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authorIvo De Decker <ivodd@debian.org>2014-12-06 18:58:19 +0000
committerIvo De Decker <ivodd@debian.org>2014-12-06 18:58:19 +0000
commitdd986e8b547c0dde924c4b566ad0894ad4f1beb9 (patch)
treea87ee49df2a732f2be8d1b3c9e46a341e6fb8698 /doc/pcregrep.txt
pcre3 (2:8.35-3.3) unstable; urgency=medium
* Non-maintainer upload. * Upstream patch for heap buffer overflow, CVE-2014-8964, taken from 1:8.36-1 (Closes: #770478) Thanks to Salvatore Bonaccorso for the reminder. # imported from the archive
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+PCREGREP(1) General Commands Manual PCREGREP(1)
+
+
+
+NAME
+ pcregrep - a grep with Perl-compatible regular expressions.
+
+SYNOPSIS
+ pcregrep [options] [long options] [pattern] [path1 path2 ...]
+
+
+DESCRIPTION
+
+ pcregrep searches files for character patterns, in the same way as
+ other grep commands do, but it uses the PCRE regular expression library
+ to support patterns that are compatible with the regular expressions of
+ Perl 5. See pcresyntax(3) for a quick-reference summary of pattern syn-
+ tax, or pcrepattern(3) for a full description of the syntax and seman-
+ tics of the regular expressions that PCRE supports.
+
+ Patterns, whether supplied on the command line or in a separate file,
+ are given without delimiters. For example:
+
+ pcregrep Thursday /etc/motd
+
+ If you attempt to use delimiters (for example, by surrounding a pattern
+ with slashes, as is common in Perl scripts), they are interpreted as
+ part of the pattern. Quotes can of course be used to delimit patterns
+ on the command line because they are interpreted by the shell, and
+ indeed quotes are required if a pattern contains white space or shell
+ metacharacters.
+
+ The first argument that follows any option settings is treated as the
+ single pattern to be matched when neither -e nor -f is present. Con-
+ versely, when one or both of these options are used to specify pat-
+ terns, all arguments are treated as path names. At least one of -e, -f,
+ or an argument pattern must be provided.
+
+ If no files are specified, pcregrep reads the standard input. The stan-
+ dard input can also be referenced by a name consisting of a single
+ hyphen. For example:
+
+ pcregrep some-pattern /file1 - /file3
+
+ By default, each line that matches a pattern is copied to the standard
+ output, and if there is more than one file, the file name is output at
+ the start of each line, followed by a colon. However, there are options
+ that can change how pcregrep behaves. In particular, the -M option
+ makes it possible to search for patterns that span line boundaries.
+ What defines a line boundary is controlled by the -N (--newline)
+ option.
+
+ The amount of memory used for buffering files that are being scanned is
+ controlled by a parameter that can be set by the --buffer-size option.
+ The default value for this parameter is specified when pcregrep is
+ built, with the default default being 20K. A block of memory three
+ times this size is used (to allow for buffering "before" and "after"
+ lines). An error occurs if a line overflows the buffer.
+
+ Patterns can be no longer than 8K or BUFSIZ bytes, whichever is the
+ greater. BUFSIZ is defined in <stdio.h>. When there is more than one
+ pattern (specified by the use of -e and/or -f), each pattern is applied
+ to each line in the order in which they are defined, except that all
+ the -e patterns are tried before the -f patterns.
+
+ By default, as soon as one pattern matches a line, no further patterns
+ are considered. However, if --colour (or --color) is used to colour the
+ matching substrings, or if --only-matching, --file-offsets, or --line-
+ offsets is used to output only the part of the line that matched
+ (either shown literally, or as an offset), scanning resumes immediately
+ following the match, so that further matches on the same line can be
+ found. If there are multiple patterns, they are all tried on the
+ remainder of the line, but patterns that follow the one that matched
+ are not tried on the earlier part of the line.
+
+ This behaviour means that the order in which multiple patterns are
+ specified can affect the output when one of the above options is used.
+ This is no longer the same behaviour as GNU grep, which now manages to
+ display earlier matches for later patterns (as long as there is no
+ overlap).
+
+ Patterns that can match an empty string are accepted, but empty string
+ matches are never recognized. An example is the pattern
+ "(super)?(man)?", in which all components are optional. This pattern
+ finds all occurrences of both "super" and "man"; the output differs
+ from matching with "super|man" when only the matching substrings are
+ being shown.
+
+ If the LC_ALL or LC_CTYPE environment variable is set, pcregrep uses
+ the value to set a locale when calling the PCRE library. The --locale
+ option can be used to override this.
+
+
+SUPPORT FOR COMPRESSED FILES
+
+ It is possible to compile pcregrep so that it uses libz or libbz2 to
+ read files whose names end in .gz or .bz2, respectively. You can find
+ out whether your binary has support for one or both of these file types
+ by running it with the --help option. If the appropriate support is not
+ present, files are treated as plain text. The standard input is always
+ so treated.
+
+
+BINARY FILES
+
+ By default, a file that contains a binary zero byte within the first
+ 1024 bytes is identified as a binary file, and is processed specially.
+ (GNU grep also identifies binary files in this manner.) See the
+ --binary-files option for a means of changing the way binary files are
+ handled.
+
+
+OPTIONS
+
+ The order in which some of the options appear can affect the output.
+ For example, both the -h and -l options affect the printing of file
+ names. Whichever comes later in the command line will be the one that
+ takes effect. Similarly, except where noted below, if an option is
+ given twice, the later setting is used. Numerical values for options
+ may be followed by K or M, to signify multiplication by 1024 or
+ 1024*1024 respectively.
+
+ -- This terminates the list of options. It is useful if the next
+ item on the command line starts with a hyphen but is not an
+ option. This allows for the processing of patterns and file-
+ names that start with hyphens.
+
+ -A number, --after-context=number
+ Output number lines of context after each matching line. If
+ filenames and/or line numbers are being output, a hyphen sep-
+ arator is used instead of a colon for the context lines. A
+ line containing "--" is output between each group of lines,
+ unless they are in fact contiguous in the input file. The
+ value of number is expected to be relatively small. However,
+ pcregrep guarantees to have up to 8K of following text avail-
+ able for context output.
+
+ -a, --text
+ Treat binary files as text. This is equivalent to --binary-
+ files=text.
+
+ -B number, --before-context=number
+ Output number lines of context before each matching line. If
+ filenames and/or line numbers are being output, a hyphen sep-
+ arator is used instead of a colon for the context lines. A
+ line containing "--" is output between each group of lines,
+ unless they are in fact contiguous in the input file. The
+ value of number is expected to be relatively small. However,
+ pcregrep guarantees to have up to 8K of preceding text avail-
+ able for context output.
+
+ --binary-files=word
+ Specify how binary files are to be processed. If the word is
+ "binary" (the default), pattern matching is performed on
+ binary files, but the only output is "Binary file <name>
+ matches" when a match succeeds. If the word is "text", which
+ is equivalent to the -a or --text option, binary files are
+ processed in the same way as any other file. In this case,
+ when a match succeeds, the output may be binary garbage,
+ which can have nasty effects if sent to a terminal. If the
+ word is "without-match", which is equivalent to the -I
+ option, binary files are not processed at all; they are
+ assumed not to be of interest.
+
+ --buffer-size=number
+ Set the parameter that controls how much memory is used for
+ buffering files that are being scanned.
+
+ -C number, --context=number
+ Output number lines of context both before and after each
+ matching line. This is equivalent to setting both -A and -B
+ to the same value.
+
+ -c, --count
+ Do not output individual lines from the files that are being
+ scanned; instead output the number of lines that would other-
+ wise have been shown. If no lines are selected, the number
+ zero is output. If several files are are being scanned, a
+ count is output for each of them. However, if the --files-
+ with-matches option is also used, only those files whose
+ counts are greater than zero are listed. When -c is used, the
+ -A, -B, and -C options are ignored.
+
+ --colour, --color
+ If this option is given without any data, it is equivalent to
+ "--colour=auto". If data is required, it must be given in
+ the same shell item, separated by an equals sign.
+
+ --colour=value, --color=value
+ This option specifies under what circumstances the parts of a
+ line that matched a pattern should be coloured in the output.
+ By default, the output is not coloured. The value (which is
+ optional, see above) may be "never", "always", or "auto". In
+ the latter case, colouring happens only if the standard out-
+ put is connected to a terminal. More resources are used when
+ colouring is enabled, because pcregrep has to search for all
+ possible matches in a line, not just one, in order to colour
+ them all.
+
+ The colour that is used can be specified by setting the envi-
+ ronment variable PCREGREP_COLOUR or PCREGREP_COLOR. The value
+ of this variable should be a string of two numbers, separated
+ by a semicolon. They are copied directly into the control
+ string for setting colour on a terminal, so it is your
+ responsibility to ensure that they make sense. If neither of
+ the environment variables is set, the default is "1;31",
+ which gives red.
+
+ -D action, --devices=action
+ If an input path is not a regular file or a directory,
+ "action" specifies how it is to be processed. Valid values
+ are "read" (the default) or "skip" (silently skip the path).
+
+ -d action, --directories=action
+ If an input path is a directory, "action" specifies how it is
+ to be processed. Valid values are "read" (the default in
+ non-Windows environments, for compatibility with GNU grep),
+ "recurse" (equivalent to the -r option), or "skip" (silently
+ skip the path, the default in Windows environments). In the
+ "read" case, directories are read as if they were ordinary
+ files. In some operating systems the effect of reading a
+ directory like this is an immediate end-of-file; in others it
+ may provoke an error.
+
+ -e pattern, --regex=pattern, --regexp=pattern
+ Specify a pattern to be matched. This option can be used mul-
+ tiple times in order to specify several patterns. It can also
+ be used as a way of specifying a single pattern that starts
+ with a hyphen. When -e is used, no argument pattern is taken
+ from the command line; all arguments are treated as file
+ names. There is no limit to the number of patterns. They are
+ applied to each line in the order in which they are defined
+ until one matches.
+
+ If -f is used with -e, the command line patterns are matched
+ first, followed by the patterns from the file(s), independent
+ of the order in which these options are specified. Note that
+ multiple use of -e is not the same as a single pattern with
+ alternatives. For example, X|Y finds the first character in a
+ line that is X or Y, whereas if the two patterns are given
+ separately, with X first, pcregrep finds X if it is present,
+ even if it follows Y in the line. It finds Y only if there is
+ no X in the line. This matters only if you are using -o or
+ --colo(u)r to show the part(s) of the line that matched.
+
+ --exclude=pattern
+ Files (but not directories) whose names match the pattern are
+ skipped without being processed. This applies to all files,
+ whether listed on the command line, obtained from --file-
+ list, or by scanning a directory. The pattern is a PCRE regu-
+ lar expression, and is matched against the final component of
+ the file name, not the entire path. The -F, -w, and -x
+ options do not apply to this pattern. The option may be given
+ any number of times in order to specify multiple patterns. If
+ a file name matches both an --include and an --exclude pat-
+ tern, it is excluded. There is no short form for this option.
+
+ --exclude-from=filename
+ Treat each non-empty line of the file as the data for an
+ --exclude option. What constitutes a newline when reading the
+ file is the operating system's default. The --newline option
+ has no effect on this option. This option may be given more
+ than once in order to specify a number of files to read.
+
+ --exclude-dir=pattern
+ Directories whose names match the pattern are skipped without
+ being processed, whatever the setting of the --recursive
+ option. This applies to all directories, whether listed on
+ the command line, obtained from --file-list, or by scanning a
+ parent directory. The pattern is a PCRE regular expression,
+ and is matched against the final component of the directory
+ name, not the entire path. The -F, -w, and -x options do not
+ apply to this pattern. The option may be given any number of
+ times in order to specify more than one pattern. If a direc-
+ tory matches both --include-dir and --exclude-dir, it is
+ excluded. There is no short form for this option.
+
+ -F, --fixed-strings
+ Interpret each data-matching pattern as a list of fixed
+ strings, separated by newlines, instead of as a regular
+ expression. What constitutes a newline for this purpose is
+ controlled by the --newline option. The -w (match as a word)
+ and -x (match whole line) options can be used with -F. They
+ apply to each of the fixed strings. A line is selected if any
+ of the fixed strings are found in it (subject to -w or -x, if
+ present). This option applies only to the patterns that are
+ matched against the contents of files; it does not apply to
+ patterns specified by any of the --include or --exclude
+ options.
+
+ -f filename, --file=filename
+ Read patterns from the file, one per line, and match them
+ against each line of input. What constitutes a newline when
+ reading the file is the operating system's default. The
+ --newline option has no effect on this option. Trailing white
+ space is removed from each line, and blank lines are ignored.
+ An empty file contains no patterns and therefore matches
+ nothing. See also the comments about multiple patterns versus
+ a single pattern with alternatives in the description of -e
+ above.
+
+ If this option is given more than once, all the specified
+ files are read. A data line is output if any of the patterns
+ match it. A filename can be given as "-" to refer to the
+ standard input. When -f is used, patterns specified on the
+ command line using -e may also be present; they are tested
+ before the file's patterns. However, no other pattern is
+ taken from the command line; all arguments are treated as the
+ names of paths to be searched.
+
+ --file-list=filename
+ Read a list of files and/or directories that are to be
+ scanned from the given file, one per line. Trailing white
+ space is removed from each line, and blank lines are ignored.
+ These paths are processed before any that are listed on the
+ command line. The filename can be given as "-" to refer to
+ the standard input. If --file and --file-list are both spec-
+ ified as "-", patterns are read first. This is useful only
+ when the standard input is a terminal, from which further
+ lines (the list of files) can be read after an end-of-file
+ indication. If this option is given more than once, all the
+ specified files are read.
+
+ --file-offsets
+ Instead of showing lines or parts of lines that match, show
+ each match as an offset from the start of the file and a
+ length, separated by a comma. In this mode, no context is
+ shown. That is, the -A, -B, and -C options are ignored. If
+ there is more than one match in a line, each of them is shown
+ separately. This option is mutually exclusive with --line-
+ offsets and --only-matching.
+
+ -H, --with-filename
+ Force the inclusion of the filename at the start of output
+ lines when searching a single file. By default, the filename
+ is not shown in this case. For matching lines, the filename
+ is followed by a colon; for context lines, a hyphen separator
+ is used. If a line number is also being output, it follows
+ the file name.
+
+ -h, --no-filename
+ Suppress the output filenames when searching multiple files.
+ By default, filenames are shown when multiple files are
+ searched. For matching lines, the filename is followed by a
+ colon; for context lines, a hyphen separator is used. If a
+ line number is also being output, it follows the file name.
+
+ --help Output a help message, giving brief details of the command
+ options and file type support, and then exit. Anything else
+ on the command line is ignored.
+
+ -I Treat binary files as never matching. This is equivalent to
+ --binary-files=without-match.
+
+ -i, --ignore-case
+ Ignore upper/lower case distinctions during comparisons.
+
+ --include=pattern
+ If any --include patterns are specified, the only files that
+ are processed are those that match one of the patterns (and
+ do not match an --exclude pattern). This option does not
+ affect directories, but it applies to all files, whether
+ listed on the command line, obtained from --file-list, or by
+ scanning a directory. The pattern is a PCRE regular expres-
+ sion, and is matched against the final component of the file
+ name, not the entire path. The -F, -w, and -x options do not
+ apply to this pattern. The option may be given any number of
+ times. If a file name matches both an --include and an
+ --exclude pattern, it is excluded. There is no short form
+ for this option.
+
+ --include-from=filename
+ Treat each non-empty line of the file as the data for an
+ --include option. What constitutes a newline for this purpose
+ is the operating system's default. The --newline option has
+ no effect on this option. This option may be given any number
+ of times; all the files are read.
+
+ --include-dir=pattern
+ If any --include-dir patterns are specified, the only direc-
+ tories that are processed are those that match one of the
+ patterns (and do not match an --exclude-dir pattern). This
+ applies to all directories, whether listed on the command
+ line, obtained from --file-list, or by scanning a parent
+ directory. The pattern is a PCRE regular expression, and is
+ matched against the final component of the directory name,
+ not the entire path. The -F, -w, and -x options do not apply
+ to this pattern. The option may be given any number of times.
+ If a directory matches both --include-dir and --exclude-dir,
+ it is excluded. There is no short form for this option.
+
+ -L, --files-without-match
+ Instead of outputting lines from the files, just output the
+ names of the files that do not contain any lines that would
+ have been output. Each file name is output once, on a sepa-
+ rate line.
+
+ -l, --files-with-matches
+ Instead of outputting lines from the files, just output the
+ names of the files containing lines that would have been out-
+ put. Each file name is output once, on a separate line.
+ Searching normally stops as soon as a matching line is found
+ in a file. However, if the -c (count) option is also used,
+ matching continues in order to obtain the correct count, and
+ those files that have at least one match are listed along
+ with their counts. Using this option with -c is a way of sup-
+ pressing the listing of files with no matches.
+
+ --label=name
+ This option supplies a name to be used for the standard input
+ when file names are being output. If not supplied, "(standard
+ input)" is used. There is no short form for this option.
+
+ --line-buffered
+ When this option is given, input is read and processed line
+ by line, and the output is flushed after each write. By
+ default, input is read in large chunks, unless pcregrep can
+ determine that it is reading from a terminal (which is cur-
+ rently possible only in Unix-like environments). Output to
+ terminal is normally automatically flushed by the operating
+ system. This option can be useful when the input or output is
+ attached to a pipe and you do not want pcregrep to buffer up
+ large amounts of data. However, its use will affect perfor-
+ mance, and the -M (multiline) option ceases to work.
+
+ --line-offsets
+ Instead of showing lines or parts of lines that match, show
+ each match as a line number, the offset from the start of the
+ line, and a length. The line number is terminated by a colon
+ (as usual; see the -n option), and the offset and length are
+ separated by a comma. In this mode, no context is shown.
+ That is, the -A, -B, and -C options are ignored. If there is
+ more than one match in a line, each of them is shown sepa-
+ rately. This option is mutually exclusive with --file-offsets
+ and --only-matching.
+
+ --locale=locale-name
+ This option specifies a locale to be used for pattern match-
+ ing. It overrides the value in the LC_ALL or LC_CTYPE envi-
+ ronment variables. If no locale is specified, the PCRE
+ library's default (usually the "C" locale) is used. There is
+ no short form for this option.
+
+ --match-limit=number
+ Processing some regular expression patterns can require a
+ very large amount of memory, leading in some cases to a pro-
+ gram crash if not enough is available. Other patterns may
+ take a very long time to search for all possible matching
+ strings. The pcre_exec() function that is called by pcregrep
+ to do the matching has two parameters that can limit the
+ resources that it uses.
+
+ The --match-limit option provides a means of limiting
+ resource usage when processing patterns that are not going to
+ match, but which have a very large number of possibilities in
+ their search trees. The classic example is a pattern that
+ uses nested unlimited repeats. Internally, PCRE uses a func-
+ tion called match() which it calls repeatedly (sometimes
+ recursively). The limit set by --match-limit is imposed on
+ the number of times this function is called during a match,
+ which has the effect of limiting the amount of backtracking
+ that can take place.
+
+ The --recursion-limit option is similar to --match-limit, but
+ instead of limiting the total number of times that match() is
+ called, it limits the depth of recursive calls, which in turn
+ limits the amount of memory that can be used. The recursion
+ depth is a smaller number than the total number of calls,
+ because not all calls to match() are recursive. This limit is
+ of use only if it is set smaller than --match-limit.
+
+ There are no short forms for these options. The default set-
+ tings are specified when the PCRE library is compiled, with
+ the default default being 10 million.
+
+ -M, --multiline
+ Allow patterns to match more than one line. When this option
+ is given, patterns may usefully contain literal newline char-
+ acters and internal occurrences of ^ and $ characters. The
+ output for a successful match may consist of more than one
+ line, the last of which is the one in which the match ended.
+ If the matched string ends with a newline sequence the output
+ ends at the end of that line.
+
+ When this option is set, the PCRE library is called in "mul-
+ tiline" mode. There is a limit to the number of lines that
+ can be matched, imposed by the way that pcregrep buffers the
+ input file as it scans it. However, pcregrep ensures that at
+ least 8K characters or the rest of the document (whichever is
+ the shorter) are available for forward matching, and simi-
+ larly the previous 8K characters (or all the previous charac-
+ ters, if fewer than 8K) are guaranteed to be available for
+ lookbehind assertions. This option does not work when input
+ is read line by line (see --line-buffered.)
+
+ -N newline-type, --newline=newline-type
+ The PCRE library supports five different conventions for
+ indicating the ends of lines. They are the single-character
+ sequences CR (carriage return) and LF (linefeed), the two-
+ character sequence CRLF, an "anycrlf" convention, which rec-
+ ognizes any of the preceding three types, and an "any" con-
+ vention, in which any Unicode line ending sequence is assumed
+ to end a line. The Unicode sequences are the three just men-
+ tioned, plus VT (vertical tab, U+000B), FF (form feed,
+ U+000C), NEL (next line, U+0085), LS (line separator,
+ U+2028), and PS (paragraph separator, U+2029).
+
+ When the PCRE library is built, a default line-ending
+ sequence is specified. This is normally the standard
+ sequence for the operating system. Unless otherwise specified
+ by this option, pcregrep uses the library's default. The
+ possible values for this option are CR, LF, CRLF, ANYCRLF, or
+ ANY. This makes it possible to use pcregrep to scan files
+ that have come from other environments without having to mod-
+ ify their line endings. If the data that is being scanned
+ does not agree with the convention set by this option, pcre-
+ grep may behave in strange ways. Note that this option does
+ not apply to files specified by the -f, --exclude-from, or
+ --include-from options, which are expected to use the operat-
+ ing system's standard newline sequence.
+
+ -n, --line-number
+ Precede each output line by its line number in the file, fol-
+ lowed by a colon for matching lines or a hyphen for context
+ lines. If the filename is also being output, it precedes the
+ line number. This option is forced if --line-offsets is used.
+
+ --no-jit If the PCRE library is built with support for just-in-time
+ compiling (which speeds up matching), pcregrep automatically
+ makes use of this, unless it was explicitly disabled at build
+ time. This option can be used to disable the use of JIT at
+ run time. It is provided for testing and working round prob-
+ lems. It should never be needed in normal use.
+
+ -o, --only-matching
+ Show only the part of the line that matched a pattern instead
+ of the whole line. In this mode, no context is shown. That
+ is, the -A, -B, and -C options are ignored. If there is more
+ than one match in a line, each of them is shown separately.
+ If -o is combined with -v (invert the sense of the match to
+ find non-matching lines), no output is generated, but the
+ return code is set appropriately. If the matched portion of
+ the line is empty, nothing is output unless the file name or
+ line number are being printed, in which case they are shown
+ on an otherwise empty line. This option is mutually exclusive
+ with --file-offsets and --line-offsets.
+
+ -onumber, --only-matching=number
+ Show only the part of the line that matched the capturing
+ parentheses of the given number. Up to 32 capturing parenthe-
+ ses are supported, and -o0 is equivalent to -o without a num-
+ ber. Because these options can be given without an argument
+ (see above), if an argument is present, it must be given in
+ the same shell item, for example, -o3 or --only-matching=2.
+ The comments given for the non-argument case above also apply
+ to this case. If the specified capturing parentheses do not
+ exist in the pattern, or were not set in the match, nothing
+ is output unless the file name or line number are being
+ printed.
+
+ If this option is given multiple times, multiple substrings
+ are output, in the order the options are given. For example,
+ -o3 -o1 -o3 causes the substrings matched by capturing paren-
+ theses 3 and 1 and then 3 again to be output. By default,
+ there is no separator (but see the next option).
+
+ --om-separator=text
+ Specify a separating string for multiple occurrences of -o.
+ The default is an empty string. Separating strings are never
+ coloured.
+
+ -q, --quiet
+ Work quietly, that is, display nothing except error messages.
+ The exit status indicates whether or not any matches were
+ found.
+
+ -r, --recursive
+ If any given path is a directory, recursively scan the files
+ it contains, taking note of any --include and --exclude set-
+ tings. By default, a directory is read as a normal file; in
+ some operating systems this gives an immediate end-of-file.
+ This option is a shorthand for setting the -d option to
+ "recurse".
+
+ --recursion-limit=number
+ See --match-limit above.
+
+ -s, --no-messages
+ Suppress error messages about non-existent or unreadable
+ files. Such files are quietly skipped. However, the return
+ code is still 2, even if matches were found in other files.
+
+ -u, --utf-8
+ Operate in UTF-8 mode. This option is available only if PCRE
+ has been compiled with UTF-8 support. All patterns (including
+ those for any --exclude and --include options) and all sub-
+ ject lines that are scanned must be valid strings of UTF-8
+ characters.
+
+ -V, --version
+ Write the version numbers of pcregrep and the PCRE library to
+ the standard output and then exit. Anything else on the com-
+ mand line is ignored.
+
+ -v, --invert-match
+ Invert the sense of the match, so that lines which do not
+ match any of the patterns are the ones that are found.
+
+ -w, --word-regex, --word-regexp
+ Force the patterns to match only whole words. This is equiva-
+ lent to having \b at the start and end of the pattern. This
+ option applies only to the patterns that are matched against
+ the contents of files; it does not apply to patterns speci-
+ fied by any of the --include or --exclude options.
+
+ -x, --line-regex, --line-regexp
+ Force the patterns to be anchored (each must start matching
+ at the beginning of a line) and in addition, require them to
+ match entire lines. This is equivalent to having ^ and $
+ characters at the start and end of each alternative branch in
+ every pattern. This option applies only to the patterns that
+ are matched against the contents of files; it does not apply
+ to patterns specified by any of the --include or --exclude
+ options.
+
+
+ENVIRONMENT VARIABLES
+
+ The environment variables LC_ALL and LC_CTYPE are examined, in that
+ order, for a locale. The first one that is set is used. This can be
+ overridden by the --locale option. If no locale is set, the PCRE
+ library's default (usually the "C" locale) is used.
+
+
+NEWLINES
+
+ The -N (--newline) option allows pcregrep to scan files with different
+ newline conventions from the default. Any parts of the input files that
+ are written to the standard output are copied identically, with what-
+ ever newline sequences they have in the input. However, the setting of
+ this option does not affect the interpretation of files specified by
+ the -f, --exclude-from, or --include-from options, which are assumed to
+ use the operating system's standard newline sequence, nor does it
+ affect the way in which pcregrep writes informational messages to the
+ standard error and output streams. For these it uses the string "\n" to
+ indicate newlines, relying on the C I/O library to convert this to an
+ appropriate sequence.
+
+
+OPTIONS COMPATIBILITY
+
+ Many of the short and long forms of pcregrep's options are the same as
+ in the GNU grep program. Any long option of the form --xxx-regexp (GNU
+ terminology) is also available as --xxx-regex (PCRE terminology). How-
+ ever, the --file-list, --file-offsets, --include-dir, --line-offsets,
+ --locale, --match-limit, -M, --multiline, -N, --newline, --om-separa-
+ tor, --recursion-limit, -u, and --utf-8 options are specific to pcre-
+ grep, as is the use of the --only-matching option with a capturing
+ parentheses number.
+
+ Although most of the common options work the same way, a few are dif-
+ ferent in pcregrep. For example, the --include option's argument is a
+ glob for GNU grep, but a regular expression for pcregrep. If both the
+ -c and -l options are given, GNU grep lists only file names, without
+ counts, but pcregrep gives the counts.
+
+
+OPTIONS WITH DATA
+
+ There are four different ways in which an option with data can be spec-
+ ified. If a short form option is used, the data may follow immedi-
+ ately, or (with one exception) in the next command line item. For exam-
+ ple:
+
+ -f/some/file
+ -f /some/file
+
+ The exception is the -o option, which may appear with or without data.
+ Because of this, if data is present, it must follow immediately in the
+ same item, for example -o3.
+
+ If a long form option is used, the data may appear in the same command
+ line item, separated by an equals character, or (with two exceptions)
+ it may appear in the next command line item. For example:
+
+ --file=/some/file
+ --file /some/file
+
+ Note, however, that if you want to supply a file name beginning with ~
+ as data in a shell command, and have the shell expand ~ to a home
+ directory, you must separate the file name from the option, because the
+ shell does not treat ~ specially unless it is at the start of an item.
+
+ The exceptions to the above are the --colour (or --color) and --only-
+ matching options, for which the data is optional. If one of these
+ options does have data, it must be given in the first form, using an
+ equals character. Otherwise pcregrep will assume that it has no data.
+
+
+MATCHING ERRORS
+
+ It is possible to supply a regular expression that takes a very long
+ time to fail to match certain lines. Such patterns normally involve
+ nested indefinite repeats, for example: (a+)*\d when matched against a
+ line of a's with no final digit. The PCRE matching function has a
+ resource limit that causes it to abort in these circumstances. If this
+ happens, pcregrep outputs an error message and the line that caused the
+ problem to the standard error stream. If there are more than 20 such
+ errors, pcregrep gives up.
+
+ The --match-limit option of pcregrep can be used to set the overall
+ resource limit; there is a second option called --recursion-limit that
+ sets a limit on the amount of memory (usually stack) that is used (see
+ the discussion of these options above).
+
+
+DIAGNOSTICS
+
+ Exit status is 0 if any matches were found, 1 if no matches were found,
+ and 2 for syntax errors, overlong lines, non-existent or inaccessible
+ files (even if matches were found in other files) or too many matching
+ errors. Using the -s option to suppress error messages about inaccessi-
+ ble files does not affect the return code.
+
+
+SEE ALSO
+
+ pcrepattern(3), pcresyntax(3), pcretest(1).
+
+
+AUTHOR
+
+ Philip Hazel
+ University Computing Service
+ Cambridge CB2 3QH, England.
+
+
+REVISION
+
+ Last updated: 03 April 2014
+ Copyright (c) 1997-2014 University of Cambridge.