Tristan Matthews | 0461646 | 2013-11-14 16:09:34 -0500 | [diff] [blame] | 1 | <html> |
| 2 | <head> |
| 3 | <title>pcregrep specification</title> |
| 4 | </head> |
| 5 | <body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> |
| 6 | <h1>pcregrep man page</h1> |
| 7 | <p> |
| 8 | Return to the <a href="index.html">PCRE index page</a>. |
| 9 | </p> |
| 10 | <p> |
| 11 | This page is part of the PCRE HTML documentation. It was generated automatically |
| 12 | from the original man page. If there is any nonsense in it, please consult the |
| 13 | man page, in case the conversion went wrong. |
| 14 | <br> |
| 15 | <ul> |
| 16 | <li><a name="TOC1" href="#SEC1">SYNOPSIS</a> |
| 17 | <li><a name="TOC2" href="#SEC2">DESCRIPTION</a> |
| 18 | <li><a name="TOC3" href="#SEC3">SUPPORT FOR COMPRESSED FILES</a> |
| 19 | <li><a name="TOC4" href="#SEC4">OPTIONS</a> |
| 20 | <li><a name="TOC5" href="#SEC5">ENVIRONMENT VARIABLES</a> |
| 21 | <li><a name="TOC6" href="#SEC6">NEWLINES</a> |
| 22 | <li><a name="TOC7" href="#SEC7">OPTIONS COMPATIBILITY</a> |
| 23 | <li><a name="TOC8" href="#SEC8">OPTIONS WITH DATA</a> |
| 24 | <li><a name="TOC9" href="#SEC9">MATCHING ERRORS</a> |
| 25 | <li><a name="TOC10" href="#SEC10">DIAGNOSTICS</a> |
| 26 | <li><a name="TOC11" href="#SEC11">SEE ALSO</a> |
| 27 | <li><a name="TOC12" href="#SEC12">AUTHOR</a> |
| 28 | <li><a name="TOC13" href="#SEC13">REVISION</a> |
| 29 | </ul> |
| 30 | <br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br> |
| 31 | <P> |
| 32 | <b>pcregrep [options] [long options] [pattern] [path1 path2 ...]</b> |
| 33 | </P> |
| 34 | <br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br> |
| 35 | <P> |
| 36 | <b>pcregrep</b> searches files for character patterns, in the same way as other |
| 37 | grep commands do, but it uses the PCRE regular expression library to support |
| 38 | patterns that are compatible with the regular expressions of Perl 5. See |
| 39 | <a href="pcrepattern.html"><b>pcrepattern</b>(3)</a> |
| 40 | for a full description of syntax and semantics of the regular expressions |
| 41 | that PCRE supports. |
| 42 | </P> |
| 43 | <P> |
| 44 | Patterns, whether supplied on the command line or in a separate file, are given |
| 45 | without delimiters. For example: |
| 46 | <pre> |
| 47 | pcregrep Thursday /etc/motd |
| 48 | </pre> |
| 49 | If you attempt to use delimiters (for example, by surrounding a pattern with |
| 50 | slashes, as is common in Perl scripts), they are interpreted as part of the |
| 51 | pattern. Quotes can of course be used to delimit patterns on the command line |
| 52 | because they are interpreted by the shell, and indeed they are required if a |
| 53 | pattern contains white space or shell metacharacters. |
| 54 | </P> |
| 55 | <P> |
| 56 | The first argument that follows any option settings is treated as the single |
| 57 | pattern to be matched when neither <b>-e</b> nor <b>-f</b> is present. |
| 58 | Conversely, when one or both of these options are used to specify patterns, all |
| 59 | arguments are treated as path names. At least one of <b>-e</b>, <b>-f</b>, or an |
| 60 | argument pattern must be provided. |
| 61 | </P> |
| 62 | <P> |
| 63 | If no files are specified, <b>pcregrep</b> reads the standard input. The |
| 64 | standard input can also be referenced by a name consisting of a single hyphen. |
| 65 | For example: |
| 66 | <pre> |
| 67 | pcregrep some-pattern /file1 - /file3 |
| 68 | </pre> |
| 69 | By default, each line that matches a pattern is copied to the standard |
| 70 | output, and if there is more than one file, the file name is output at the |
| 71 | start of each line, followed by a colon. However, there are options that can |
| 72 | change how <b>pcregrep</b> behaves. In particular, the <b>-M</b> option makes it |
| 73 | possible to search for patterns that span line boundaries. What defines a line |
| 74 | boundary is controlled by the <b>-N</b> (<b>--newline</b>) option. |
| 75 | </P> |
| 76 | <P> |
| 77 | The amount of memory used for buffering files that are being scanned is |
| 78 | controlled by a parameter that can be set by the <b>--buffer-size</b> option. |
| 79 | The default value for this parameter is specified when <b>pcregrep</b> is built, |
| 80 | with the default default being 20K. A block of memory three times this size is |
| 81 | used (to allow for buffering "before" and "after" lines). An error occurs if a |
| 82 | line overflows the buffer. |
| 83 | </P> |
| 84 | <P> |
| 85 | Patterns are limited to 8K or BUFSIZ bytes, whichever is the greater. BUFSIZ is |
| 86 | defined in <b><stdio.h></b>. When there is more than one pattern (specified by |
| 87 | the use of <b>-e</b> and/or <b>-f</b>), each pattern is applied to each line in |
| 88 | the order in which they are defined, except that all the <b>-e</b> patterns are |
| 89 | tried before the <b>-f</b> patterns. |
| 90 | </P> |
| 91 | <P> |
| 92 | By default, as soon as one pattern matches (or fails to match when <b>-v</b> is |
| 93 | used), no further patterns are considered. However, if <b>--colour</b> (or |
| 94 | <b>--color</b>) is used to colour the matching substrings, or if |
| 95 | <b>--only-matching</b>, <b>--file-offsets</b>, or <b>--line-offsets</b> is used to |
| 96 | output only the part of the line that matched (either shown literally, or as an |
| 97 | offset), scanning resumes immediately following the match, so that further |
| 98 | matches on the same line can be found. If there are multiple patterns, they are |
| 99 | all tried on the remainder of the line, but patterns that follow the one that |
| 100 | matched are not tried on the earlier part of the line. |
| 101 | </P> |
| 102 | <P> |
| 103 | This is the same behaviour as GNU grep, but it does mean that the order in |
| 104 | which multiple patterns are specified can affect the output when one of the |
| 105 | above options is used. |
| 106 | </P> |
| 107 | <P> |
| 108 | Patterns that can match an empty string are accepted, but empty string |
| 109 | matches are never recognized. An example is the pattern "(super)?(man)?", in |
| 110 | which all components are optional. This pattern finds all occurrences of both |
| 111 | "super" and "man"; the output differs from matching with "super|man" when only |
| 112 | the matching substrings are being shown. |
| 113 | </P> |
| 114 | <P> |
| 115 | If the <b>LC_ALL</b> or <b>LC_CTYPE</b> environment variable is set, |
| 116 | <b>pcregrep</b> uses the value to set a locale when calling the PCRE library. |
| 117 | The <b>--locale</b> option can be used to override this. |
| 118 | </P> |
| 119 | <br><a name="SEC3" href="#TOC1">SUPPORT FOR COMPRESSED FILES</a><br> |
| 120 | <P> |
| 121 | It is possible to compile <b>pcregrep</b> so that it uses <b>libz</b> or |
| 122 | <b>libbz2</b> to read files whose names end in <b>.gz</b> or <b>.bz2</b>, |
| 123 | respectively. You can find out whether your binary has support for one or both |
| 124 | of these file types by running it with the <b>--help</b> option. If the |
| 125 | appropriate support is not present, files are treated as plain text. The |
| 126 | standard input is always so treated. |
| 127 | </P> |
| 128 | <br><a name="SEC4" href="#TOC1">OPTIONS</a><br> |
| 129 | <P> |
| 130 | The order in which some of the options appear can affect the output. For |
| 131 | example, both the <b>-h</b> and <b>-l</b> options affect the printing of file |
| 132 | names. Whichever comes later in the command line will be the one that takes |
| 133 | effect. Numerical values for options may be followed by K or M, to signify |
| 134 | multiplication by 1024 or 1024*1024 respectively. |
| 135 | </P> |
| 136 | <P> |
| 137 | <b>--</b> |
| 138 | This terminates the list of options. It is useful if the next item on the |
| 139 | command line starts with a hyphen but is not an option. This allows for the |
| 140 | processing of patterns and filenames that start with hyphens. |
| 141 | </P> |
| 142 | <P> |
| 143 | <b>-A</b> <i>number</i>, <b>--after-context=</b><i>number</i> |
| 144 | Output <i>number</i> lines of context after each matching line. If filenames |
| 145 | and/or line numbers are being output, a hyphen separator is used instead of a |
| 146 | colon for the context lines. A line containing "--" is output between each |
| 147 | group of lines, unless they are in fact contiguous in the input file. The value |
| 148 | of <i>number</i> is expected to be relatively small. However, <b>pcregrep</b> |
| 149 | guarantees to have up to 8K of following text available for context output. |
| 150 | </P> |
| 151 | <P> |
| 152 | <b>-B</b> <i>number</i>, <b>--before-context=</b><i>number</i> |
| 153 | Output <i>number</i> lines of context before each matching line. If filenames |
| 154 | and/or line numbers are being output, a hyphen separator is used instead of a |
| 155 | colon for the context lines. A line containing "--" is output between each |
| 156 | group of lines, unless they are in fact contiguous in the input file. The value |
| 157 | of <i>number</i> is expected to be relatively small. However, <b>pcregrep</b> |
| 158 | guarantees to have up to 8K of preceding text available for context output. |
| 159 | </P> |
| 160 | <P> |
| 161 | <b>--buffer-size=</b><i>number</i> |
| 162 | Set the parameter that controls how much memory is used for buffering files |
| 163 | that are being scanned. |
| 164 | </P> |
| 165 | <P> |
| 166 | <b>-C</b> <i>number</i>, <b>--context=</b><i>number</i> |
| 167 | Output <i>number</i> lines of context both before and after each matching line. |
| 168 | This is equivalent to setting both <b>-A</b> and <b>-B</b> to the same value. |
| 169 | </P> |
| 170 | <P> |
| 171 | <b>-c</b>, <b>--count</b> |
| 172 | Do not output individual lines from the files that are being scanned; instead |
| 173 | output the number of lines that would otherwise have been shown. If no lines |
| 174 | are selected, the number zero is output. If several files are are being |
| 175 | scanned, a count is output for each of them. However, if the |
| 176 | <b>--files-with-matches</b> option is also used, only those files whose counts |
| 177 | are greater than zero are listed. When <b>-c</b> is used, the <b>-A</b>, |
| 178 | <b>-B</b>, and <b>-C</b> options are ignored. |
| 179 | </P> |
| 180 | <P> |
| 181 | <b>--colour</b>, <b>--color</b> |
| 182 | If this option is given without any data, it is equivalent to "--colour=auto". |
| 183 | If data is required, it must be given in the same shell item, separated by an |
| 184 | equals sign. |
| 185 | </P> |
| 186 | <P> |
| 187 | <b>--colour=</b><i>value</i>, <b>--color=</b><i>value</i> |
| 188 | This option specifies under what circumstances the parts of a line that matched |
| 189 | a pattern should be coloured in the output. By default, the output is not |
| 190 | coloured. The value (which is optional, see above) may be "never", "always", or |
| 191 | "auto". In the latter case, colouring happens only if the standard output is |
| 192 | connected to a terminal. More resources are used when colouring is enabled, |
| 193 | because <b>pcregrep</b> has to search for all possible matches in a line, not |
| 194 | just one, in order to colour them all. |
| 195 | <br> |
| 196 | <br> |
| 197 | The colour that is used can be specified by setting the environment variable |
| 198 | PCREGREP_COLOUR or PCREGREP_COLOR. The value of this variable should be a |
| 199 | string of two numbers, separated by a semicolon. They are copied directly into |
| 200 | the control string for setting colour on a terminal, so it is your |
| 201 | responsibility to ensure that they make sense. If neither of the environment |
| 202 | variables is set, the default is "1;31", which gives red. |
| 203 | </P> |
| 204 | <P> |
| 205 | <b>-D</b> <i>action</i>, <b>--devices=</b><i>action</i> |
| 206 | If an input path is not a regular file or a directory, "action" specifies how |
| 207 | it is to be processed. Valid values are "read" (the default) or "skip" |
| 208 | (silently skip the path). |
| 209 | </P> |
| 210 | <P> |
| 211 | <b>-d</b> <i>action</i>, <b>--directories=</b><i>action</i> |
| 212 | If an input path is a directory, "action" specifies how it is to be processed. |
| 213 | Valid values are "read" (the default), "recurse" (equivalent to the <b>-r</b> |
| 214 | option), or "skip" (silently skip the path). In the default case, directories |
| 215 | are read as if they were ordinary files. In some operating systems the effect |
| 216 | of reading a directory like this is an immediate end-of-file. |
| 217 | </P> |
| 218 | <P> |
| 219 | <b>-e</b> <i>pattern</i>, <b>--regex=</b><i>pattern</i>, <b>--regexp=</b><i>pattern</i> |
| 220 | Specify a pattern to be matched. This option can be used multiple times in |
| 221 | order to specify several patterns. It can also be used as a way of specifying a |
| 222 | single pattern that starts with a hyphen. When <b>-e</b> is used, no argument |
| 223 | pattern is taken from the command line; all arguments are treated as file |
| 224 | names. There is an overall maximum of 100 patterns. They are applied to each |
| 225 | line in the order in which they are defined until one matches (or fails to |
| 226 | match if <b>-v</b> is used). If <b>-f</b> is used with <b>-e</b>, the command line |
| 227 | patterns are matched first, followed by the patterns from the file, independent |
| 228 | of the order in which these options are specified. Note that multiple use of |
| 229 | <b>-e</b> is not the same as a single pattern with alternatives. For example, |
| 230 | X|Y finds the first character in a line that is X or Y, whereas if the two |
| 231 | patterns are given separately, <b>pcregrep</b> finds X if it is present, even if |
| 232 | it follows Y in the line. It finds Y only if there is no X in the line. This |
| 233 | really matters only if you are using <b>-o</b> to show the part(s) of the line |
| 234 | that matched. |
| 235 | </P> |
| 236 | <P> |
| 237 | <b>--exclude</b>=<i>pattern</i> |
| 238 | When <b>pcregrep</b> is searching the files in a directory as a consequence of |
| 239 | the <b>-r</b> (recursive search) option, any regular files whose names match the |
| 240 | pattern are excluded. Subdirectories are not excluded by this option; they are |
| 241 | searched recursively, subject to the <b>--exclude-dir</b> and |
| 242 | <b>--include_dir</b> options. The pattern is a PCRE regular expression, and is |
| 243 | matched against the final component of the file name (not the entire path). If |
| 244 | a file name matches both <b>--include</b> and <b>--exclude</b>, it is excluded. |
| 245 | There is no short form for this option. |
| 246 | </P> |
| 247 | <P> |
| 248 | <b>--exclude-dir</b>=<i>pattern</i> |
| 249 | When <b>pcregrep</b> is searching the contents of a directory as a consequence |
| 250 | of the <b>-r</b> (recursive search) option, any subdirectories whose names match |
| 251 | the pattern are excluded. (Note that the \fP--exclude\fP option does not affect |
| 252 | subdirectories.) The pattern is a PCRE regular expression, and is matched |
| 253 | against the final component of the name (not the entire path). If a |
| 254 | subdirectory name matches both <b>--include-dir</b> and <b>--exclude-dir</b>, it |
| 255 | is excluded. There is no short form for this option. |
| 256 | </P> |
| 257 | <P> |
| 258 | <b>-F</b>, <b>--fixed-strings</b> |
| 259 | Interpret each pattern as a list of fixed strings, separated by newlines, |
| 260 | instead of as a regular expression. The <b>-w</b> (match as a word) and <b>-x</b> |
| 261 | (match whole line) options can be used with <b>-F</b>. They apply to each of the |
| 262 | fixed strings. A line is selected if any of the fixed strings are found in it |
| 263 | (subject to <b>-w</b> or <b>-x</b>, if present). |
| 264 | </P> |
| 265 | <P> |
| 266 | <b>-f</b> <i>filename</i>, <b>--file=</b><i>filename</i> |
| 267 | Read a number of patterns from the file, one per line, and match them against |
| 268 | each line of input. A data line is output if any of the patterns match it. The |
| 269 | filename can be given as "-" to refer to the standard input. When <b>-f</b> is |
| 270 | used, patterns specified on the command line using <b>-e</b> may also be |
| 271 | present; they are tested before the file's patterns. However, no other pattern |
| 272 | is taken from the command line; all arguments are treated as file names. There |
| 273 | is an overall maximum of 100 patterns. Trailing white space is removed from |
| 274 | each line, and blank lines are ignored. An empty file contains no patterns and |
| 275 | therefore matches nothing. See also the comments about multiple patterns versus |
| 276 | a single pattern with alternatives in the description of <b>-e</b> above. |
| 277 | </P> |
| 278 | <P> |
| 279 | <b>--file-offsets</b> |
| 280 | Instead of showing lines or parts of lines that match, show each match as an |
| 281 | offset from the start of the file and a length, separated by a comma. In this |
| 282 | mode, no context is shown. That is, the <b>-A</b>, <b>-B</b>, and <b>-C</b> |
| 283 | options are ignored. If there is more than one match in a line, each of them is |
| 284 | shown separately. This option is mutually exclusive with <b>--line-offsets</b> |
| 285 | and <b>--only-matching</b>. |
| 286 | </P> |
| 287 | <P> |
| 288 | <b>-H</b>, <b>--with-filename</b> |
| 289 | Force the inclusion of the filename at the start of output lines when searching |
| 290 | a single file. By default, the filename is not shown in this case. For matching |
| 291 | lines, the filename is followed by a colon; for context lines, a hyphen |
| 292 | separator is used. If a line number is also being output, it follows the file |
| 293 | name. |
| 294 | </P> |
| 295 | <P> |
| 296 | <b>-h</b>, <b>--no-filename</b> |
| 297 | Suppress the output filenames when searching multiple files. By default, |
| 298 | filenames are shown when multiple files are searched. For matching lines, the |
| 299 | filename is followed by a colon; for context lines, a hyphen separator is used. |
| 300 | If a line number is also being output, it follows the file name. |
| 301 | </P> |
| 302 | <P> |
| 303 | <b>--help</b> |
| 304 | Output a help message, giving brief details of the command options and file |
| 305 | type support, and then exit. |
| 306 | </P> |
| 307 | <P> |
| 308 | <b>-i</b>, <b>--ignore-case</b> |
| 309 | Ignore upper/lower case distinctions during comparisons. |
| 310 | </P> |
| 311 | <P> |
| 312 | <b>--include</b>=<i>pattern</i> |
| 313 | When <b>pcregrep</b> is searching the files in a directory as a consequence of |
| 314 | the <b>-r</b> (recursive search) option, only those regular files whose names |
| 315 | match the pattern are included. Subdirectories are always included and searched |
| 316 | recursively, subject to the \fP--include-dir\fP and <b>--exclude-dir</b> |
| 317 | options. The pattern is a PCRE regular expression, and is matched against the |
| 318 | final component of the file name (not the entire path). If a file name matches |
| 319 | both <b>--include</b> and <b>--exclude</b>, it is excluded. There is no short |
| 320 | form for this option. |
| 321 | </P> |
| 322 | <P> |
| 323 | <b>--include-dir</b>=<i>pattern</i> |
| 324 | When <b>pcregrep</b> is searching the contents of a directory as a consequence |
| 325 | of the <b>-r</b> (recursive search) option, only those subdirectories whose |
| 326 | names match the pattern are included. (Note that the <b>--include</b> option |
| 327 | does not affect subdirectories.) The pattern is a PCRE regular expression, and |
| 328 | is matched against the final component of the name (not the entire path). If a |
| 329 | subdirectory name matches both <b>--include-dir</b> and <b>--exclude-dir</b>, it |
| 330 | is excluded. There is no short form for this option. |
| 331 | </P> |
| 332 | <P> |
| 333 | <b>-L</b>, <b>--files-without-match</b> |
| 334 | Instead of outputting lines from the files, just output the names of the files |
| 335 | that do not contain any lines that would have been output. Each file name is |
| 336 | output once, on a separate line. |
| 337 | </P> |
| 338 | <P> |
| 339 | <b>-l</b>, <b>--files-with-matches</b> |
| 340 | Instead of outputting lines from the files, just output the names of the files |
| 341 | containing lines that would have been output. Each file name is output |
| 342 | once, on a separate line. Searching normally stops as soon as a matching line |
| 343 | is found in a file. However, if the <b>-c</b> (count) option is also used, |
| 344 | matching continues in order to obtain the correct count, and those files that |
| 345 | have at least one match are listed along with their counts. Using this option |
| 346 | with <b>-c</b> is a way of suppressing the listing of files with no matches. |
| 347 | </P> |
| 348 | <P> |
| 349 | <b>--label</b>=<i>name</i> |
| 350 | This option supplies a name to be used for the standard input when file names |
| 351 | are being output. If not supplied, "(standard input)" is used. There is no |
| 352 | short form for this option. |
| 353 | </P> |
| 354 | <P> |
| 355 | <b>--line-buffered</b> |
| 356 | When this option is given, input is read and processed line by line, and the |
| 357 | output is flushed after each write. By default, input is read in large chunks, |
| 358 | unless <b>pcregrep</b> can determine that it is reading from a terminal (which |
| 359 | is currently possible only in Unix environments). Output to terminal is |
| 360 | normally automatically flushed by the operating system. This option can be |
| 361 | useful when the input or output is attached to a pipe and you do not want |
| 362 | <b>pcregrep</b> to buffer up large amounts of data. However, its use will affect |
| 363 | performance, and the <b>-M</b> (multiline) option ceases to work. |
| 364 | </P> |
| 365 | <P> |
| 366 | <b>--line-offsets</b> |
| 367 | Instead of showing lines or parts of lines that match, show each match as a |
| 368 | line number, the offset from the start of the line, and a length. The line |
| 369 | number is terminated by a colon (as usual; see the <b>-n</b> option), and the |
| 370 | offset and length are separated by a comma. In this mode, no context is shown. |
| 371 | That is, the <b>-A</b>, <b>-B</b>, and <b>-C</b> options are ignored. If there is |
| 372 | more than one match in a line, each of them is shown separately. This option is |
| 373 | mutually exclusive with <b>--file-offsets</b> and <b>--only-matching</b>. |
| 374 | </P> |
| 375 | <P> |
| 376 | <b>--locale</b>=<i>locale-name</i> |
| 377 | This option specifies a locale to be used for pattern matching. It overrides |
| 378 | the value in the <b>LC_ALL</b> or <b>LC_CTYPE</b> environment variables. If no |
| 379 | locale is specified, the PCRE library's default (usually the "C" locale) is |
| 380 | used. There is no short form for this option. |
| 381 | </P> |
| 382 | <P> |
| 383 | <b>--match-limit</b>=<i>number</i> |
| 384 | Processing some regular expression patterns can require a very large amount of |
| 385 | memory, leading in some cases to a program crash if not enough is available. |
| 386 | Other patterns may take a very long time to search for all possible matching |
| 387 | strings. The <b>pcre_exec()</b> function that is called by <b>pcregrep</b> to do |
| 388 | the matching has two parameters that can limit the resources that it uses. |
| 389 | <br> |
| 390 | <br> |
| 391 | The <b>--match-limit</b> option provides a means of limiting resource usage |
| 392 | when processing patterns that are not going to match, but which have a very |
| 393 | large number of possibilities in their search trees. The classic example is a |
| 394 | pattern that uses nested unlimited repeats. Internally, PCRE uses a function |
| 395 | called <b>match()</b> which it calls repeatedly (sometimes recursively). The |
| 396 | limit set by <b>--match-limit</b> is imposed on the number of times this |
| 397 | function is called during a match, which has the effect of limiting the amount |
| 398 | of backtracking that can take place. |
| 399 | <br> |
| 400 | <br> |
| 401 | The <b>--recursion-limit</b> option is similar to <b>--match-limit</b>, but |
| 402 | instead of limiting the total number of times that <b>match()</b> is called, it |
| 403 | limits the depth of recursive calls, which in turn limits the amount of memory |
| 404 | that can be used. The recursion depth is a smaller number than the total number |
| 405 | of calls, because not all calls to <b>match()</b> are recursive. This limit is |
| 406 | of use only if it is set smaller than <b>--match-limit</b>. |
| 407 | <br> |
| 408 | <br> |
| 409 | There are no short forms for these options. The default settings are specified |
| 410 | when the PCRE library is compiled, with the default default being 10 million. |
| 411 | </P> |
| 412 | <P> |
| 413 | <b>-M</b>, <b>--multiline</b> |
| 414 | Allow patterns to match more than one line. When this option is given, patterns |
| 415 | may usefully contain literal newline characters and internal occurrences of ^ |
| 416 | and $ characters. The output for a successful match may consist of more than |
| 417 | one line, the last of which is the one in which the match ended. If the matched |
| 418 | string ends with a newline sequence the output ends at the end of that line. |
| 419 | <br> |
| 420 | <br> |
| 421 | When this option is set, the PCRE library is called in "multiline" mode. |
| 422 | There is a limit to the number of lines that can be matched, imposed by the way |
| 423 | that <b>pcregrep</b> buffers the input file as it scans it. However, |
| 424 | <b>pcregrep</b> ensures that at least 8K characters or the rest of the document |
| 425 | (whichever is the shorter) are available for forward matching, and similarly |
| 426 | the previous 8K characters (or all the previous characters, if fewer than 8K) |
| 427 | are guaranteed to be available for lookbehind assertions. This option does not |
| 428 | work when input is read line by line (see \fP--line-buffered\fP.) |
| 429 | </P> |
| 430 | <P> |
| 431 | <b>-N</b> <i>newline-type</i>, <b>--newline</b>=<i>newline-type</i> |
| 432 | The PCRE library supports five different conventions for indicating |
| 433 | the ends of lines. They are the single-character sequences CR (carriage return) |
| 434 | and LF (linefeed), the two-character sequence CRLF, an "anycrlf" convention, |
| 435 | which recognizes any of the preceding three types, and an "any" convention, in |
| 436 | which any Unicode line ending sequence is assumed to end a line. The Unicode |
| 437 | sequences are the three just mentioned, plus VT (vertical tab, U+000B), FF |
| 438 | (form feed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and |
| 439 | PS (paragraph separator, U+2029). |
| 440 | <br> |
| 441 | <br> |
| 442 | When the PCRE library is built, a default line-ending sequence is specified. |
| 443 | This is normally the standard sequence for the operating system. Unless |
| 444 | otherwise specified by this option, <b>pcregrep</b> uses the library's default. |
| 445 | The possible values for this option are CR, LF, CRLF, ANYCRLF, or ANY. This |
| 446 | makes it possible to use <b>pcregrep</b> on files that have come from other |
| 447 | environments without having to modify their line endings. If the data that is |
| 448 | being scanned does not agree with the convention set by this option, |
| 449 | <b>pcregrep</b> may behave in strange ways. |
| 450 | </P> |
| 451 | <P> |
| 452 | <b>-n</b>, <b>--line-number</b> |
| 453 | Precede each output line by its line number in the file, followed by a colon |
| 454 | for matching lines or a hyphen for context lines. If the filename is also being |
| 455 | output, it precedes the line number. This option is forced if |
| 456 | <b>--line-offsets</b> is used. |
| 457 | </P> |
| 458 | <P> |
| 459 | <b>--no-jit</b> |
| 460 | If the PCRE library is built with support for just-in-time compiling (which |
| 461 | speeds up matching), <b>pcregrep</b> automatically makes use of this, unless it |
| 462 | was explicitly disabled at build time. This option can be used to disable the |
| 463 | use of JIT at run time. It is provided for testing and working round problems. |
| 464 | It should never be needed in normal use. |
| 465 | </P> |
| 466 | <P> |
| 467 | <b>-o</b>, <b>--only-matching</b> |
| 468 | Show only the part of the line that matched a pattern instead of the whole |
| 469 | line. In this mode, no context is shown. That is, the <b>-A</b>, <b>-B</b>, and |
| 470 | <b>-C</b> options are ignored. If there is more than one match in a line, each |
| 471 | of them is shown separately. If <b>-o</b> is combined with <b>-v</b> (invert the |
| 472 | sense of the match to find non-matching lines), no output is generated, but the |
| 473 | return code is set appropriately. If the matched portion of the line is empty, |
| 474 | nothing is output unless the file name or line number are being printed, in |
| 475 | which case they are shown on an otherwise empty line. This option is mutually |
| 476 | exclusive with <b>--file-offsets</b> and <b>--line-offsets</b>. |
| 477 | </P> |
| 478 | <P> |
| 479 | <b>-o</b><i>number</i>, <b>--only-matching</b>=<i>number</i> |
| 480 | Show only the part of the line that matched the capturing parentheses of the |
| 481 | given number. Up to 32 capturing parentheses are supported. Because these |
| 482 | options can be given without an argument (see above), if an argument is |
| 483 | present, it must be given in the same shell item, for example, -o3 or |
| 484 | --only-matching=2. The comments given for the non-argument case above also |
| 485 | apply to this case. If the specified capturing parentheses do not exist in the |
| 486 | pattern, or were not set in the match, nothing is output unless the file name |
| 487 | or line number are being printed. |
| 488 | </P> |
| 489 | <P> |
| 490 | <b>-q</b>, <b>--quiet</b> |
| 491 | Work quietly, that is, display nothing except error messages. The exit |
| 492 | status indicates whether or not any matches were found. |
| 493 | </P> |
| 494 | <P> |
| 495 | <b>-r</b>, <b>--recursive</b> |
| 496 | If any given path is a directory, recursively scan the files it contains, |
| 497 | taking note of any <b>--include</b> and <b>--exclude</b> settings. By default, a |
| 498 | directory is read as a normal file; in some operating systems this gives an |
| 499 | immediate end-of-file. This option is a shorthand for setting the <b>-d</b> |
| 500 | option to "recurse". |
| 501 | </P> |
| 502 | <P> |
| 503 | <b>--recursion-limit</b>=<i>number</i> |
| 504 | See <b>--match-limit</b> above. |
| 505 | </P> |
| 506 | <P> |
| 507 | <b>-s</b>, <b>--no-messages</b> |
| 508 | Suppress error messages about non-existent or unreadable files. Such files are |
| 509 | quietly skipped. However, the return code is still 2, even if matches were |
| 510 | found in other files. |
| 511 | </P> |
| 512 | <P> |
| 513 | <b>-u</b>, <b>--utf-8</b> |
| 514 | Operate in UTF-8 mode. This option is available only if PCRE has been compiled |
| 515 | with UTF-8 support. Both patterns and subject lines must be valid strings of |
| 516 | UTF-8 characters. |
| 517 | </P> |
| 518 | <P> |
| 519 | <b>-V</b>, <b>--version</b> |
| 520 | Write the version numbers of <b>pcregrep</b> and the PCRE library that is being |
| 521 | used to the standard error stream. |
| 522 | </P> |
| 523 | <P> |
| 524 | <b>-v</b>, <b>--invert-match</b> |
| 525 | Invert the sense of the match, so that lines which do <i>not</i> match any of |
| 526 | the patterns are the ones that are found. |
| 527 | </P> |
| 528 | <P> |
| 529 | <b>-w</b>, <b>--word-regex</b>, <b>--word-regexp</b> |
| 530 | Force the patterns to match only whole words. This is equivalent to having \b |
| 531 | at the start and end of the pattern. |
| 532 | </P> |
| 533 | <P> |
| 534 | <b>-x</b>, <b>--line-regex</b>, <b>--line-regexp</b> |
| 535 | Force the patterns to be anchored (each must start matching at the beginning of |
| 536 | a line) and in addition, require them to match entire lines. This is |
| 537 | equivalent to having ^ and $ characters at the start and end of each |
| 538 | alternative branch in every pattern. |
| 539 | </P> |
| 540 | <br><a name="SEC5" href="#TOC1">ENVIRONMENT VARIABLES</a><br> |
| 541 | <P> |
| 542 | The environment variables <b>LC_ALL</b> and <b>LC_CTYPE</b> are examined, in that |
| 543 | order, for a locale. The first one that is set is used. This can be overridden |
| 544 | by the <b>--locale</b> option. If no locale is set, the PCRE library's default |
| 545 | (usually the "C" locale) is used. |
| 546 | </P> |
| 547 | <br><a name="SEC6" href="#TOC1">NEWLINES</a><br> |
| 548 | <P> |
| 549 | The <b>-N</b> (<b>--newline</b>) option allows <b>pcregrep</b> to scan files with |
| 550 | different newline conventions from the default. However, the setting of this |
| 551 | option does not affect the way in which <b>pcregrep</b> writes information to |
| 552 | the standard error and output streams. It uses the string "\n" in C |
| 553 | <b>printf()</b> calls to indicate newlines, relying on the C I/O library to |
| 554 | convert this to an appropriate sequence if the output is sent to a file. |
| 555 | </P> |
| 556 | <br><a name="SEC7" href="#TOC1">OPTIONS COMPATIBILITY</a><br> |
| 557 | <P> |
| 558 | Many of the short and long forms of <b>pcregrep</b>'s options are the same |
| 559 | as in the GNU <b>grep</b> program (version 2.5.4). Any long option of the form |
| 560 | <b>--xxx-regexp</b> (GNU terminology) is also available as <b>--xxx-regex</b> |
| 561 | (PCRE terminology). However, the <b>--file-offsets</b>, <b>--include-dir</b>, |
| 562 | <b>--line-offsets</b>, <b>--locale</b>, <b>--match-limit</b>, <b>-M</b>, |
| 563 | <b>--multiline</b>, <b>-N</b>, <b>--newline</b>, <b>--recursion-limit</b>, |
| 564 | <b>-u</b>, and <b>--utf-8</b> options are specific to <b>pcregrep</b>, as is the |
| 565 | use of the <b>--only-matching</b> option with a capturing parentheses number. |
| 566 | </P> |
| 567 | <P> |
| 568 | Although most of the common options work the same way, a few are different in |
| 569 | <b>pcregrep</b>. For example, the <b>--include</b> option's argument is a glob |
| 570 | for GNU <b>grep</b>, but a regular expression for <b>pcregrep</b>. If both the |
| 571 | <b>-c</b> and <b>-l</b> options are given, GNU grep lists only file names, |
| 572 | without counts, but <b>pcregrep</b> gives the counts. |
| 573 | </P> |
| 574 | <br><a name="SEC8" href="#TOC1">OPTIONS WITH DATA</a><br> |
| 575 | <P> |
| 576 | There are four different ways in which an option with data can be specified. |
| 577 | If a short form option is used, the data may follow immediately, or (with one |
| 578 | exception) in the next command line item. For example: |
| 579 | <pre> |
| 580 | -f/some/file |
| 581 | -f /some/file |
| 582 | </pre> |
| 583 | The exception is the <b>-o</b> option, which may appear with or without data. |
| 584 | Because of this, if data is present, it must follow immediately in the same |
| 585 | item, for example -o3. |
| 586 | </P> |
| 587 | <P> |
| 588 | If a long form option is used, the data may appear in the same command line |
| 589 | item, separated by an equals character, or (with two exceptions) it may appear |
| 590 | in the next command line item. For example: |
| 591 | <pre> |
| 592 | --file=/some/file |
| 593 | --file /some/file |
| 594 | </pre> |
| 595 | Note, however, that if you want to supply a file name beginning with ~ as data |
| 596 | in a shell command, and have the shell expand ~ to a home directory, you must |
| 597 | separate the file name from the option, because the shell does not treat ~ |
| 598 | specially unless it is at the start of an item. |
| 599 | </P> |
| 600 | <P> |
| 601 | The exceptions to the above are the <b>--colour</b> (or <b>--color</b>) and |
| 602 | <b>--only-matching</b> options, for which the data is optional. If one of these |
| 603 | options does have data, it must be given in the first form, using an equals |
| 604 | character. Otherwise <b>pcregrep</b> will assume that it has no data. |
| 605 | </P> |
| 606 | <br><a name="SEC9" href="#TOC1">MATCHING ERRORS</a><br> |
| 607 | <P> |
| 608 | It is possible to supply a regular expression that takes a very long time to |
| 609 | fail to match certain lines. Such patterns normally involve nested indefinite |
| 610 | repeats, for example: (a+)*\d when matched against a line of a's with no final |
| 611 | digit. The PCRE matching function has a resource limit that causes it to abort |
| 612 | in these circumstances. If this happens, <b>pcregrep</b> outputs an error |
| 613 | message and the line that caused the problem to the standard error stream. If |
| 614 | there are more than 20 such errors, <b>pcregrep</b> gives up. |
| 615 | </P> |
| 616 | <P> |
| 617 | The <b>--match-limit</b> option of <b>pcregrep</b> can be used to set the overall |
| 618 | resource limit; there is a second option called <b>--recursion-limit</b> that |
| 619 | sets a limit on the amount of memory (usually stack) that is used (see the |
| 620 | discussion of these options above). |
| 621 | </P> |
| 622 | <br><a name="SEC10" href="#TOC1">DIAGNOSTICS</a><br> |
| 623 | <P> |
| 624 | Exit status is 0 if any matches were found, 1 if no matches were found, and 2 |
| 625 | for syntax errors, overlong lines, non-existent or inaccessible files (even if |
| 626 | matches were found in other files) or too many matching errors. Using the |
| 627 | <b>-s</b> option to suppress error messages about inaccessible files does not |
| 628 | affect the return code. |
| 629 | </P> |
| 630 | <br><a name="SEC11" href="#TOC1">SEE ALSO</a><br> |
| 631 | <P> |
| 632 | <b>pcrepattern</b>(3), <b>pcretest</b>(1). |
| 633 | </P> |
| 634 | <br><a name="SEC12" href="#TOC1">AUTHOR</a><br> |
| 635 | <P> |
| 636 | Philip Hazel |
| 637 | <br> |
| 638 | University Computing Service |
| 639 | <br> |
| 640 | Cambridge CB2 3QH, England. |
| 641 | <br> |
| 642 | </P> |
| 643 | <br><a name="SEC13" href="#TOC1">REVISION</a><br> |
| 644 | <P> |
| 645 | Last updated: 06 September 2011 |
| 646 | <br> |
| 647 | Copyright © 1997-2011 University of Cambridge. |
| 648 | <br> |
| 649 | <p> |
| 650 | Return to the <a href="index.html">PCRE index page</a>. |
| 651 | </p> |