NAME | SYNOPSIS | DESCRIPTION | SUPPORT FOR COMPRESSED FILES | BINARY FILES | OPTIONS | ENVIRONMENT VARIABLES | NEWLINES | OPTIONS COMPATIBILITY | OPTIONS WITH DATA | MATCHING ERRORS | DIAGNOSTICS | SEE ALSO | AUTHOR | REVISION | COLOPHON

PCREGREP(1)                General Commands Manual               PCREGREP(1)

NAME         top

       pcregrep - a grep with Perl-compatible regular expressions.

SYNOPSIS         top

       pcregrep [options] [long options] [pattern] [path1 path2 ...]

DESCRIPTION         top


       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 syntax, or pcrepattern(3) for a full description
       of the 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         top


       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         top


       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         top


       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         top


       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         top


       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         top


       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         top


       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         top


       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         top


       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         top


       pcrepattern(3), pcresyntax(3), pcretest(1).

AUTHOR         top


       Philip Hazel
       University Computing Service
       Cambridge CB2 3QH, England.

REVISION         top


       Last updated: 03 April 2014
       Copyright (c) 1997-2014 University of Cambridge.

COLOPHON         top

       This page is part of the PCRE (Perl Compatible Regular Expressions)
       project.  Information about the project can be found at 
       ⟨http://www.pcre.org/⟩.  If you have a bug report for this manual
       page, see ⟨http://bugs.exim.org/enter_bug.cgi?product=PCRE⟩.  This
       page was obtained from the tarball pcre-8.41.tar.gz fetched from 
       ⟨ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/⟩ on
       2017-09-15.  If you discover any rendering problems in this HTML ver‐
       sion of the page, or you believe there is a better or more up-to-date
       source for the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original man‐
       ual page), send a mail to man-pages@man7.org

PCRE 8.35                       03 April 2014                    PCREGREP(1)