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8.33

    1: .TH PCREGREP 1 "13 September 2012" "PCRE 8.32"
    2: .SH NAME
    3: pcregrep - a grep with Perl-compatible regular expressions.
    4: .SH SYNOPSIS
    5: .B pcregrep [options] [long options] [pattern] [path1 path2 ...]
    6: .
    7: .SH DESCRIPTION
    8: .rs
    9: .sp
   10: \fBpcregrep\fP searches files for character patterns, in the same way as other
   11: grep commands do, but it uses the PCRE regular expression library to support
   12: patterns that are compatible with the regular expressions of Perl 5. See
   13: .\" HREF
   14: \fBpcrepattern\fP(3)
   15: .\"
   16: for a full description of syntax and semantics of the regular expressions
   17: that PCRE supports.
   18: .P
   19: Patterns, whether supplied on the command line or in a separate file, are given
   20: without delimiters. For example:
   21: .sp
   22:   pcregrep Thursday /etc/motd
   23: .sp
   24: If you attempt to use delimiters (for example, by surrounding a pattern with
   25: slashes, as is common in Perl scripts), they are interpreted as part of the
   26: pattern. Quotes can of course be used to delimit patterns on the command line
   27: because they are interpreted by the shell, and indeed quotes are required if a
   28: pattern contains white space or shell metacharacters.
   29: .P
   30: The first argument that follows any option settings is treated as the single
   31: pattern to be matched when neither \fB-e\fP nor \fB-f\fP is present.
   32: Conversely, when one or both of these options are used to specify patterns, all
   33: arguments are treated as path names. At least one of \fB-e\fP, \fB-f\fP, or an
   34: argument pattern must be provided.
   35: .P
   36: If no files are specified, \fBpcregrep\fP reads the standard input. The
   37: standard input can also be referenced by a name consisting of a single hyphen.
   38: For example:
   39: .sp
   40:   pcregrep some-pattern /file1 - /file3
   41: .sp
   42: By default, each line that matches a pattern is copied to the standard
   43: output, and if there is more than one file, the file name is output at the
   44: start of each line, followed by a colon. However, there are options that can
   45: change how \fBpcregrep\fP behaves. In particular, the \fB-M\fP option makes it
   46: possible to search for patterns that span line boundaries. What defines a line
   47: boundary is controlled by the \fB-N\fP (\fB--newline\fP) option.
   48: .P
   49: The amount of memory used for buffering files that are being scanned is
   50: controlled by a parameter that can be set by the \fB--buffer-size\fP option.
   51: The default value for this parameter is specified when \fBpcregrep\fP is built,
   52: with the default default being 20K. A block of memory three times this size is
   53: used (to allow for buffering "before" and "after" lines). An error occurs if a
   54: line overflows the buffer.
   55: .P
   56: Patterns can be no longer than 8K or BUFSIZ bytes, whichever is the greater.
   57: BUFSIZ is defined in \fB<stdio.h>\fP. When there is more than one pattern
   58: (specified by the use of \fB-e\fP and/or \fB-f\fP), each pattern is applied to
   59: each line in the order in which they are defined, except that all the \fB-e\fP
   60: patterns are tried before the \fB-f\fP patterns.
   61: .P
   62: By default, as soon as one pattern matches a line, no further patterns are
   63: considered. However, if \fB--colour\fP (or \fB--color\fP) is used to colour the
   64: matching substrings, or if \fB--only-matching\fP, \fB--file-offsets\fP, or
   65: \fB--line-offsets\fP is used to output only the part of the line that matched
   66: (either shown literally, or as an offset), scanning resumes immediately
   67: following the match, so that further matches on the same line can be found. If
   68: there are multiple patterns, they are all tried on the remainder of the line,
   69: but patterns that follow the one that matched are not tried on the earlier part
   70: of the line.
   71: .P
   72: This behaviour means that the order in which multiple patterns are specified
   73: can affect the output when one of the above options is used. This is no longer
   74: the same behaviour as GNU grep, which now manages to display earlier matches
   75: for later patterns (as long as there is no overlap).
   76: .P
   77: Patterns that can match an empty string are accepted, but empty string
   78: matches are never recognized. An example is the pattern "(super)?(man)?", in
   79: which all components are optional. This pattern finds all occurrences of both
   80: "super" and "man"; the output differs from matching with "super|man" when only
   81: the matching substrings are being shown.
   82: .P
   83: If the \fBLC_ALL\fP or \fBLC_CTYPE\fP environment variable is set,
   84: \fBpcregrep\fP uses the value to set a locale when calling the PCRE library.
   85: The \fB--locale\fP option can be used to override this.
   86: .
   87: .
   88: .SH "SUPPORT FOR COMPRESSED FILES"
   89: .rs
   90: .sp
   91: It is possible to compile \fBpcregrep\fP so that it uses \fBlibz\fP or
   92: \fBlibbz2\fP to read files whose names end in \fB.gz\fP or \fB.bz2\fP,
   93: respectively. You can find out whether your binary has support for one or both
   94: of these file types by running it with the \fB--help\fP option. If the
   95: appropriate support is not present, files are treated as plain text. The
   96: standard input is always so treated.
   97: .
   98: .
   99: .SH "BINARY FILES"
  100: .rs
  101: .sp
  102: By default, a file that contains a binary zero byte within the first 1024 bytes
  103: is identified as a binary file, and is processed specially. (GNU grep also
  104: identifies binary files in this manner.) See the \fB--binary-files\fP option
  105: for a means of changing the way binary files are handled.
  106: .
  107: .
  108: .SH OPTIONS
  109: .rs
  110: .sp
  111: The order in which some of the options appear can affect the output. For
  112: example, both the \fB-h\fP and \fB-l\fP options affect the printing of file
  113: names. Whichever comes later in the command line will be the one that takes
  114: effect. Similarly, except where noted below, if an option is given twice, the
  115: later setting is used. Numerical values for options may be followed by K or M,
  116: to signify multiplication by 1024 or 1024*1024 respectively.
  117: .TP 10
  118: \fB--\fP
  119: This terminates the list of options. It is useful if the next item on the
  120: command line starts with a hyphen but is not an option. This allows for the
  121: processing of patterns and filenames that start with hyphens.
  122: .TP
  123: \fB-A\fP \fInumber\fP, \fB--after-context=\fP\fInumber\fP
  124: Output \fInumber\fP lines of context after each matching line. If filenames
  125: and/or line numbers are being output, a hyphen separator is used instead of a
  126: colon for the context lines. A line containing "--" is output between each
  127: group of lines, unless they are in fact contiguous in the input file. The value
  128: of \fInumber\fP is expected to be relatively small. However, \fBpcregrep\fP
  129: guarantees to have up to 8K of following text available for context output.
  130: .TP
  131: \fB-a\fP, \fB--text\fP
  132: Treat binary files as text. This is equivalent to
  133: \fB--binary-files\fP=\fItext\fP.
  134: .TP
  135: \fB-B\fP \fInumber\fP, \fB--before-context=\fP\fInumber\fP
  136: Output \fInumber\fP lines of context before each matching line. If filenames
  137: and/or line numbers are being output, a hyphen separator is used instead of a
  138: colon for the context lines. A line containing "--" is output between each
  139: group of lines, unless they are in fact contiguous in the input file. The value
  140: of \fInumber\fP is expected to be relatively small. However, \fBpcregrep\fP
  141: guarantees to have up to 8K of preceding text available for context output.
  142: .TP
  143: \fB--binary-files=\fP\fIword\fP
  144: Specify how binary files are to be processed. If the word is "binary" (the
  145: default), pattern matching is performed on binary files, but the only output is
  146: "Binary file <name> matches" when a match succeeds. If the word is "text",
  147: which is equivalent to the \fB-a\fP or \fB--text\fP option, binary files are
  148: processed in the same way as any other file. In this case, when a match
  149: succeeds, the output may be binary garbage, which can have nasty effects if
  150: sent to a terminal. If the word is "without-match", which is equivalent to the
  151: \fB-I\fP option, binary files are not processed at all; they are assumed not to
  152: be of interest.
  153: .TP
  154: \fB--buffer-size=\fP\fInumber\fP
  155: Set the parameter that controls how much memory is used for buffering files
  156: that are being scanned.
  157: .TP
  158: \fB-C\fP \fInumber\fP, \fB--context=\fP\fInumber\fP
  159: Output \fInumber\fP lines of context both before and after each matching line.
  160: This is equivalent to setting both \fB-A\fP and \fB-B\fP to the same value.
  161: .TP
  162: \fB-c\fP, \fB--count\fP
  163: Do not output individual lines from the files that are being scanned; instead
  164: output the number of lines that would otherwise have been shown. If no lines
  165: are selected, the number zero is output. If several files are are being
  166: scanned, a count is output for each of them. However, if the
  167: \fB--files-with-matches\fP option is also used, only those files whose counts
  168: are greater than zero are listed. When \fB-c\fP is used, the \fB-A\fP,
  169: \fB-B\fP, and \fB-C\fP options are ignored.
  170: .TP
  171: \fB--colour\fP, \fB--color\fP
  172: If this option is given without any data, it is equivalent to "--colour=auto".
  173: If data is required, it must be given in the same shell item, separated by an
  174: equals sign.
  175: .TP
  176: \fB--colour=\fP\fIvalue\fP, \fB--color=\fP\fIvalue\fP
  177: This option specifies under what circumstances the parts of a line that matched
  178: a pattern should be coloured in the output. By default, the output is not
  179: coloured. The value (which is optional, see above) may be "never", "always", or
  180: "auto". In the latter case, colouring happens only if the standard output is
  181: connected to a terminal. More resources are used when colouring is enabled,
  182: because \fBpcregrep\fP has to search for all possible matches in a line, not
  183: just one, in order to colour them all.
  184: .sp
  185: The colour that is used can be specified by setting the environment variable
  186: PCREGREP_COLOUR or PCREGREP_COLOR. The value of this variable should be a
  187: string of two numbers, separated by a semicolon. They are copied directly into
  188: the control string for setting colour on a terminal, so it is your
  189: responsibility to ensure that they make sense. If neither of the environment
  190: variables is set, the default is "1;31", which gives red.
  191: .TP
  192: \fB-D\fP \fIaction\fP, \fB--devices=\fP\fIaction\fP
  193: If an input path is not a regular file or a directory, "action" specifies how
  194: it is to be processed. Valid values are "read" (the default) or "skip"
  195: (silently skip the path).
  196: .TP
  197: \fB-d\fP \fIaction\fP, \fB--directories=\fP\fIaction\fP
  198: If an input path is a directory, "action" specifies how it is to be processed.
  199: Valid values are "read" (the default in non-Windows environments, for
  200: compatibility with GNU grep), "recurse" (equivalent to the \fB-r\fP option), or
  201: "skip" (silently skip the path, the default in Windows environments). In the
  202: "read" case, directories are read as if they were ordinary files. In some
  203: operating systems the effect of reading a directory like this is an immediate
  204: end-of-file; in others it may provoke an error.
  205: .TP
  206: \fB-e\fP \fIpattern\fP, \fB--regex=\fP\fIpattern\fP, \fB--regexp=\fP\fIpattern\fP
  207: Specify a pattern to be matched. This option can be used multiple times in
  208: order to specify several patterns. It can also be used as a way of specifying a
  209: single pattern that starts with a hyphen. When \fB-e\fP is used, no argument
  210: pattern is taken from the command line; all arguments are treated as file
  211: names. There is no limit to the number of patterns. They are applied to each
  212: line in the order in which they are defined until one matches.
  213: .sp
  214: If \fB-f\fP is used with \fB-e\fP, the command line patterns are matched first,
  215: followed by the patterns from the file(s), independent of the order in which
  216: these options are specified. Note that multiple use of \fB-e\fP is not the same
  217: as a single pattern with alternatives. For example, X|Y finds the first
  218: character in a line that is X or Y, whereas if the two patterns are given
  219: separately, with X first, \fBpcregrep\fP finds X if it is present, even if it
  220: follows Y in the line. It finds Y only if there is no X in the line. This
  221: matters only if you are using \fB-o\fP or \fB--colo(u)r\fP to show the part(s)
  222: of the line that matched.
  223: .TP
  224: \fB--exclude\fP=\fIpattern\fP
  225: Files (but not directories) whose names match the pattern are skipped without
  226: being processed. This applies to all files, whether listed on the command line,
  227: obtained from \fB--file-list\fP, or by scanning a directory. The pattern is a
  228: PCRE regular expression, and is matched against the final component of the file
  229: name, not the entire path. The \fB-F\fP, \fB-w\fP, and \fB-x\fP options do not
  230: apply to this pattern. The option may be given any number of times in order to
  231: specify multiple patterns. If a file name matches both an \fB--include\fP
  232: and an \fB--exclude\fP pattern, it is excluded. There is no short form for this
  233: option.
  234: .TP
  235: \fB--exclude-from=\fP\fIfilename\fP
  236: Treat each non-empty line of the file as the data for an \fB--exclude\fP
  237: option. What constitutes a newline when reading the file is the operating
  238: system's default. The \fB--newline\fP option has no effect on this option. This
  239: option may be given more than once in order to specify a number of files to
  240: read.
  241: .TP
  242: \fB--exclude-dir\fP=\fIpattern\fP
  243: Directories whose names match the pattern are skipped without being processed,
  244: whatever the setting of the \fB--recursive\fP option. This applies to all
  245: directories, whether listed on the command line, obtained from
  246: \fB--file-list\fP, or by scanning a parent directory. The pattern is a PCRE
  247: regular expression, and is matched against the final component of the directory
  248: name, not the entire path. The \fB-F\fP, \fB-w\fP, and \fB-x\fP options do not
  249: apply to this pattern. The option may be given any number of times in order to
  250: specify more than one pattern. If a directory matches both \fB--include-dir\fP
  251: and \fB--exclude-dir\fP, it is excluded. There is no short form for this
  252: option.
  253: .TP
  254: \fB-F\fP, \fB--fixed-strings\fP
  255: Interpret each data-matching pattern as a list of fixed strings, separated by
  256: newlines, instead of as a regular expression. What constitutes a newline for
  257: this purpose is controlled by the \fB--newline\fP option. The \fB-w\fP (match
  258: as a word) and \fB-x\fP (match whole line) options can be used with \fB-F\fP.
  259: They apply to each of the fixed strings. A line is selected if any of the fixed
  260: strings are found in it (subject to \fB-w\fP or \fB-x\fP, if present). This
  261: option applies only to the patterns that are matched against the contents of
  262: files; it does not apply to patterns specified by any of the \fB--include\fP or
  263: \fB--exclude\fP options.
  264: .TP
  265: \fB-f\fP \fIfilename\fP, \fB--file=\fP\fIfilename\fP
  266: Read patterns from the file, one per line, and match them against
  267: each line of input. What constitutes a newline when reading the file is the
  268: operating system's default. The \fB--newline\fP option has no effect on this
  269: option. Trailing white space is removed from each line, and blank lines are
  270: ignored. An empty file contains no patterns and therefore matches nothing. See
  271: also the comments about multiple patterns versus a single pattern with
  272: alternatives in the description of \fB-e\fP above.
  273: .sp
  274: If this option is given more than once, all the specified files are
  275: read. A data line is output if any of the patterns match it. A filename can
  276: be given as "-" to refer to the standard input. When \fB-f\fP is used, patterns
  277: specified on the command line using \fB-e\fP may also be present; they are
  278: tested before the file's patterns. However, no other pattern is taken from the
  279: command line; all arguments are treated as the names of paths to be searched.
  280: .TP
  281: \fB--file-list\fP=\fIfilename\fP
  282: Read a list of files and/or directories that are to be scanned from the given
  283: file, one per line. Trailing white space is removed from each line, and blank
  284: lines are ignored. These paths are processed before any that are listed on the
  285: command line. The filename can be given as "-" to refer to the standard input.
  286: If \fB--file\fP and \fB--file-list\fP are both specified as "-", patterns are
  287: read first. This is useful only when the standard input is a terminal, from
  288: which further lines (the list of files) can be read after an end-of-file
  289: indication. If this option is given more than once, all the specified files are
  290: read.
  291: .TP
  292: \fB--file-offsets\fP
  293: Instead of showing lines or parts of lines that match, show each match as an
  294: offset from the start of the file and a length, separated by a comma. In this
  295: mode, no context is shown. That is, the \fB-A\fP, \fB-B\fP, and \fB-C\fP
  296: options are ignored. If there is more than one match in a line, each of them is
  297: shown separately. This option is mutually exclusive with \fB--line-offsets\fP
  298: and \fB--only-matching\fP.
  299: .TP
  300: \fB-H\fP, \fB--with-filename\fP
  301: Force the inclusion of the filename at the start of output lines when searching
  302: a single file. By default, the filename is not shown in this case. For matching
  303: lines, the filename is followed by a colon; for context lines, a hyphen
  304: separator is used. If a line number is also being output, it follows the file
  305: name.
  306: .TP
  307: \fB-h\fP, \fB--no-filename\fP
  308: Suppress the output filenames when searching multiple files. By default,
  309: filenames are shown when multiple files are searched. For matching lines, the
  310: filename is followed by a colon; for context lines, a hyphen separator is used.
  311: If a line number is also being output, it follows the file name.
  312: .TP
  313: \fB--help\fP
  314: Output a help message, giving brief details of the command options and file
  315: type support, and then exit. Anything else on the command line is
  316: ignored.
  317: .TP
  318: \fB-I\fP
  319: Treat binary files as never matching. This is equivalent to
  320: \fB--binary-files\fP=\fIwithout-match\fP.
  321: .TP
  322: \fB-i\fP, \fB--ignore-case\fP
  323: Ignore upper/lower case distinctions during comparisons.
  324: .TP
  325: \fB--include\fP=\fIpattern\fP
  326: If any \fB--include\fP patterns are specified, the only files that are
  327: processed are those that match one of the patterns (and do not match an
  328: \fB--exclude\fP pattern). This option does not affect directories, but it
  329: applies to all files, whether listed on the command line, obtained from
  330: \fB--file-list\fP, or by scanning a directory. The pattern is a PCRE regular
  331: expression, and is matched against the final component of the file name, not
  332: the entire path. The \fB-F\fP, \fB-w\fP, and \fB-x\fP options do not apply to
  333: this pattern. The option may be given any number of times. If a file name
  334: matches both an \fB--include\fP and an \fB--exclude\fP pattern, it is excluded.
  335: There is no short form for this option.
  336: .TP
  337: \fB--include-from=\fP\fIfilename\fP
  338: Treat each non-empty line of the file as the data for an \fB--include\fP
  339: option. What constitutes a newline for this purpose is the operating system's
  340: default. The \fB--newline\fP option has no effect on this option. This option
  341: may be given any number of times; all the files are read.
  342: .TP
  343: \fB--include-dir\fP=\fIpattern\fP
  344: If any \fB--include-dir\fP patterns are specified, the only directories that
  345: are processed are those that match one of the patterns (and do not match an
  346: \fB--exclude-dir\fP pattern). This applies to all directories, whether listed
  347: on the command line, obtained from \fB--file-list\fP, or by scanning a parent
  348: directory. The pattern is a PCRE regular expression, and is matched against the
  349: final component of the directory name, not the entire path. The \fB-F\fP,
  350: \fB-w\fP, and \fB-x\fP options do not apply to this pattern. The option may be
  351: given any number of times. If a directory matches both \fB--include-dir\fP and
  352: \fB--exclude-dir\fP, it is excluded. There is no short form for this option.
  353: .TP
  354: \fB-L\fP, \fB--files-without-match\fP
  355: Instead of outputting lines from the files, just output the names of the files
  356: that do not contain any lines that would have been output. Each file name is
  357: output once, on a separate line.
  358: .TP
  359: \fB-l\fP, \fB--files-with-matches\fP
  360: Instead of outputting lines from the files, just output the names of the files
  361: containing lines that would have been output. Each file name is output
  362: once, on a separate line. Searching normally stops as soon as a matching line
  363: is found in a file. However, if the \fB-c\fP (count) option is also used,
  364: matching continues in order to obtain the correct count, and those files that
  365: have at least one match are listed along with their counts. Using this option
  366: with \fB-c\fP is a way of suppressing the listing of files with no matches.
  367: .TP
  368: \fB--label\fP=\fIname\fP
  369: This option supplies a name to be used for the standard input when file names
  370: are being output. If not supplied, "(standard input)" is used. There is no
  371: short form for this option.
  372: .TP
  373: \fB--line-buffered\fP
  374: When this option is given, input is read and processed line by line, and the
  375: output is flushed after each write. By default, input is read in large chunks,
  376: unless \fBpcregrep\fP can determine that it is reading from a terminal (which
  377: is currently possible only in Unix-like environments). Output to terminal is
  378: normally automatically flushed by the operating system. This option can be
  379: useful when the input or output is attached to a pipe and you do not want
  380: \fBpcregrep\fP to buffer up large amounts of data. However, its use will affect
  381: performance, and the \fB-M\fP (multiline) option ceases to work.
  382: .TP
  383: \fB--line-offsets\fP
  384: Instead of showing lines or parts of lines that match, show each match as a
  385: line number, the offset from the start of the line, and a length. The line
  386: number is terminated by a colon (as usual; see the \fB-n\fP option), and the
  387: offset and length are separated by a comma. In this mode, no context is shown.
  388: That is, the \fB-A\fP, \fB-B\fP, and \fB-C\fP options are ignored. If there is
  389: more than one match in a line, each of them is shown separately. This option is
  390: mutually exclusive with \fB--file-offsets\fP and \fB--only-matching\fP.
  391: .TP
  392: \fB--locale\fP=\fIlocale-name\fP
  393: This option specifies a locale to be used for pattern matching. It overrides
  394: the value in the \fBLC_ALL\fP or \fBLC_CTYPE\fP environment variables. If no
  395: locale is specified, the PCRE library's default (usually the "C" locale) is
  396: used. There is no short form for this option.
  397: .TP
  398: \fB--match-limit\fP=\fInumber\fP
  399: Processing some regular expression patterns can require a very large amount of
  400: memory, leading in some cases to a program crash if not enough is available.
  401: Other patterns may take a very long time to search for all possible matching
  402: strings. The \fBpcre_exec()\fP function that is called by \fBpcregrep\fP to do
  403: the matching has two parameters that can limit the resources that it uses.
  404: .sp
  405: The \fB--match-limit\fP option provides a means of limiting resource usage
  406: when processing patterns that are not going to match, but which have a very
  407: large number of possibilities in their search trees. The classic example is a
  408: pattern that uses nested unlimited repeats. Internally, PCRE uses a function
  409: called \fBmatch()\fP which it calls repeatedly (sometimes recursively). The
  410: limit set by \fB--match-limit\fP is imposed on the number of times this
  411: function is called during a match, which has the effect of limiting the amount
  412: of backtracking that can take place.
  413: .sp
  414: The \fB--recursion-limit\fP option is similar to \fB--match-limit\fP, but
  415: instead of limiting the total number of times that \fBmatch()\fP is called, it
  416: limits the depth of recursive calls, which in turn limits the amount of memory
  417: that can be used. The recursion depth is a smaller number than the total number
  418: of calls, because not all calls to \fBmatch()\fP are recursive. This limit is
  419: of use only if it is set smaller than \fB--match-limit\fP.
  420: .sp
  421: There are no short forms for these options. The default settings are specified
  422: when the PCRE library is compiled, with the default default being 10 million.
  423: .TP
  424: \fB-M\fP, \fB--multiline\fP
  425: Allow patterns to match more than one line. When this option is given, patterns
  426: may usefully contain literal newline characters and internal occurrences of ^
  427: and $ characters. The output for a successful match may consist of more than
  428: one line, the last of which is the one in which the match ended. If the matched
  429: string ends with a newline sequence the output ends at the end of that line.
  430: .sp
  431: When this option is set, the PCRE library is called in "multiline" mode.
  432: There is a limit to the number of lines that can be matched, imposed by the way
  433: that \fBpcregrep\fP buffers the input file as it scans it. However,
  434: \fBpcregrep\fP ensures that at least 8K characters or the rest of the document
  435: (whichever is the shorter) are available for forward matching, and similarly
  436: the previous 8K characters (or all the previous characters, if fewer than 8K)
  437: are guaranteed to be available for lookbehind assertions. This option does not
  438: work when input is read line by line (see \fP--line-buffered\fP.)
  439: .TP
  440: \fB-N\fP \fInewline-type\fP, \fB--newline\fP=\fInewline-type\fP
  441: The PCRE library supports five different conventions for indicating
  442: the ends of lines. They are the single-character sequences CR (carriage return)
  443: and LF (linefeed), the two-character sequence CRLF, an "anycrlf" convention,
  444: which recognizes any of the preceding three types, and an "any" convention, in
  445: which any Unicode line ending sequence is assumed to end a line. The Unicode
  446: sequences are the three just mentioned, plus VT (vertical tab, U+000B), FF
  447: (form feed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and
  448: PS (paragraph separator, U+2029).
  449: .sp
  450: When the PCRE library is built, a default line-ending sequence is specified.
  451: This is normally the standard sequence for the operating system. Unless
  452: otherwise specified by this option, \fBpcregrep\fP uses the library's default.
  453: The possible values for this option are CR, LF, CRLF, ANYCRLF, or ANY. This
  454: makes it possible to use \fBpcregrep\fP to scan files that have come from other
  455: environments without having to modify their line endings. If the data that is
  456: being scanned does not agree with the convention set by this option,
  457: \fBpcregrep\fP may behave in strange ways. Note that this option does not
  458: apply to files specified by the \fB-f\fP, \fB--exclude-from\fP, or
  459: \fB--include-from\fP options, which are expected to use the operating system's
  460: standard newline sequence.
  461: .TP
  462: \fB-n\fP, \fB--line-number\fP
  463: Precede each output line by its line number in the file, followed by a colon
  464: for matching lines or a hyphen for context lines. If the filename is also being
  465: output, it precedes the line number. This option is forced if
  466: \fB--line-offsets\fP is used.
  467: .TP
  468: \fB--no-jit\fP
  469: If the PCRE library is built with support for just-in-time compiling (which
  470: speeds up matching), \fBpcregrep\fP automatically makes use of this, unless it
  471: was explicitly disabled at build time. This option can be used to disable the
  472: use of JIT at run time. It is provided for testing and working round problems.
  473: It should never be needed in normal use.
  474: .TP
  475: \fB-o\fP, \fB--only-matching\fP
  476: Show only the part of the line that matched a pattern instead of the whole
  477: line. In this mode, no context is shown. That is, the \fB-A\fP, \fB-B\fP, and
  478: \fB-C\fP options are ignored. If there is more than one match in a line, each
  479: of them is shown separately. If \fB-o\fP is combined with \fB-v\fP (invert the
  480: sense of the match to find non-matching lines), no output is generated, but the
  481: return code is set appropriately. If the matched portion of the line is empty,
  482: nothing is output unless the file name or line number are being printed, in
  483: which case they are shown on an otherwise empty line. This option is mutually
  484: exclusive with \fB--file-offsets\fP and \fB--line-offsets\fP.
  485: .TP
  486: \fB-o\fP\fInumber\fP, \fB--only-matching\fP=\fInumber\fP
  487: Show only the part of the line that matched the capturing parentheses of the
  488: given number. Up to 32 capturing parentheses are supported, and -o0 is
  489: equivalent to \fB-o\fP without a number. Because these options can be given
  490: without an argument (see above), if an argument is present, it must be given in
  491: the same shell item, for example, -o3 or --only-matching=2. The comments given
  492: for the non-argument case above also apply to this case. If the specified
  493: capturing parentheses do not exist in the pattern, or were not set in the
  494: match, nothing is output unless the file name or line number are being printed.
  495: .sp
  496: If this option is given multiple times, multiple substrings are output, in the
  497: order the options are given. For example, -o3 -o1 -o3 causes the substrings
  498: matched by capturing parentheses 3 and 1 and then 3 again to be output. By
  499: default, there is no separator (but see the next option).
  500: .TP
  501: \fB--om-separator\fP=\fItext\fP
  502: Specify a separating string for multiple occurrences of \fB-o\fP. The default
  503: is an empty string. Separating strings are never coloured.
  504: .TP
  505: \fB-q\fP, \fB--quiet\fP
  506: Work quietly, that is, display nothing except error messages. The exit
  507: status indicates whether or not any matches were found.
  508: .TP
  509: \fB-r\fP, \fB--recursive\fP
  510: If any given path is a directory, recursively scan the files it contains,
  511: taking note of any \fB--include\fP and \fB--exclude\fP settings. By default, a
  512: directory is read as a normal file; in some operating systems this gives an
  513: immediate end-of-file. This option is a shorthand for setting the \fB-d\fP
  514: option to "recurse".
  515: .TP
  516: \fB--recursion-limit\fP=\fInumber\fP
  517: See \fB--match-limit\fP above.
  518: .TP
  519: \fB-s\fP, \fB--no-messages\fP
  520: Suppress error messages about non-existent or unreadable files. Such files are
  521: quietly skipped. However, the return code is still 2, even if matches were
  522: found in other files.
  523: .TP
  524: \fB-u\fP, \fB--utf-8\fP
  525: Operate in UTF-8 mode. This option is available only if PCRE has been compiled
  526: with UTF-8 support. All patterns (including those for any \fB--exclude\fP and
  527: \fB--include\fP options) and all subject lines that are scanned must be valid
  528: strings of UTF-8 characters.
  529: .TP
  530: \fB-V\fP, \fB--version\fP
  531: Write the version numbers of \fBpcregrep\fP and the PCRE library to the
  532: standard output and then exit. Anything else on the command line is
  533: ignored.
  534: .TP
  535: \fB-v\fP, \fB--invert-match\fP
  536: Invert the sense of the match, so that lines which do \fInot\fP match any of
  537: the patterns are the ones that are found.
  538: .TP
  539: \fB-w\fP, \fB--word-regex\fP, \fB--word-regexp\fP
  540: Force the patterns to match only whole words. This is equivalent to having \eb
  541: at the start and end of the pattern. This option applies only to the patterns
  542: that are matched against the contents of files; it does not apply to patterns
  543: specified by any of the \fB--include\fP or \fB--exclude\fP options.
  544: .TP
  545: \fB-x\fP, \fB--line-regex\fP, \fB--line-regexp\fP
  546: Force the patterns to be anchored (each must start matching at the beginning of
  547: a line) and in addition, require them to match entire lines. This is equivalent
  548: to having ^ and $ characters at the start and end of each alternative branch in
  549: every pattern. This option applies only to the patterns that are matched
  550: against the contents of files; it does not apply to patterns specified by any
  551: of the \fB--include\fP or \fB--exclude\fP options.
  552: .
  553: .
  554: .SH "ENVIRONMENT VARIABLES"
  555: .rs
  556: .sp
  557: The environment variables \fBLC_ALL\fP and \fBLC_CTYPE\fP are examined, in that
  558: order, for a locale. The first one that is set is used. This can be overridden
  559: by the \fB--locale\fP option. If no locale is set, the PCRE library's default
  560: (usually the "C" locale) is used.
  561: .
  562: .
  563: .SH "NEWLINES"
  564: .rs
  565: .sp
  566: The \fB-N\fP (\fB--newline\fP) option allows \fBpcregrep\fP to scan files with
  567: different newline conventions from the default. Any parts of the input files
  568: that are written to the standard output are copied identically, with whatever
  569: newline sequences they have in the input. However, the setting of this option
  570: does not affect the interpretation of files specified by the \fB-f\fP,
  571: \fB--exclude-from\fP, or \fB--include-from\fP options, which are assumed to use
  572: the operating system's standard newline sequence, nor does it affect the way in
  573: which \fBpcregrep\fP writes informational messages to the standard error and
  574: output streams. For these it uses the string "\en" to indicate newlines,
  575: relying on the C I/O library to convert this to an appropriate sequence.
  576: .
  577: .
  578: .SH "OPTIONS COMPATIBILITY"
  579: .rs
  580: .sp
  581: Many of the short and long forms of \fBpcregrep\fP's options are the same
  582: as in the GNU \fBgrep\fP program. Any long option of the form
  583: \fB--xxx-regexp\fP (GNU terminology) is also available as \fB--xxx-regex\fP
  584: (PCRE terminology). However, the \fB--file-list\fP, \fB--file-offsets\fP,
  585: \fB--include-dir\fP, \fB--line-offsets\fP, \fB--locale\fP, \fB--match-limit\fP,
  586: \fB-M\fP, \fB--multiline\fP, \fB-N\fP, \fB--newline\fP, \fB--om-separator\fP,
  587: \fB--recursion-limit\fP, \fB-u\fP, and \fB--utf-8\fP options are specific to
  588: \fBpcregrep\fP, as is the use of the \fB--only-matching\fP option with a
  589: capturing parentheses number.
  590: .P
  591: Although most of the common options work the same way, a few are different in
  592: \fBpcregrep\fP. For example, the \fB--include\fP option's argument is a glob
  593: for GNU \fBgrep\fP, but a regular expression for \fBpcregrep\fP. If both the
  594: \fB-c\fP and \fB-l\fP options are given, GNU grep lists only file names,
  595: without counts, but \fBpcregrep\fP gives the counts.
  596: .
  597: .
  598: .SH "OPTIONS WITH DATA"
  599: .rs
  600: .sp
  601: There are four different ways in which an option with data can be specified.
  602: If a short form option is used, the data may follow immediately, or (with one
  603: exception) in the next command line item. For example:
  604: .sp
  605:   -f/some/file
  606:   -f /some/file
  607: .sp
  608: The exception is the \fB-o\fP option, which may appear with or without data.
  609: Because of this, if data is present, it must follow immediately in the same
  610: item, for example -o3.
  611: .P
  612: If a long form option is used, the data may appear in the same command line
  613: item, separated by an equals character, or (with two exceptions) it may appear
  614: in the next command line item. For example:
  615: .sp
  616:   --file=/some/file
  617:   --file /some/file
  618: .sp
  619: Note, however, that if you want to supply a file name beginning with ~ as data
  620: in a shell command, and have the shell expand ~ to a home directory, you must
  621: separate the file name from the option, because the shell does not treat ~
  622: specially unless it is at the start of an item.
  623: .P
  624: The exceptions to the above are the \fB--colour\fP (or \fB--color\fP) and
  625: \fB--only-matching\fP options, for which the data is optional. If one of these
  626: options does have data, it must be given in the first form, using an equals
  627: character. Otherwise \fBpcregrep\fP will assume that it has no data.
  628: .
  629: .
  630: .SH "MATCHING ERRORS"
  631: .rs
  632: .sp
  633: It is possible to supply a regular expression that takes a very long time to
  634: fail to match certain lines. Such patterns normally involve nested indefinite
  635: repeats, for example: (a+)*\ed when matched against a line of a's with no final
  636: digit. The PCRE matching function has a resource limit that causes it to abort
  637: in these circumstances. If this happens, \fBpcregrep\fP outputs an error
  638: message and the line that caused the problem to the standard error stream. If
  639: there are more than 20 such errors, \fBpcregrep\fP gives up.
  640: .P
  641: The \fB--match-limit\fP option of \fBpcregrep\fP can be used to set the overall
  642: resource limit; there is a second option called \fB--recursion-limit\fP that
  643: sets a limit on the amount of memory (usually stack) that is used (see the
  644: discussion of these options above).
  645: .
  646: .
  647: .SH DIAGNOSTICS
  648: .rs
  649: .sp
  650: Exit status is 0 if any matches were found, 1 if no matches were found, and 2
  651: for syntax errors, overlong lines, non-existent or inaccessible files (even if
  652: matches were found in other files) or too many matching errors. Using the
  653: \fB-s\fP option to suppress error messages about inaccessible files does not
  654: affect the return code.
  655: .
  656: .
  657: .SH "SEE ALSO"
  658: .rs
  659: .sp
  660: \fBpcrepattern\fP(3), \fBpcresyntax\fP(3), \fBpcretest\fP(1).
  661: .
  662: .
  663: .SH AUTHOR
  664: .rs
  665: .sp
  666: .nf
  667: Philip Hazel
  668: University Computing Service
  669: Cambridge CB2 3QH, England.
  670: .fi
  671: .
  672: .
  673: .SH REVISION
  674: .rs
  675: .sp
  676: .nf
  677: Last updated: 13 September 2012
  678: Copyright (c) 1997-2012 University of Cambridge.
  679: .fi