pcregrep(1)
PCREGREP(1) USER COMMANDS PCREGREP(1)
NAME
pcregrep - a grep with Perl-compatible regular expressions.
SYNOPSIS
pcregrep [options] [long options] [pattern] [path1
DESCRIPTION
pcregrep searches files for character patterns, in the same
way as other grep commands do, but it uses the PCRE regular
expression library to support patterns that are compatible
with the regular expressions of Perl 5. See pcresyntax(3)
for a quick-reference summary of pattern syntax, or pcrepat-
tern(3) for a full description of the syntax and semantics
of the regular expressions that PCRE supports. Patterns,
whether supplied on the command line or in a separate file,
are given without delimiters. For example:
pcregrep Thursday /etc/motd
If you attempt to use delimiters (for example, by surround-
ing a pattern with slashes, as is common in Perl scripts),
they are interpreted as part of the pattern. Quotes can of
course be used to delimit patterns on the command line
because they are interpreted by the shell, and indeed quotes
are required if a pattern contains white space or shell
metacharacters. The first argument that follows any option
settings is treated as the single pattern to be matched when
neither -e nor -f is present. Conversely, when one or both
of these options are used to specify patterns, all arguments
are treated as path names. At least one of -e, -f, or an
argument pattern must be provided. If no files are speci-
fied, pcregrep reads the standard input. The standard input
can also be referenced by a name consisting of a single
hyphen. For example:
pcregrep some-pattern /file1 - /file3
By default, each line that matches a pattern is copied to
the standard output, and if there is more than one file, the
file name is output at the start of each line, followed by a
colon. However, there are options that can change how pcre-
grep behaves. In particular, the -M option makes it possible
to search for patterns that span line boundaries. What
defines a line boundary is controlled by the -N (--newline)
option. The amount of memory used for buffering files that
are being scanned is controlled by a parameter that can be
set by the --buffer-size option. The default value for this
parameter is specified when pcregrep is built, with the
default default being 20K. A block of memory three times
this size is used (to allow for buffering "before" and
"after" lines). An error occurs if a line overflows the
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buffer. Patterns can be no longer than 8K or BUFSIZ bytes,
whichever is the greater. BUFSIZ is defined in <stdio.h>.
When there is more than one pattern (specified by the use of
-e and/or -f), each pattern is applied to each line in the
order in which they are defined, except that all the -e pat-
terns are tried before the -f patterns. By default, as soon
as one pattern matches a line, no further patterns are con-
sidered. However, if --colour (or --color) is used to colour
the matching substrings, or if --only-matching, --file-
offsets, or --line-offsets is used to output only the part
of the line that matched (either shown literally, or as an
offset), scanning resumes immediately following the match,
so that further matches on the same line can be found. If
there are multiple patterns, they are all tried on the
remainder of the line, but patterns that follow the one that
matched are not tried on the earlier part of the line. This
behaviour means that the order in which multiple patterns
are specified can affect the output when one of the above
options is used. This is no longer the same behaviour as GNU
grep, which now manages to display earlier matches for later
patterns (as long as there is no overlap). Patterns that
can match an empty string are accepted, but empty string
matches are never recognized. An example is the pattern
"(super)?(man)?", in which all components are optional. This
pattern finds all occurrences of both "super" and "man"; the
output differs from matching with "super|man" when only the
matching substrings are being shown. If the LC_ALL or
LC_CTYPE environment variable is set, pcregrep uses the
value to set a locale when calling the PCRE library. The
--locale option can be used to override this.
SUPPORT FOR COMPRESSED FILES
It is possible to compile pcregrep so that it uses libz or
libbz2 to read files whose names end in .gz or .bz2, respec-
tively. You can find out whether your binary has support for
one or both of these file types by running it with the --
help option. If the appropriate support is not present,
files are treated as plain text. The standard input is
always so treated.
BINARY FILES
By default, a file that contains a binary zero byte within
the first 1024 bytes is identified as a binary file, and is
processed specially. (GNU grep also identifies binary files
in this manner.) See the --binary-files option for a means
of changing the way binary files are handled.
OPTIONS
The order in which some of the options appear can affect the
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output. For example, both the -h and -l options affect the
printing of file names. Whichever comes later in the command
line will be the one that takes effect. Similarly, except
where noted below, if an option is given twice, the later
setting is used. Numerical values for options may be fol-
lowed by K or M, to signify multiplication by 1024 or
1024*1024 respectively.
-- This terminates the list of options. It is useful
if the next item on the command line starts with a
hyphen but is not an option. This allows for the
processing of patterns and filenames that start
with hyphens.
-A number, --after-context=number
Output number lines of context after each matching
line. If filenames and/or line numbers are being
output, a hyphen separator is used instead of a
colon for the context lines. A line containing "-
-" is output between each group of lines, unless
they are in fact contiguous in the input file. The
value of number is expected to be relatively
small. However, pcregrep guarantees to have up to
8K of following text available for context output.
-a, --text
Treat binary files as text. This is equivalent to
--binary-files=text.
-B number, --before-context=number
Output number lines of context before each match-
ing line. If filenames and/or line numbers are
being output, a hyphen separator is used instead
of a colon for the context lines. A line contain-
ing "--" is output between each group of lines,
unless they are in fact contiguous in the input
file. The value of number is expected to be rela-
tively small. However, pcregrep guarantees to have
up to 8K of preceding text available for context
output.
--binary-files=word
Specify how binary files are to be processed. If
the word is "binary" (the default), pattern match-
ing is performed on binary files, but the only
output is "Binary file <name> matches" when a
match succeeds. If the word is "text", which is
equivalent to the -a or --text option, binary
files are processed in the same way as any other
file. In this case, when a match succeeds, the
output may be binary garbage, which can have nasty
effects if sent to a terminal. If the word is
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"without-match", which is equivalent to the -I
option, binary files are not processed at all;
they are assumed not to be of interest.
--buffer-size=number
Set the parameter that controls how much memory is
used for buffering files that are being scanned.
-C number, --context=number
Output number lines of context both before and
after each matching line. This is equivalent to
setting both -A and -B to the same value.
-c, --count
Do not output individual lines from the files that
are being scanned; instead output the number of
lines that would otherwise have been shown. If no
lines are selected, the number zero is output. If
several files are are being scanned, a count is
output for each of them. However, if the --files-
with-matches option is also used, only those files
whose counts are greater than zero are listed.
When -c is used, the -A, -B, and -C options are
ignored.
--colour, --color
If this option is given without any data, it is
equivalent to "--colour=auto". If data is
required, it must be given in the same shell item,
separated by an equals sign.
--colour=value, --color=value
This option specifies under what circumstances the
parts of a line that matched a pattern should be
coloured in the output. By default, the output is
not coloured. The value (which is optional, see
above) may be "never", "always", or "auto". In the
latter case, colouring happens only if the stan-
dard output is connected to a terminal. More
resources are used when colouring is enabled,
because pcregrep has to search for all possible
matches in a line, not just one, in order to
colour them all.
The colour that is used can be specified by set-
ting the environment variable PCREGREP_COLOUR or
PCREGREP_COLOR. The value of this variable should
be a string of two numbers, separated by a semi-
colon. They are copied directly into the control
string for setting colour on a terminal, so it is
your responsibility to ensure that they make
sense. If neither of the environment variables is
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set, the default is "1;31", which gives red.
-D action, --devices=action
If an input path is not a regular file or a direc-
tory, "action" specifies how it is to be pro-
cessed. Valid values are "read" (the default) or
"skip" (silently skip the path).
-d action, --directories=action
If an input path is a directory, "action" speci-
fies how it is to be processed. Valid values are
"read" (the default in non-Windows environments,
for compatibility with GNU grep), "recurse"
(equivalent to the -r option), or "skip" (silently
skip the path, the default in Windows environ-
ments). In the "read" case, directories are read
as if they were ordinary files. In some operating
systems the effect of reading a directory like
this is an immediate end-of-file; in others it may
provoke an error.
-e pattern, --regex=pattern, --regexp=pattern
Specify a pattern to be matched. This option can
be used multiple times in order to specify several
patterns. It can also be used as a way of specify-
ing a single pattern that starts with a hyphen.
When -e is used, no argument pattern is taken from
the command line; all arguments are treated as
file names. There is no limit to the number of
patterns. They are applied to each line in the
order in which they are defined until one matches.
If -f is used with -e, the command line patterns
are matched first, followed by the patterns from
the file(s), independent of the order in which
these options are specified. Note that multiple
use of -e is not the same as a single pattern with
alternatives. For example, X|Y finds the first
character in a line that is X or Y, whereas if the
two patterns are given separately, with X first,
pcregrep finds X if it is present, even if it fol-
lows Y in the line. It finds Y only if there is no
X in the line. This matters only if you are using
-o or --colo(u)r to show the part(s) of the line
that matched.
--exclude=pattern
Files (but not directories) whose names match the
pattern are skipped without being processed. This
applies to all files, whether listed on the com-
mand line, obtained from --file-list, or by scan-
ning a directory. The pattern is a PCRE regular
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expression, and is matched against the final com-
ponent of the file name, not the entire path. The
-F, -w, and -x options do not apply to this pat-
tern. The option may be given any number of times
in order to specify multiple patterns. If a file
name matches both an --include and an --exclude
pattern, it is excluded. There is no short form
for this option.
--exclude-from=filename
Treat each non-empty line of the file as the data
for an --exclude option. What constitutes a new-
line when reading the file is the operating
system's default. The --newline option has no
effect on this option. This option may be given
more than once in order to specify a number of
files to read.
--exclude-dir=pattern
Directories whose names match the pattern are
skipped without being processed, whatever the set-
ting of the --recursive option. This applies to
all directories, whether listed on the command
line, obtained from --file-list, or by scanning a
parent directory. The pattern is a PCRE regular
expression, and is matched against the final com-
ponent of the directory name, not the entire path.
The -F, -w, and -x options do not apply to this
pattern. The option may be given any number of
times in order to specify more than one pattern.
If a directory matches both --include-dir and --
exclude-dir, it is excluded. There is no short
form for this option.
-F, --fixed-strings
Interpret each data-matching pattern as a list of
fixed strings, separated by newlines, instead of
as a regular expression. What constitutes a new-
line for this purpose is controlled by the --
newline option. The -w (match as a word) and -x
(match whole line) options can be used with -F.
They apply to each of the fixed strings. A line is
selected if any of the fixed strings are found in
it (subject to -w or -x, if present). This option
applies only to the patterns that are matched
against the contents of files; it does not apply
to patterns specified by any of the --include or
--exclude options.
-f filename, --file=filename
Read patterns from the file, one per line, and
match them against each line of input. What
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constitutes a newline when reading the file is the
operating system's default. The --newline option
has no effect on this option. Trailing white space
is removed from each line, and blank lines are
ignored. An empty file contains no patterns and
therefore matches nothing. See also the comments
about multiple patterns versus a single pattern
with alternatives in the description of -e above.
If this option is given more than once, all the
specified files are read. A data line is output if
any of the patterns match it. A filename can be
given as "-" to refer to the standard input. When
-f is used, patterns specified on the command line
using -e may also be present; they are tested
before the file's patterns. However, no other pat-
tern is taken from the command line; all arguments
are treated as the names of paths to be searched.
--file-list=filename
Read a list of files and/or directories that are
to be scanned from the given file, one per line.
Trailing white space is removed from each line,
and blank lines are ignored. These paths are pro-
cessed before any that are listed on the command
line. The filename can be given as "-" to refer to
the standard input. If --file and --file-list are
both specified as "-", patterns are read first.
This is useful only when the standard input is a
terminal, from which further lines (the list of
files) can be read after an end-of-file indica-
tion. If this option is given more than once, all
the specified files are read.
--file-offsets
Instead of showing lines or parts of lines that
match, show each match as an offset from the start
of the file and a length, separated by a comma. In
this mode, no context is shown. That is, the -A,
-B, and -C options are ignored. If there is more
than one match in a line, each of them is shown
separately. This option is mutually exclusive with
--line-offsets and --only-matching.
-H, --with-filename
Force the inclusion of the filename at the start
of output lines when searching a single file. By
default, the filename is not shown in this case.
For matching lines, the filename is followed by a
colon; for context lines, a hyphen separator is
used. If a line number is also being output, it
follows the file name.
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-h, --no-filename
Suppress the output filenames when searching mul-
tiple files. By default, filenames are shown when
multiple files are searched. For matching lines,
the filename is followed by a colon; for context
lines, a hyphen separator is used. If a line
number is also being output, it follows the file
name.
--help Output a help message, giving brief details of the
command options and file type support, and then
exit. Anything else on the command line is
ignored.
-I Treat binary files as never matching. This is
equivalent to --binary-files=without-match.
-i, --ignore-case
Ignore upper/lower case distinctions during com-
parisons.
--include=pattern
If any --include patterns are specified, the only
files that are processed are those that match one
of the patterns (and do not match an --exclude
pattern). This option does not affect directories,
but it applies to all files, whether listed on the
command line, obtained from --file-list, or by
scanning a directory. The pattern is a PCRE regu-
lar expression, and is matched against the final
component of the file name, not the entire path.
The -F, -w, and -x options do not apply to this
pattern. The option may be given any number of
times. If a file name matches both an --include
and an --exclude pattern, it is excluded. There
is no short form for this option.
--include-from=filename
Treat each non-empty line of the file as the data
for an --include option. What constitutes a new-
line for this purpose is the operating system's
default. The --newline option has no effect on
this option. This option may be given any number
of times; all the files are read.
--include-dir=pattern
If any --include-dir patterns are specified, the
only directories that are processed are those that
match one of the patterns (and do not match an --
exclude-dir pattern). This applies to all direc-
tories, whether listed on the command line,
obtained from --file-list, or by scanning a parent
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directory. The pattern is a PCRE regular expres-
sion, and is matched against the final component
of the directory name, not the entire path. The
-F, -w, and -x options do not apply to this pat-
tern. The option may be given any number of times.
If a directory matches both --include-dir and --
exclude-dir, it is excluded. There is no short
form for this option.
-L, --files-without-match
Instead of outputting lines from the files, just
output the names of the files that do not contain
any lines that would have been output. Each file
name is output once, on a separate line.
-l, --files-with-matches
Instead of outputting lines from the files, just
output the names of the files containing lines
that would have been output. Each file name is
output once, on a separate line. Searching nor-
mally stops as soon as a matching line is found in
a file. However, if the -c (count) option is also
used, matching continues in order to obtain the
correct count, and those files that have at least
one match are listed along with their counts.
Using this option with -c is a way of suppressing
the listing of files with no matches.
--label=name
This option supplies a name to be used for the
standard input when file names are being output.
If not supplied, "(standard input)" is used. There
is no short form for this option.
--line-buffered
When this option is given, input is read and pro-
cessed line by line, and the output is flushed
after each write. By default, input is read in
large chunks, unless pcregrep can determine that
it is reading from a terminal (which is currently
possible only in Unix-like environments). Output
to terminal is normally automatically flushed by
the operating system. This option can be useful
when the input or output is attached to a pipe and
you do not want pcregrep to buffer up large
amounts of data. However, its use will affect per-
formance, and the -M (multiline) option ceases to
work.
--line-offsets
Instead of showing lines or parts of lines that
match, show each match as a line number, the
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offset from the start of the line, and a length.
The line number is terminated by a colon (as
usual; see the -n option), and the offset and
length are separated by a comma. In this mode, no
context is shown. That is, the -A, -B, and -C
options are ignored. If there is more than one
match in a line, each of them is shown separately.
This option is mutually exclusive with --file-
offsets and --only-matching.
--locale=locale-name
This option specifies a locale to be used for pat-
tern matching. It overrides the value in the
LC_ALL or LC_CTYPE environment variables. If no
locale is specified, the PCRE library's default
(usually the "C" locale) is used. There is no
short form for this option.
--match-limit=number
Processing some regular expression patterns can
require a very large amount of memory, leading in
some cases to a program crash if not enough is
available. Other patterns may take a very long
time to search for all possible matching strings.
The pcre_exec() function that is called by pcre-
grep to do the matching has two parameters that
can limit the resources that it uses.
The --match-limit option provides a means of lim-
iting resource usage when processing patterns that
are not going to match, but which have a very
large number of possibilities in their search
trees. The classic example is a pattern that uses
nested unlimited repeats. Internally, PCRE uses a
function called match() which it calls repeatedly
(sometimes recursively). The limit set by --
match-limit is imposed on the number of times this
function is called during a match, which has the
effect of limiting the amount of backtracking that
can take place.
The --recursion-limit option is similar to --
match-limit, but instead of limiting the total
number of times that match() is called, it limits
the depth of recursive calls, which in turn limits
the amount of memory that can be used. The recur-
sion depth is a smaller number than the total
number of calls, because not all calls to match()
are recursive. This limit is of use only if it is
set smaller than --match-limit.
There are no short forms for these options. The
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default settings are specified when the PCRE
library is compiled, with the default default
being 10 million.
-M, --multiline
Allow patterns to match more than one line. When
this option is given, patterns may usefully con-
tain literal newline characters and internal
occurrences of ^ and $ characters. The output for
a successful match may consist of more than one
line, the last of which is the one in which the
match ended. If the matched string ends with a
newline sequence the output ends at the end of
that line.
When this option is set, the PCRE library is
called in "multiline" mode. There is a limit to
the number of lines that can be matched, imposed
by the way that pcregrep buffers the input file as
it scans it. However, pcregrep ensures that at
least 8K characters or the rest of the document
(whichever is the shorter) are available for for-
ward matching, and similarly the previous 8K char-
acters (or all the previous characters, if fewer
than 8K) are guaranteed to be available for look-
behind assertions. This option does not work when
input is read line by line (see --line-buffered.)
-N newline-type, --newline=newline-type
The PCRE library supports five different conven-
tions for indicating the ends of lines. They are
the single-character sequences CR (carriage
return) and LF (linefeed), the two-character
sequence CRLF, an "anycrlf" convention, which
recognizes any of the preceding three types, and
an "any" convention, in which any Unicode line
ending sequence is assumed to end a line. The
Unicode sequences are the three just mentioned,
plus VT (vertical tab, U+000B), FF (form feed,
U+000C), NEL (next line, U+0085), LS (line separa-
tor, U+2028), and PS (paragraph separator,
U+2029).
When the PCRE library is built, a default line-
ending sequence is specified. This is normally
the standard sequence for the operating system.
Unless otherwise specified by this option, pcre-
grep uses the library's default. The possible
values for this option are CR, LF, CRLF, ANYCRLF,
or ANY. This makes it possible to use pcregrep to
scan files that have come from other environments
without having to modify their line endings. If
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the data that is being scanned does not agree with
the convention set by this option, pcregrep may
behave in strange ways. Note that this option does
not apply to files specified by the -f, --
exclude-from, or --include-from options, which are
expected to use the operating system's standard
newline sequence.
-n, --line-number
Precede each output line by its line number in the
file, followed by a colon for matching lines or a
hyphen for context lines. If the filename is also
being output, it precedes the line number. This
option is forced if --line-offsets is used.
--no-jit If the PCRE library is built with support for
just-in-time compiling (which speeds up matching),
pcregrep automatically makes use of this, unless
it was explicitly disabled at build time. This
option can be used to disable the use of JIT at
run time. It is provided for testing and working
round problems. It should never be needed in nor-
mal use.
-o, --only-matching
Show only the part of the line that matched a pat-
tern instead of the whole line. In this mode, no
context is shown. That is, the -A, -B, and -C
options are ignored. If there is more than one
match in a line, each of them is shown separately.
If -o is combined with -v (invert the sense of the
match to find non-matching lines), no output is
generated, but the return code is set appropri-
ately. If the matched portion of the line is
empty, nothing is output unless the file name or
line number are being printed, in which case they
are shown on an otherwise empty line. This option
is mutually exclusive with --file-offsets and --
line-offsets.
-onumber, --only-matching=number
Show only the part of the line that matched the
capturing parentheses of the given number. Up to
32 capturing parentheses are supported, and -o0 is
equivalent to -o without a number. Because these
options can be given without an argument (see
above), if an argument is present, it must be
given in the same shell item, for example, -o3 or
--only-matching=2. The comments given for the
non-argument case above also apply to this case.
If the specified capturing parentheses do not
exist in the pattern, or were not set in the
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match, nothing is output unless the file name or
line number are being printed.
If this option is given multiple times, multiple
substrings are output, in the order the options
are given. For example, -o3 -o1 -o3 causes the
substrings matched by capturing parentheses 3 and
1 and then 3 again to be output. By default, there
is no separator (but see the next option).
--om-separator=text
Specify a separating string for multiple
occurrences of -o. The default is an empty string.
Separating strings are never coloured.
-q, --quiet
Work quietly, that is, display nothing except
error messages. The exit status indicates whether
or not any matches were found.
-r, --recursive
If any given path is a directory, recursively scan
the files it contains, taking note of any --
include and --exclude settings. By default, a
directory is read as a normal file; in some
operating systems this gives an immediate end-of-
file. This option is a shorthand for setting the
-d option to "recurse".
--recursion-limit=number
See --match-limit above.
-s, --no-messages
Suppress error messages about non-existent or
unreadable files. Such files are quietly skipped.
However, the return code is still 2, even if
matches were found in other files.
-u, --utf-8
Operate in UTF-8 mode. This option is available
only if PCRE has been compiled with UTF-8 support.
All patterns (including those for any --exclude
and --include options) and all subject lines that
are scanned must be valid strings of UTF-8 charac-
ters.
-V, --version
Write the version numbers of pcregrep and the PCRE
library to the standard output and then exit. Any-
thing else on the command line is ignored.
-v, --invert-match
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Invert the sense of the match, so that lines which
do not match any of the patterns are the ones that
are found.
-w, --word-regex, --word-regexp
Force the patterns to match only whole words. This
is equivalent to having \b at the start and end of
the pattern. This option applies only to the pat-
terns that are matched against the contents of
files; it does not apply to patterns specified by
any of the --include or --exclude options.
-x, --line-regex, --line-regexp
Force the patterns to be anchored (each must start
matching at the beginning of a line) and in addi-
tion, require them to match entire lines. This is
equivalent to having ^ and $ characters at the
start and end of each alternative branch in every
pattern. This option applies only to the patterns
that are matched against the contents of files; it
does not apply to patterns specified by any of the
--include or --exclude options.
ENVIRONMENT VARIABLES
The environment variables LC_ALL and LC_CTYPE are examined,
in that order, for a locale. The first one that is set is
used. This can be overridden by the --locale option. If no
locale is set, the PCRE library's default (usually the "C"
locale) is used.
NEWLINES
The -N (--newline) option allows pcregrep to scan files with
different newline conventions from the default. Any parts of
the input files that are written to the standard output are
copied identically, with whatever newline sequences they
have in the input. However, the setting of this option does
not affect the interpretation of files specified by the -f,
--exclude-from, or --include-from options, which are assumed
to use the operating system's standard newline sequence, nor
does it affect the way in which pcregrep writes informa-
tional messages to the standard error and output streams.
For these it uses the string "\n" to indicate newlines,
relying on the C I/O library to convert this to an appropri-
ate sequence.
OPTIONS COMPATIBILITY
Many of the short and long forms of pcregrep's options are
the same as in the GNU grep program. Any long option of the
form --xxx-regexp (GNU terminology) is also available as --
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xxx-regex (PCRE terminology). However, the --file-list, --
file-offsets, --include-dir, --line-offsets, --locale, --
match-limit, -M, --multiline, -N, --newline, --om-separator,
--recursion-limit, -u, and --utf-8 options are specific to
pcregrep, as is the use of the --only-matching option with a
capturing parentheses number. Although most of the common
options work the same way, a few are different in pcregrep.
For example, the --include option's argument is a glob for
GNU grep, but a regular expression for pcregrep. If both the
-c and -l options are given, GNU grep lists only file names,
without counts, but pcregrep gives the counts.
OPTIONS WITH DATA
There are four different ways in which an option with data
can be specified. If a short form option is used, the data
may follow immediately, or (with one exception) in the next
command line item. For example:
-f/some/file
-f /some/file
The exception is the -o option, which may appear with or
without data. Because of this, if data is present, it must
follow immediately in the same item, for example -o3. If a
long form option is used, the data may appear in the same
command line item, separated by an equals character, or
(with two exceptions) it may appear in the next command line
item. For example:
--file=/some/file
--file /some/file
Note, however, that if you want to supply a file name begin-
ning with ~ as data in a shell command, and have the shell
expand ~ to a home directory, you must separate the file
name from the option, because the shell does not treat ~
specially unless it is at the start of an item. The excep-
tions to the above are the --colour (or --color) and --
only-matching options, for which the data is optional. If
one of these options does have data, it must be given in the
first form, using an equals character. Otherwise pcregrep
will assume that it has no data.
MATCHING ERRORS
It is possible to supply a regular expression that takes a
very long time to fail to match certain lines. Such patterns
normally involve nested indefinite repeats, for example:
(a+)*\d when matched against a line of a's with no final
digit. The PCRE matching function has a resource limit that
causes it to abort in these circumstances. If this happens,
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pcregrep outputs an error message and the line that caused
the problem to the standard error stream. If there are more
than 20 such errors, pcregrep gives up. The --match-limit
option of pcregrep can be used to set the overall resource
limit; there is a second option called --recursion-limit
that sets a limit on the amount of memory (usually stack)
that is used (see the discussion of these options above).
DIAGNOSTICS
Exit status is 0 if any matches were found, 1 if no matches
were found, and 2 for syntax errors, overlong lines, non-
existent or inaccessible files (even if matches were found
in other files) or too many matching errors. Using the -s
option to suppress error messages about inaccessible files
does not affect the return code.
SEE ALSO
pcrepattern(3), pcresyntax(3), pcretest(1).
AUTHOR
Philip Hazel
University Computing Service
Cambridge CB2 3QH, England.
REVISION
Last updated: 03 April 2014
Copyright (c) 1997-2014 University of Cambridge.
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