PCREGREP(1)                                                        PCREGREP(1)

NAME

       pcregrep - a grep with Perl-compatible regular expressions.

SYNOPSIS

       pcregrep [options] [long options] [pattern] [path1 path2 ...]

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  seman-

       tics 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.   Con-

       versely,  when  one  or  both of these options are used to specify pat-

       terns, 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 stan-

       dard 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. As soon as one pat-

       tern 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  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, 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

       --        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  file-

                 names 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 sep-

                 arator  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 avail-

                 able 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 sep-

                 arator 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 avail-

                 able 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 output a count

                 of the number of lines that would otherwise 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

                 output is connected to a terminal. The colour can  be  speci-

                 fied  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 ter-

                 minal,  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 mul-

                 tiple 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  multi-

                 ple use of -e is not the same as a single pattern with alter-

                 natives. For example, X|Y finds the first character in a line

                 that  is  X or Y, whereas if the two patterns are given sepa-

                 rately, 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 con-

                 sequence of the -r (recursive  search)  option,  any  regular

                 files whose names match the pattern are excluded. Subdirecto-

                 ries 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 subdi-

                 rectories 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 (sub-

                 ject 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 and a  space;  for  context  lines,  a

                 hyphen separator is used. If a line number is also being out-

                 put, it follows the file name without a space.

       -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  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 comparisons.

       --include=pattern

                 When pcregrep is searching the files in a directory as a con-

                 sequence of the -r (recursive search) option, only those reg-

                 ular files whose names match the pattern are included. Subdi-

                 rectories  are always included and searched recursively, sub-

                 ject to the --include_dir and --exclude_dir options. The pat-

                 tern 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 subdirecto-

                 ries.) 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  sepa-

                 rate 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 out-

                 put.  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 sepa-

                 rately. This option is mutually exclusive with --file-offsets

                 and --only-matching.

       --locale=locale-name

                 This  option specifies a locale to be used for pattern match-

                 ing. It overrides the value in the LC_ALL or  LC_CTYPE  envi-

                 ronment  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 contain literal newline char-

                 acters  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 "mul-

                 tiline" 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  simi-

                 larly the previous 8K characters (or all the previous charac-

                 ters, if fewer than 8K) are guaranteed to  be  available  for

                 lookbehind assertions.

       -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  rec-

                 ognizes  any  of the preceding three types, and an "any" con-

                 vention, in which any Unicode line ending sequence is assumed

                 to  end a line. The Unicode sequences are the three just men-

                 tioned,  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, fol-

                 lowed 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 pattern. 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 the  files

                 it  contains, taking note of any --include and --exclude set-

                 tings. 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  sub-

                 ject 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 equiva-

                 lent 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

       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 pcregrep.

OPTIONS WITH DATA

       There are four different ways in which an option with data can be spec-

       ified.  If a short form option is used, the  data  may  follow  immedi-

       ately, 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 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  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 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.

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 inacessible 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.