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pcre2grep(1)                General Commands Manual               pcre2grep(1)


NAME

       pcre2grep - a grep with Perl-compatible regular expressions.


SYNOPSIS

       pcre2grep [options] [long options] [pattern] [path1 path2 ...]


DESCRIPTION

       pcre2grep searches files for character patterns, in the same way as
       other grep commands do, but it uses the PCRE2 regular expression
       library to support patterns that are compatible with the regular
       expressions of Perl 5. See pcre2syntax(3) for a quick-reference summary
       of pattern syntax, or pcre2pattern(3) for a full description of the
       syntax and semantics of the regular expressions that PCRE2 supports.

       Patterns, whether supplied on the command line or in a separate file,
       are given without delimiters. For example:

         pcre2grep 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, pcre2grep reads the standard input. The
       standard input can also be referenced by a name consisting of a single
       hyphen.  For example:

         pcre2grep some-pattern file1 - file3

       By default, input files are searched line by line, so pattern
       assertions about the beginning and end of a subject string (^, $, \A,
       \Z, and \z) match at the beginning and end of each line. When a line
       matches a pattern, it 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
       pcre2grep behaves. For example, the -M option makes it possible to
       search for strings that span line boundaries. What defines a line
       boundary is controlled by the -N (--newline) option.  The -h and -H
       options control whether or not file names are shown, and the -Z option
       changes the file name terminator to a zero byte.

       The amount of memory used for buffering files that are being scanned is
       controlled by parameters that can be set by the --buffer-size and
       --max-buffer-size options. The first of these sets the size of buffer
       that is obtained at the start of processing. If an input file contains
       very long lines, a larger buffer may be needed; this is handled by
       automatically extending the buffer, up to the limit specified by --max-
       buffer-size. The default values for these parameters can be set when
       pcre2grep is built; if nothing is specified, the defaults are set to
       20KiB and 1MiB respectively. An error occurs if a line is too long and
       the buffer can no longer be expanded.

       The block of memory that is actually used is three times the "buffer
       size", to allow for buffering "before" and "after" lines. If the buffer
       size is too small, fewer than requested "before" and "after" lines may
       be output.

       When matching with a multiline pattern, the size of the buffer must be
       at least half of the maximum match expected or the pattern might fail
       to match.

       Patterns can be no longer than 8KiB 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, --line-
       offsets, or --output is used to output only the part of the line that
       matched (either shown literally, or as an offset), the behaviour is
       different. In this situation, all the patterns are applied to the line.
       If there is more than one match, the one that begins nearest to the
       start of the subject is processed; if there is more than one match at
       that position, the one with the longest matching substring is
       processed; if the matching substrings are equal, the first match found
       is processed.

       Scanning with all the patterns resumes immediately following the match,
       so that later matches on the same line can be found. Note, however,
       that an overlapping match that starts in the middle of another match
       will not be processed.

       The above behaviour was changed at release 10.41 to be more compatible
       with GNU grep. In earlier releases, pcre2grep did not recognize matches
       from later patterns that were earlier in the subject.

       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, pcre2grep uses
       the value to set a locale when calling the PCRE2 library.  The --locale
       option can be used to override this.


SUPPORT FOR COMPRESSED FILES

       Compile-time options for pcre2grep can set it up to use libz or libbz2
       for reading compressed files whose names end in .gz or .bz2,
       respectively. You can find out whether your pcre2grep 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, all files are
       treated as plain text. The standard input is always so treated. If a
       file with a .gz or .bz2 extension is not in fact compressed, it is read
       as a plain text file. When input is from a compressed .gz or .bz2 file,
       the --line-buffered option is ignored.


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.
       However, if the newline type is specified as NUL, that is, the line
       terminator is a binary zero, the test for a binary file is not applied.
       See the --binary-files option for a means of changing the way binary
       files are handled.


BINARY ZEROS IN PATTERNS

       Patterns passed from the command line are strings that are terminated
       by a binary zero, so cannot contain internal zeros. However, patterns
       that are read from a file via the -f option may contain binary zeros.


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 up to number lines of context after each matching
                 line. Fewer lines are output if the next match or the end of
                 the file is reached, or if the processing buffer size has
                 been set too small. If file names and/or line numbers are
                 being output, a hyphen separator is used instead of a colon
                 for the context lines (the -Z option can be used to change
                 the file name terminator to a zero byte). 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. When -c is used, -A is
                 ignored.

       -a, --text
                 Treat binary files as text. This is equivalent to --binary-
                 files=text.

       --allow-lookaround-bsk
                 PCRE2 now forbids the use of \K in lookarounds by default, in
                 line with Perl.  This option causes pcre2grep to set the
                 PCRE2_EXTRA_ALLOW_LOOKAROUND_BSK option, which enables this
                 somewhat dangerous usage.

       -B number, --before-context=number
                 Output up to number lines of context before each matching
                 line. Fewer lines are output if the previous match or the
                 start of the file is within number lines, or if the
                 processing buffer size has been set too small. If file names
                 and/or line numbers are being output, a hyphen separator is
                 used instead of a colon for the context lines (the -Z option
                 can be used to change the file name terminator to a zero
                 byte). 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. When
                 -c is used, -B is ignored.

       --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 and are skipped without causing
                 any output or affecting the return code.

       --buffer-size=number
                 Set the parameter that controls how much memory is obtained
                 at the start of processing for buffering files that are being
                 scanned. See also --max-buffer-size below.

       -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 lines from the files that are being scanned;
                 instead output the number of lines that would have been
                 shown, either because they matched, or, if -v is set, because
                 they failed to match. By default, this count is exactly the
                 same as the number of lines that would have been output, but
                 if the -M (multiline) option is used (without -v), there may
                 be more suppressed lines than the count (that is, the number
                 of matches).

                 If no lines are selected, the number zero is output. If
                 several files are being scanned, a count is output for each
                 of them and the -t option can be used to cause a total to be
                 output at the end. 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.
                 It is ignored if --file-offsets, --line-offsets, or --output
                 is set. By default, output is not coloured. The value for the
                 --colour option (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 pcre2grep 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 one of
                 the environment variables PCRE2GREP_COLOUR, PCRE2GREP_COLOR,
                 PCREGREP_COLOUR, or PCREGREP_COLOR, which are checked in that
                 order. If none of these are set, pcre2grep looks for
                 GREP_COLORS or GREP_COLOR (in that order). The value of the
                 variable should be a string of two numbers, separated by a
                 semicolon, except in the case of GREP_COLORS, which must
                 start with "ms=" or "mt=" followed by two semicolon-separated
                 colours, terminated by the end of the string or by a colon.
                 If GREP_COLORS does not start with "ms=" or "mt=" it is
                 ignored, and GREP_COLOR is checked.

                 If the string obtained from one of the above variables
                 contains any characters other than semicolon or digits, the
                 setting is ignored and the default colour is used. The string
                 is copied directly into the control string for setting colour
                 on a terminal, so it is your responsibility to ensure that
                 the values make sense. If no relevant environment variable 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.

       --depth-limit=number
                 See --match-limit below.

       -E, --case-restrict
                 When case distinctions are being ignored in Unicode mode, two
                 ASCII letters (K and S) will by default match Unicode
                 characters U+212A (Kelvin sign) and U+017F (long S)
                 respectively, as well as their lower case ASCII counterparts.
                 When this option is set, case equivalences are restricted
                 such that no ASCII character matches a non-ASCII character,
                 and vice versa.

       -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.

                 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.

       --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 PCRE2
                 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 PCRE2 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. As is the case
                 with patterns on the command line, no delimiters should be
                 used. What constitutes a newline when reading the file is the
                 operating system's default interpretation of \n. 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. Patterns read from a file in this way may contain
                 binary zeros, which are treated as ordinary data characters.

                 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 file name 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 matched
                 before the file's patterns. However, no 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. What constitutes a
                 newline when reading the file is the operating system's
                 default. 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 file name 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, --colour has no
                 effect, and 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 --output, --line-offsets, and --only-
                 matching.

       --group-separator=text
                 Output this text string instead of two hyphens between groups
                 of lines when -A, -B, or -C is in use. See also --no-group-
                 separator.

       -H, --with-filename
                 Force the inclusion of the file name at the start of output
                 lines when searching a single file. The file name is not
                 normally shown in this case.  By default, for matching lines,
                 the file name is followed by a colon; for context lines, a
                 hyphen separator is used. The -Z option can be used to change
                 the terminator to a zero byte. If a line number is also being
                 output, it follows the file name. When the -M option causes a
                 pattern to match more than one line, only the first is
                 preceded by the file name. This option overrides any previous
                 -h, -l, or -L options.

       -h, --no-filename
                 Suppress the output file names when searching multiple files.
                 File names are normally shown when multiple files are
                 searched. By default, for matching lines, the file name is
                 followed by a colon; for context lines, a hyphen separator is
                 used. The -Z option can be used to change the terminator to a
                 zero byte. If a line number is also being output, it follows
                 the file name.  This option overrides any previous -H, -L, or
                 -l options.

       --heap-limit=number
                 See --match-limit below.

       --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        Ignore binary files. This is equivalent to --binary-
                 files=without-match.

       -i, --ignore-case
                 Ignore upper/lower case distinctions when pattern matching.
                 This applies when matching path names for inclusion or
                 exclusion as well as when matching lines in files.

       --include=pattern
                 If any --include patterns are specified, the only files that
                 are processed are those whose names 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 PCRE2 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 whose names 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 PCRE2 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 by default, but if the -Z option is set, they
                 are separated by zero bytes instead of newlines. This option
                 overrides any previous -H, -h, or -l options.

       -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,
                 but if the -Z option is set, they are separated by zero bytes
                 instead of newlines. 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 that occurs with -c on its own. This option overrides
                 any previous -H, -h, or -L options.

       --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, non-compressed 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
                 pcre2grep can determine that it is reading from a terminal,
                 which is currently possible only in Unix-like environments or
                 Windows. 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
                 pcre2grep to buffer up large amounts of data.  However, its
                 use will affect performance, and the -M (multiline) option
                 ceases to work. When input is from a compressed .gz or .bz2
                 file, --line-buffered is ignored.

       --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, --colour has no effect,
                 and 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 --output, --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 PCRE2
                 library's default (usually the "C" locale) is used. There is
                 no short form for this option.

       -M, --multiline
                 Allow patterns to match more than one line. When this option
                 is set, the PCRE2 library is called in "multiline" mode, and
                 a match is allowed to continue past the end of the initial
                 line and onto one or more subsequent lines.

                 Patterns used with -M may usefully contain literal newline
                 characters and internal occurrences of ^ and $ characters,
                 because in multiline mode these can match at internal
                 newlines. Because pcre2grep is scanning multiple lines, the
                 \Z and \z assertions match only at the end of the last line
                 in the file.  The \A assertion matches at the start of the
                 first line of a match. This can be any line in the file; it
                 is not anchored to the first line.

                 The output for a successful match may consist of more than
                 one line. The first line is the line in which the match
                 started, and the last line is the line in which the match
                 ended. If the matched string ends with a newline sequence,
                 the output ends at the end of that line. If -v is set, none
                 of the lines in a multi-line match are output. Once a match
                 has been handled, scanning restarts at the beginning of the
                 line after the one in which the match ended.

                 The newline sequence that separates multiple lines must be
                 matched as part of the pattern. For example, to find the
                 phrase "regular expression" in a file where "regular" might
                 be at the end of a line and "expression" at the start of the
                 next line, you could use this command:

                   pcre2grep -M 'regular\s+expression' <file>

                 The \s escape sequence matches any white space character,
                 including newlines, and is followed by + so as to match
                 trailing white space on the first line as well as possibly
                 handling a two-character newline sequence.

                 There is a limit to the number of lines that can be matched,
                 imposed by the way that pcre2grep buffers the input file as
                 it scans it. With a sufficiently large processing buffer,
                 this should not be a problem.

                 The -M option does not work when input is read line by line
                 (see --line-buffered.)

       -m number, --max-count=number
                 Stop processing after finding number matching lines, or non-
                 matching lines if -v is also set. Any trailing context lines
                 are output after the final match. In multiline mode, each
                 multiline match counts as just one line for this purpose. If
                 this limit is reached when reading the standard input from a
                 regular file, the file is left positioned just after the last
                 matching line.  If -c is also set, the count that is output
                 is never greater than number. This option has no effect if
                 used with -L, -l, or -q, or when just checking for a match in
                 a binary file.

       --match-limit=number
                 Processing some regular expression patterns may take a very
                 long time to search for all possible matching strings. Others
                 may require a very large amount of memory. There are three
                 options that set resource limits for matching.

                 The --match-limit option provides a means of limiting
                 computing 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, PCRE2
                 has a counter that is incremented each time around its main
                 processing loop. If the value set by --match-limit is
                 reached, an error occurs.

                 The --heap-limit option specifies, as a number of kibibytes
                 (units of 1024 bytes), the maximum amount of heap memory that
                 may be used for matching.

                 The --depth-limit option limits the depth of nested
                 backtracking points, which indirectly limits the amount of
                 memory that is used. The amount of memory needed for each
                 backtracking point depends on the number of capturing
                 parentheses in the pattern, so the amount of memory that is
                 used before this limit acts varies from pattern to pattern.
                 This limit is of use only if it is set smaller than --match-
                 limit.

                 There are no short forms for these options. The default
                 limits can be set when the PCRE2 library is compiled; if they
                 are not specified, the defaults are very large and so
                 effectively unlimited.

       --max-buffer-size=number
                 This limits the expansion of the processing buffer, whose
                 initial size can be set by --buffer-size. The maximum buffer
                 size is silently forced to be no smaller than the starting
                 buffer size.

       -N newline-type, --newline=newline-type
                 Six different conventions for indicating the ends of lines in
                 scanned files are supported. For example:

                   pcre2grep -N CRLF 'some pattern' <file>

                 The newline type may be specified in upper, lower, or mixed
                 case. If the newline type is NUL, lines are separated by
                 binary zero characters. The other types are the single-
                 character sequences CR (carriage return) and LF (linefeed),
                 the two-character sequence CRLF, an "anycrlf" type, which
                 recognizes any of the preceding three types, and an "any"
                 type, for 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 PCRE2 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, pcre2grep uses the library's default.

                 This option makes it possible to use pcre2grep 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,
                 pcre2grep 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 file name is also being output, it
                 precedes the line number. When the -M option causes a pattern
                 to match more than one line, only the first is preceded by
                 its line number. This option is forced if --line-offsets is
                 used.

       --no-group-separator
                 Do not output a separator between groups of lines when -A,
                 -B, or -C is in use. The default is to output a line
                 containing two hyphens. See also --group-separator.

       --no-jit  If the PCRE2 library is built with support for just-in-time
                 compiling (which speeds up matching), pcre2grep 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 around
                 problems.  It should never be needed in normal use.

       -O text, --output=text
                 When there is a match, instead of outputting the line that
                 matched, output just the text specified in this option,
                 followed by an operating-system standard newline. In this
                 mode, --colour has no effect, and no context is shown.  That
                 is, the -A, -B, and -C options are ignored. The --newline
                 option has no effect on this option, which is mutually
                 exclusive with --only-matching, --file-offsets, and --line-
                 offsets. However, like --only-matching, if there is more than
                 one match in a line, each of them causes a line of output.

                 Escape sequences starting with a dollar character may be used
                 to insert the contents of the matched part of the line and/or
                 captured substrings into the text.

                 $<digits> or ${<digits>} is replaced by the captured
                 substring of the given decimal number; zero substitutes the
                 whole match. If the number is greater than the number of
                 capturing substrings, or if the capture is unset, the
                 replacement is empty.

                 $a is replaced by bell; $b by backspace; $e by escape; $f by
                 form feed; $n by newline; $r by carriage return; $t by tab;
                 $v by vertical tab.

                 $o<digits> or $o{<digits>} is replaced by the character whose
                 code point is the given octal number. In the first form, up
                 to three octal digits are processed.  When more digits are
                 needed in Unicode mode to specify a wide character, the
                 second form must be used.

                 $x<digits> or $x{<digits>} is replaced by the character
                 represented by the given hexadecimal number. In the first
                 form, up to two hexadecimal digits are processed. When more
                 digits are needed in Unicode mode to specify a wide
                 character, the second form must be used.

                 Any other character is substituted by itself. In particular,
                 $$ is replaced by a single dollar.

       -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,
                 on a separate line of output. 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 --output,
                 --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 50 capturing
                 parentheses are supported by default. This limit can be
                 changed via the --om-capture option. A pattern may contain
                 any number of capturing parentheses, but only those whose
                 number is within the limit can be accessed by -o. An error
                 occurs if the number specified by -o is greater than the
                 limit.

                 -o0 is the same as -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 option. 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 output.

                 If this option is given multiple times, multiple substrings
                 are output for each match, in the order the options are
                 given, and all on one line. 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 but one option).

       --om-capture=number
                 Set the number of capturing parentheses that can be accessed
                 by -o. The default is 50.

       --om-separator=text
                 Specify a separating string for multiple occurrences of -o.
                 The default is an empty string. Separating strings are never
                 coloured.

       -P, --no-ucp
                 Starting from release 10.43, when UTF/Unicode mode is
                 specified with -u or -U, the PCRE2_UCP option is used by
                 default. This means that the POSIX classes in patterns match
                 more than just ASCII characters. For example, [:digit:]
                 matches any Unicode decimal digit. The --no-ucp option
                 suppresses PCRE2_UCP, thus restricting the POSIX classes to
                 ASCII characters, as was the case in earlier releases. Note
                 that there are now more fine-grained option settings within
                 patterns that affect individual classes. For example, when in
                 UCP mode, the sequence (?aP) restricts [:word:] to ASCII
                 letters, while allowing \w to match Unicode letters and
                 digits.

       -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
                 This is an obsolete synonym for --depth-limit. See --match-
                 limit above for details.

       -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.

       -t, --total-count
                 This option is useful when scanning more than one file. If
                 used on its own, -t suppresses all output except for a grand
                 total number of matching lines (or non-matching lines if -v
                 is used) in all the files. If -t is used with -c, a grand
                 total is output except when the previous output is just one
                 line. In other words, it is not output when just one file's
                 count is listed. If file names are being output, the grand
                 total is preceded by "TOTAL:". Otherwise, it appears as just
                 another number. The -t option is ignored when used with -L
                 (list files without matches), because the grand total would
                 always be zero.

       -u, --utf Operate in UTF/Unicode mode. This option is available only if
                 PCRE2 has been compiled with UTF-8 support. All patterns
                 (including those for any --exclude and --include options) and
                 all lines that are scanned must be valid strings of UTF-8
                 characters. If an invalid UTF-8 string is encountered, an
                 error occurs.

       -U, --utf-allow-invalid
                 As --utf, but in addition subject lines may contain invalid
                 UTF-8 code unit sequences. These can never form part of any
                 pattern match. Patterns themselves, however, must still be
                 valid UTF-8 strings. This facility allows valid UTF-8 strings
                 to be sought within arbitrary byte sequences in executable or
                 other binary files. For more details about matching in non-
                 valid UTF-8 strings, see the pcre2unicode(3) documentation.

       -V, --version
                 Write the version numbers of pcre2grep and the PCRE2 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. When
                 this option is set, options such as --only-matching and
                 --output, which specify parts of a match that are to be
                 output, are ignored.

       -w, --word-regex, --word-regexp
                 Force the patterns only to match "words". That is, there must
                 be a word boundary at the start and end of each matched
                 string. This is equivalent to having "\b(?:" at the start of
                 each pattern, and ")\b" at the end. 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 start matching only at the beginnings
                 of lines, and in addition, require them to match entire
                 lines. In multiline mode the match may be more than one line.
                 This is equivalent to having "^(?:" at the start of each
                 pattern and ")$" at the end. 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.

       -Z, --null
                 Terminate files names in the regular output with a zero byte
                 (the NUL character) instead of what would normally appear.
                 This is useful when file names contain unusual characters
                 such as colons, hyphens, or even newlines. The option does
                 not apply to file names in error messages.


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 PCRE2
       library's default (usually the "C" locale) is used.


NEWLINES

       The -N (--newline) option allows pcre2grep to scan files with newline
       conventions that differ from the default. This option affects only the
       way scanned files are processed. It does not affect the interpretation
       of files specified by the -f, --file-list, --exclude-from, or
       --include-from options.

       Any parts of the scanned input files that are written to the standard
       output are copied with whatever newline sequences they have in the
       input. However, if the final line of a file is output, and it does not
       end with a newline sequence, a newline sequence is added. If the
       newline setting is CR, LF, CRLF or NUL, that line ending is output; for
       the other settings (ANYCRLF or ANY) a single NL is used.

       The newline setting does not affect the way in which pcre2grep writes
       newlines in informational messages to the standard output and error
       streams.  Under Windows, the standard output is set to be binary, so
       that "\r\n" at the ends of output lines that are copied from the input
       is not converted to "\r\r\n" by the C I/O library. This means that any
       messages written to the standard output must end with "\r\n". For all
       other operating systems, and for all messages to the standard error
       stream, "\n" is used.


OPTIONS COMPATIBILITY WITH GNU GREP

       Many of the short and long forms of pcre2grep'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 (PCRE2 terminology).
       However, the --case-restrict, --depth-limit, -E, --file-list, --file-
       offsets, --heap-limit, --include-dir, --line-offsets, --locale,
       --match-limit, -M, --multiline, -N, --newline, --no-ucp, --om-
       separator, --output, -P, -u, --utf, -U, and --utf-allow-invalid options
       are specific to pcre2grep, 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 pcre2grep. For example, the --include option's argument is
       a glob for GNU grep, but in pcre2grep it is a regular expression to
       which the -i option applies. If both the -c and -l options are given,
       GNU grep lists only file names, without counts, but pcre2grep gives the
       counts as well.


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 pcre2grep will assume that it has no data.


USING PCRE2'S CALLOUT FACILITY

       pcre2grep has, by default, support for calling external programs or
       scripts or echoing specific strings during matching by making use of
       PCRE2's callout facility. However, this support can be completely or
       partially disabled when pcre2grep is built. You can find out whether
       your binary has support for callouts by running it with the --help
       option. If callout support is completely disabled, all callouts in
       patterns are ignored by pcre2grep.  If the facility is partially
       disabled, calling external programs is not supported, and callouts that
       request it are ignored.

       A callout in a PCRE2 pattern is of the form (?C<arg>) where the
       argument is either a number or a quoted string (see the pcre2callout
       documentation for details). Numbered callouts are ignored by pcre2grep;
       only callouts with string arguments are useful.

   Echoing a specific string
       Starting the callout string with a pipe character invokes an echoing
       facility that avoids calling an external program or script. This
       facility is always available, provided that callouts were not
       completely disabled when pcre2grep was built. The rest of the callout
       string is processed as a zero-terminated string, which means it should
       not contain any internal binary zeros. It is written to the output,
       having first been passed through the same escape processing as text
       from the --output (-O) option (see above). However, $0 cannot be used
       to insert a matched substring because the match is still in progress.
       Instead, the single character '0' is inserted. Any syntax errors in the
       string (for example, a dollar not followed by another character) causes
       the callout to be ignored. No terminator is added to the output string,
       so if you want a newline, you must include it explicitly using the
       escape $n. For example:

         pcre2grep '(.)(..(.))(?C"|[$1] [$2] [$3]$n")' <some file>

       Matching continues normally after the string is output. If you want to
       see only the callout output but not any output from an actual match,
       you should end the pattern with (*FAIL).

   Calling external programs or scripts
       This facility can be independently disabled when pcre2grep is built. It
       is supported for Windows, where a call to _spawnvp() is used, for VMS,
       where lib$spawn() is used, and for any Unix-like environment where
       fork() and execv() are available.

       If the callout string does not start with a pipe (vertical bar)
       character, it is parsed into a list of substrings separated by pipe
       characters. The first substring must be an executable name, with the
       following substrings specifying arguments:

         executable_name|arg1|arg2|...

       Any substring (including the executable name) may contain escape
       sequences started by a dollar character. These are the same as for the
       --output (-O) option documented above, except that $0 cannot insert the
       matched string because the match is still in progress. Instead, the
       character '0' is inserted. If you need a literal dollar or pipe
       character in any substring, use $$ or $| respectively. Here is an
       example:

         echo -e "abcde\n12345" | pcre2grep \
           '(?x)(.)(..(.))
           (?C"/bin/echo|Arg1: [$1] [$2] [$3]|Arg2: $|${1}$| ($4)")()' -

         Output:

           Arg1: [a] [bcd] [d] Arg2: |a| ()
           abcde
           Arg1: [1] [234] [4] Arg2: |1| ()
           12345

       The parameters for the system call that is used to run the program or
       script are zero-terminated strings. This means that binary zero
       characters in the callout argument will cause premature termination of
       their substrings, and therefore should not be present. Any syntax
       errors in the string (for example, a dollar not followed by another
       character) causes the callout to be ignored.  If running the program
       fails for any reason (including the non-existence of the executable), a
       local matching failure occurs and the matcher backtracks in the normal
       way.


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 PCRE2 matching function has a
       resource limit that causes it to abort in these circumstances. If this
       happens, pcre2grep outputs an error message and the line that caused
       the problem to the standard error stream. If there are more than 20
       such errors, pcre2grep gives up.

       The --match-limit option of pcre2grep can be used to set the overall
       resource limit. There are also other limits that affect the amount of
       memory used during matching; see the discussion of --heap-limit and
       --depth-limit 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.

       When run under VMS, the return code is placed in the symbol
       PCRE2GREP_RC because VMS does not distinguish between exit(0) and
       exit(1).


SEE ALSO

       pcre2pattern(3), pcre2syntax(3), pcre2callout(3), pcre2unicode(3).


AUTHOR

       Philip Hazel
       Retired from University Computing Service
       Cambridge, England.


REVISION

       Last updated: 22 December 2023
       Copyright (c) 1997-2023 University of Cambridge.

PCRE2 10.43                    22 December 2023                   pcre2grep(1)

pcre2 10.43 - Generated Sat Mar 2 10:17:50 CST 2024
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