| 1 |
PCREGREP(1) PCREGREP(1)
|
| 2 |
|
| 3 |
|
| 4 |
NAME
|
| 5 |
pcregrep - a grep with Perl-compatible regular expressions.
|
| 6 |
|
| 7 |
|
| 8 |
SYNOPSIS
|
| 9 |
pcregrep [options] [long options] [pattern] [path1 path2 ...]
|
| 10 |
|
| 11 |
|
| 12 |
DESCRIPTION
|
| 13 |
|
| 14 |
pcregrep searches files for character patterns, in the same way as
|
| 15 |
other grep commands do, but it uses the PCRE regular expression library
|
| 16 |
to support patterns that are compatible with the regular expressions of
|
| 17 |
Perl 5. See pcrepattern(3) for a full description of syntax and seman-
|
| 18 |
tics of the regular expressions that PCRE supports.
|
| 19 |
|
| 20 |
Patterns, whether supplied on the command line or in a separate file,
|
| 21 |
are given without delimiters. For example:
|
| 22 |
|
| 23 |
pcregrep Thursday /etc/motd
|
| 24 |
|
| 25 |
If you attempt to use delimiters (for example, by surrounding a pattern
|
| 26 |
with slashes, as is common in Perl scripts), they are interpreted as
|
| 27 |
part of the pattern. Quotes can of course be used to delimit patterns
|
| 28 |
on the command line because they are interpreted by the shell, and
|
| 29 |
indeed they are required if a pattern contains white space or shell
|
| 30 |
metacharacters.
|
| 31 |
|
| 32 |
The first argument that follows any option settings is treated as the
|
| 33 |
single pattern to be matched when neither -e nor -f is present. Con-
|
| 34 |
versely, when one or both of these options are used to specify pat-
|
| 35 |
terns, all arguments are treated as path names. At least one of -e, -f,
|
| 36 |
or an argument pattern must be provided.
|
| 37 |
|
| 38 |
If no files are specified, pcregrep reads the standard input. The stan-
|
| 39 |
dard input can also be referenced by a name consisting of a single
|
| 40 |
hyphen. For example:
|
| 41 |
|
| 42 |
pcregrep some-pattern /file1 - /file3
|
| 43 |
|
| 44 |
By default, each line that matches a pattern is copied to the standard
|
| 45 |
output, and if there is more than one file, the file name is output at
|
| 46 |
the start of each line, followed by a colon. However, there are options
|
| 47 |
that can change how pcregrep behaves. In particular, the -M option
|
| 48 |
makes it possible to search for patterns that span line boundaries.
|
| 49 |
What defines a line boundary is controlled by the -N (--newline)
|
| 50 |
option.
|
| 51 |
|
| 52 |
The amount of memory used for buffering files that are being scanned is
|
| 53 |
controlled by a parameter that can be set by the --buffer-size option.
|
| 54 |
The default value for this parameter is specified when pcregrep is
|
| 55 |
built, with the default default being 20K. A block of memory three
|
| 56 |
times this size is used (to allow for buffering "before" and "after"
|
| 57 |
lines). An error occurs if a line overflows the buffer.
|
| 58 |
|
| 59 |
Patterns are limited to 8K or BUFSIZ bytes, whichever is the greater.
|
| 60 |
BUFSIZ is defined in <stdio.h>. When there is more than one pattern
|
| 61 |
(specified by the use of -e and/or -f), each pattern is applied to each
|
| 62 |
line in the order in which they are defined, except that all the -e
|
| 63 |
patterns are tried before the -f patterns.
|
| 64 |
|
| 65 |
By default, as soon as one pattern matches (or fails to match when -v
|
| 66 |
is used), no further patterns are considered. However, if --colour (or
|
| 67 |
--color) is used to colour the matching substrings, or if --only-match-
|
| 68 |
ing, --file-offsets, or --line-offsets is used to output only the part
|
| 69 |
of the line that matched (either shown literally, or as an offset),
|
| 70 |
scanning resumes immediately following the match, so that further
|
| 71 |
matches on the same line can be found. If there are multiple patterns,
|
| 72 |
they are all tried on the remainder of the line, but patterns that fol-
|
| 73 |
low the one that matched are not tried on the earlier part of the line.
|
| 74 |
|
| 75 |
This is the same behaviour as GNU grep, but it does mean that the order
|
| 76 |
in which multiple patterns are specified can affect the output when one
|
| 77 |
of the above options is used.
|
| 78 |
|
| 79 |
Patterns that can match an empty string are accepted, but empty string
|
| 80 |
matches are never recognized. An example is the pattern
|
| 81 |
"(super)?(man)?", in which all components are optional. This pattern
|
| 82 |
finds all occurrences of both "super" and "man"; the output differs
|
| 83 |
from matching with "super|man" when only the matching substrings are
|
| 84 |
being shown.
|
| 85 |
|
| 86 |
If the LC_ALL or LC_CTYPE environment variable is set, pcregrep uses
|
| 87 |
the value to set a locale when calling the PCRE library. The --locale
|
| 88 |
option can be used to override this.
|
| 89 |
|
| 90 |
|
| 91 |
SUPPORT FOR COMPRESSED FILES
|
| 92 |
|
| 93 |
It is possible to compile pcregrep so that it uses libz or libbz2 to
|
| 94 |
read files whose names end in .gz or .bz2, respectively. You can find
|
| 95 |
out whether your binary has support for one or both of these file types
|
| 96 |
by running it with the --help option. If the appropriate support is not
|
| 97 |
present, files are treated as plain text. The standard input is always
|
| 98 |
so treated.
|
| 99 |
|
| 100 |
|
| 101 |
BINARY FILES
|
| 102 |
|
| 103 |
By default, a file that contains a binary zero byte within the first
|
| 104 |
1024 bytes is identified as a binary file, and is processed specially.
|
| 105 |
(GNU grep also identifies binary files in this manner.) See the
|
| 106 |
--binary-files option for a means of changing the way binary files are
|
| 107 |
handled.
|
| 108 |
|
| 109 |
|
| 110 |
OPTIONS
|
| 111 |
|
| 112 |
The order in which some of the options appear can affect the output.
|
| 113 |
For example, both the -h and -l options affect the printing of file
|
| 114 |
names. Whichever comes later in the command line will be the one that
|
| 115 |
takes effect. Numerical values for options may be followed by K or M,
|
| 116 |
to signify multiplication by 1024 or 1024*1024 respectively.
|
| 117 |
|
| 118 |
-- This terminates the list of options. It is useful if the next
|
| 119 |
item on the command line starts with a hyphen but is not an
|
| 120 |
option. This allows for the processing of patterns and file-
|
| 121 |
names that start with hyphens.
|
| 122 |
|
| 123 |
-A number, --after-context=number
|
| 124 |
Output number lines of context after each matching line. If
|
| 125 |
filenames and/or line numbers are being output, a hyphen sep-
|
| 126 |
arator is used instead of a colon for the context lines. A
|
| 127 |
line containing "--" is output between each group of lines,
|
| 128 |
unless they are in fact contiguous in the input file. The
|
| 129 |
value of number is expected to be relatively small. However,
|
| 130 |
pcregrep guarantees to have up to 8K of following text avail-
|
| 131 |
able for context output.
|
| 132 |
|
| 133 |
-a, --text
|
| 134 |
Treat binary files as text. This is equivalent to --binary-
|
| 135 |
files=text.
|
| 136 |
|
| 137 |
-B number, --before-context=number
|
| 138 |
Output number lines of context before each matching line. If
|
| 139 |
filenames and/or line numbers are being output, a hyphen sep-
|
| 140 |
arator is used instead of a colon for the context lines. A
|
| 141 |
line containing "--" is output between each group of lines,
|
| 142 |
unless they are in fact contiguous in the input file. The
|
| 143 |
value of number is expected to be relatively small. However,
|
| 144 |
pcregrep guarantees to have up to 8K of preceding text avail-
|
| 145 |
able for context output.
|
| 146 |
|
| 147 |
--binary-files=word
|
| 148 |
Specify how binary files are to be processed. If the word is
|
| 149 |
"binary" (the default), pattern matching is performed on
|
| 150 |
binary files, but the only output is "Binary file <name>
|
| 151 |
matches" when a match succeeds. If the word is "text", which
|
| 152 |
is equivalent to the -a or --text option, binary files are
|
| 153 |
processed in the same way as any other file. In this case,
|
| 154 |
when a match succeeds, the output may be binary garbage,
|
| 155 |
which can have nasty effects if sent to a terminal. If the
|
| 156 |
word is "without-match", which is equivalent to the -I
|
| 157 |
option, binary files are not processed at all; they are
|
| 158 |
assumed not to be of interest.
|
| 159 |
|
| 160 |
--buffer-size=number
|
| 161 |
Set the parameter that controls how much memory is used for
|
| 162 |
buffering files that are being scanned.
|
| 163 |
|
| 164 |
-C number, --context=number
|
| 165 |
Output number lines of context both before and after each
|
| 166 |
matching line. This is equivalent to setting both -A and -B
|
| 167 |
to the same value.
|
| 168 |
|
| 169 |
-c, --count
|
| 170 |
Do not output individual lines from the files that are being
|
| 171 |
scanned; instead output the number of lines that would other-
|
| 172 |
wise have been shown. If no lines are selected, the number
|
| 173 |
zero is output. If several files are are being scanned, a
|
| 174 |
count is output for each of them. However, if the --files-
|
| 175 |
with-matches option is also used, only those files whose
|
| 176 |
counts are greater than zero are listed. When -c is used, the
|
| 177 |
-A, -B, and -C options are ignored.
|
| 178 |
|
| 179 |
--colour, --color
|
| 180 |
If this option is given without any data, it is equivalent to
|
| 181 |
"--colour=auto". If data is required, it must be given in
|
| 182 |
the same shell item, separated by an equals sign.
|
| 183 |
|
| 184 |
--colour=value, --color=value
|
| 185 |
This option specifies under what circumstances the parts of a
|
| 186 |
line that matched a pattern should be coloured in the output.
|
| 187 |
By default, the output is not coloured. The value (which is
|
| 188 |
optional, see above) may be "never", "always", or "auto". In
|
| 189 |
the latter case, colouring happens only if the standard out-
|
| 190 |
put is connected to a terminal. More resources are used when
|
| 191 |
colouring is enabled, because pcregrep has to search for all
|
| 192 |
possible matches in a line, not just one, in order to colour
|
| 193 |
them all.
|
| 194 |
|
| 195 |
The colour that is used can be specified by setting the envi-
|
| 196 |
ronment variable PCREGREP_COLOUR or PCREGREP_COLOR. The value
|
| 197 |
of this variable should be a string of two numbers, separated
|
| 198 |
by a semicolon. They are copied directly into the control
|
| 199 |
string for setting colour on a terminal, so it is your
|
| 200 |
responsibility to ensure that they make sense. If neither of
|
| 201 |
the environment variables is set, the default is "1;31",
|
| 202 |
which gives red.
|
| 203 |
|
| 204 |
-D action, --devices=action
|
| 205 |
If an input path is not a regular file or a directory,
|
| 206 |
"action" specifies how it is to be processed. Valid values
|
| 207 |
are "read" (the default) or "skip" (silently skip the path).
|
| 208 |
|
| 209 |
-d action, --directories=action
|
| 210 |
If an input path is a directory, "action" specifies how it is
|
| 211 |
to be processed. Valid values are "read" (the default),
|
| 212 |
"recurse" (equivalent to the -r option), or "skip" (silently
|
| 213 |
skip the path). In the default case, directories are read as
|
| 214 |
if they were ordinary files. In some operating systems the
|
| 215 |
effect of reading a directory like this is an immediate end-
|
| 216 |
of-file.
|
| 217 |
|
| 218 |
-e pattern, --regex=pattern, --regexp=pattern
|
| 219 |
Specify a pattern to be matched. This option can be used mul-
|
| 220 |
tiple times in order to specify several patterns. It can also
|
| 221 |
be used as a way of specifying a single pattern that starts
|
| 222 |
with a hyphen. When -e is used, no argument pattern is taken
|
| 223 |
from the command line; all arguments are treated as file
|
| 224 |
names. There is an overall maximum of 100 patterns. They are
|
| 225 |
applied to each line in the order in which they are defined
|
| 226 |
until one matches (or fails to match if -v is used). If -f is
|
| 227 |
used with -e, the command line patterns are matched first,
|
| 228 |
followed by the patterns from the file, independent of the
|
| 229 |
order in which these options are specified. Note that multi-
|
| 230 |
ple use of -e is not the same as a single pattern with alter-
|
| 231 |
natives. For example, X|Y finds the first character in a line
|
| 232 |
that is X or Y, whereas if the two patterns are given sepa-
|
| 233 |
rately, pcregrep finds X if it is present, even if it follows
|
| 234 |
Y in the line. It finds Y only if there is no X in the line.
|
| 235 |
This really matters only if you are using -o to show the
|
| 236 |
part(s) of the line that matched.
|
| 237 |
|
| 238 |
--exclude=pattern
|
| 239 |
When pcregrep is searching the files in a directory as a con-
|
| 240 |
sequence of the -r (recursive search) option, any regular
|
| 241 |
files whose names match the pattern are excluded. Subdirecto-
|
| 242 |
ries are not excluded by this option; they are searched
|
| 243 |
recursively, subject to the --exclude-dir and --include_dir
|
| 244 |
options. The pattern is a PCRE regular expression, and is
|
| 245 |
matched against the final component of the file name (not the
|
| 246 |
entire path). If a file name matches both --include and
|
| 247 |
--exclude, it is excluded. There is no short form for this
|
| 248 |
option.
|
| 249 |
|
| 250 |
--exclude-dir=pattern
|
| 251 |
When pcregrep is searching the contents of a directory as a
|
| 252 |
consequence of the -r (recursive search) option, any subdi-
|
| 253 |
rectories whose names match the pattern are excluded. (Note
|
| 254 |
that the --exclude option does not affect subdirectories.)
|
| 255 |
The pattern is a PCRE regular expression, and is matched
|
| 256 |
against the final component of the name (not the entire
|
| 257 |
path). If a subdirectory name matches both --include-dir and
|
| 258 |
--exclude-dir, it is excluded. There is no short form for
|
| 259 |
this option.
|
| 260 |
|
| 261 |
-F, --fixed-strings
|
| 262 |
Interpret each pattern as a list of fixed strings, separated
|
| 263 |
by newlines, instead of as a regular expression. The -w
|
| 264 |
(match as a word) and -x (match whole line) options can be
|
| 265 |
used with -F. They apply to each of the fixed strings. A line
|
| 266 |
is selected if any of the fixed strings are found in it (sub-
|
| 267 |
ject to -w or -x, if present).
|
| 268 |
|
| 269 |
-f filename, --file=filename
|
| 270 |
Read a number of patterns from the file, one per line, and
|
| 271 |
match them against each line of input. A data line is output
|
| 272 |
if any of the patterns match it. The filename can be given as
|
| 273 |
"-" to refer to the standard input. When -f is used, patterns
|
| 274 |
specified on the command line using -e may also be present;
|
| 275 |
they are tested before the file's patterns. However, no other
|
| 276 |
pattern is taken from the command line; all arguments are
|
| 277 |
treated as the names of paths to be searched. There is an
|
| 278 |
overall maximum of 100 patterns. Trailing white space is
|
| 279 |
removed from each line, and blank lines are ignored. An empty
|
| 280 |
file contains no patterns and therefore matches nothing. See
|
| 281 |
also the comments about multiple patterns versus a single
|
| 282 |
pattern with alternatives in the description of -e above.
|
| 283 |
|
| 284 |
--file-list=filename
|
| 285 |
Read a list of files to be searched from the given file, one
|
| 286 |
per line. Trailing white space is removed from each line, and
|
| 287 |
blank lines are ignored. These files are searched before any
|
| 288 |
others that may be listed on the command line. The filename
|
| 289 |
can be given as "-" to refer to the standard input. If --file
|
| 290 |
and --file-list are both specified as "-", patterns are read
|
| 291 |
first. This is useful only when the standard input is a ter-
|
| 292 |
minal, from which further lines (the list of files) can be
|
| 293 |
read after an end-of-file indication.
|
| 294 |
|
| 295 |
--file-offsets
|
| 296 |
Instead of showing lines or parts of lines that match, show
|
| 297 |
each match as an offset from the start of the file and a
|
| 298 |
length, separated by a comma. In this mode, no context is
|
| 299 |
shown. That is, the -A, -B, and -C options are ignored. If
|
| 300 |
there is more than one match in a line, each of them is shown
|
| 301 |
separately. This option is mutually exclusive with --line-
|
| 302 |
offsets and --only-matching.
|
| 303 |
|
| 304 |
-H, --with-filename
|
| 305 |
Force the inclusion of the filename at the start of output
|
| 306 |
lines when searching a single file. By default, the filename
|
| 307 |
is not shown in this case. For matching lines, the filename
|
| 308 |
is followed by a colon; for context lines, a hyphen separator
|
| 309 |
is used. If a line number is also being output, it follows
|
| 310 |
the file name.
|
| 311 |
|
| 312 |
-h, --no-filename
|
| 313 |
Suppress the output filenames when searching multiple files.
|
| 314 |
By default, filenames are shown when multiple files are
|
| 315 |
searched. For matching lines, the filename is followed by a
|
| 316 |
colon; for context lines, a hyphen separator is used. If a
|
| 317 |
line number is also being output, it follows the file name.
|
| 318 |
|
| 319 |
--help Output a help message, giving brief details of the command
|
| 320 |
options and file type support, and then exit.
|
| 321 |
|
| 322 |
-I Treat binary files as never matching. This is equivalent to
|
| 323 |
--binary-files=without-match.
|
| 324 |
|
| 325 |
-i, --ignore-case
|
| 326 |
Ignore upper/lower case distinctions during comparisons.
|
| 327 |
|
| 328 |
--include=pattern
|
| 329 |
When pcregrep is searching the files in a directory as a con-
|
| 330 |
sequence of the -r (recursive search) option, only those reg-
|
| 331 |
ular files whose names match the pattern are included. Subdi-
|
| 332 |
rectories are always included and searched recursively, sub-
|
| 333 |
ject to the --include-dir and --exclude-dir options. The pat-
|
| 334 |
tern is a PCRE regular expression, and is matched against the
|
| 335 |
final component of the file name (not the entire path). If a
|
| 336 |
file name matches both --include and --exclude, it is
|
| 337 |
excluded. There is no short form for this option.
|
| 338 |
|
| 339 |
--include-dir=pattern
|
| 340 |
When pcregrep is searching the contents of a directory as a
|
| 341 |
consequence of the -r (recursive search) option, only those
|
| 342 |
subdirectories whose names match the pattern are included.
|
| 343 |
(Note that the --include option does not affect subdirecto-
|
| 344 |
ries.) The pattern is a PCRE regular expression, and is
|
| 345 |
matched against the final component of the name (not the
|
| 346 |
entire path). If a subdirectory name matches both --include-
|
| 347 |
dir and --exclude-dir, it is excluded. There is no short form
|
| 348 |
for this option.
|
| 349 |
|
| 350 |
-L, --files-without-match
|
| 351 |
Instead of outputting lines from the files, just output the
|
| 352 |
names of the files that do not contain any lines that would
|
| 353 |
have been output. Each file name is output once, on a sepa-
|
| 354 |
rate line.
|
| 355 |
|
| 356 |
-l, --files-with-matches
|
| 357 |
Instead of outputting lines from the files, just output the
|
| 358 |
names of the files containing lines that would have been out-
|
| 359 |
put. Each file name is output once, on a separate line.
|
| 360 |
Searching normally stops as soon as a matching line is found
|
| 361 |
in a file. However, if the -c (count) option is also used,
|
| 362 |
matching continues in order to obtain the correct count, and
|
| 363 |
those files that have at least one match are listed along
|
| 364 |
with their counts. Using this option with -c is a way of sup-
|
| 365 |
pressing the listing of files with no matches.
|
| 366 |
|
| 367 |
--label=name
|
| 368 |
This option supplies a name to be used for the standard input
|
| 369 |
when file names are being output. If not supplied, "(standard
|
| 370 |
input)" is used. There is no short form for this option.
|
| 371 |
|
| 372 |
--line-buffered
|
| 373 |
When this option is given, input is read and processed line
|
| 374 |
by line, and the output is flushed after each write. By
|
| 375 |
default, input is read in large chunks, unless pcregrep can
|
| 376 |
determine that it is reading from a terminal (which is cur-
|
| 377 |
rently possible only in Unix environments). Output to termi-
|
| 378 |
nal is normally automatically flushed by the operating sys-
|
| 379 |
tem. This option can be useful when the input or output is
|
| 380 |
attached to a pipe and you do not want pcregrep to buffer up
|
| 381 |
large amounts of data. However, its use will affect perfor-
|
| 382 |
mance, and the -M (multiline) option ceases to work.
|
| 383 |
|
| 384 |
--line-offsets
|
| 385 |
Instead of showing lines or parts of lines that match, show
|
| 386 |
each match as a line number, the offset from the start of the
|
| 387 |
line, and a length. The line number is terminated by a colon
|
| 388 |
(as usual; see the -n option), and the offset and length are
|
| 389 |
separated by a comma. In this mode, no context is shown.
|
| 390 |
That is, the -A, -B, and -C options are ignored. If there is
|
| 391 |
more than one match in a line, each of them is shown sepa-
|
| 392 |
rately. This option is mutually exclusive with --file-offsets
|
| 393 |
and --only-matching.
|
| 394 |
|
| 395 |
--locale=locale-name
|
| 396 |
This option specifies a locale to be used for pattern match-
|
| 397 |
ing. It overrides the value in the LC_ALL or LC_CTYPE envi-
|
| 398 |
ronment variables. If no locale is specified, the PCRE
|
| 399 |
library's default (usually the "C" locale) is used. There is
|
| 400 |
no short form for this option.
|
| 401 |
|
| 402 |
--match-limit=number
|
| 403 |
Processing some regular expression patterns can require a
|
| 404 |
very large amount of memory, leading in some cases to a pro-
|
| 405 |
gram crash if not enough is available. Other patterns may
|
| 406 |
take a very long time to search for all possible matching
|
| 407 |
strings. The pcre_exec() function that is called by pcregrep
|
| 408 |
to do the matching has two parameters that can limit the
|
| 409 |
resources that it uses.
|
| 410 |
|
| 411 |
The --match-limit option provides a means of limiting
|
| 412 |
resource usage when processing patterns that are not going to
|
| 413 |
match, but which have a very large number of possibilities in
|
| 414 |
their search trees. The classic example is a pattern that
|
| 415 |
uses nested unlimited repeats. Internally, PCRE uses a func-
|
| 416 |
tion called match() which it calls repeatedly (sometimes
|
| 417 |
recursively). The limit set by --match-limit is imposed on
|
| 418 |
the number of times this function is called during a match,
|
| 419 |
which has the effect of limiting the amount of backtracking
|
| 420 |
that can take place.
|
| 421 |
|
| 422 |
The --recursion-limit option is similar to --match-limit, but
|
| 423 |
instead of limiting the total number of times that match() is
|
| 424 |
called, it limits the depth of recursive calls, which in turn
|
| 425 |
limits the amount of memory that can be used. The recursion
|
| 426 |
depth is a smaller number than the total number of calls,
|
| 427 |
because not all calls to match() are recursive. This limit is
|
| 428 |
of use only if it is set smaller than --match-limit.
|
| 429 |
|
| 430 |
There are no short forms for these options. The default set-
|
| 431 |
tings are specified when the PCRE library is compiled, with
|
| 432 |
the default default being 10 million.
|
| 433 |
|
| 434 |
-M, --multiline
|
| 435 |
Allow patterns to match more than one line. When this option
|
| 436 |
is given, patterns may usefully contain literal newline char-
|
| 437 |
acters and internal occurrences of ^ and $ characters. The
|
| 438 |
output for a successful match may consist of more than one
|
| 439 |
line, the last of which is the one in which the match ended.
|
| 440 |
If the matched string ends with a newline sequence the output
|
| 441 |
ends at the end of that line.
|
| 442 |
|
| 443 |
When this option is set, the PCRE library is called in "mul-
|
| 444 |
tiline" mode. There is a limit to the number of lines that
|
| 445 |
can be matched, imposed by the way that pcregrep buffers the
|
| 446 |
input file as it scans it. However, pcregrep ensures that at
|
| 447 |
least 8K characters or the rest of the document (whichever is
|
| 448 |
the shorter) are available for forward matching, and simi-
|
| 449 |
larly the previous 8K characters (or all the previous charac-
|
| 450 |
ters, if fewer than 8K) are guaranteed to be available for
|
| 451 |
lookbehind assertions. This option does not work when input
|
| 452 |
is read line by line (see --line-buffered.)
|
| 453 |
|
| 454 |
-N newline-type, --newline=newline-type
|
| 455 |
The PCRE library supports five different conventions for
|
| 456 |
indicating the ends of lines. They are the single-character
|
| 457 |
sequences CR (carriage return) and LF (linefeed), the two-
|
| 458 |
character sequence CRLF, an "anycrlf" convention, which rec-
|
| 459 |
ognizes any of the preceding three types, and an "any" con-
|
| 460 |
vention, in which any Unicode line ending sequence is assumed
|
| 461 |
to end a line. The Unicode sequences are the three just men-
|
| 462 |
tioned, plus VT (vertical tab, U+000B), FF (form feed,
|
| 463 |
U+000C), NEL (next line, U+0085), LS (line separator,
|
| 464 |
U+2028), and PS (paragraph separator, U+2029).
|
| 465 |
|
| 466 |
When the PCRE library is built, a default line-ending
|
| 467 |
sequence is specified. This is normally the standard
|
| 468 |
sequence for the operating system. Unless otherwise specified
|
| 469 |
by this option, pcregrep uses the library's default. The
|
| 470 |
possible values for this option are CR, LF, CRLF, ANYCRLF, or
|
| 471 |
ANY. This makes it possible to use pcregrep on files that
|
| 472 |
have come from other environments without having to modify
|
| 473 |
their line endings. If the data that is being scanned does
|
| 474 |
not agree with the convention set by this option, pcregrep
|
| 475 |
may behave in strange ways.
|
| 476 |
|
| 477 |
-n, --line-number
|
| 478 |
Precede each output line by its line number in the file, fol-
|
| 479 |
lowed by a colon for matching lines or a hyphen for context
|
| 480 |
lines. If the filename is also being output, it precedes the
|
| 481 |
line number. This option is forced if --line-offsets is used.
|
| 482 |
|
| 483 |
--no-jit If the PCRE library is built with support for just-in-time
|
| 484 |
compiling (which speeds up matching), pcregrep automatically
|
| 485 |
makes use of this, unless it was explicitly disabled at build
|
| 486 |
time. This option can be used to disable the use of JIT at
|
| 487 |
run time. It is provided for testing and working round prob-
|
| 488 |
lems. It should never be needed in normal use.
|
| 489 |
|
| 490 |
-o, --only-matching
|
| 491 |
Show only the part of the line that matched a pattern instead
|
| 492 |
of the whole line. In this mode, no context is shown. That
|
| 493 |
is, the -A, -B, and -C options are ignored. If there is more
|
| 494 |
than one match in a line, each of them is shown separately.
|
| 495 |
If -o is combined with -v (invert the sense of the match to
|
| 496 |
find non-matching lines), no output is generated, but the
|
| 497 |
return code is set appropriately. If the matched portion of
|
| 498 |
the line is empty, nothing is output unless the file name or
|
| 499 |
line number are being printed, in which case they are shown
|
| 500 |
on an otherwise empty line. This option is mutually exclusive
|
| 501 |
with --file-offsets and --line-offsets.
|
| 502 |
|
| 503 |
-onumber, --only-matching=number
|
| 504 |
Show only the part of the line that matched the capturing
|
| 505 |
parentheses of the given number. Up to 32 capturing parenthe-
|
| 506 |
ses are supported. Because these options can be given without
|
| 507 |
an argument (see above), if an argument is present, it must
|
| 508 |
be given in the same shell item, for example, -o3 or --only-
|
| 509 |
matching=2. The comments given for the non-argument case
|
| 510 |
above also apply to this case. If the specified capturing
|
| 511 |
parentheses do not exist in the pattern, or were not set in
|
| 512 |
the match, nothing is output unless the file name or line
|
| 513 |
number are being printed.
|
| 514 |
|
| 515 |
-q, --quiet
|
| 516 |
Work quietly, that is, display nothing except error messages.
|
| 517 |
The exit status indicates whether or not any matches were
|
| 518 |
found.
|
| 519 |
|
| 520 |
-r, --recursive
|
| 521 |
If any given path is a directory, recursively scan the files
|
| 522 |
it contains, taking note of any --include and --exclude set-
|
| 523 |
tings. By default, a directory is read as a normal file; in
|
| 524 |
some operating systems this gives an immediate end-of-file.
|
| 525 |
This option is a shorthand for setting the -d option to
|
| 526 |
"recurse".
|
| 527 |
|
| 528 |
--recursion-limit=number
|
| 529 |
See --match-limit above.
|
| 530 |
|
| 531 |
-s, --no-messages
|
| 532 |
Suppress error messages about non-existent or unreadable
|
| 533 |
files. Such files are quietly skipped. However, the return
|
| 534 |
code is still 2, even if matches were found in other files.
|
| 535 |
|
| 536 |
-u, --utf-8
|
| 537 |
Operate in UTF-8 mode. This option is available only if PCRE
|
| 538 |
has been compiled with UTF-8 support. Both patterns and sub-
|
| 539 |
ject lines must be valid strings of UTF-8 characters.
|
| 540 |
|
| 541 |
-V, --version
|
| 542 |
Write the version numbers of pcregrep and the PCRE library
|
| 543 |
that is being used to the standard error stream.
|
| 544 |
|
| 545 |
-v, --invert-match
|
| 546 |
Invert the sense of the match, so that lines which do not
|
| 547 |
match any of the patterns are the ones that are found.
|
| 548 |
|
| 549 |
-w, --word-regex, --word-regexp
|
| 550 |
Force the patterns to match only whole words. This is equiva-
|
| 551 |
lent to having \b at the start and end of the pattern.
|
| 552 |
|
| 553 |
-x, --line-regex, --line-regexp
|
| 554 |
Force the patterns to be anchored (each must start matching
|
| 555 |
at the beginning of a line) and in addition, require them to
|
| 556 |
match entire lines. This is equivalent to having ^ and $
|
| 557 |
characters at the start and end of each alternative branch in
|
| 558 |
every pattern.
|
| 559 |
|
| 560 |
|
| 561 |
ENVIRONMENT VARIABLES
|
| 562 |
|
| 563 |
The environment variables LC_ALL and LC_CTYPE are examined, in that
|
| 564 |
order, for a locale. The first one that is set is used. This can be
|
| 565 |
overridden by the --locale option. If no locale is set, the PCRE
|
| 566 |
library's default (usually the "C" locale) is used.
|
| 567 |
|
| 568 |
|
| 569 |
NEWLINES
|
| 570 |
|
| 571 |
The -N (--newline) option allows pcregrep to scan files with different
|
| 572 |
newline conventions from the default. However, the setting of this
|
| 573 |
option does not affect the way in which pcregrep writes information to
|
| 574 |
the standard error and output streams. It uses the string "\n" in C
|
| 575 |
printf() calls to indicate newlines, relying on the C I/O library to
|
| 576 |
convert this to an appropriate sequence if the output is sent to a
|
| 577 |
file.
|
| 578 |
|
| 579 |
|
| 580 |
OPTIONS COMPATIBILITY
|
| 581 |
|
| 582 |
Many of the short and long forms of pcregrep's options are the same as
|
| 583 |
in the GNU grep program. Any long option of the form --xxx-regexp (GNU
|
| 584 |
terminology) is also available as --xxx-regex (PCRE terminology). How-
|
| 585 |
ever, the --file-list, --file-offsets, --include-dir, --line-offsets,
|
| 586 |
--locale, --match-limit, -M, --multiline, -N, --newline, --recursion-
|
| 587 |
limit, -u, and --utf-8 options are specific to pcregrep, as is the use
|
| 588 |
of the --only-matching option with a capturing parentheses number.
|
| 589 |
|
| 590 |
Although most of the common options work the same way, a few are dif-
|
| 591 |
ferent in pcregrep. For example, the --include option's argument is a
|
| 592 |
glob for GNU grep, but a regular expression for pcregrep. If both the
|
| 593 |
-c and -l options are given, GNU grep lists only file names, without
|
| 594 |
counts, but pcregrep gives the counts.
|
| 595 |
|
| 596 |
|
| 597 |
OPTIONS WITH DATA
|
| 598 |
|
| 599 |
There are four different ways in which an option with data can be spec-
|
| 600 |
ified. If a short form option is used, the data may follow immedi-
|
| 601 |
ately, or (with one exception) in the next command line item. For exam-
|
| 602 |
ple:
|
| 603 |
|
| 604 |
-f/some/file
|
| 605 |
-f /some/file
|
| 606 |
|
| 607 |
The exception is the -o option, which may appear with or without data.
|
| 608 |
Because of this, if data is present, it must follow immediately in the
|
| 609 |
same item, for example -o3.
|
| 610 |
|
| 611 |
If a long form option is used, the data may appear in the same command
|
| 612 |
line item, separated by an equals character, or (with two exceptions)
|
| 613 |
it may appear in the next command line item. For example:
|
| 614 |
|
| 615 |
--file=/some/file
|
| 616 |
--file /some/file
|
| 617 |
|
| 618 |
Note, however, that if you want to supply a file name beginning with ~
|
| 619 |
as data in a shell command, and have the shell expand ~ to a home
|
| 620 |
directory, you must separate the file name from the option, because the
|
| 621 |
shell does not treat ~ specially unless it is at the start of an item.
|
| 622 |
|
| 623 |
The exceptions to the above are the --colour (or --color) and --only-
|
| 624 |
matching options, for which the data is optional. If one of these
|
| 625 |
options does have data, it must be given in the first form, using an
|
| 626 |
equals character. Otherwise pcregrep will assume that it has no data.
|
| 627 |
|
| 628 |
|
| 629 |
MATCHING ERRORS
|
| 630 |
|
| 631 |
It is possible to supply a regular expression that takes a very long
|
| 632 |
time to fail to match certain lines. Such patterns normally involve
|
| 633 |
nested indefinite repeats, for example: (a+)*\d when matched against a
|
| 634 |
line of a's with no final digit. The PCRE matching function has a
|
| 635 |
resource limit that causes it to abort in these circumstances. If this
|
| 636 |
happens, pcregrep outputs an error message and the line that caused the
|
| 637 |
problem to the standard error stream. If there are more than 20 such
|
| 638 |
errors, pcregrep gives up.
|
| 639 |
|
| 640 |
The --match-limit option of pcregrep can be used to set the overall
|
| 641 |
resource limit; there is a second option called --recursion-limit that
|
| 642 |
sets a limit on the amount of memory (usually stack) that is used (see
|
| 643 |
the discussion of these options above).
|
| 644 |
|
| 645 |
|
| 646 |
DIAGNOSTICS
|
| 647 |
|
| 648 |
Exit status is 0 if any matches were found, 1 if no matches were found,
|
| 649 |
and 2 for syntax errors, overlong lines, non-existent or inaccessible
|
| 650 |
files (even if matches were found in other files) or too many matching
|
| 651 |
errors. Using the -s option to suppress error messages about inaccessi-
|
| 652 |
ble files does not affect the return code.
|
| 653 |
|
| 654 |
|
| 655 |
SEE ALSO
|
| 656 |
|
| 657 |
pcrepattern(3), pcretest(1).
|
| 658 |
|
| 659 |
|
| 660 |
AUTHOR
|
| 661 |
|
| 662 |
Philip Hazel
|
| 663 |
University Computing Service
|
| 664 |
Cambridge CB2 3QH, England.
|
| 665 |
|
| 666 |
|
| 667 |
REVISION
|
| 668 |
|
| 669 |
Last updated: 04 March 2012
|
| 670 |
Copyright (c) 1997-2012 University of Cambridge.
|
Parent Directory
| 
Revision Log