--colo(u)r\fP to show the part(s)
222 of the line that matched.
223 .TP
224 \fB--exclude\fP=\fIpattern\fP
225 Files (but not directories) whose names match the pattern are skipped without
226 being processed. This applies to all files, whether listed on the command line,
227 obtained from \fB--file-list\fP, or by scanning a directory. The pattern is a
228 PCRE regular expression, and is matched against the final component of the file
229 name, not the entire path. The \fB-F\fP, \fB-w\fP, and \fB-x\fP options do not
230 apply to this pattern. The option may be given any number of times in order to
231 specify multiple patterns. If a file name matches both an \fB--include\fP
232 and an \fB--exclude\fP pattern, it is excluded. There is no short form for this
233 option.
234 .TP
235 \fB--exclude-from=\fP\fIfilename\fP
236 Treat each non-empty line of the file as the data for an \fB--exclude\fP
237 option. What constitutes a newline when reading the file is the operating
238 system's default. The \fB--newline\fP option has no effect on this option. This
239 option may be given more than once in order to specify a number of files to
240 read.
241 .TP
242 \fB--exclude-dir\fP=\fIpattern\fP
243 Directories whose names match the pattern are skipped without being processed,
244 whatever the setting of the \fB--recursive\fP option. This applies to all
245 directories, whether listed on the command line, obtained from
246 \fB--file-list\fP, or by scanning a parent directory. The pattern is a PCRE
247 regular expression, and is matched against the final component of the directory
248 name, not the entire path. The \fB-F\fP, \fB-w\fP, and \fB-x\fP options do not
249 apply to this pattern. The option may be given any number of times in order to
250 specify more than one pattern. If a directory matches both \fB--include-dir\fP
251 and \fB--exclude-dir\fP, it is excluded. There is no short form for this
252 option.
253 .TP
254 \fB-F\fP, \fB--fixed-strings\fP
255 Interpret each data-matching pattern as a list of fixed strings, separated by
256 newlines, instead of as a regular expression. What constitutes a newline for
257 this purpose is controlled by the \fB--newline\fP option. The \fB-w\fP (match
258 as a word) and \fB-x\fP (match whole line) options can be used with \fB-F\fP.
259 They apply to each of the fixed strings. A line is selected if any of the fixed
260 strings are found in it (subject to \fB-w\fP or \fB-x\fP, if present). This
261 option applies only to the patterns that are matched against the contents of
262 files; it does not apply to patterns specified by any of the \fB--include\fP or
263 \fB--exclude\fP options.
264 .TP
265 \fB-f\fP \fIfilename\fP, \fB--file=\fP\fIfilename\fP
266 Read patterns from the file, one per line, and match them against
267 each line of input. What constitutes a newline when reading the file is the
268 operating system's default. The \fB--newline\fP option has no effect on this
269 option. Trailing white space is removed from each line, and blank lines are
270 ignored. An empty file contains no patterns and therefore matches nothing. See
271 also the comments about multiple patterns versus a single pattern with
272 alternatives in the description of \fB-e\fP above.
273 .sp
274 If this option is given more than once, all the specified files are
275 read. A data line is output if any of the patterns match it. A filename can
276 be given as "-" to refer to the standard input. When \fB-f\fP is used, patterns
277 specified on the command line using \fB-e\fP may also be present; they are
278 tested before the file's patterns. However, no other pattern is taken from the
279 command line; all arguments are treated as the names of paths to be searched.
280 .TP
281 \fB--file-list\fP=\fIfilename\fP
282 Read a list of files and/or directories that are to be scanned from the given
283 file, one per line. Trailing white space is removed from each line, and blank
284 lines are ignored. These paths are processed before any that are listed on the
285 command line. The filename can be given as "-" to refer to the standard input.
286 If \fB--file\fP and \fB--file-list\fP are both specified as "-", patterns are
287 read first. This is useful only when the standard input is a terminal, from
288 which further lines (the list of files) can be read after an end-of-file
289 indication. If this option is given more than once, all the specified files are
290 read.
291 .TP
292 \fB--file-offsets\fP
293 Instead of showing lines or parts of lines that match, show each match as an
294 offset from the start of the file and a length, separated by a comma. In this
295 mode, no context is shown. That is, the \fB-A\fP, \fB-B\fP, and \fB-C\fP
296 options are ignored. If there is more than one match in a line, each of them is
297 shown separately. This option is mutually exclusive with \fB--line-offsets\fP
298 and \fB--only-matching\fP.
299 .TP
300 \fB-H\fP, \fB--with-filename\fP
301 Force the inclusion of the filename at the start of output lines when searching
302 a single file. By default, the filename is not shown in this case. For matching
303 lines, the filename is followed by a colon; for context lines, a hyphen
304 separator is used. If a line number is also being output, it follows the file
305 name.
306 .TP
307 \fB-h\fP, \fB--no-filename\fP
308 Suppress the output filenames when searching multiple files. By default,
309 filenames are shown when multiple files are searched. For matching lines, the
310 filename is followed by a colon; for context lines, a hyphen separator is used.
311 If a line number is also being output, it follows the file name.
312 .TP
313 \fB--help\fP
314 Output a help message, giving brief details of the command options and file
315 type support, and then exit. Anything else on the command line is
316 ignored.
317 .TP
318 \fB-I\fP
319 Treat binary files as never matching. This is equivalent to
320 \fB--binary-files\fP=\fIwithout-match\fP.
321 .TP
322 \fB-i\fP, \fB--ignore-case\fP
323 Ignore upper/lower case distinctions during comparisons.
324 .TP
325 \fB--include\fP=\fIpattern\fP
326 If any \fB--include\fP patterns are specified, the only files that are
327 processed are those that match one of the patterns (and do not match an
328 \fB--exclude\fP pattern). This option does not affect directories, but it
329 applies to all files, whether listed on the command line, obtained from
330 \fB--file-list\fP, or by scanning a directory. The pattern is a PCRE regular
331 expression, and is matched against the final component of the file name, not
332 the entire path. The \fB-F\fP, \fB-w\fP, and \fB-x\fP options do not apply to
333 this pattern. The option may be given any number of times. If a file name
334 matches both an \fB--include\fP and an \fB--exclude\fP pattern, it is excluded.
335 There is no short form for this option.
336 .TP
337 \fB--include-from=\fP\fIfilename\fP
338 Treat each non-empty line of the file as the data for an \fB--include\fP
339 option. What constitutes a newline for this purpose is the operating system's
340 default. The \fB--newline\fP option has no effect on this option. This option
341 may be given any number of times; all the files are read.
342 .TP
343 \fB--include-dir\fP=\fIpattern\fP
344 If any \fB--include-dir\fP patterns are specified, the only directories that
345 are processed are those that match one of the patterns (and do not match an
346 \fB--exclude-dir\fP pattern). This applies to all directories, whether listed
347 on the command line, obtained from \fB--file-list\fP, or by scanning a parent
348 directory. The pattern is a PCRE regular expression, and is matched against the
349 final component of the directory name, not the entire path. The \fB-F\fP,
350 \fB-w\fP, and \fB-x\fP options do not apply to this pattern. The option may be
351 given any number of times. If a directory matches both \fB--include-dir\fP and
352 \fB--exclude-dir\fP, it is excluded. There is no short form for this option.
353 .TP
354 \fB-L\fP, \fB--files-without-match\fP
355 Instead of outputting lines from the files, just output the names of the files
356 that do not contain any lines that would have been output. Each file name is
357 output once, on a separate line.
358 .TP
359 \fB-l\fP, \fB--files-with-matches\fP
360 Instead of outputting lines from the files, just output the names of the files
361 containing lines that would have been output. Each file name is output
362 once, on a separate line. Searching normally stops as soon as a matching line
363 is found in a file. However, if the \fB-c\fP (count) option is also used,
364 matching continues in order to obtain the correct count, and those files that
365 have at least one match are listed along with their counts. Using this option
366 with \fB-c\fP is a way of suppressing the listing of files with no matches.
367 .TP
368 \fB--label\fP=\fIname\fP
369 This option supplies a name to be used for the standard input when file names
370 are being output. If not supplied, "(standard input)" is used. There is no
371 short form for this option.
372 .TP
373 \fB--line-buffered\fP
374 When this option is given, input is read and processed line by line, and the
375 output is flushed after each write. By default, input is read in large chunks,
376 unless \fBpcregrep\fP can determine that it is reading from a terminal (which
377 is currently possible only in Unix-like environments). Output to terminal is
378 normally automatically flushed by the operating system. This option can be
379 useful when the input or output is attached to a pipe and you do not want
380 \fBpcregrep\fP to buffer up large amounts of data. However, its use will affect
381 performance, and the \fB-M\fP (multiline) option ceases to work.
382 .TP
383 \fB--line-offsets\fP
384 Instead of showing lines or parts of lines that match, show each match as a
385 line number, the offset from the start of the line, and a length. The line
386 number is terminated by a colon (as usual; see the \fB-n\fP option), and the
387 offset and length are separated by a comma. In this mode, no context is shown.
388 That is, the \fB-A\fP, \fB-B\fP, and \fB-C\fP options are ignored. If there is
389 more than one match in a line, each of them is shown separately. This option is
390 mutually exclusive with \fB--file-offsets\fP and \fB--only-matching\fP.
391 .TP
392 \fB--locale\fP=\fIlocale-name\fP
393 This option specifies a locale to be used for pattern matching. It overrides
394 the value in the \fBLC_ALL\fP or \fBLC_CTYPE\fP environment variables. If no
395 locale is specified, the PCRE library's default (usually the "C" locale) is
396 used. There is no short form for this option.
397 .TP
398 \fB--match-limit\fP=\fInumber\fP
399 Processing some regular expression patterns can require a very large amount of
400 memory, leading in some cases to a program crash if not enough is available.
401 Other patterns may take a very long time to search for all possible matching
402 strings. The \fBpcre_exec()\fP function that is called by \fBpcregrep\fP to do
403 the matching has two parameters that can limit the resources that it uses.
404 .sp
405 The \fB--match-limit\fP option provides a means of limiting resource usage
406 when processing patterns that are not going to match, but which have a very
407 large number of possibilities in their search trees. The classic example is a
408 pattern that uses nested unlimited repeats. Internally, PCRE uses a function
409 called \fBmatch()\fP which it calls repeatedly (sometimes recursively). The
410 limit set by \fB--match-limit\fP is imposed on the number of times this
411 function is called during a match, which has the effect of limiting the amount
412 of backtracking that can take place.
413 .sp
414 The \fB--recursion-limit\fP option is similar to \fB--match-limit\fP, but
415 instead of limiting the total number of times that \fBmatch()\fP is called, it
416 limits the depth of recursive calls, which in turn limits the amount of memory
417 that can be used. The recursion depth is a smaller number than the total number
418 of calls, because not all calls to \fBmatch()\fP are recursive. This limit is
419 of use only if it is set smaller than \fB--match-limit\fP.
420 .sp
421 There are no short forms for these options. The default settings are specified
422 when the PCRE library is compiled, with the default default being 10 million.
423 .TP
424 \fB-M\fP, \fB--multiline\fP
425 Allow patterns to match more than one line. When this option is given, patterns
426 may usefully contain literal newline characters and internal occurrences of ^
427 and $ characters. The output for a successful match may consist of more than
428 one line, the last of which is the one in which the match ended. If the matched
429 string ends with a newline sequence the output ends at the end of that line.
430 .sp
431 When this option is set, the PCRE library is called in "multiline" mode.
432 There is a limit to the number of lines that can be matched, imposed by the way
433 that \fBpcregrep\fP buffers the input file as it scans it. However,
434 \fBpcregrep\fP ensures that at least 8K characters or the rest of the document
435 (whichever is the shorter) are available for forward matching, and similarly
436 the previous 8K characters (or all the previous characters, if fewer than 8K)
437 are guaranteed to be available for lookbehind assertions. This option does not
438 work when input is read line by line (see \fP--line-buffered\fP.)
439 .TP
440 \fB-N\fP \fInewline-type\fP, \fB--newline\fP=\fInewline-type\fP
441 The PCRE library supports five different conventions for indicating
442 the ends of lines. They are the single-character sequences CR (carriage return)
443 and LF (linefeed), the two-character sequence CRLF, an "anycrlf" convention,
444 which recognizes any of the preceding three types, and an "any" convention, in
445 which any Unicode line ending sequence is assumed to end a line. The Unicode
446 sequences are the three just mentioned, plus VT (vertical tab, U+000B), FF
447 (form feed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and
448 PS (paragraph separator, U+2029).
449 .sp
450 When the PCRE library is built, a default line-ending sequence is specified.
451 This is normally the standard sequence for the operating system. Unless
452 otherwise specified by this option, \fBpcregrep\fP uses the library's default.
453 The possible values for this option are CR, LF, CRLF, ANYCRLF, or ANY. This
454 makes it possible to use \fBpcregrep\fP to scan files that have come from other
455 environments without having to modify their line endings. If the data that is
456 being scanned does not agree with the convention set by this option,
457 \fBpcregrep\fP may behave in strange ways. Note that this option does not
458 apply to files specified by the \fB-f\fP, \fB--exclude-from\fP, or
459 \fB--include-from\fP options, which are expected to use the operating system's
460 standard newline sequence.
461 .TP
462 \fB-n\fP, \fB--line-number\fP
463 Precede each output line by its line number in the file, followed by a colon
464 for matching lines or a hyphen for context lines. If the filename is also being
465 output, it precedes the line number. This option is forced if
466 \fB--line-offsets\fP is used.
467 .TP
468 \fB--no-jit\fP
469 If the PCRE library is built with support for just-in-time compiling (which
470 speeds up matching), \fBpcregrep\fP automatically makes use of this, unless it
471 was explicitly disabled at build time. This option can be used to disable the
472 use of JIT at run time. It is provided for testing and working round problems.
473 It should never be needed in normal use.
474 .TP
475 \fB-o\fP, \fB--only-matching\fP
476 Show only the part of the line that matched a pattern instead of the whole
477 line. In this mode, no context is shown. That is, the \fB-A\fP, \fB-B\fP, and
478 \fB-C\fP options are ignored. If there is more than one match in a line, each
479 of them is shown separately. If \fB-o\fP is combined with \fB-v\fP (invert the
480 sense of the match to find non-matching lines), no output is generated, but the
481 return code is set appropriately. If the matched portion of the line is empty,
482 nothing is output unless the file name or line number are being printed, in
483 which case they are shown on an otherwise empty line. This option is mutually
484 exclusive with \fB--file-offsets\fP and \fB--line-offsets\fP.
485 .TP
486 \fB-o\fP\fInumber\fP, \fB--only-matching\fP=\fInumber\fP
487 Show only the part of the line that matched the capturing parentheses of the
488 given number. Up to 32 capturing parentheses are supported, and -o0 is
489 equivalent to \fB-o\fP without a number. Because these options can be given
490 without an argument (see above), if an argument is present, it must be given in
491 the same shell item, for example, -o3 or --only-matching=2. The comments given
492 for the non-argument case above also apply to this case. If the specified
493 capturing parentheses do not exist in the pattern, or were not set in the
494 match, nothing is output unless the file name or line number are being printed.
495 .sp
496 If this option is given multiple times, multiple substrings are output, in the
497 order the options are given. For example, -o3 -o1 -o3 causes the substrings
498 matched by capturing parentheses 3 and 1 and then 3 again to be output. By
499 default, there is no separator (but see the next option).
500 .TP
501 \fB--om-separator\fP=\fItext\fP
502 Specify a separating string for multiple occurrences of \fB-o\fP. The default
503 is an empty string. Separating strings are never coloured.
504 .TP
505 \fB-q\fP, \fB--quiet\fP
506 Work quietly, that is, display nothing except error messages. The exit
507 status indicates whether or not any matches were found.
508 .TP
509 \fB-r\fP, \fB--recursive\fP
510 If any given path is a directory, recursively scan the files it contains,
511 taking note of any \fB--include\fP and \fB--exclude\fP settings. By default, a
512 directory is read as a normal file; in some operating systems this gives an
513 immediate end-of-file. This option is a shorthand for setting the \fB-d\fP
514 option to "recurse".
515 .TP
516 \fB--recursion-limit\fP=\fInumber\fP
517 See \fB--match-limit\fP above.
518 .TP
519 \fB-s\fP, \fB--no-messages\fP
520 Suppress error messages about non-existent or unreadable files. Such files are
521 quietly skipped. However, the return code is still 2, even if matches were
522 found in other files.
523 .TP
524 \fB-u\fP, \fB--utf-8\fP
525 Operate in UTF-8 mode. This option is available only if PCRE has been compiled
526 with UTF-8 support. All patterns (including those for any \fB--exclude\fP and
527 \fB--include\fP options) and all subject lines that are scanned must be valid
528 strings of UTF-8 characters.
529 .TP
530 \fB-V\fP, \fB--version\fP
531 Write the version numbers of \fBpcregrep\fP and the PCRE library to the
532 standard output and then exit. Anything else on the command line is
533 ignored.
534 .TP
535 \fB-v\fP, \fB--invert-match\fP
536 Invert the sense of the match, so that lines which do \fInot\fP match any of
537 the patterns are the ones that are found.
538 .TP
539 \fB-w\fP, \fB--word-regex\fP, \fB--word-regexp\fP
540 Force the patterns to match only whole words. This is equivalent to having \eb
541 at the start and end of the pattern. This option applies only to the patterns
542 that are matched against the contents of files; it does not apply to patterns
543 specified by any of the \fB--include\fP or \fB--exclude\fP options.
544 .TP
545 \fB-x\fP, \fB--line-regex\fP, \fB--line-regexp\fP
546 Force the patterns to be anchored (each must start matching at the beginning of
547 a line) and in addition, require them to match entire lines. This is equivalent
548 to having ^ and $ characters at the start and end of each alternative branch in
549 every pattern. This option applies only to the patterns that are matched
550 against the contents of files; it does not apply to patterns specified by any
551 of the \fB--include\fP or \fB--exclude\fP options.
552 .
553 .
554 .SH "ENVIRONMENT VARIABLES"
555 .rs
556 .sp
557 The environment variables \fBLC_ALL\fP and \fBLC_CTYPE\fP are examined, in that
558 order, for a locale. The first one that is set is used. This can be overridden
559 by the \fB--locale\fP option. If no locale is set, the PCRE library's default
560 (usually the "C" locale) is used.
561 .
562 .
563 .SH "NEWLINES"
564 .rs
565 .sp
566 The \fB-N\fP (\fB--newline\fP) option allows \fBpcregrep\fP to scan files with
567 different newline conventions from the default. Any parts of the input files
568 that are written to the standard output are copied identically, with whatever
569 newline sequences they have in the input. However, the setting of this option
570 does not affect the interpretation of files specified by the \fB-f\fP,
571 \fB--exclude-from\fP, or \fB--include-from\fP options, which are assumed to use
572 the operating system's standard newline sequence, nor does it affect the way in
573 which \fBpcregrep\fP writes informational messages to the standard error and
574 output streams. For these it uses the string "\en" to indicate newlines,
575 relying on the C I/O library to convert this to an appropriate sequence.
576 .
577 .
578 .SH "OPTIONS COMPATIBILITY"
579 .rs
580 .sp
581 Many of the short and long forms of \fBpcregrep\fP's options are the same
582 as in the GNU \fBgrep\fP program. Any long option of the form
583 \fB--xxx-regexp\fP (GNU terminology) is also available as \fB--xxx-regex\fP
584 (PCRE terminology). However, the \fB--file-list\fP, \fB--file-offsets\fP,
585 \fB--include-dir\fP, \fB--line-offsets\fP, \fB--locale\fP, \fB--match-limit\fP,
586 \fB-M\fP, \fB--multiline\fP, \fB-N\fP, \fB--newline\fP, \fB--om-separator\fP,
587 \fB--recursion-limit\fP, \fB-u\fP, and \fB--utf-8\fP options are specific to
588 \fBpcregrep\fP, as is the use of the \fB--only-matching\fP option with a
589 capturing parentheses number.
590 .P
591 Although most of the common options work the same way, a few are different in
592 \fBpcregrep\fP. For example, the \fB--include\fP option's argument is a glob
593 for GNU \fBgrep\fP, but a regular expression for \fBpcregrep\fP. If both the
594 \fB-c\fP and \fB-l\fP options are given, GNU grep lists only file names,
595 without counts, but \fBpcregrep\fP gives the counts.
596 .
597 .
598 .SH "OPTIONS WITH DATA"
599 .rs
600 .sp
601 There are four different ways in which an option with data can be specified.
602 If a short form option is used, the data may follow immediately, or (with one
603 exception) in the next command line item. For example:
604 .sp
605 -f/some/file
606 -f /some/file
607 .sp
608 The exception is the \fB-o\fP option, which may appear with or without data.
609 Because of this, if data is present, it must follow immediately in the same
610 item, for example -o3.
611 .P
612 If a long form option is used, the data may appear in the same command line
613 item, separated by an equals character, or (with two exceptions) it may appear
614 in the next command line item. For example:
615 .sp
616 --file=/some/file
617 --file /some/file
618 .sp
619 Note, however, that if you want to supply a file name beginning with ~ as data
620 in a shell command, and have the shell expand ~ to a home directory, you must
621 separate the file name from the option, because the shell does not treat ~
622 specially unless it is at the start of an item.
623 .P
624 The exceptions to the above are the \fB--colour\fP (or \fB--color\fP) and
625 \fB--only-matching\fP options, for which the data is optional. If one of these
626 options does have data, it must be given in the first form, using an equals
627 character. Otherwise \fBpcregrep\fP will assume that it has no data.
628 .
629 .
630 .SH "MATCHING ERRORS"
631 .rs
632 .sp
633 It is possible to supply a regular expression that takes a very long time to
634 fail to match certain lines. Such patterns normally involve nested indefinite
635 repeats, for example: (a+)*\ed when matched against a line of a's with no final
636 digit. The PCRE matching function has a resource limit that causes it to abort
637 in these circumstances. If this happens, \fBpcregrep\fP outputs an error
638 message and the line that caused the problem to the standard error stream. If
639 there are more than 20 such errors, \fBpcregrep\fP gives up.
640 .P
641 The \fB--match-limit\fP option of \fBpcregrep\fP can be used to set the overall
642 resource limit; there is a second option called \fB--recursion-limit\fP that
643 sets a limit on the amount of memory (usually stack) that is used (see the
644 discussion of these options above).
645 .
646 .
647 .SH DIAGNOSTICS
648 .rs
649 .sp
650 Exit status is 0 if any matches were found, 1 if no matches were found, and 2
651 for syntax errors, overlong lines, non-existent or inaccessible files (even if
652 matches were found in other files) or too many matching errors. Using the
653 \fB-s\fP option to suppress error messages about inaccessible files does not
654 affect the return code.
655 .
656 .
657 .SH "SEE ALSO"
658 .rs
659 .sp
660 \fBpcrepattern\fP(3), \fBpcresyntax\fP(3), \fBpcretest\fP(1).
661 .
662 .
663 .SH AUTHOR
664 .rs
665 .sp
666 .nf
667 Philip Hazel
668 University Computing Service
669 Cambridge CB2 3QH, England.
670 .fi
671 .
672 .
673 .SH REVISION
674 .rs
675 .sp
676 .nf
677 Last updated: 13 September 2012
678 Copyright (c) 1997-2012 University of Cambridge.
679 .fi

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