PCREGREP(1)                OpenBSD Reference 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 pcrepattern(3) for a full description of syntax and
       semantics 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.
       Conversely, when one or both of these options are used to specify
       patterns, 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
       standard 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
                 filenames 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
                 separator 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
                 available 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
                 separator 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
                 available 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
                 otherwise 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
                 output 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
                 environment 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
                 multiple 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
                 regular 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 pattern, 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
                 directory 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
                 specified 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
                 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. 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
                 directories 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
                 separate 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
                 output. 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
                 suppressing 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
                 currently 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
                 performance, 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
                 separately. This option is mutually exclusive with --file-
                 offsets and --only-matching.

       --locale=locale-name
                 This option specifies a locale to be used for pattern
                 matching. It overrides the value in the LC_ALL or LC_CTYPE
                 environment 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
                 program 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
                 function 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
                 settings 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
                 characters 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
                 "multiline" 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
                 similarly the previous 8K characters (or all the previous
                 characters, 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
                 recognizes any of the preceding three types, and an "any"
                 convention, in which any Unicode line ending sequence is
                 assumed to end a line. The Unicode sequences are the three
                 just mentioned, 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
                 modify their line endings. If the data that is being scanned
                 does not agree with the convention set by this option,
                 pcregrep 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
                 operating system's standard newline sequence.

       -n, --line-number
                 Precede each output line by its line number in the file,
                 followed 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
                 problems.  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
                 parentheses are supported, and -o0 is equivalent to -o
                 without a number. 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
                 parentheses 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
                 settings. 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
                 subject 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
                 command 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
                 equivalent 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
                 specified 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
       whatever 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).
       However, the --file-list, --file-offsets, --include-dir, --line-
       offsets, --locale, --match-limit, -M, --multiline, -N, --newline, --om-
       separator, --recursion-limit, -u, and --utf-8 options are specific to
       pcregrep, 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
       different 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
       specified.  If a short form option is used, the data may follow
       immediately, or (with one exception) in the next command line item. For
       example:

         -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
       inaccessible 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: 13 September 2012
       Copyright (c) 1997-2012 University of Cambridge.



PCRE 8.32                      13 September 2012                   PCREGREP(1)
