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 pcrepattern(3)
for a full description of syntax and semantics of the regu-
lar 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 they
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 argu-
ment pattern must be provided.
If no files are specified, 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.
Patterns are limited to 8K or BUFSIZ characters, whichever
is the greater. BUFSIZ is defined in . When there
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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 patterns are
tried before the -f patterns. As soon as one pattern matches
(or fails to match when -v is used), no further patterns are
considered.
When --only-matching, --file-offsets, or --line-offsets is
used, the output is the part of the line that matched
(either shown literally, or as an offset). In this case,
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. However, patterns that follow the one that matched
are not tried on the earlier part of the line.
If the LCAL or LCTYPE environment variable is set, pcre-
grep uses the value to set a locale when calling the PCRE
library. The --locale option can be used to override this.
SUPORT FOR COMPRESED 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.
OPTIONS
-- This terminate 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.
-B number, --before-context=number
Output number lines of context before each match-
ing line. If filenames and/or line numbers are
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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.
-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; instead just out-
put a count of the number of lines that would oth-
erwise have been output. If several files are
given, a count is output for each of them. In this
mode, 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
part of a line that matched a pattern should be
coloured in the output. The value may be "never"
(the default), "always", or "auto". In the latter
case, colouring happens only if the standard out-
put is connected to a terminal. The colour can be
specified by setting the environment variable
PCREGREPCOLOUR or PCREGREPCOLOR. The value of
this variable should be a string of two numbers,
separated by a semicolon. 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 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"
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specifies how it is to be processed. Valid values
are "read" (the default), "recurse" (equivalent to
the -r option), or "skip" (silently skip the
path). In the default 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.
-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 an overall maximum of 100
patterns. They are applied to each line in the
order in which they are defined until one matches
(or fails to match if -v is used). If -f is used
with -e, the command line patterns are matched
first, followed by the patterns from the file,
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, XY finds the first character in a
line that is X or Y, whereas if the two patterns
are given separately, pcregrep finds X if it is
present, even if it follows Y in the line. It
finds Y only if there is no X in the line. This
really matters only if you are using -o to show
the part(s) of the line that matched.
--exclude=pattern
When pcregrep is searching the files in a direc-
tory as a consequence of the -r (recursive search)
option, any regular files whose names match the
pattern are excluded. Subdirectories are not
excluded by this option; they are searched recur-
sively, subject to the --excludedir and --
includedir options. The pattern is a PCRE regular
expression, and is matched against the final com-
ponent of the file name (not the entire path). If
a file name matches both --include and --exclude,
it is excluded. There is no short form for this
option.
--excludedir=pattern
When pcregrep is searching the contents of a
directory as a consequence of the -r (recursive
search) option, any subdirectories whose names
match the pattern are excluded. (Note that the --
exclude option does not affect subdirectories.)
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The pattern is a PCRE regular expression, and is
matched against the final component of the name
(not the entire path). If a subdirectory name
matches both --includedir and --excludedir, it
is excluded. There is no short form for this
option.
-F, --fixed-strings
Interpret each pattern as a list of fixed strings,
separated by newlines, instead of as a regular
expression. 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).
-f filename, --file=filename
Read a number of patterns from the file, one per
line, and match them against each line of input. A
data line is output if any of the patterns match
it. The 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 pat-
terns. However, no other pattern is taken from the
command line; all arguments are treated as file
names. There is an overall maximum of 100 pat-
terns. Trailing white space is removed from each
line, and blank lines are ignored. An empty file
contains no patterns and therefore matches noth-
ing. See also the comments about multiple patterns
versus a single pattern with alternatives in the
description of -e above.
--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 and a space; for context lines, a hyphen
separator is used. If a line number is also being
output, it follows the file name without a space.
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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 and a space;
for context lines, a hyphen separator is used. If
a line number is also being output, it follows the
file name without a space.
--help Output a help message, giving brief details of the
command options and file type support, and then
exit.
-i, --ignore-case
Ignore upper/lower case distinctions during com-
parisons.
--include=pattern
When pcregrep is searching the files in a direc-
tory as a consequence of the -r (recursive search)
option, only those regular files whose names match
the pattern are included. Subdirectories are
always included and searched recursively, subject
to the --includedir and --excludedir options.
The pattern is a PCRE regular expression, and is
matched against the final component of the file
name (not the entire path). If a file name matches
both --include and --exclude, it is excluded.
There is no short form for this option.
--includedir=pattern
When pcregrep is searching the contents of a
directory as a consequence of the -r (recursive
search) option, only those subdirectories whose
names match the pattern are included. (Note that
the --include option does not affect subdirec-
tories.) The pattern is a PCRE regular expression,
and is matched against the final component of the
name (not the entire path). If a subdirectory name
matches both --includedir and --excludedir, 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
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that would have been output. Each file name is
output once, on a separate line. Searching stops
as soon as a matching line is found in a file.
--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-offsets
Instead of showing lines or parts of lines that
match, show each match as a line number, the
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
LCAL or LCTYPE 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.
-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
any one match may consist of more than one 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.
-N newline-type, --newline=newline-type
The PCRE library supports five different conven-
tions for indicating the ends of lines. They are
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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), F (formfeed,
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 on
files that have come from other environments
without having to modify their line endings. If
the data that is being scanned does not agree with
the convention set by this option, pcregrep may
behave in strange ways.
-n, --line-number
Precede each output line by its line number in the
file, followed by a colon and a space for matching
lines or a hyphen and a space for context lines.
If the filename is also being output, it precedes
the line number. This option is forced if --line-
offsets is used.
-o, --only-matching
Show only the part of the line that matched a pat-
tern. 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 appropriately. This option is
mutually exclusive with --file-offsets and --
line-offsets.
-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
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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".
-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.
Both patterns and subject lines must be valid
strings of UTF-8 characters.
-V, --version
Write the version numbers of pcregrep and the PCRE
library that is being used to the standard error
stream.
-v, --invert-match
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.
-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.
ENVIRONMENT VARIABLES
The environment variables LCAL and LCTYPE 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
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The -N (--newline) option allows pcregrep to scan files with
different newline conventions from the default. However, the
setting of this option does not affect the way in which
pcregrep writes information to the standard error and output
streams. It uses the string "\n" in C printf() calls to
indicate newlines, relying on the C I/O library to convert
this to an appropriate sequence if the output is sent to a
file.
OPTIONS COMPATIBILITY
The majority of 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
--xxx-regex (PCRE terminology). However, the --locale, -M,
--multiline, -u, and --utf-8 options are specific to pcre-
grep.
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 in the next command line item.
For example:
-f/some/file
-f /some/file
If a long form option is used, the data may appear in the
same command line item, separated by an equals character, or
(with one exception) 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 exception to the above is the --colour (or --color)
option, for which the data is optional. If this option does
have data, it must be given in the first form, using an
equals character. Otherwise it will be assumed that it has
no data.
MATCHING ERORS
It is possible to supply a regular expression that takes a
very long time to fail to match certain lines. Such patterns
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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,
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.
DIAGNOSTICS
Exit status is 0 if any matches were found, 1 if no matches
were found, and 2 for syntax errors and non-existent or ina-
cessible files (even if matches were found in other files)
or too many matching errors. Using the -s option to suppress
error messages about inaccessble files does not affect the
return code.
SEE ALSO
pcrepattern(3), pcretest(1).
AUTHOR
Philip Hazel
University Computing Service
Cambridge CB2 3QH, England.
REVISION
Last updated: 08 March 2008
Copyright (c) 1997-2008 University of Cambridge.
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
ATRIBUTE TYPE ATRIBUTE VALUE
Availability SUNWpcre
Interface Stability Uncommitted
NOTES
Source for PCRE is available on http:/opensolaris.org.
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