Provided by: pcregrep_8.12-4_amd64 bug

NAME

       pcregrep - a grep with Perl-compatible regular expressions.

SYNOPSIS

       pcregrep  [options]  [long options] [pattern] [path1 path2 ...]  zpcregrep [options] [long
       options] [pattern] [file1 file2 ...]

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 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 surrounding 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 argument 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  pcregrep  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  <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 patterns are tried before the -f patterns.

       By default, as soon as one pattern matches (or fails to match when -v is used), no further
       patterns are considered. 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 is the same behaviour as GNU grep, but it does mean that the order in which  multiple
       patterns are specified can affect the output when one of the above options is used.

       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.

       zpcregrep is a wrapper script that allows pcregrep to work on gzip compressed files.

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, respectively. 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


       The order in which some of the options appear can affect the 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.

       --        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 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 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 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  standard  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 setting the environment variable
                 PCREGREP_COLOUR or PCREGREP_COLOR. 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 directory, "action" specifies how it
                 is  to  be  processed. Valid values are "read" (the default) or "skip" (silently
                 skip the path).

       -d action, --directories=action
                 If an input path is a directory, "action" 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 specifying 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, X|Y 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 directory 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
                 recursively, subject to the --exclude-dir and --include_dir 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.

       --exclude-dir=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.)
                 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
                 --include-dir and --exclude-dir, 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 patterns. However, no other pattern is taken from the
                 command line; all arguments are treated as  file  names.  There  is  an  overall
                 maximum  of  100  patterns.  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.

       --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.

       -h, --no-filename
                 Suppress the  output  filenames  when  searching  multiple  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.

       -i, --ignore-case
                 Ignore upper/lower case distinctions during comparisons.

       --include=pattern
                 When pcregrep is searching the files in a directory 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 --include-dir and --exclude-dir 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.

       --include-dir=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
                 subdirectories.)  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 --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 normally 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 processed 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 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 performance, 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 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 pattern 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 pcregrep to do the matching
                 has two parameters that can limit the resources that it uses.

                 The --match-limit option provides  a  means  of  limiting  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 recursion 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 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 contain 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 forward matching, and similarly the previous 8K characters (or
                 all the previous characters, if fewer than 8K) are guaranteed  to  be  available
                 for  lookbehind 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 conventions 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 (formfeed,
                 U+000C), NEL (next line, U+0085), LS (line separator, 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, pcregrep 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 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.

       -o, --only-matching
                 Show only the part of the line that matched a pattern 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
                 appropriately. 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.  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  match,  nothing is output unless the file name or line number are being
                 printed.

       -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.  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 addition, 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 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.  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


       Many of the short and long forms of pcregrep's options are the same as  in  the  GNU  grep
       program  (version  2.5.4).  Any  long option of the form --xxx-regexp (GNU terminology) is
       also available as --xxx-regex (PCRE terminology). However, the --file-offsets,  --include-
       dir, --line-offsets, --locale, --match-limit, -M, --multiline, -N, --newline, --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 beginning 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 exceptions 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,
       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  and 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
       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: 14 January 2011
       Copyright (c) 1997-2011 University of Cambridge.

                                                                                      PCREGREP(1)