| .TH PCREGREP 1 |
| .SH NAME |
| pcregrep - a grep with Perl-compatible regular expressions. |
| .SH SYNOPSIS |
| .B pcregrep [options] [long options] [pattern] [path1 path2 ...] |
| . |
| .SH DESCRIPTION |
| .rs |
| .sp |
| \fBpcregrep\fP 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 |
| .\" HREF |
| \fBpcrepattern\fP(3) |
| .\" |
| for a full description of syntax and semantics of the regular expressions |
| that PCRE supports. |
| .P |
| Patterns, whether supplied on the command line or in a separate file, are given |
| without delimiters. For example: |
| .sp |
| pcregrep Thursday /etc/motd |
| .sp |
| 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 they are required if a |
| pattern contains white space or shell metacharacters. |
| .P |
| The first argument that follows any option settings is treated as the single |
| pattern to be matched when neither \fB-e\fP nor \fB-f\fP 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 \fB-e\fP, \fB-f\fP, or an |
| argument pattern must be provided. |
| .P |
| If no files are specified, \fBpcregrep\fP reads the standard input. The |
| standard input can also be referenced by a name consisting of a single hyphen. |
| For example: |
| .sp |
| pcregrep some-pattern /file1 - /file3 |
| .sp |
| 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 \fBpcregrep\fP behaves. In particular, the \fB-M\fP option makes it |
| possible to search for patterns that span line boundaries. What defines a line |
| boundary is controlled by the \fB-N\fP (\fB--newline\fP) option. |
| .P |
| The amount of memory used for buffering files that are being scanned is |
| controlled by a parameter that can be set by the \fB--buffer-size\fP option. |
| The default value for this parameter is specified when \fBpcregrep\fP 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. |
| .P |
| Patterns are limited to 8K or BUFSIZ bytes, whichever is the greater. BUFSIZ is |
| defined in \fB<stdio.h>\fP. When there is more than one pattern (specified by |
| the use of \fB-e\fP and/or \fB-f\fP), each pattern is applied to each line in |
| the order in which they are defined, except that all the \fB-e\fP patterns are |
| tried before the \fB-f\fP patterns. |
| .P |
| By default, as soon as one pattern matches (or fails to match when \fB-v\fP is |
| used), no further patterns are considered. However, if \fB--colour\fP (or |
| \fB--color\fP) is used to colour the matching substrings, or if |
| \fB--only-matching\fP, \fB--file-offsets\fP, or \fB--line-offsets\fP 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. |
| .P |
| This is the same behaviour as GNU grep, but it does mean that the order in |
| which multiple patterns are specified can affect the output when one of the |
| above options is used. |
| .P |
| 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. |
| .P |
| If the \fBLC_ALL\fP or \fBLC_CTYPE\fP environment variable is set, |
| \fBpcregrep\fP uses the value to set a locale when calling the PCRE library. |
| The \fB--locale\fP option can be used to override this. |
| . |
| . |
| .SH "SUPPORT FOR COMPRESSED FILES" |
| .rs |
| .sp |
| It is possible to compile \fBpcregrep\fP so that it uses \fBlibz\fP or |
| \fBlibbz2\fP to read files whose names end in \fB.gz\fP or \fB.bz2\fP, |
| respectively. You can find out whether your binary has support for one or both |
| of these file types by running it with the \fB--help\fP option. If the |
| appropriate support is not present, files are treated as plain text. The |
| standard input is always so treated. |
| . |
| . |
| .SH OPTIONS |
| .rs |
| .sp |
| The order in which some of the options appear can affect the output. For |
| example, both the \fB-h\fP and \fB-l\fP options affect the printing of file |
| names. Whichever comes later in the command line will be the one that takes |
| effect. Numerical values for options may be followed by K or M, to signify |
| multiplication by 1024 or 1024*1024 respectively. |
| .TP 10 |
| \fB--\fP |
| 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. |
| .TP |
| \fB-A\fP \fInumber\fP, \fB--after-context=\fP\fInumber\fP |
| Output \fInumber\fP 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 \fInumber\fP is expected to be relatively small. However, \fBpcregrep\fP |
| guarantees to have up to 8K of following text available for context output. |
| .TP |
| \fB-B\fP \fInumber\fP, \fB--before-context=\fP\fInumber\fP |
| Output \fInumber\fP 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 \fInumber\fP is expected to be relatively small. However, \fBpcregrep\fP |
| guarantees to have up to 8K of preceding text available for context output. |
| .TP |
| \fB--buffer-size=\fP\fInumber\fP |
| Set the parameter that controls how much memory is used for buffering files |
| that are being scanned. |
| .TP |
| \fB-C\fP \fInumber\fP, \fB--context=\fP\fInumber\fP |
| Output \fInumber\fP lines of context both before and after each matching line. |
| This is equivalent to setting both \fB-A\fP and \fB-B\fP to the same value. |
| .TP |
| \fB-c\fP, \fB--count\fP |
| 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 |
| \fB--files-with-matches\fP option is also used, only those files whose counts |
| are greater than zero are listed. When \fB-c\fP is used, the \fB-A\fP, |
| \fB-B\fP, and \fB-C\fP options are ignored. |
| .TP |
| \fB--colour\fP, \fB--color\fP |
| 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. |
| .TP |
| \fB--colour=\fP\fIvalue\fP, \fB--color=\fP\fIvalue\fP |
| 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 \fBpcregrep\fP has to search for all possible matches in a line, not |
| just one, in order to colour them all. |
| .sp |
| 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. |
| .TP |
| \fB-D\fP \fIaction\fP, \fB--devices=\fP\fIaction\fP |
| 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). |
| .TP |
| \fB-d\fP \fIaction\fP, \fB--directories=\fP\fIaction\fP |
| 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 \fB-r\fP |
| 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. |
| .TP |
| \fB-e\fP \fIpattern\fP, \fB--regex=\fP\fIpattern\fP, \fB--regexp=\fP\fIpattern\fP |
| 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 \fB-e\fP 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 \fB-v\fP is used). If \fB-f\fP is used with \fB-e\fP, 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 |
| \fB-e\fP 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, \fBpcregrep\fP 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 \fB-o\fP to show the part(s) of the line |
| that matched. |
| .TP |
| \fB--exclude\fP=\fIpattern\fP |
| When \fBpcregrep\fP is searching the files in a directory as a consequence of |
| the \fB-r\fP (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 \fB--exclude-dir\fP and |
| \fB--include_dir\fP 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 \fB--include\fP and \fB--exclude\fP, it is excluded. |
| There is no short form for this option. |
| .TP |
| \fB--exclude-dir\fP=\fIpattern\fP |
| When \fBpcregrep\fP is searching the contents of a directory as a consequence |
| of the \fB-r\fP (recursive search) option, any subdirectories whose names match |
| the pattern are excluded. (Note that the \fP--exclude\fP 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 \fB--include-dir\fP and \fB--exclude-dir\fP, it |
| is excluded. There is no short form for this option. |
| .TP |
| \fB-F\fP, \fB--fixed-strings\fP |
| Interpret each pattern as a list of fixed strings, separated by newlines, |
| instead of as a regular expression. The \fB-w\fP (match as a word) and \fB-x\fP |
| (match whole line) options can be used with \fB-F\fP. They apply to each of the |
| fixed strings. A line is selected if any of the fixed strings are found in it |
| (subject to \fB-w\fP or \fB-x\fP, if present). |
| .TP |
| \fB-f\fP \fIfilename\fP, \fB--file=\fP\fIfilename\fP |
| 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 \fB-f\fP is |
| used, patterns specified on the command line using \fB-e\fP 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 \fB-e\fP above. |
| .TP |
| \fB--file-offsets\fP |
| 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 \fB-A\fP, \fB-B\fP, and \fB-C\fP |
| 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 \fB--line-offsets\fP |
| and \fB--only-matching\fP. |
| .TP |
| \fB-H\fP, \fB--with-filename\fP |
| 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. |
| .TP |
| \fB-h\fP, \fB--no-filename\fP |
| 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. |
| .TP |
| \fB--help\fP |
| Output a help message, giving brief details of the command options and file |
| type support, and then exit. |
| .TP |
| \fB-i\fP, \fB--ignore-case\fP |
| Ignore upper/lower case distinctions during comparisons. |
| .TP |
| \fB--include\fP=\fIpattern\fP |
| When \fBpcregrep\fP is searching the files in a directory as a consequence of |
| the \fB-r\fP (recursive search) option, only those regular files whose names |
| match the pattern are included. Subdirectories are always included and searched |
| recursively, subject to the \fP--include-dir\fP and \fB--exclude-dir\fP |
| 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 \fB--include\fP and \fB--exclude\fP, it is excluded. There is no short |
| form for this option. |
| .TP |
| \fB--include-dir\fP=\fIpattern\fP |
| When \fBpcregrep\fP is searching the contents of a directory as a consequence |
| of the \fB-r\fP (recursive search) option, only those subdirectories whose |
| names match the pattern are included. (Note that the \fB--include\fP 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 \fB--include-dir\fP and \fB--exclude-dir\fP, it |
| is excluded. There is no short form for this option. |
| .TP |
| \fB-L\fP, \fB--files-without-match\fP |
| 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. |
| .TP |
| \fB-l\fP, \fB--files-with-matches\fP |
| 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 \fB-c\fP (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 \fB-c\fP is a way of suppressing the listing of files with no matches. |
| .TP |
| \fB--label\fP=\fIname\fP |
| 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. |
| .TP |
| \fB--line-buffered\fP |
| 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 \fBpcregrep\fP 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 |
| \fBpcregrep\fP to buffer up large amounts of data. However, its use will affect |
| performance, and the \fB-M\fP (multiline) option ceases to work. |
| .TP |
| \fB--line-offsets\fP |
| 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 \fB-n\fP option), and the |
| offset and length are separated by a comma. In this mode, no context is shown. |
| That is, the \fB-A\fP, \fB-B\fP, and \fB-C\fP 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 \fB--file-offsets\fP and \fB--only-matching\fP. |
| .TP |
| \fB--locale\fP=\fIlocale-name\fP |
| This option specifies a locale to be used for pattern matching. It overrides |
| the value in the \fBLC_ALL\fP or \fBLC_CTYPE\fP 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. |
| .TP |
| \fB--match-limit\fP=\fInumber\fP |
| 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 \fBpcre_exec()\fP function that is called by \fBpcregrep\fP to do |
| the matching has two parameters that can limit the resources that it uses. |
| .sp |
| The \fB--match-limit\fP 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 \fBmatch()\fP which it calls repeatedly (sometimes recursively). The |
| limit set by \fB--match-limit\fP 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. |
| .sp |
| The \fB--recursion-limit\fP option is similar to \fB--match-limit\fP, but |
| instead of limiting the total number of times that \fBmatch()\fP 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 \fBmatch()\fP are recursive. This limit is |
| of use only if it is set smaller than \fB--match-limit\fP. |
| .sp |
| 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. |
| .TP |
| \fB-M\fP, \fB--multiline\fP |
| 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. |
| .sp |
| 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 \fBpcregrep\fP buffers the input file as it scans it. However, |
| \fBpcregrep\fP 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 \fP--line-buffered\fP.) |
| .TP |
| \fB-N\fP \fInewline-type\fP, \fB--newline\fP=\fInewline-type\fP |
| 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). |
| .sp |
| 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, \fBpcregrep\fP uses the library's default. |
| The possible values for this option are CR, LF, CRLF, ANYCRLF, or ANY. This |
| makes it possible to use \fBpcregrep\fP 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, |
| \fBpcregrep\fP may behave in strange ways. |
| .TP |
| \fB-n\fP, \fB--line-number\fP |
| 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 |
| \fB--line-offsets\fP is used. |
| .TP |
| \fB--no-jit\fP |
| If the PCRE library is built with support for just-in-time compiling (which |
| speeds up matching), \fBpcregrep\fP 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. |
| .TP |
| \fB-o\fP, \fB--only-matching\fP |
| 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 \fB-A\fP, \fB-B\fP, and |
| \fB-C\fP options are ignored. If there is more than one match in a line, each |
| of them is shown separately. If \fB-o\fP is combined with \fB-v\fP (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 \fB--file-offsets\fP and \fB--line-offsets\fP. |
| .TP |
| \fB-o\fP\fInumber\fP, \fB--only-matching\fP=\fInumber\fP |
| 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. |
| .TP |
| \fB-q\fP, \fB--quiet\fP |
| Work quietly, that is, display nothing except error messages. The exit |
| status indicates whether or not any matches were found. |
| .TP |
| \fB-r\fP, \fB--recursive\fP |
| If any given path is a directory, recursively scan the files it contains, |
| taking note of any \fB--include\fP and \fB--exclude\fP 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 \fB-d\fP |
| option to "recurse". |
| .TP |
| \fB--recursion-limit\fP=\fInumber\fP |
| See \fB--match-limit\fP above. |
| .TP |
| \fB-s\fP, \fB--no-messages\fP |
| 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. |
| .TP |
| \fB-u\fP, \fB--utf-8\fP |
| 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. |
| .TP |
| \fB-V\fP, \fB--version\fP |
| Write the version numbers of \fBpcregrep\fP and the PCRE library that is being |
| used to the standard error stream. |
| .TP |
| \fB-v\fP, \fB--invert-match\fP |
| Invert the sense of the match, so that lines which do \fInot\fP match any of |
| the patterns are the ones that are found. |
| .TP |
| \fB-w\fP, \fB--word-regex\fP, \fB--word-regexp\fP |
| Force the patterns to match only whole words. This is equivalent to having \eb |
| at the start and end of the pattern. |
| .TP |
| \fB-x\fP, \fB--line-regex\fP, \fB--line-regexp\fP |
| 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. |
| . |
| . |
| .SH "ENVIRONMENT VARIABLES" |
| .rs |
| .sp |
| The environment variables \fBLC_ALL\fP and \fBLC_CTYPE\fP are examined, in that |
| order, for a locale. The first one that is set is used. This can be overridden |
| by the \fB--locale\fP option. If no locale is set, the PCRE library's default |
| (usually the "C" locale) is used. |
| . |
| . |
| .SH "NEWLINES" |
| .rs |
| .sp |
| The \fB-N\fP (\fB--newline\fP) option allows \fBpcregrep\fP to scan files with |
| different newline conventions from the default. However, the setting of this |
| option does not affect the way in which \fBpcregrep\fP writes information to |
| the standard error and output streams. It uses the string "\en" in C |
| \fBprintf()\fP calls to indicate newlines, relying on the C I/O library to |
| convert this to an appropriate sequence if the output is sent to a file. |
| . |
| . |
| .SH "OPTIONS COMPATIBILITY" |
| .rs |
| .sp |
| Many of the short and long forms of \fBpcregrep\fP's options are the same |
| as in the GNU \fBgrep\fP program (version 2.5.4). Any long option of the form |
| \fB--xxx-regexp\fP (GNU terminology) is also available as \fB--xxx-regex\fP |
| (PCRE terminology). However, the \fB--file-offsets\fP, \fB--include-dir\fP, |
| \fB--line-offsets\fP, \fB--locale\fP, \fB--match-limit\fP, \fB-M\fP, |
| \fB--multiline\fP, \fB-N\fP, \fB--newline\fP, \fB--recursion-limit\fP, |
| \fB-u\fP, and \fB--utf-8\fP options are specific to \fBpcregrep\fP, as is the |
| use of the \fB--only-matching\fP option with a capturing parentheses number. |
| .P |
| Although most of the common options work the same way, a few are different in |
| \fBpcregrep\fP. For example, the \fB--include\fP option's argument is a glob |
| for GNU \fBgrep\fP, but a regular expression for \fBpcregrep\fP. If both the |
| \fB-c\fP and \fB-l\fP options are given, GNU grep lists only file names, |
| without counts, but \fBpcregrep\fP gives the counts. |
| . |
| . |
| .SH "OPTIONS WITH DATA" |
| .rs |
| .sp |
| 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: |
| .sp |
| -f/some/file |
| -f /some/file |
| .sp |
| The exception is the \fB-o\fP 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. |
| .P |
| 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: |
| .sp |
| --file=/some/file |
| --file /some/file |
| .sp |
| 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. |
| .P |
| The exceptions to the above are the \fB--colour\fP (or \fB--color\fP) and |
| \fB--only-matching\fP 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 \fBpcregrep\fP will assume that it has no data. |
| . |
| . |
| .SH "MATCHING ERRORS" |
| .rs |
| .sp |
| 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+)*\ed 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, \fBpcregrep\fP outputs an error |
| message and the line that caused the problem to the standard error stream. If |
| there are more than 20 such errors, \fBpcregrep\fP gives up. |
| .P |
| The \fB--match-limit\fP option of \fBpcregrep\fP can be used to set the overall |
| resource limit; there is a second option called \fB--recursion-limit\fP that |
| sets a limit on the amount of memory (usually stack) that is used (see the |
| discussion of these options above). |
| . |
| . |
| .SH DIAGNOSTICS |
| .rs |
| .sp |
| 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 |
| \fB-s\fP option to suppress error messages about inaccessible files does not |
| affect the return code. |
| . |
| . |
| .SH "SEE ALSO" |
| .rs |
| .sp |
| \fBpcrepattern\fP(3), \fBpcretest\fP(1). |
| . |
| . |
| .SH AUTHOR |
| .rs |
| .sp |
| .nf |
| Philip Hazel |
| University Computing Service |
| Cambridge CB2 3QH, England. |
| .fi |
| . |
| . |
| .SH REVISION |
| .rs |
| .sp |
| .nf |
| Last updated: 06 September 2011 |
| Copyright (c) 1997-2011 University of Cambridge. |
| .fi |