Annotation of embedaddon/pcre/doc/pcregrep.1, revision 1.1
1.1 ! misho 1: .TH PCREGREP 1
! 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 they 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 are limited to 8K or BUFSIZ bytes, whichever is the greater. BUFSIZ is
! 57: defined in \fB<stdio.h>\fP. When there is more than one pattern (specified by
! 58: the use of \fB-e\fP and/or \fB-f\fP), each pattern is applied to each line in
! 59: the order in which they are defined, except that all the \fB-e\fP patterns are
! 60: tried before the \fB-f\fP patterns.
! 61: .P
! 62: By default, as soon as one pattern matches (or fails to match when \fB-v\fP is
! 63: used), no further patterns are considered. However, if \fB--colour\fP (or
! 64: \fB--color\fP) is used to colour the matching substrings, or if
! 65: \fB--only-matching\fP, \fB--file-offsets\fP, or \fB--line-offsets\fP is used to
! 66: output only the part of the line that matched (either shown literally, or as an
! 67: offset), scanning resumes immediately following the match, so that further
! 68: matches on the same line can be found. If there are multiple patterns, they are
! 69: all tried on the remainder of the line, but patterns that follow the one that
! 70: matched are not tried on the earlier part of the line.
! 71: .P
! 72: This is the same behaviour as GNU grep, but it does mean that the order in
! 73: which multiple patterns are specified can affect the output when one of the
! 74: above options is used.
! 75: .P
! 76: Patterns that can match an empty string are accepted, but empty string
! 77: matches are never recognized. An example is the pattern "(super)?(man)?", in
! 78: which all components are optional. This pattern finds all occurrences of both
! 79: "super" and "man"; the output differs from matching with "super|man" when only
! 80: the matching substrings are being shown.
! 81: .P
! 82: If the \fBLC_ALL\fP or \fBLC_CTYPE\fP environment variable is set,
! 83: \fBpcregrep\fP uses the value to set a locale when calling the PCRE library.
! 84: The \fB--locale\fP option can be used to override this.
! 85: .
! 86: .
! 87: .SH "SUPPORT FOR COMPRESSED FILES"
! 88: .rs
! 89: .sp
! 90: It is possible to compile \fBpcregrep\fP so that it uses \fBlibz\fP or
! 91: \fBlibbz2\fP to read files whose names end in \fB.gz\fP or \fB.bz2\fP,
! 92: respectively. You can find out whether your binary has support for one or both
! 93: of these file types by running it with the \fB--help\fP option. If the
! 94: appropriate support is not present, files are treated as plain text. The
! 95: standard input is always so treated.
! 96: .
! 97: .
! 98: .SH OPTIONS
! 99: .rs
! 100: .sp
! 101: The order in which some of the options appear can affect the output. For
! 102: example, both the \fB-h\fP and \fB-l\fP options affect the printing of file
! 103: names. Whichever comes later in the command line will be the one that takes
! 104: effect. Numerical values for options may be followed by K or M, to signify
! 105: multiplication by 1024 or 1024*1024 respectively.
! 106: .TP 10
! 107: \fB--\fP
! 108: This terminates the list of options. It is useful if the next item on the
! 109: command line starts with a hyphen but is not an option. This allows for the
! 110: processing of patterns and filenames that start with hyphens.
! 111: .TP
! 112: \fB-A\fP \fInumber\fP, \fB--after-context=\fP\fInumber\fP
! 113: Output \fInumber\fP lines of context after each matching line. If filenames
! 114: and/or line numbers are being output, a hyphen separator is used instead of a
! 115: colon for the context lines. A line containing "--" is output between each
! 116: group of lines, unless they are in fact contiguous in the input file. The value
! 117: of \fInumber\fP is expected to be relatively small. However, \fBpcregrep\fP
! 118: guarantees to have up to 8K of following text available for context output.
! 119: .TP
! 120: \fB-B\fP \fInumber\fP, \fB--before-context=\fP\fInumber\fP
! 121: Output \fInumber\fP lines of context before each matching line. If filenames
! 122: and/or line numbers are being output, a hyphen separator is used instead of a
! 123: colon for the context lines. A line containing "--" is output between each
! 124: group of lines, unless they are in fact contiguous in the input file. The value
! 125: of \fInumber\fP is expected to be relatively small. However, \fBpcregrep\fP
! 126: guarantees to have up to 8K of preceding text available for context output.
! 127: .TP
! 128: \fB--buffer-size=\fP\fInumber\fP
! 129: Set the parameter that controls how much memory is used for buffering files
! 130: that are being scanned.
! 131: .TP
! 132: \fB-C\fP \fInumber\fP, \fB--context=\fP\fInumber\fP
! 133: Output \fInumber\fP lines of context both before and after each matching line.
! 134: This is equivalent to setting both \fB-A\fP and \fB-B\fP to the same value.
! 135: .TP
! 136: \fB-c\fP, \fB--count\fP
! 137: Do not output individual lines from the files that are being scanned; instead
! 138: output the number of lines that would otherwise have been shown. If no lines
! 139: are selected, the number zero is output. If several files are are being
! 140: scanned, a count is output for each of them. However, if the
! 141: \fB--files-with-matches\fP option is also used, only those files whose counts
! 142: are greater than zero are listed. When \fB-c\fP is used, the \fB-A\fP,
! 143: \fB-B\fP, and \fB-C\fP options are ignored.
! 144: .TP
! 145: \fB--colour\fP, \fB--color\fP
! 146: If this option is given without any data, it is equivalent to "--colour=auto".
! 147: If data is required, it must be given in the same shell item, separated by an
! 148: equals sign.
! 149: .TP
! 150: \fB--colour=\fP\fIvalue\fP, \fB--color=\fP\fIvalue\fP
! 151: This option specifies under what circumstances the parts of a line that matched
! 152: a pattern should be coloured in the output. By default, the output is not
! 153: coloured. The value (which is optional, see above) may be "never", "always", or
! 154: "auto". In the latter case, colouring happens only if the standard output is
! 155: connected to a terminal. More resources are used when colouring is enabled,
! 156: because \fBpcregrep\fP has to search for all possible matches in a line, not
! 157: just one, in order to colour them all.
! 158: .sp
! 159: The colour that is used can be specified by setting the environment variable
! 160: PCREGREP_COLOUR or PCREGREP_COLOR. The value of this variable should be a
! 161: string of two numbers, separated by a semicolon. They are copied directly into
! 162: the control string for setting colour on a terminal, so it is your
! 163: responsibility to ensure that they make sense. If neither of the environment
! 164: variables is set, the default is "1;31", which gives red.
! 165: .TP
! 166: \fB-D\fP \fIaction\fP, \fB--devices=\fP\fIaction\fP
! 167: If an input path is not a regular file or a directory, "action" specifies how
! 168: it is to be processed. Valid values are "read" (the default) or "skip"
! 169: (silently skip the path).
! 170: .TP
! 171: \fB-d\fP \fIaction\fP, \fB--directories=\fP\fIaction\fP
! 172: If an input path is a directory, "action" specifies how it is to be processed.
! 173: Valid values are "read" (the default), "recurse" (equivalent to the \fB-r\fP
! 174: option), or "skip" (silently skip the path). In the default case, directories
! 175: are read as if they were ordinary files. In some operating systems the effect
! 176: of reading a directory like this is an immediate end-of-file.
! 177: .TP
! 178: \fB-e\fP \fIpattern\fP, \fB--regex=\fP\fIpattern\fP, \fB--regexp=\fP\fIpattern\fP
! 179: Specify a pattern to be matched. This option can be used multiple times in
! 180: order to specify several patterns. It can also be used as a way of specifying a
! 181: single pattern that starts with a hyphen. When \fB-e\fP is used, no argument
! 182: pattern is taken from the command line; all arguments are treated as file
! 183: names. There is an overall maximum of 100 patterns. They are applied to each
! 184: line in the order in which they are defined until one matches (or fails to
! 185: match if \fB-v\fP is used). If \fB-f\fP is used with \fB-e\fP, the command line
! 186: patterns are matched first, followed by the patterns from the file, independent
! 187: of the order in which these options are specified. Note that multiple use of
! 188: \fB-e\fP is not the same as a single pattern with alternatives. For example,
! 189: X|Y finds the first character in a line that is X or Y, whereas if the two
! 190: patterns are given separately, \fBpcregrep\fP finds X if it is present, even if
! 191: it follows Y in the line. It finds Y only if there is no X in the line. This
! 192: really matters only if you are using \fB-o\fP to show the part(s) of the line
! 193: that matched.
! 194: .TP
! 195: \fB--exclude\fP=\fIpattern\fP
! 196: When \fBpcregrep\fP is searching the files in a directory as a consequence of
! 197: the \fB-r\fP (recursive search) option, any regular files whose names match the
! 198: pattern are excluded. Subdirectories are not excluded by this option; they are
! 199: searched recursively, subject to the \fB--exclude-dir\fP and
! 200: \fB--include_dir\fP options. The pattern is a PCRE regular expression, and is
! 201: matched against the final component of the file name (not the entire path). If
! 202: a file name matches both \fB--include\fP and \fB--exclude\fP, it is excluded.
! 203: There is no short form for this option.
! 204: .TP
! 205: \fB--exclude-dir\fP=\fIpattern\fP
! 206: When \fBpcregrep\fP is searching the contents of a directory as a consequence
! 207: of the \fB-r\fP (recursive search) option, any subdirectories whose names match
! 208: the pattern are excluded. (Note that the \fP--exclude\fP option does not affect
! 209: subdirectories.) The pattern is a PCRE regular expression, and is matched
! 210: against the final component of the name (not the entire path). If a
! 211: subdirectory name matches both \fB--include-dir\fP and \fB--exclude-dir\fP, it
! 212: is excluded. There is no short form for this option.
! 213: .TP
! 214: \fB-F\fP, \fB--fixed-strings\fP
! 215: Interpret each pattern as a list of fixed strings, separated by newlines,
! 216: instead of as a regular expression. The \fB-w\fP (match as a word) and \fB-x\fP
! 217: (match whole line) options can be used with \fB-F\fP. They apply to each of the
! 218: fixed strings. A line is selected if any of the fixed strings are found in it
! 219: (subject to \fB-w\fP or \fB-x\fP, if present).
! 220: .TP
! 221: \fB-f\fP \fIfilename\fP, \fB--file=\fP\fIfilename\fP
! 222: Read a number of patterns from the file, one per line, and match them against
! 223: each line of input. A data line is output if any of the patterns match it. The
! 224: filename can be given as "-" to refer to the standard input. When \fB-f\fP is
! 225: used, patterns specified on the command line using \fB-e\fP may also be
! 226: present; they are tested before the file's patterns. However, no other pattern
! 227: is taken from the command line; all arguments are treated as file names. There
! 228: is an overall maximum of 100 patterns. Trailing white space is removed from
! 229: each line, and blank lines are ignored. An empty file contains no patterns and
! 230: therefore matches nothing. See also the comments about multiple patterns versus
! 231: a single pattern with alternatives in the description of \fB-e\fP above.
! 232: .TP
! 233: \fB--file-offsets\fP
! 234: Instead of showing lines or parts of lines that match, show each match as an
! 235: offset from the start of the file and a length, separated by a comma. In this
! 236: mode, no context is shown. That is, the \fB-A\fP, \fB-B\fP, and \fB-C\fP
! 237: options are ignored. If there is more than one match in a line, each of them is
! 238: shown separately. This option is mutually exclusive with \fB--line-offsets\fP
! 239: and \fB--only-matching\fP.
! 240: .TP
! 241: \fB-H\fP, \fB--with-filename\fP
! 242: Force the inclusion of the filename at the start of output lines when searching
! 243: a single file. By default, the filename is not shown in this case. For matching
! 244: lines, the filename is followed by a colon; for context lines, a hyphen
! 245: separator is used. If a line number is also being output, it follows the file
! 246: name.
! 247: .TP
! 248: \fB-h\fP, \fB--no-filename\fP
! 249: Suppress the output filenames when searching multiple files. By default,
! 250: filenames are shown when multiple files are searched. For matching lines, the
! 251: filename is followed by a colon; for context lines, a hyphen separator is used.
! 252: If a line number is also being output, it follows the file name.
! 253: .TP
! 254: \fB--help\fP
! 255: Output a help message, giving brief details of the command options and file
! 256: type support, and then exit.
! 257: .TP
! 258: \fB-i\fP, \fB--ignore-case\fP
! 259: Ignore upper/lower case distinctions during comparisons.
! 260: .TP
! 261: \fB--include\fP=\fIpattern\fP
! 262: When \fBpcregrep\fP is searching the files in a directory as a consequence of
! 263: the \fB-r\fP (recursive search) option, only those regular files whose names
! 264: match the pattern are included. Subdirectories are always included and searched
! 265: recursively, subject to the \fP--include-dir\fP and \fB--exclude-dir\fP
! 266: options. The pattern is a PCRE regular expression, and is matched against the
! 267: final component of the file name (not the entire path). If a file name matches
! 268: both \fB--include\fP and \fB--exclude\fP, it is excluded. There is no short
! 269: form for this option.
! 270: .TP
! 271: \fB--include-dir\fP=\fIpattern\fP
! 272: When \fBpcregrep\fP is searching the contents of a directory as a consequence
! 273: of the \fB-r\fP (recursive search) option, only those subdirectories whose
! 274: names match the pattern are included. (Note that the \fB--include\fP option
! 275: does not affect subdirectories.) The pattern is a PCRE regular expression, and
! 276: is matched against the final component of the name (not the entire path). If a
! 277: subdirectory name matches both \fB--include-dir\fP and \fB--exclude-dir\fP, it
! 278: is excluded. There is no short form for this option.
! 279: .TP
! 280: \fB-L\fP, \fB--files-without-match\fP
! 281: Instead of outputting lines from the files, just output the names of the files
! 282: that do not contain any lines that would have been output. Each file name is
! 283: output once, on a separate line.
! 284: .TP
! 285: \fB-l\fP, \fB--files-with-matches\fP
! 286: Instead of outputting lines from the files, just output the names of the files
! 287: containing lines that would have been output. Each file name is output
! 288: once, on a separate line. Searching normally stops as soon as a matching line
! 289: is found in a file. However, if the \fB-c\fP (count) option is also used,
! 290: matching continues in order to obtain the correct count, and those files that
! 291: have at least one match are listed along with their counts. Using this option
! 292: with \fB-c\fP is a way of suppressing the listing of files with no matches.
! 293: .TP
! 294: \fB--label\fP=\fIname\fP
! 295: This option supplies a name to be used for the standard input when file names
! 296: are being output. If not supplied, "(standard input)" is used. There is no
! 297: short form for this option.
! 298: .TP
! 299: \fB--line-buffered\fP
! 300: When this option is given, input is read and processed line by line, and the
! 301: output is flushed after each write. By default, input is read in large chunks,
! 302: unless \fBpcregrep\fP can determine that it is reading from a terminal (which
! 303: is currently possible only in Unix environments). Output to terminal is
! 304: normally automatically flushed by the operating system. This option can be
! 305: useful when the input or output is attached to a pipe and you do not want
! 306: \fBpcregrep\fP to buffer up large amounts of data. However, its use will affect
! 307: performance, and the \fB-M\fP (multiline) option ceases to work.
! 308: .TP
! 309: \fB--line-offsets\fP
! 310: Instead of showing lines or parts of lines that match, show each match as a
! 311: line number, the offset from the start of the line, and a length. The line
! 312: number is terminated by a colon (as usual; see the \fB-n\fP option), and the
! 313: offset and length are separated by a comma. In this mode, no context is shown.
! 314: That is, the \fB-A\fP, \fB-B\fP, and \fB-C\fP options are ignored. If there is
! 315: more than one match in a line, each of them is shown separately. This option is
! 316: mutually exclusive with \fB--file-offsets\fP and \fB--only-matching\fP.
! 317: .TP
! 318: \fB--locale\fP=\fIlocale-name\fP
! 319: This option specifies a locale to be used for pattern matching. It overrides
! 320: the value in the \fBLC_ALL\fP or \fBLC_CTYPE\fP environment variables. If no
! 321: locale is specified, the PCRE library's default (usually the "C" locale) is
! 322: used. There is no short form for this option.
! 323: .TP
! 324: \fB--match-limit\fP=\fInumber\fP
! 325: Processing some regular expression patterns can require a very large amount of
! 326: memory, leading in some cases to a program crash if not enough is available.
! 327: Other patterns may take a very long time to search for all possible matching
! 328: strings. The \fBpcre_exec()\fP function that is called by \fBpcregrep\fP to do
! 329: the matching has two parameters that can limit the resources that it uses.
! 330: .sp
! 331: The \fB--match-limit\fP option provides a means of limiting resource usage
! 332: when processing patterns that are not going to match, but which have a very
! 333: large number of possibilities in their search trees. The classic example is a
! 334: pattern that uses nested unlimited repeats. Internally, PCRE uses a function
! 335: called \fBmatch()\fP which it calls repeatedly (sometimes recursively). The
! 336: limit set by \fB--match-limit\fP is imposed on the number of times this
! 337: function is called during a match, which has the effect of limiting the amount
! 338: of backtracking that can take place.
! 339: .sp
! 340: The \fB--recursion-limit\fP option is similar to \fB--match-limit\fP, but
! 341: instead of limiting the total number of times that \fBmatch()\fP is called, it
! 342: limits the depth of recursive calls, which in turn limits the amount of memory
! 343: that can be used. The recursion depth is a smaller number than the total number
! 344: of calls, because not all calls to \fBmatch()\fP are recursive. This limit is
! 345: of use only if it is set smaller than \fB--match-limit\fP.
! 346: .sp
! 347: There are no short forms for these options. The default settings are specified
! 348: when the PCRE library is compiled, with the default default being 10 million.
! 349: .TP
! 350: \fB-M\fP, \fB--multiline\fP
! 351: Allow patterns to match more than one line. When this option is given, patterns
! 352: may usefully contain literal newline characters and internal occurrences of ^
! 353: and $ characters. The output for a successful match may consist of more than
! 354: one line, the last of which is the one in which the match ended. If the matched
! 355: string ends with a newline sequence the output ends at the end of that line.
! 356: .sp
! 357: When this option is set, the PCRE library is called in "multiline" mode.
! 358: There is a limit to the number of lines that can be matched, imposed by the way
! 359: that \fBpcregrep\fP buffers the input file as it scans it. However,
! 360: \fBpcregrep\fP ensures that at least 8K characters or the rest of the document
! 361: (whichever is the shorter) are available for forward matching, and similarly
! 362: the previous 8K characters (or all the previous characters, if fewer than 8K)
! 363: are guaranteed to be available for lookbehind assertions. This option does not
! 364: work when input is read line by line (see \fP--line-buffered\fP.)
! 365: .TP
! 366: \fB-N\fP \fInewline-type\fP, \fB--newline\fP=\fInewline-type\fP
! 367: The PCRE library supports five different conventions for indicating
! 368: the ends of lines. They are the single-character sequences CR (carriage return)
! 369: and LF (linefeed), the two-character sequence CRLF, an "anycrlf" convention,
! 370: which recognizes any of the preceding three types, and an "any" convention, in
! 371: which any Unicode line ending sequence is assumed to end a line. The Unicode
! 372: sequences are the three just mentioned, plus VT (vertical tab, U+000B), FF
! 373: (form feed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and
! 374: PS (paragraph separator, U+2029).
! 375: .sp
! 376: When the PCRE library is built, a default line-ending sequence is specified.
! 377: This is normally the standard sequence for the operating system. Unless
! 378: otherwise specified by this option, \fBpcregrep\fP uses the library's default.
! 379: The possible values for this option are CR, LF, CRLF, ANYCRLF, or ANY. This
! 380: makes it possible to use \fBpcregrep\fP on files that have come from other
! 381: environments without having to modify their line endings. If the data that is
! 382: being scanned does not agree with the convention set by this option,
! 383: \fBpcregrep\fP may behave in strange ways.
! 384: .TP
! 385: \fB-n\fP, \fB--line-number\fP
! 386: Precede each output line by its line number in the file, followed by a colon
! 387: for matching lines or a hyphen for context lines. If the filename is also being
! 388: output, it precedes the line number. This option is forced if
! 389: \fB--line-offsets\fP is used.
! 390: .TP
! 391: \fB--no-jit\fP
! 392: If the PCRE library is built with support for just-in-time compiling (which
! 393: speeds up matching), \fBpcregrep\fP automatically makes use of this, unless it
! 394: was explicitly disabled at build time. This option can be used to disable the
! 395: use of JIT at run time. It is provided for testing and working round problems.
! 396: It should never be needed in normal use.
! 397: .TP
! 398: \fB-o\fP, \fB--only-matching\fP
! 399: Show only the part of the line that matched a pattern instead of the whole
! 400: line. In this mode, no context is shown. That is, the \fB-A\fP, \fB-B\fP, and
! 401: \fB-C\fP options are ignored. If there is more than one match in a line, each
! 402: of them is shown separately. If \fB-o\fP is combined with \fB-v\fP (invert the
! 403: sense of the match to find non-matching lines), no output is generated, but the
! 404: return code is set appropriately. If the matched portion of the line is empty,
! 405: nothing is output unless the file name or line number are being printed, in
! 406: which case they are shown on an otherwise empty line. This option is mutually
! 407: exclusive with \fB--file-offsets\fP and \fB--line-offsets\fP.
! 408: .TP
! 409: \fB-o\fP\fInumber\fP, \fB--only-matching\fP=\fInumber\fP
! 410: Show only the part of the line that matched the capturing parentheses of the
! 411: given number. Up to 32 capturing parentheses are supported. Because these
! 412: options can be given without an argument (see above), if an argument is
! 413: present, it must be given in the same shell item, for example, -o3 or
! 414: --only-matching=2. The comments given for the non-argument case above also
! 415: apply to this case. If the specified capturing parentheses do not exist in the
! 416: pattern, or were not set in the match, nothing is output unless the file name
! 417: or line number are being printed.
! 418: .TP
! 419: \fB-q\fP, \fB--quiet\fP
! 420: Work quietly, that is, display nothing except error messages. The exit
! 421: status indicates whether or not any matches were found.
! 422: .TP
! 423: \fB-r\fP, \fB--recursive\fP
! 424: If any given path is a directory, recursively scan the files it contains,
! 425: taking note of any \fB--include\fP and \fB--exclude\fP settings. By default, a
! 426: directory is read as a normal file; in some operating systems this gives an
! 427: immediate end-of-file. This option is a shorthand for setting the \fB-d\fP
! 428: option to "recurse".
! 429: .TP
! 430: \fB--recursion-limit\fP=\fInumber\fP
! 431: See \fB--match-limit\fP above.
! 432: .TP
! 433: \fB-s\fP, \fB--no-messages\fP
! 434: Suppress error messages about non-existent or unreadable files. Such files are
! 435: quietly skipped. However, the return code is still 2, even if matches were
! 436: found in other files.
! 437: .TP
! 438: \fB-u\fP, \fB--utf-8\fP
! 439: Operate in UTF-8 mode. This option is available only if PCRE has been compiled
! 440: with UTF-8 support. Both patterns and subject lines must be valid strings of
! 441: UTF-8 characters.
! 442: .TP
! 443: \fB-V\fP, \fB--version\fP
! 444: Write the version numbers of \fBpcregrep\fP and the PCRE library that is being
! 445: used to the standard error stream.
! 446: .TP
! 447: \fB-v\fP, \fB--invert-match\fP
! 448: Invert the sense of the match, so that lines which do \fInot\fP match any of
! 449: the patterns are the ones that are found.
! 450: .TP
! 451: \fB-w\fP, \fB--word-regex\fP, \fB--word-regexp\fP
! 452: Force the patterns to match only whole words. This is equivalent to having \eb
! 453: at the start and end of the pattern.
! 454: .TP
! 455: \fB-x\fP, \fB--line-regex\fP, \fB--line-regexp\fP
! 456: Force the patterns to be anchored (each must start matching at the beginning of
! 457: a line) and in addition, require them to match entire lines. This is
! 458: equivalent to having ^ and $ characters at the start and end of each
! 459: alternative branch in every pattern.
! 460: .
! 461: .
! 462: .SH "ENVIRONMENT VARIABLES"
! 463: .rs
! 464: .sp
! 465: The environment variables \fBLC_ALL\fP and \fBLC_CTYPE\fP are examined, in that
! 466: order, for a locale. The first one that is set is used. This can be overridden
! 467: by the \fB--locale\fP option. If no locale is set, the PCRE library's default
! 468: (usually the "C" locale) is used.
! 469: .
! 470: .
! 471: .SH "NEWLINES"
! 472: .rs
! 473: .sp
! 474: The \fB-N\fP (\fB--newline\fP) option allows \fBpcregrep\fP to scan files with
! 475: different newline conventions from the default. However, the setting of this
! 476: option does not affect the way in which \fBpcregrep\fP writes information to
! 477: the standard error and output streams. It uses the string "\en" in C
! 478: \fBprintf()\fP calls to indicate newlines, relying on the C I/O library to
! 479: convert this to an appropriate sequence if the output is sent to a file.
! 480: .
! 481: .
! 482: .SH "OPTIONS COMPATIBILITY"
! 483: .rs
! 484: .sp
! 485: Many of the short and long forms of \fBpcregrep\fP's options are the same
! 486: as in the GNU \fBgrep\fP program (version 2.5.4). Any long option of the form
! 487: \fB--xxx-regexp\fP (GNU terminology) is also available as \fB--xxx-regex\fP
! 488: (PCRE terminology). However, the \fB--file-offsets\fP, \fB--include-dir\fP,
! 489: \fB--line-offsets\fP, \fB--locale\fP, \fB--match-limit\fP, \fB-M\fP,
! 490: \fB--multiline\fP, \fB-N\fP, \fB--newline\fP, \fB--recursion-limit\fP,
! 491: \fB-u\fP, and \fB--utf-8\fP options are specific to \fBpcregrep\fP, as is the
! 492: use of the \fB--only-matching\fP option with a capturing parentheses number.
! 493: .P
! 494: Although most of the common options work the same way, a few are different in
! 495: \fBpcregrep\fP. For example, the \fB--include\fP option's argument is a glob
! 496: for GNU \fBgrep\fP, but a regular expression for \fBpcregrep\fP. If both the
! 497: \fB-c\fP and \fB-l\fP options are given, GNU grep lists only file names,
! 498: without counts, but \fBpcregrep\fP gives the counts.
! 499: .
! 500: .
! 501: .SH "OPTIONS WITH DATA"
! 502: .rs
! 503: .sp
! 504: There are four different ways in which an option with data can be specified.
! 505: If a short form option is used, the data may follow immediately, or (with one
! 506: exception) in the next command line item. For example:
! 507: .sp
! 508: -f/some/file
! 509: -f /some/file
! 510: .sp
! 511: The exception is the \fB-o\fP option, which may appear with or without data.
! 512: Because of this, if data is present, it must follow immediately in the same
! 513: item, for example -o3.
! 514: .P
! 515: If a long form option is used, the data may appear in the same command line
! 516: item, separated by an equals character, or (with two exceptions) it may appear
! 517: in the next command line item. For example:
! 518: .sp
! 519: --file=/some/file
! 520: --file /some/file
! 521: .sp
! 522: Note, however, that if you want to supply a file name beginning with ~ as data
! 523: in a shell command, and have the shell expand ~ to a home directory, you must
! 524: separate the file name from the option, because the shell does not treat ~
! 525: specially unless it is at the start of an item.
! 526: .P
! 527: The exceptions to the above are the \fB--colour\fP (or \fB--color\fP) and
! 528: \fB--only-matching\fP options, for which the data is optional. If one of these
! 529: options does have data, it must be given in the first form, using an equals
! 530: character. Otherwise \fBpcregrep\fP will assume that it has no data.
! 531: .
! 532: .
! 533: .SH "MATCHING ERRORS"
! 534: .rs
! 535: .sp
! 536: It is possible to supply a regular expression that takes a very long time to
! 537: fail to match certain lines. Such patterns normally involve nested indefinite
! 538: repeats, for example: (a+)*\ed when matched against a line of a's with no final
! 539: digit. The PCRE matching function has a resource limit that causes it to abort
! 540: in these circumstances. If this happens, \fBpcregrep\fP outputs an error
! 541: message and the line that caused the problem to the standard error stream. If
! 542: there are more than 20 such errors, \fBpcregrep\fP gives up.
! 543: .P
! 544: The \fB--match-limit\fP option of \fBpcregrep\fP can be used to set the overall
! 545: resource limit; there is a second option called \fB--recursion-limit\fP that
! 546: sets a limit on the amount of memory (usually stack) that is used (see the
! 547: discussion of these options above).
! 548: .
! 549: .
! 550: .SH DIAGNOSTICS
! 551: .rs
! 552: .sp
! 553: Exit status is 0 if any matches were found, 1 if no matches were found, and 2
! 554: for syntax errors, overlong lines, non-existent or inaccessible files (even if
! 555: matches were found in other files) or too many matching errors. Using the
! 556: \fB-s\fP option to suppress error messages about inaccessible files does not
! 557: affect the return code.
! 558: .
! 559: .
! 560: .SH "SEE ALSO"
! 561: .rs
! 562: .sp
! 563: \fBpcrepattern\fP(3), \fBpcretest\fP(1).
! 564: .
! 565: .
! 566: .SH AUTHOR
! 567: .rs
! 568: .sp
! 569: .nf
! 570: Philip Hazel
! 571: University Computing Service
! 572: Cambridge CB2 3QH, England.
! 573: .fi
! 574: .
! 575: .
! 576: .SH REVISION
! 577: .rs
! 578: .sp
! 579: .nf
! 580: Last updated: 06 September 2011
! 581: Copyright (c) 1997-2011 University of Cambridge.
! 582: .fi
FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>
![[BACK]](/icons/cvsweb/back.gif){kind=icon}
Return to pcregrep.1 CVS log ![[TXT]](/icons/cvsweb/text.gif){kind=icon}
![[DIR]](/icons/cvsweb/dir.gif){kind=icon}
Up to [ELWIX - Embedded LightWeight unIX -] / embedaddon / pcre / doc