Annotation of embedaddon/pcre/doc/pcregrep.1, revision 1.1.1.2
1.1.1.2 ! misho 1: .TH PCREGREP 1 "04 March 2012" "PCRE 8.31"
1.1 misho 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: 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 are limited to 8K or BUFSIZ bytes, whichever is the greater. BUFSIZ is
57: defined in \fB<stdio.h>\fP. When there is more than one pattern (specified by
58: the use of \fB-e\fP and/or \fB-f\fP), each pattern is applied to each line in
59: the order in which they are defined, except that all the \fB-e\fP patterns are
60: tried before the \fB-f\fP patterns.
61: .P
62: By default, as soon as one pattern matches (or fails to match when \fB-v\fP is
63: used), no further patterns are considered. However, if \fB--colour\fP (or
64: \fB--color\fP) is used to colour the matching substrings, or if
65: \fB--only-matching\fP, \fB--file-offsets\fP, or \fB--line-offsets\fP is used to
66: output only the part of the line that matched (either shown literally, or as an
67: offset), scanning resumes immediately following the match, so that further
68: matches on the same line can be found. If there are multiple patterns, they are
69: all tried on the remainder of the line, but patterns that follow the one that
70: matched are not tried on the earlier part of the line.
71: .P
72: This is the same behaviour as GNU grep, but it does mean that the order in
73: which multiple patterns are specified can affect the output when one of the
74: above options is used.
75: .P
76: Patterns that can match an empty string are accepted, but empty string
77: matches are never recognized. An example is the pattern "(super)?(man)?", in
78: which all components are optional. This pattern finds all occurrences of both
79: "super" and "man"; the output differs from matching with "super|man" when only
80: the matching substrings are being shown.
81: .P
82: If the \fBLC_ALL\fP or \fBLC_CTYPE\fP environment variable is set,
83: \fBpcregrep\fP uses the value to set a locale when calling the PCRE library.
84: The \fB--locale\fP option can be used to override this.
85: .
86: .
87: .SH "SUPPORT FOR COMPRESSED FILES"
88: .rs
89: .sp
90: It is possible to compile \fBpcregrep\fP so that it uses \fBlibz\fP or
91: \fBlibbz2\fP to read files whose names end in \fB.gz\fP or \fB.bz2\fP,
92: respectively. You can find out whether your binary has support for one or both
93: of these file types by running it with the \fB--help\fP option. If the
94: appropriate support is not present, files are treated as plain text. The
95: standard input is always so treated.
96: .
97: .
1.1.1.2 ! misho 98: .SH "BINARY FILES"
! 99: .rs
! 100: .sp
! 101: By default, a file that contains a binary zero byte within the first 1024 bytes
! 102: is identified as a binary file, and is processed specially. (GNU grep also
! 103: identifies binary files in this manner.) See the \fB--binary-files\fP option
! 104: for a means of changing the way binary files are handled.
! 105: .
! 106: .
1.1 misho 107: .SH OPTIONS
108: .rs
109: .sp
110: The order in which some of the options appear can affect the output. For
111: example, both the \fB-h\fP and \fB-l\fP options affect the printing of file
112: names. Whichever comes later in the command line will be the one that takes
113: effect. Numerical values for options may be followed by K or M, to signify
114: multiplication by 1024 or 1024*1024 respectively.
115: .TP 10
116: \fB--\fP
117: This terminates the list of options. It is useful if the next item on the
118: command line starts with a hyphen but is not an option. This allows for the
119: processing of patterns and filenames that start with hyphens.
120: .TP
121: \fB-A\fP \fInumber\fP, \fB--after-context=\fP\fInumber\fP
122: Output \fInumber\fP lines of context after each matching line. If filenames
123: and/or line numbers are being output, a hyphen separator is used instead of a
124: colon for the context lines. A line containing "--" is output between each
125: group of lines, unless they are in fact contiguous in the input file. The value
126: of \fInumber\fP is expected to be relatively small. However, \fBpcregrep\fP
127: guarantees to have up to 8K of following text available for context output.
128: .TP
1.1.1.2 ! misho 129: \fB-a\fP, \fB--text\fP
! 130: Treat binary files as text. This is equivalent to
! 131: \fB--binary-files\fP=\fItext\fP.
! 132: .TP
1.1 misho 133: \fB-B\fP \fInumber\fP, \fB--before-context=\fP\fInumber\fP
134: Output \fInumber\fP lines of context before each matching line. If filenames
135: and/or line numbers are being output, a hyphen separator is used instead of a
136: colon for the context lines. A line containing "--" is output between each
137: group of lines, unless they are in fact contiguous in the input file. The value
138: of \fInumber\fP is expected to be relatively small. However, \fBpcregrep\fP
139: guarantees to have up to 8K of preceding text available for context output.
140: .TP
1.1.1.2 ! misho 141: \fB--binary-files=\fP\fIword\fP
! 142: Specify how binary files are to be processed. If the word is "binary" (the
! 143: default), pattern matching is performed on binary files, but the only output is
! 144: "Binary file <name> matches" when a match succeeds. If the word is "text",
! 145: which is equivalent to the \fB-a\fP or \fB--text\fP option, binary files are
! 146: processed in the same way as any other file. In this case, when a match
! 147: succeeds, the output may be binary garbage, which can have nasty effects if
! 148: sent to a terminal. If the word is "without-match", which is equivalent to the
! 149: \fB-I\fP option, binary files are not processed at all; they are assumed not to
! 150: be of interest.
! 151: .TP
1.1 misho 152: \fB--buffer-size=\fP\fInumber\fP
153: Set the parameter that controls how much memory is used for buffering files
154: that are being scanned.
155: .TP
156: \fB-C\fP \fInumber\fP, \fB--context=\fP\fInumber\fP
157: Output \fInumber\fP lines of context both before and after each matching line.
158: This is equivalent to setting both \fB-A\fP and \fB-B\fP to the same value.
159: .TP
160: \fB-c\fP, \fB--count\fP
161: Do not output individual lines from the files that are being scanned; instead
162: output the number of lines that would otherwise have been shown. If no lines
163: are selected, the number zero is output. If several files are are being
164: scanned, a count is output for each of them. However, if the
165: \fB--files-with-matches\fP option is also used, only those files whose counts
166: are greater than zero are listed. When \fB-c\fP is used, the \fB-A\fP,
167: \fB-B\fP, and \fB-C\fP options are ignored.
168: .TP
169: \fB--colour\fP, \fB--color\fP
170: If this option is given without any data, it is equivalent to "--colour=auto".
171: If data is required, it must be given in the same shell item, separated by an
172: equals sign.
173: .TP
174: \fB--colour=\fP\fIvalue\fP, \fB--color=\fP\fIvalue\fP
175: This option specifies under what circumstances the parts of a line that matched
176: a pattern should be coloured in the output. By default, the output is not
177: coloured. The value (which is optional, see above) may be "never", "always", or
178: "auto". In the latter case, colouring happens only if the standard output is
179: connected to a terminal. More resources are used when colouring is enabled,
180: because \fBpcregrep\fP has to search for all possible matches in a line, not
181: just one, in order to colour them all.
182: .sp
183: The colour that is used can be specified by setting the environment variable
184: PCREGREP_COLOUR or PCREGREP_COLOR. The value of this variable should be a
185: string of two numbers, separated by a semicolon. They are copied directly into
186: the control string for setting colour on a terminal, so it is your
187: responsibility to ensure that they make sense. If neither of the environment
188: variables is set, the default is "1;31", which gives red.
189: .TP
190: \fB-D\fP \fIaction\fP, \fB--devices=\fP\fIaction\fP
191: If an input path is not a regular file or a directory, "action" specifies how
192: it is to be processed. Valid values are "read" (the default) or "skip"
193: (silently skip the path).
194: .TP
195: \fB-d\fP \fIaction\fP, \fB--directories=\fP\fIaction\fP
196: If an input path is a directory, "action" specifies how it is to be processed.
197: Valid values are "read" (the default), "recurse" (equivalent to the \fB-r\fP
198: option), or "skip" (silently skip the path). In the default case, directories
199: are read as if they were ordinary files. In some operating systems the effect
200: of reading a directory like this is an immediate end-of-file.
201: .TP
202: \fB-e\fP \fIpattern\fP, \fB--regex=\fP\fIpattern\fP, \fB--regexp=\fP\fIpattern\fP
203: Specify a pattern to be matched. This option can be used multiple times in
204: order to specify several patterns. It can also be used as a way of specifying a
205: single pattern that starts with a hyphen. When \fB-e\fP is used, no argument
206: pattern is taken from the command line; all arguments are treated as file
207: names. There is an overall maximum of 100 patterns. They are applied to each
208: line in the order in which they are defined until one matches (or fails to
209: match if \fB-v\fP is used). If \fB-f\fP is used with \fB-e\fP, the command line
210: patterns are matched first, followed by the patterns from the file, independent
211: of the order in which these options are specified. Note that multiple use of
212: \fB-e\fP is not the same as a single pattern with alternatives. For example,
213: X|Y finds the first character in a line that is X or Y, whereas if the two
214: patterns are given separately, \fBpcregrep\fP finds X if it is present, even if
215: it follows Y in the line. It finds Y only if there is no X in the line. This
216: really matters only if you are using \fB-o\fP to show the part(s) of the line
217: that matched.
218: .TP
219: \fB--exclude\fP=\fIpattern\fP
220: When \fBpcregrep\fP is searching the files in a directory as a consequence of
221: the \fB-r\fP (recursive search) option, any regular files whose names match the
222: pattern are excluded. Subdirectories are not excluded by this option; they are
223: searched recursively, subject to the \fB--exclude-dir\fP and
224: \fB--include_dir\fP options. The pattern is a PCRE regular expression, and is
225: matched against the final component of the file name (not the entire path). If
226: a file name matches both \fB--include\fP and \fB--exclude\fP, it is excluded.
227: There is no short form for this option.
228: .TP
229: \fB--exclude-dir\fP=\fIpattern\fP
230: When \fBpcregrep\fP is searching the contents of a directory as a consequence
231: of the \fB-r\fP (recursive search) option, any subdirectories whose names match
232: the pattern are excluded. (Note that the \fP--exclude\fP option does not affect
233: subdirectories.) The pattern is a PCRE regular expression, and is matched
234: against the final component of the name (not the entire path). If a
235: subdirectory name matches both \fB--include-dir\fP and \fB--exclude-dir\fP, it
236: is excluded. There is no short form for this option.
237: .TP
238: \fB-F\fP, \fB--fixed-strings\fP
239: Interpret each pattern as a list of fixed strings, separated by newlines,
240: instead of as a regular expression. The \fB-w\fP (match as a word) and \fB-x\fP
241: (match whole line) options can be used with \fB-F\fP. They apply to each of the
242: fixed strings. A line is selected if any of the fixed strings are found in it
243: (subject to \fB-w\fP or \fB-x\fP, if present).
244: .TP
245: \fB-f\fP \fIfilename\fP, \fB--file=\fP\fIfilename\fP
246: Read a number of patterns from the file, one per line, and match them against
247: each line of input. A data line is output if any of the patterns match it. The
248: filename can be given as "-" to refer to the standard input. When \fB-f\fP is
249: used, patterns specified on the command line using \fB-e\fP may also be
250: present; they are tested before the file's patterns. However, no other pattern
1.1.1.2 ! misho 251: is taken from the command line; all arguments are treated as the names of paths
! 252: to be searched. There is an overall maximum of 100 patterns. Trailing white
! 253: space is removed from each line, and blank lines are ignored. An empty file
! 254: contains no patterns and therefore matches nothing. See also the comments about
! 255: multiple patterns versus a single pattern with alternatives in the description
! 256: of \fB-e\fP above.
! 257: .TP
! 258: \fB--file-list\fP=\fIfilename\fP
! 259: Read a list of files to be searched from the given file, one per line. Trailing
! 260: white space is removed from each line, and blank lines are ignored. These files
! 261: are searched before any others that may be listed on the command line. The
! 262: filename can be given as "-" to refer to the standard input. If \fB--file\fP
! 263: and \fB--file-list\fP are both specified as "-", patterns are read first. This
! 264: is useful only when the standard input is a terminal, from which further lines
! 265: (the list of files) can be read after an end-of-file indication.
1.1 misho 266: .TP
267: \fB--file-offsets\fP
268: Instead of showing lines or parts of lines that match, show each match as an
269: offset from the start of the file and a length, separated by a comma. In this
270: mode, no context is shown. That is, the \fB-A\fP, \fB-B\fP, and \fB-C\fP
271: options are ignored. If there is more than one match in a line, each of them is
272: shown separately. This option is mutually exclusive with \fB--line-offsets\fP
273: and \fB--only-matching\fP.
274: .TP
275: \fB-H\fP, \fB--with-filename\fP
276: Force the inclusion of the filename at the start of output lines when searching
277: a single file. By default, the filename is not shown in this case. For matching
278: lines, the filename is followed by a colon; for context lines, a hyphen
279: separator is used. If a line number is also being output, it follows the file
280: name.
281: .TP
282: \fB-h\fP, \fB--no-filename\fP
283: Suppress the output filenames when searching multiple files. By default,
284: filenames are shown when multiple files are searched. For matching lines, the
285: filename is followed by a colon; for context lines, a hyphen separator is used.
286: If a line number is also being output, it follows the file name.
287: .TP
288: \fB--help\fP
289: Output a help message, giving brief details of the command options and file
290: type support, and then exit.
291: .TP
1.1.1.2 ! misho 292: \fB-I\fP
! 293: Treat binary files as never matching. This is equivalent to
! 294: \fB--binary-files\fP=\fIwithout-match\fP.
! 295: .TP
1.1 misho 296: \fB-i\fP, \fB--ignore-case\fP
297: Ignore upper/lower case distinctions during comparisons.
298: .TP
299: \fB--include\fP=\fIpattern\fP
300: When \fBpcregrep\fP is searching the files in a directory as a consequence of
301: the \fB-r\fP (recursive search) option, only those regular files whose names
302: match the pattern are included. Subdirectories are always included and searched
303: recursively, subject to the \fP--include-dir\fP and \fB--exclude-dir\fP
304: options. The pattern is a PCRE regular expression, and is matched against the
305: final component of the file name (not the entire path). If a file name matches
306: both \fB--include\fP and \fB--exclude\fP, it is excluded. There is no short
307: form for this option.
308: .TP
309: \fB--include-dir\fP=\fIpattern\fP
310: When \fBpcregrep\fP is searching the contents of a directory as a consequence
311: of the \fB-r\fP (recursive search) option, only those subdirectories whose
312: names match the pattern are included. (Note that the \fB--include\fP option
313: does not affect subdirectories.) The pattern is a PCRE regular expression, and
314: is matched against the final component of the name (not the entire path). If a
315: subdirectory name matches both \fB--include-dir\fP and \fB--exclude-dir\fP, it
316: is excluded. There is no short form for this option.
317: .TP
318: \fB-L\fP, \fB--files-without-match\fP
319: Instead of outputting lines from the files, just output the names of the files
320: that do not contain any lines that would have been output. Each file name is
321: output once, on a separate line.
322: .TP
323: \fB-l\fP, \fB--files-with-matches\fP
324: Instead of outputting lines from the files, just output the names of the files
325: containing lines that would have been output. Each file name is output
326: once, on a separate line. Searching normally stops as soon as a matching line
327: is found in a file. However, if the \fB-c\fP (count) option is also used,
328: matching continues in order to obtain the correct count, and those files that
329: have at least one match are listed along with their counts. Using this option
330: with \fB-c\fP is a way of suppressing the listing of files with no matches.
331: .TP
332: \fB--label\fP=\fIname\fP
333: This option supplies a name to be used for the standard input when file names
334: are being output. If not supplied, "(standard input)" is used. There is no
335: short form for this option.
336: .TP
337: \fB--line-buffered\fP
338: When this option is given, input is read and processed line by line, and the
339: output is flushed after each write. By default, input is read in large chunks,
340: unless \fBpcregrep\fP can determine that it is reading from a terminal (which
341: is currently possible only in Unix environments). Output to terminal is
342: normally automatically flushed by the operating system. This option can be
343: useful when the input or output is attached to a pipe and you do not want
344: \fBpcregrep\fP to buffer up large amounts of data. However, its use will affect
345: performance, and the \fB-M\fP (multiline) option ceases to work.
346: .TP
347: \fB--line-offsets\fP
348: Instead of showing lines or parts of lines that match, show each match as a
349: line number, the offset from the start of the line, and a length. The line
350: number is terminated by a colon (as usual; see the \fB-n\fP option), and the
351: offset and length are separated by a comma. In this mode, no context is shown.
352: That is, the \fB-A\fP, \fB-B\fP, and \fB-C\fP options are ignored. If there is
353: more than one match in a line, each of them is shown separately. This option is
354: mutually exclusive with \fB--file-offsets\fP and \fB--only-matching\fP.
355: .TP
356: \fB--locale\fP=\fIlocale-name\fP
357: This option specifies a locale to be used for pattern matching. It overrides
358: the value in the \fBLC_ALL\fP or \fBLC_CTYPE\fP environment variables. If no
359: locale is specified, the PCRE library's default (usually the "C" locale) is
360: used. There is no short form for this option.
361: .TP
362: \fB--match-limit\fP=\fInumber\fP
363: Processing some regular expression patterns can require a very large amount of
364: memory, leading in some cases to a program crash if not enough is available.
365: Other patterns may take a very long time to search for all possible matching
366: strings. The \fBpcre_exec()\fP function that is called by \fBpcregrep\fP to do
367: the matching has two parameters that can limit the resources that it uses.
368: .sp
369: The \fB--match-limit\fP option provides a means of limiting resource usage
370: when processing patterns that are not going to match, but which have a very
371: large number of possibilities in their search trees. The classic example is a
372: pattern that uses nested unlimited repeats. Internally, PCRE uses a function
373: called \fBmatch()\fP which it calls repeatedly (sometimes recursively). The
374: limit set by \fB--match-limit\fP is imposed on the number of times this
375: function is called during a match, which has the effect of limiting the amount
376: of backtracking that can take place.
377: .sp
378: The \fB--recursion-limit\fP option is similar to \fB--match-limit\fP, but
379: instead of limiting the total number of times that \fBmatch()\fP is called, it
380: limits the depth of recursive calls, which in turn limits the amount of memory
381: that can be used. The recursion depth is a smaller number than the total number
382: of calls, because not all calls to \fBmatch()\fP are recursive. This limit is
383: of use only if it is set smaller than \fB--match-limit\fP.
384: .sp
385: There are no short forms for these options. The default settings are specified
386: when the PCRE library is compiled, with the default default being 10 million.
387: .TP
388: \fB-M\fP, \fB--multiline\fP
389: Allow patterns to match more than one line. When this option is given, patterns
390: may usefully contain literal newline characters and internal occurrences of ^
391: and $ characters. The output for a successful match may consist of more than
392: one line, the last of which is the one in which the match ended. If the matched
393: string ends with a newline sequence the output ends at the end of that line.
394: .sp
395: When this option is set, the PCRE library is called in "multiline" mode.
396: There is a limit to the number of lines that can be matched, imposed by the way
397: that \fBpcregrep\fP buffers the input file as it scans it. However,
398: \fBpcregrep\fP ensures that at least 8K characters or the rest of the document
399: (whichever is the shorter) are available for forward matching, and similarly
400: the previous 8K characters (or all the previous characters, if fewer than 8K)
401: are guaranteed to be available for lookbehind assertions. This option does not
402: work when input is read line by line (see \fP--line-buffered\fP.)
403: .TP
404: \fB-N\fP \fInewline-type\fP, \fB--newline\fP=\fInewline-type\fP
405: The PCRE library supports five different conventions for indicating
406: the ends of lines. They are the single-character sequences CR (carriage return)
407: and LF (linefeed), the two-character sequence CRLF, an "anycrlf" convention,
408: which recognizes any of the preceding three types, and an "any" convention, in
409: which any Unicode line ending sequence is assumed to end a line. The Unicode
410: sequences are the three just mentioned, plus VT (vertical tab, U+000B), FF
411: (form feed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and
412: PS (paragraph separator, U+2029).
413: .sp
414: When the PCRE library is built, a default line-ending sequence is specified.
415: This is normally the standard sequence for the operating system. Unless
416: otherwise specified by this option, \fBpcregrep\fP uses the library's default.
417: The possible values for this option are CR, LF, CRLF, ANYCRLF, or ANY. This
418: makes it possible to use \fBpcregrep\fP on files that have come from other
419: environments without having to modify their line endings. If the data that is
420: being scanned does not agree with the convention set by this option,
421: \fBpcregrep\fP may behave in strange ways.
422: .TP
423: \fB-n\fP, \fB--line-number\fP
424: Precede each output line by its line number in the file, followed by a colon
425: for matching lines or a hyphen for context lines. If the filename is also being
426: output, it precedes the line number. This option is forced if
427: \fB--line-offsets\fP is used.
428: .TP
429: \fB--no-jit\fP
430: If the PCRE library is built with support for just-in-time compiling (which
431: speeds up matching), \fBpcregrep\fP automatically makes use of this, unless it
432: was explicitly disabled at build time. This option can be used to disable the
433: use of JIT at run time. It is provided for testing and working round problems.
434: It should never be needed in normal use.
435: .TP
436: \fB-o\fP, \fB--only-matching\fP
437: Show only the part of the line that matched a pattern instead of the whole
438: line. In this mode, no context is shown. That is, the \fB-A\fP, \fB-B\fP, and
439: \fB-C\fP options are ignored. If there is more than one match in a line, each
440: of them is shown separately. If \fB-o\fP is combined with \fB-v\fP (invert the
441: sense of the match to find non-matching lines), no output is generated, but the
442: return code is set appropriately. If the matched portion of the line is empty,
443: nothing is output unless the file name or line number are being printed, in
444: which case they are shown on an otherwise empty line. This option is mutually
445: exclusive with \fB--file-offsets\fP and \fB--line-offsets\fP.
446: .TP
447: \fB-o\fP\fInumber\fP, \fB--only-matching\fP=\fInumber\fP
448: Show only the part of the line that matched the capturing parentheses of the
449: given number. Up to 32 capturing parentheses are supported. Because these
450: options can be given without an argument (see above), if an argument is
451: present, it must be given in the same shell item, for example, -o3 or
452: --only-matching=2. The comments given for the non-argument case above also
453: apply to this case. If the specified capturing parentheses do not exist in the
454: pattern, or were not set in the match, nothing is output unless the file name
455: or line number are being printed.
456: .TP
457: \fB-q\fP, \fB--quiet\fP
458: Work quietly, that is, display nothing except error messages. The exit
459: status indicates whether or not any matches were found.
460: .TP
461: \fB-r\fP, \fB--recursive\fP
462: If any given path is a directory, recursively scan the files it contains,
463: taking note of any \fB--include\fP and \fB--exclude\fP settings. By default, a
464: directory is read as a normal file; in some operating systems this gives an
465: immediate end-of-file. This option is a shorthand for setting the \fB-d\fP
466: option to "recurse".
467: .TP
468: \fB--recursion-limit\fP=\fInumber\fP
469: See \fB--match-limit\fP above.
470: .TP
471: \fB-s\fP, \fB--no-messages\fP
472: Suppress error messages about non-existent or unreadable files. Such files are
473: quietly skipped. However, the return code is still 2, even if matches were
474: found in other files.
475: .TP
476: \fB-u\fP, \fB--utf-8\fP
477: Operate in UTF-8 mode. This option is available only if PCRE has been compiled
478: with UTF-8 support. Both patterns and subject lines must be valid strings of
479: UTF-8 characters.
480: .TP
481: \fB-V\fP, \fB--version\fP
482: Write the version numbers of \fBpcregrep\fP and the PCRE library that is being
483: used to the standard error stream.
484: .TP
485: \fB-v\fP, \fB--invert-match\fP
486: Invert the sense of the match, so that lines which do \fInot\fP match any of
487: the patterns are the ones that are found.
488: .TP
489: \fB-w\fP, \fB--word-regex\fP, \fB--word-regexp\fP
490: Force the patterns to match only whole words. This is equivalent to having \eb
491: at the start and end of the pattern.
492: .TP
493: \fB-x\fP, \fB--line-regex\fP, \fB--line-regexp\fP
494: Force the patterns to be anchored (each must start matching at the beginning of
495: a line) and in addition, require them to match entire lines. This is
496: equivalent to having ^ and $ characters at the start and end of each
497: alternative branch in every pattern.
498: .
499: .
500: .SH "ENVIRONMENT VARIABLES"
501: .rs
502: .sp
503: The environment variables \fBLC_ALL\fP and \fBLC_CTYPE\fP are examined, in that
504: order, for a locale. The first one that is set is used. This can be overridden
505: by the \fB--locale\fP option. If no locale is set, the PCRE library's default
506: (usually the "C" locale) is used.
507: .
508: .
509: .SH "NEWLINES"
510: .rs
511: .sp
512: The \fB-N\fP (\fB--newline\fP) option allows \fBpcregrep\fP to scan files with
513: different newline conventions from the default. However, the setting of this
514: option does not affect the way in which \fBpcregrep\fP writes information to
515: the standard error and output streams. It uses the string "\en" in C
516: \fBprintf()\fP calls to indicate newlines, relying on the C I/O library to
517: convert this to an appropriate sequence if the output is sent to a file.
518: .
519: .
520: .SH "OPTIONS COMPATIBILITY"
521: .rs
522: .sp
523: Many of the short and long forms of \fBpcregrep\fP's options are the same
1.1.1.2 ! misho 524: as in the GNU \fBgrep\fP program. Any long option of the form
1.1 misho 525: \fB--xxx-regexp\fP (GNU terminology) is also available as \fB--xxx-regex\fP
1.1.1.2 ! misho 526: (PCRE terminology). However, the \fB--file-list\fP, \fB--file-offsets\fP,
! 527: \fB--include-dir\fP, \fB--line-offsets\fP, \fB--locale\fP, \fB--match-limit\fP,
! 528: \fB-M\fP, \fB--multiline\fP, \fB-N\fP, \fB--newline\fP,
! 529: \fB--recursion-limit\fP, \fB-u\fP, and \fB--utf-8\fP options are specific to
! 530: \fBpcregrep\fP, as is the use of the \fB--only-matching\fP option with a
! 531: capturing parentheses number.
1.1 misho 532: .P
533: Although most of the common options work the same way, a few are different in
534: \fBpcregrep\fP. For example, the \fB--include\fP option's argument is a glob
535: for GNU \fBgrep\fP, but a regular expression for \fBpcregrep\fP. If both the
536: \fB-c\fP and \fB-l\fP options are given, GNU grep lists only file names,
537: without counts, but \fBpcregrep\fP gives the counts.
538: .
539: .
540: .SH "OPTIONS WITH DATA"
541: .rs
542: .sp
543: There are four different ways in which an option with data can be specified.
544: If a short form option is used, the data may follow immediately, or (with one
545: exception) in the next command line item. For example:
546: .sp
547: -f/some/file
548: -f /some/file
549: .sp
550: The exception is the \fB-o\fP option, which may appear with or without data.
551: Because of this, if data is present, it must follow immediately in the same
552: item, for example -o3.
553: .P
554: If a long form option is used, the data may appear in the same command line
555: item, separated by an equals character, or (with two exceptions) it may appear
556: in the next command line item. For example:
557: .sp
558: --file=/some/file
559: --file /some/file
560: .sp
561: Note, however, that if you want to supply a file name beginning with ~ as data
562: in a shell command, and have the shell expand ~ to a home directory, you must
563: separate the file name from the option, because the shell does not treat ~
564: specially unless it is at the start of an item.
565: .P
566: The exceptions to the above are the \fB--colour\fP (or \fB--color\fP) and
567: \fB--only-matching\fP options, for which the data is optional. If one of these
568: options does have data, it must be given in the first form, using an equals
569: character. Otherwise \fBpcregrep\fP will assume that it has no data.
570: .
571: .
572: .SH "MATCHING ERRORS"
573: .rs
574: .sp
575: It is possible to supply a regular expression that takes a very long time to
576: fail to match certain lines. Such patterns normally involve nested indefinite
577: repeats, for example: (a+)*\ed when matched against a line of a's with no final
578: digit. The PCRE matching function has a resource limit that causes it to abort
579: in these circumstances. If this happens, \fBpcregrep\fP outputs an error
580: message and the line that caused the problem to the standard error stream. If
581: there are more than 20 such errors, \fBpcregrep\fP gives up.
582: .P
583: The \fB--match-limit\fP option of \fBpcregrep\fP can be used to set the overall
584: resource limit; there is a second option called \fB--recursion-limit\fP that
585: sets a limit on the amount of memory (usually stack) that is used (see the
586: discussion of these options above).
587: .
588: .
589: .SH DIAGNOSTICS
590: .rs
591: .sp
592: Exit status is 0 if any matches were found, 1 if no matches were found, and 2
593: for syntax errors, overlong lines, non-existent or inaccessible files (even if
594: matches were found in other files) or too many matching errors. Using the
595: \fB-s\fP option to suppress error messages about inaccessible files does not
596: affect the return code.
597: .
598: .
599: .SH "SEE ALSO"
600: .rs
601: .sp
602: \fBpcrepattern\fP(3), \fBpcretest\fP(1).
603: .
604: .
605: .SH AUTHOR
606: .rs
607: .sp
608: .nf
609: Philip Hazel
610: University Computing Service
611: Cambridge CB2 3QH, England.
612: .fi
613: .
614: .
615: .SH REVISION
616: .rs
617: .sp
618: .nf
1.1.1.2 ! misho 619: Last updated: 04 March 2012
! 620: Copyright (c) 1997-2012 University of Cambridge.
1.1 misho 621: .fi
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