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.

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.

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.

Set the parameter that controls how much memory is used for buffering files that are being scanned.

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.

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.

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.

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.

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).

If an input path is a directory, "action" specifies how it is to be processed. Valid values are "read" (the default), "recurse" (equivalent to the −r option), or "skip" (silently skip the path). In the default 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.

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 an overall maximum of 100 patterns. They are applied to each line in the order in which they are defined until one matches (or fails to match if −v is used). If −f is used with −e, the command line patterns are matched first, followed by the patterns from the file, 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, 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 really matters only if you are using −o to show the part(s) of the line that matched.

When pcregrep is searching the files in a directory as a consequence of the −r (recursive search) option, any regular files whose names match the pattern are excluded. Subdirectories are not excluded by this option; they are searched recursively, subject to the −−exclude−dir and −−include_dir options. The pattern is a PCRE regular expression, and is matched against the final component of the file name (not the entire path). If a file name matches both −−include and −−exclude, it is excluded. There is no short form for this option.

When pcregrep is searching the contents of a directory as a consequence of the −r (recursive search) option, any subdirectories whose names match the pattern are excluded. (Note that the −−exclude option does not affect subdirectories.) The pattern is a PCRE regular expression, and is matched against the final component of the name (not the entire path). If a subdirectory name matches both −−include−dir and −−exclude−dir, it is excluded. There is no short form for this option.

Interpret each pattern as a list of fixed strings, separated by newlines, instead of as a regular expression. 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).

Read a number of patterns from the file, one per line, and match them against each line of input. A data line is output if any of the patterns match it. The 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 file names. There is an overall maximum of 100 patterns. 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.

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.

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.

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.

Output a help message, giving brief details of the command options and file type support, and then exit.

Ignore upper/lower case distinctions during comparisons.

When pcregrep is searching the files in a directory as a consequence of the −r (recursive search) option, only those regular files whose names match the pattern are included. Subdirectories are always included and searched recursively, subject to the −−include−dir and −−exclude−dir options. The pattern is a PCRE regular expression, and is matched against the final component of the file name (not the entire path). If a file name matches both −−include and −−exclude, it is excluded. There is no short form for this option.

When pcregrep is searching the contents of a directory as a consequence of the −r (recursive search) option, only those subdirectories whose names match the pattern are included. (Note that the −−include option does not affect subdirectories.) The pattern is a PCRE regular expression, and is matched against the final component of the name (not the entire path). If a subdirectory name matches both −−include−dir and −−exclude−dir, it is excluded. There is no short form for this option.

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.

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.

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.

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 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.

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.

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.

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.

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.)

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 on 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.

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.

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.

Show only the part of the line that matched the capturing parentheses of the given number. Up to 32 capturing parentheses are supported. 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.

Work quietly, that is, display nothing except error messages. The exit status indicates whether or not any matches were found.

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".

See −−match−limit above.

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.

Operate in UTF-8 mode. This option is available only if PCRE has been compiled with UTF-8 support. Both patterns and subject lines must be valid strings of UTF-8 characters.

Write the version numbers of pcregrep and the PCRE library that is being used to the standard error stream.

Invert the sense of the match, so that lines which do not match any of the patterns are the ones that are found.

Force the patterns to match only whole words. This is equivalent to having \b at the start and end of the pattern.

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.

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.

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.