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revision 75 by nigel, Sat Feb 24 21:40:37 2007 UTC revision 91 by nigel, Sat Feb 24 21:41:34 2007 UTC
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2  .SH NAME  .SH NAME
3  pcregrep - a grep with Perl-compatible regular expressions.  pcregrep - a grep with Perl-compatible regular expressions.
4  .SH SYNOPSIS  .SH SYNOPSIS
5  .B pcregrep [-Vcfhilnrsuvx] [long options] [pattern] [file1 file2 ...]  .B pcregrep [options] [long options] [pattern] [path1 path2 ...]
6  .  .
7  .SH DESCRIPTION  .SH DESCRIPTION
8  .rs  .rs
# Line 16  patterns that are compatible with the re Line 16  patterns that are compatible with the re
16  for a full description of syntax and semantics of the regular expressions that  for a full description of syntax and semantics of the regular expressions that
17  PCRE supports.  PCRE supports.
18  .P  .P
19  A pattern must be specified on the command line unless the \fB-f\fP option is  Patterns, whether supplied on the command line or in a separate file, are given
20  used (see below).  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 on the command line because they are
27    interpreted by the shell, and indeed they are required if a pattern contains
28    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 the 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. However, there are options that can change how
45    \fBpcregrep\fP behaves. In particular, the \fB-M\fP option makes it possible to
46    search for patterns that span line boundaries. What defines a line boundary is
47    controlled by the \fB-N\fP (\fB--newline\fP) option.
48  .P  .P
49  If no files are specified, \fBpcregrep\fP reads the standard input. By default,  Patterns are limited to 8K or BUFSIZ characters, whichever is the greater.
50  each line that matches the pattern is copied to the standard output, and if  BUFSIZ is defined in \fB<stdio.h>\fP.
51  there is more than one file, the file name is printed before each line of  .P
52  output. However, there are options that can change how \fBpcregrep\fP behaves.  If the \fBLC_ALL\fP or \fBLC_CTYPE\fP environment variable is set,
53  .P  \fBpcregrep\fP uses the value to set a locale when calling the PCRE library.
54  Lines are limited to BUFSIZ characters. BUFSIZ is defined in \fB<stdio.h>\fP.  The \fB--locale\fP option can be used to override this.
 The newline character is removed from the end of each line before it is matched  
 against the pattern.  
55  .  .
56  .SH OPTIONS  .SH OPTIONS
57  .rs  .rs
 .sp  
58  .TP 10  .TP 10
59  \fB-V\fP  \fB--\fP
60  Write the version number of the PCRE library being used to the standard error  This terminate the list of options. It is useful if the next item on the
61  stream.  command line starts with a hyphen but is not an option. This allows for the
62  .TP  processing of patterns and filenames that start with hyphens.
63  \fB-c\fP  .TP
64  Do not print individual lines; instead just print a count of the number of  \fB-A\fP \fInumber\fP, \fB--after-context=\fP\fInumber\fP
65  lines that would otherwise have been printed. If several files are given, a  Output \fInumber\fP lines of context after each matching line. If filenames
66  count is printed for each of them.  and/or line numbers are being output, a hyphen separator is used instead of a
67  .TP  colon for the context lines. A line containing "--" is output between each
68  \fB-f\fP\fIfilename\fP  group of lines, unless they are in fact contiguous in the input file. The value
69  Read a number of patterns from the file, one per line, and match all of them  of \fInumber\fP is expected to be relatively small. However, \fBpcregrep\fP
70  against each line of input. A line is output if any of the patterns match it.  guarantees to have up to 8K of following text available for context output.
71  When \fB-f\fP is used, no pattern is taken from the command line; all arguments  .TP
72  are treated as file names. There is a maximum of 100 patterns. Trailing white  \fB-B\fP \fInumber\fP, \fB--before-context=\fP\fInumber\fP
73  space is removed, and blank lines are ignored. An empty file contains no  Output \fInumber\fP lines of context before each matching line. If filenames
74  patterns and therefore matches nothing.  and/or line numbers are being output, a hyphen separator is used instead of a
75    colon for the context lines. A line containing "--" is output between each
76    group of lines, unless they are in fact contiguous in the input file. The value
77    of \fInumber\fP is expected to be relatively small. However, \fBpcregrep\fP
78    guarantees to have up to 8K of preceding text available for context output.
79    .TP
80    \fB-C\fP \fInumber\fP, \fB--context=\fP\fInumber\fP
81    Output \fInumber\fP lines of context both before and after each matching line.
82    This is equivalent to setting both \fB-A\fP and \fB-B\fP to the same value.
83    .TP
84    \fB-c\fP, \fB--count\fP
85    Do not output individual lines; instead just output a count of the number of
86    lines that would otherwise have been output. If several files are given, a
87    count is output for each of them. In this mode, the \fB-A\fP, \fB-B\fP, and
88    \fB-C\fP options are ignored.
89    .TP
90    \fB--colour\fP, \fB--color\fP
91    If this option is given without any data, it is equivalent to "--colour=auto".
92    If data is required, it must be given in the same shell item, separated by an
93    equals sign.
94    .TP
95    \fB--colour=\fP\fIvalue\fP, \fB--color=\fP\fIvalue\fP
96    This option specifies under what circumstances the part of a line that matched
97    a pattern should be coloured in the output. The value may be "never" (the
98    default), "always", or "auto". In the latter case, colouring happens only if
99    the standard output is connected to a terminal. The colour can be specified by
100    setting the environment variable PCREGREP_COLOUR or PCREGREP_COLOR. The value
101    of this variable should be a string of two numbers, separated by a semicolon.
102    They are copied directly into the control string for setting colour on a
103    terminal, so it is your responsibility to ensure that they make sense. If
104    neither of the environment variables is set, the default is "1;31", which gives
105    red.
106    .TP
107    \fB-D\fP \fIaction\fP, \fB--devices=\fP\fIaction\fP
108    If an input path is not a regular file or a directory, "action" specifies how
109    it is to be processed. Valid values are "read" (the default) or "skip"
110    (silently skip the path).
111    .TP
112    \fB-d\fP \fIaction\fP, \fB--directories=\fP\fIaction\fP
113    If an input path is a directory, "action" specifies how it is to be processed.
114    Valid values are "read" (the default), "recurse" (equivalent to the \fB-r\fP
115    option), or "skip" (silently skip the path). In the default case, directories
116    are read as if they were ordinary files. In some operating systems the effect
117    of reading a directory like this is an immediate end-of-file.
118    .TP
119    \fB-e\fP \fIpattern\fP, \fB--regex=\fP\fIpattern\fP,
120    \fB--regexp=\fP\fIpattern\fP Specify a pattern to be matched. This option can
121    be used multiple times in order to specify several patterns. It can also be
122    used as a way of specifying a single pattern that starts with a hyphen. When
123    \fB-e\fP is used, no argument pattern is taken from the command line; all
124    arguments are treated as file names. There is an overall maximum of 100
125    patterns. They are applied to each line in the order in which they are defined
126    until one matches (or fails to match if \fB-v\fP is used). If \fB-f\fP is used
127    with \fB-e\fP, the command line patterns are matched first, followed by the
128    patterns from the file, independent of the order in which these options are
129    specified. Note that multiple use of \fB-e\fP is not the same as a single
130    pattern with alternatives. For example, X|Y finds the first character in a line
131    that is X or Y, whereas if the two patterns are given separately,
132    \fBpcregrep\fP finds X if it is present, even if it follows Y in the line. It
133    finds Y only if there is no X in the line. This really matters only if you are
134    using \fB-o\fP to show the portion of the line that matched.
135    .TP
136    \fB--exclude\fP=\fIpattern\fP
137    When \fBpcregrep\fP is searching the files in a directory as a consequence of
138    the \fB-r\fP (recursive search) option, any files whose names match the pattern
139    are excluded. The pattern is a PCRE regular expression. If a file name matches
140    both \fB--include\fP and \fB--exclude\fP, it is excluded. There is no short
141    form for this option.
142    .TP
143    \fB-F\fP, \fB--fixed-strings\fP
144    Interpret each pattern as a list of fixed strings, separated by newlines,
145    instead of as a regular expression. The \fB-w\fP (match as a word) and \fB-x\fP
146    (match whole line) options can be used with \fB-F\fP. They apply to each of the
147    fixed strings. A line is selected if any of the fixed strings are found in it
148    (subject to \fB-w\fP or \fB-x\fP, if present).
149    .TP
150    \fB-f\fP \fIfilename\fP, \fB--file=\fP\fIfilename\fP
151    Read a number of patterns from the file, one per line, and match them against
152    each line of input. A data line is output if any of the patterns match it. The
153    filename can be given as "-" to refer to the standard input. When \fB-f\fP is
154    used, patterns specified on the command line using \fB-e\fP may also be
155    present; they are tested before the file's patterns. However, no other pattern
156    is taken from the command line; all arguments are treated as file names. There
157    is an overall maximum of 100 patterns. Trailing white space is removed from
158    each line, and blank lines are ignored. An empty file contains no patterns and
159    therefore matches nothing.
160    .TP
161    \fB-H\fP, \fB--with-filename\fP
162    Force the inclusion of the filename at the start of output lines when searching
163    a single file. By default, the filename is not shown in this case. For matching
164    lines, the filename is followed by a colon and a space; for context lines, a
165    hyphen separator is used. If a line number is also being output, it follows the
166    file name without a space.
167    .TP
168    \fB-h\fP, \fB--no-filename\fP
169    Suppress the output filenames when searching multiple files. By default,
170    filenames are shown when multiple files are searched. For matching lines, the
171    filename is followed by a colon and a space; for context lines, a hyphen
172    separator is used. If a line number is also being output, it follows the file
173    name without a space.
174  .TP  .TP
175  \fB-h\fP  \fB--help\fP
176  Suppress printing of filenames when searching multiple files.  Output a brief help message and exit.
177  .TP  .TP
178  \fB-i\fP  \fB-i\fP, \fB--ignore-case\fP
179  Ignore upper/lower case distinctions during comparisons.  Ignore upper/lower case distinctions during comparisons.
180  .TP  .TP
181  \fB-l\fP  \fB--include\fP=\fIpattern\fP
182  Instead of printing lines from the files, just print the names of the files  When \fBpcregrep\fP is searching the files in a directory as a consequence of
183  containing lines that would have been printed. Each file name is printed  the \fB-r\fP (recursive search) option, only those files whose names match the
184  once, on a separate line.  pattern are included. The pattern is a PCRE regular expression. If a file name
185  .TP  matches both \fB--include\fP and \fB--exclude\fP, it is excluded. There is no
186  \fB-n\fP  short form for this option.
187  Precede each line by its line number in the file.  .TP
188  .TP  \fB-L\fP, \fB--files-without-match\fP
189  \fB-r\fP  Instead of outputting lines from the files, just output the names of the files
190  If any file is a directory, recursively scan the files it contains. Without  that do not contain any lines that would have been output. Each file name is
191  \fB-r\fP a directory is scanned as a normal file.  output once, on a separate line.
192  .TP  .TP
193  \fB-s\fP  \fB-l\fP, \fB--files-with-matches\fP
194  Work silently, that is, display nothing except error messages.  Instead of outputting lines from the files, just output the names of the files
195  The exit status indicates whether any matches were found.  containing lines that would have been output. Each file name is output
196    once, on a separate line. Searching stops as soon as a matching line is found
197    in a file.
198    .TP
199    \fB--label\fP=\fIname\fP
200    This option supplies a name to be used for the standard input when file names
201    are being output. If not supplied, "(standard input)" is used. There is no
202    short form for this option.
203    .TP
204    \fB--locale\fP=\fIlocale-name\fP
205    This option specifies a locale to be used for pattern matching. It overrides
206    the value in the \fBLC_ALL\fP or \fBLC_CTYPE\fP environment variables. If no
207    locale is specified, the PCRE library's default (usually the "C" locale) is
208    used. There is no short form for this option.
209    .TP
210    \fB-M\fP, \fB--multiline\fP
211    Allow patterns to match more than one line. When this option is given, patterns
212    may usefully contain literal newline characters and internal occurrences of ^
213    and $ characters. The output for any one match may consist of more than one
214    line. When this option is set, the PCRE library is called in "multiline" mode.
215    There is a limit to the number of lines that can be matched, imposed by the way
216    that \fBpcregrep\fP buffers the input file as it scans it. However,
217    \fBpcregrep\fP ensures that at least 8K characters or the rest of the document
218    (whichever is the shorter) are available for forward matching, and similarly
219    the previous 8K characters (or all the previous characters, if fewer than 8K)
220    are guaranteed to be available for lookbehind assertions.
221    .TP
222    \fB-N\fP \fInewline-type\fP, \fB--newline=\fP\fInewline-type\fP
223    The PCRE library supports three different character sequences for indicating
224    the ends of lines. They are the single-character sequences CR (carriage return)
225    and LF (linefeed), and the two-character sequence CR, LF. When the library is
226    built, a default line-ending sequence is specified. This is normally the
227    standard sequence for the operating system. Unless otherwise specified by this
228    option, \fBpcregrep\fP uses the default. The possible values for this option
229    are CR, LF, or CRLF. This makes it possible to use \fBpcregrep\fP on files that
230    have come from other environments without having to modify their line endings.
231    If the data that is being scanned does not agree with the convention set by
232    this option, \fBpcregrep\fP may behave in strange ways.
233    .TP
234    \fB-n\fP, \fB--line-number\fP
235    Precede each output line by its line number in the file, followed by a colon
236    and a space for matching lines or a hyphen and a space for context lines. If
237    the filename is also being output, it precedes the line number.
238    .TP
239    \fB-o\fP, \fB--only-matching\fP
240    Show only the part of the line that matched a pattern. In this mode, no
241    context is shown. That is, the \fB-A\fP, \fB-B\fP, and \fB-C\fP options are
242    ignored.
243    .TP
244    \fB-q\fP, \fB--quiet\fP
245    Work quietly, that is, display nothing except error messages. The exit
246    status indicates whether or not any matches were found.
247    .TP
248    \fB-r\fP, \fB--recursive\fP
249    If any given path is a directory, recursively scan the files it contains,
250    taking note of any \fB--include\fP and \fB--exclude\fP settings. By default, a
251    directory is read as a normal file; in some operating systems this gives an
252    immediate end-of-file. This option is a shorthand for setting the \fB-d\fP
253    option to "recurse".
254    .TP
255    \fB-s\fP, \fB--no-messages\fP
256    Suppress error messages about non-existent or unreadable files. Such files are
257    quietly skipped. However, the return code is still 2, even if matches were
258    found in other files.
259  .TP  .TP
260  \fB-u\fP  \fB-u\fP, \fB--utf-8\fP
261  Operate in UTF-8 mode. This option is available only if PCRE has been compiled  Operate in UTF-8 mode. This option is available only if PCRE has been compiled
262  with UTF-8 support. Both the pattern and each subject line must be valid  with UTF-8 support. Both patterns and subject lines must be valid strings of
263  strings of UTF-8 characters.  UTF-8 characters.
264  .TP  .TP
265  \fB-v\fP  \fB-V\fP, \fB--version\fP
266  Invert the sense of the match, so that lines which do \fInot\fP match the  Write the version numbers of \fBpcregrep\fP and the PCRE library that is being
267  pattern are now the ones that are found.  used to the standard error stream.
268  .TP  .TP
269  \fB-x\fP  \fB-v\fP, \fB--invert-match\fP
270  Force the pattern to be anchored (it must start matching at the beginning of  Invert the sense of the match, so that lines which do \fInot\fP match any of
271  the line) and in addition, require it to match the entire line. This is  the patterns are the ones that are found.
272    .TP
273    \fB-w\fP, \fB--word-regex\fP, \fB--word-regexp\fP
274    Force the patterns to match only whole words. This is equivalent to having \eb
275    at the start and end of the pattern.
276    .TP
277    \fB-x\fP, \fB--line-regex\fP, \fP--line-regexp\fP
278    Force the patterns to be anchored (each must start matching at the beginning of
279    a line) and in addition, require them to match entire lines. This is
280  equivalent to having ^ and $ characters at the start and end of each  equivalent to having ^ and $ characters at the start and end of each
281  alternative branch in the regular expression.  alternative branch in every pattern.
282  .  .
283  .SH "LONG OPTIONS"  .
284    .SH "ENVIRONMENT VARIABLES"
285  .rs  .rs
286  .sp  .sp
287  Long forms of all the options are available, as in GNU grep. They are shown in  The environment variables \fBLC_ALL\fP and \fBLC_CTYPE\fP are examined, in that
288  the following table:  order, for a locale. The first one that is set is used. This can be overridden
289    by the \fB--locale\fP option. If no locale is set, the PCRE library's default
290    (usually the "C" locale) is used.
291    .
292    .
293    .SH "NEWLINES"
294    .rs
295  .sp  .sp
296    -c   --count  The \fB-N\fP (\fB--newline\fP) option allows \fBpcregrep\fP to scan files with
297    -h   --no-filename  different newline conventions from the default. However, the setting of this
298    -i   --ignore-case  option does not affect the way in which \fBpcregrep\fP writes information to
299    -l   --files-with-matches  the standard error and output streams. It uses the string "\en" in C
300    -n   --line-number  \fBprintf()\fP calls to indicate newlines, relying on the C I/O library to
301    -r   --recursive  convert this to an appropriate sequence if the output is sent to a file.
302    -s   --no-messages  .
303    -u   --utf-8  .
304    -V   --version  .SH "OPTIONS COMPATIBILITY"
305    -v   --invert-match  .rs
   -x   --line-regex  
   -x   --line-regexp  
306  .sp  .sp
307  In addition, --file=\fIfilename\fP is equivalent to -f\fIfilename\fP, and  The majority of short and long forms of \fBpcregrep\fP's options are the same
308  --help shows the list of options and then exits.  as in the GNU \fBgrep\fP program. Any long option of the form
309    \fB--xxx-regexp\fP (GNU terminology) is also available as \fB--xxx-regex\fP
310    (PCRE terminology). However, the \fB--locale\fP, \fB-M\fP, \fB--multiline\fP,
311    \fB-u\fP, and \fB--utf-8\fP options are specific to \fBpcregrep\fP.
312    .
313    .
314    .SH "OPTIONS WITH DATA"
315    .rs
316    .sp
317    There are four different ways in which an option with data can be specified.
318    If a short form option is used, the data may follow immediately, or in the next
319    command line item. For example:
320    .sp
321      -f/some/file
322      -f /some/file
323    .sp
324    If a long form option is used, the data may appear in the same command line
325    item, separated by an equals character, or (with one exception) it may appear
326    in the next command line item. For example:
327    .sp
328      --file=/some/file
329      --file /some/file
330    .sp
331    Note, however, that if you want to supply a file name beginning with ~ as data
332    in a shell command, and have the shell expand ~ to a home directory, you must
333    separate the file name from the option, because the shell does not treat ~
334    specially unless it is at the start of an item.
335    .P
336    The exception to the above is the \fB--colour\fP (or \fB--color\fP) option,
337    for which the data is optional. If this option does have data, it must be given
338    in the first form, using an equals character. Otherwise it will be assumed that
339    it has no data.
340    .
341    .
342    .SH MATCHING ERRORS
343    .rs
344    .sp
345    It is possible to supply a regular expression that takes a very long time to
346    fail to match certain lines. Such patterns normally involve nested indefinite
347    repeats, for example: (a+)*\ed when matched against a line of a's with no final
348    digit. The PCRE matching function has a resource limit that causes it to abort
349    in these circumstances. If this happens, \fBpcregrep\fP outputs an error
350    message and the line that caused the problem to the standard error stream. If
351    there are more than 20 such errors, \fBpcregrep\fP gives up.
352    .
353  .  .
354  .SH DIAGNOSTICS  .SH DIAGNOSTICS
355  .rs  .rs
356  .sp  .sp
357  Exit status is 0 if any matches were found, 1 if no matches were found, and 2  Exit status is 0 if any matches were found, 1 if no matches were found, and 2
358  for syntax errors or inacessible files (even if matches were found).  for syntax errors and non-existent or inacessible files (even if matches were
359    found in other files) or too many matching errors. Using the \fB-s\fP option to
360    suppress error messages about inaccessble files does not affect the return
361    code.
362  .  .
363  .  .
364  .SH AUTHOR  .SH AUTHOR
365  .rs  .rs
366  .sp  .sp
367  Philip Hazel <ph10@cam.ac.uk>  Philip Hazel
368  .br  .br
369  University Computing Service  University Computing Service
370  .br  .br
371  Cambridge CB2 3QG, England.  Cambridge CB2 3QG, England.
372  .P  .P
373  .in 0  .in 0
374  Last updated: 09 September 2004  Last updated: 06 June 2006
375  .br  .br
376  Copyright (c) 1997-2004 University of Cambridge.  Copyright (c) 1997-2006 University of Cambridge.

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