Add BSD grep to the base system and make it our default grep.

Deliverables: Small and clean code (1,4 KSLOC vs GNU's 8,5 KSLOC),
              lower memory usage than GNU grep, GNU compatibility,
              BSD license.

TODO:         Performance is somewhat behind GNU grep but it is only
              significant for bigger searches.  The reason is complex, the
              most important factor is that GNU grep uses lots of
              optimizations to improve the speed of the regex library.
              First, we need a modern regex library (practically by adopting
              TRE), add support for GNU-style non-standard regexes and then
              reevalute the performance issues and look for bottlenecks.  In
              the meantime, for those, who need better performance, it is
              possible to build GNU grep by setting WITH_GNU_GREP.

Approved by:            delphij (mentor)
Obtained from:          OpenBSD (http://www.openbsd.org/cgi-bin/cvsweb/src/usr.bin/grep/),
                        freegrep (http://github.com/howardjp/freegrep)
Sponsored by:           Google SoC 2008
Portbuild tests run by: kris, pav, erwin
Acknowledgements to:    fjoe (as SoC 2008 mentor),
                        everyone who helped in reviewing and testing

1 files changed, 461 insertions, 0 deletions

diff --git a/usr.bin/grep/grep.1 b/usr.bin/grep/grep.1
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+.\"	$FreeBSD$
+.\"	$OpenBSD: grep.1,v 1.38 2010/04/05 06:30:59 jmc Exp $
+.\" Copyright (c) 1980, 1990, 1993
+.\"	The Regents of the University of California.  All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\"	@(#)grep.1	8.3 (Berkeley) 4/18/94
+.\"
+.Dd 19 September, 2009
+.Dt GREP 1
+.Os
+.Sh NAME
+.Nm grep , egrep , fgrep ,
+.Nm zgrep , zegrep , zfgrep
+.Nd file pattern searcher
+.Sh SYNOPSIS
+.Nm grep
+.Bk -words
+.Op Fl abcdDEFGHhIiJLlmnOopqRSsUVvwxZ
+.Op Fl A Ar num
+.Op Fl B Ar num
+.Op Fl C Ns Op Ar num
+.Op Fl e Ar pattern
+.Op Fl f Ar file
+.Op Fl Fl binary-files Ns = Ns Ar value
+.Op Fl Fl color Ns Op = Ns Ar when
+.Op Fl Fl colour Ns Op = Ns Ar when
+.Op Fl Fl context Ns Op = Ns Ar num
+.Op Fl Fl label
+.Op Fl Fl line-buffered
+.Op Fl Fl null
+.Op Ar pattern
+.Op Ar
+.Ek
+.Sh DESCRIPTION
+The
+.Nm grep
+utility searches any given input files,
+selecting lines that match one or more patterns.
+By default, a pattern matches an input line if the regular expression
+(RE) in the pattern matches the input line
+without its trailing newline.
+An empty expression matches every line.
+Each input line that matches at least one of the patterns is written
+to the standard output.
+.Pp
+.Nm grep
+is used for simple patterns and
+basic regular expressions
+.Pq BREs ;
+.Nm egrep
+can handle extended regular expressions
+.Pq EREs .
+See
+.Xr re_format 7
+for more information on regular expressions.
+.Nm fgrep
+is quicker than both
+.Nm grep
+and
+.Nm egrep ,
+but can only handle fixed patterns
+(i.e. it does not interpret regular expressions).
+Patterns may consist of one or more lines,
+allowing any of the pattern lines to match a portion of the input.
+.Pp
+.Nm zgrep ,
+.Nm zegrep ,
+and
+.Nm zfgrep
+act like
+.Nm grep ,
+.Nm egrep ,
+and
+.Nm fgrep ,
+respectively, but accept input files compressed with the
+.Xr compress 1
+or
+.Xr gzip 1
+compression utilities.
+.Pp
+The following options are available:
+.Bl -tag -width indent
+.It Fl A Ar num , Fl Fl after-context Ns = Ns Ar num
+Print
+.Ar num
+lines of trailing context after each match.
+See also the
+.Fl B
+and
+.Fl C
+options.
+.It Fl a , Fl Fl text
+Treat all files as ASCII text.
+Normally
+.Nm
+will simply print
+.Dq Binary file ... matches
+if files contain binary characters.
+Use of this option forces
+.Nm
+to output lines matching the specified pattern.
+.It Fl B Ar num , Fl Fl before-context Ns = Ns Ar num
+Print
+.Ar num
+lines of leading context before each match.
+See also the
+.Fl A
+and
+.Fl C
+options.
+.It Fl b , Fl Fl byte-offset
+The offset in bytes of a matched pattern is
+displayed in front of the respective matched line.
+.It Fl C Ns Op Ar num , Fl Fl context Ns = Ns Ar num
+Print
+.Ar num
+lines of leading and trailing context surrounding each match.
+The default is 2 and is equivalent to
+.Fl A
+.Ar 2
+.Fl B
+.Ar 2 .
+Note:
+no whitespace may be given between the option and its argument.
+.It Fl c , Fl Fl count
+Only a count of selected lines is written to standard output.
+.It Fl Fl colour Ns = Ns Op Ar when , Fl Fl color Ns = Ns Op Ar when
+Mark up the matching text with the expression stored in
+.Ev GREP_COLOR
+environment variable.
+The possible values of when can be `never', `always' or `auto'.
+.It Fl D Ar action , Fl Fl devices Ns = Ns Ar action
+Specify the demanded action for devices, FIFOs and sockets.
+The default action is `read', which means, that they are read
+as if they were normal files.
+If the action is set to `skip', devices will be silently skipped.
+.It Fl d Ar action , Fl Fl directories Ns = Ns Ar action
+Specify the demanded action for directories.
+It is `read' by default, which means that the directories
+are read in the same manner as normal files.
+Other possible values are `skip' to silently ignore the
+directories, and `recurse' to read them recursively, which
+has the same effect as the
+.Fl R
+and
+.Fl r
+option.
+.It Fl E , Fl Fl extended-regexp
+Interpret
+.Ar pattern
+as an extended regular expression
+(i.e. force
+.Nm grep
+to behave as
+.Nm egrep ) .
+.It Fl e Ar pattern , Fl Fl regexp Ns = Ns Ar pattern
+Specify a pattern used during the search of the input:
+an input line is selected if it matches any of the specified patterns.
+This option is most useful when multiple
+.Fl e
+options are used to specify multiple patterns,
+or when a pattern begins with a dash
+.Pq Sq - .
+.It Fl Fl exclude
+If
+.Fl R
+is specified, it excludes files matching the given
+filename pattern.
+.It Fl Fl exclude-dir
+If
+.Fl R
+is specified, it excludes directories matching the
+given filename pattern.
+.It Fl F , Fl Fl fixed-strings
+Interpret
+.Ar pattern
+as a set of fixed strings
+(i.e. force
+.Nm grep
+to behave as
+.Nm fgrep ) .
+.It Fl f Ar file , Fl Fl file Ns = Ns Ar file
+Read one or more newline separated patterns from
+.Ar file .
+Empty pattern lines match every input line.
+Newlines are not considered part of a pattern.
+If
+.Ar file
+is empty, nothing is matched.
+.It Fl G , Fl Fl basic-regexp
+Interpret
+.Ar pattern
+as a basic regular expression
+(i.e. force
+.Nm grep
+to behave as traditional
+.Nm grep ) .
+.It Fl H
+Always print filename headers with output lines.
+.It Fl h , Fl Fl no-filename
+Never print filename headers
+.Pq i.e. filenames
+with output lines.
+.It Fl Fl help
+Print a brief help message.
+.It Fl I
+Ignore binary files.
+This option is equivalent to
+.Fl Fl binary-file Ns = Ns Ar without-match
+option.
+.It Fl i , Fl Fl ignore-case
+Perform case insensitive matching.
+By default,
+.Nm grep
+is case sensitive.
+.It Fl Fl include
+If
+.Fl R
+is specified, it includes the files matching the
+given filename pattern.
+.It Fl Fl include-dir
+If
+.Fl R
+is specified, it includes the directories matching the
+given filename pattern.
+.It Fl J, Fl Fl bz2decompress
+Decompress the
+.Xr bzip2 1
+compressed file before looking for the text.
+.It Fl L , Fl Fl files-without-match
+Only the names of files not containing selected lines are written to
+standard output.
+Pathnames are listed once per file searched.
+If the standard input is searched, the string
+.Dq (standard input)
+is written.
+.It Fl l , Fl Fl files-with-matches
+Only the names of files containing selected lines are written to
+standard output.
+.Nm grep
+will only search a file until a match has been found,
+making searches potentially less expensive.
+Pathnames are listed once per file searched.
+If the standard input is searched, the string
+.Dq (standard input)
+is written.
+.It Fl Fl mmap
+Use
+.Xr mmap 2
+instead of
+.Xr read 2
+to read input, which can result in better performance under some
+circumstances but can cause undefined behaiour.
+.It Fl m Ar num, Fl Fl max-count Ns = Ns Ar num
+Stop reading the file after
+.Ar num
+matches.
+.It Fl n , Fl Fl line-number
+Each output line is preceded by its relative line number in the file,
+starting at line 1.
+The line number counter is reset for each file processed.
+This option is ignored if
+.Fl c ,
+.Fl L ,
+.Fl l ,
+or
+.Fl q
+is
+specified.
+.It Fl Fl null
+Prints a zero-byte after the file name.
+.It Fl O
+If
+.Fl R
+is specified, follow symbolic links only if they were explicitly listed
+on the command line.
+The default is not to follow symbolic links.
+.It Fl o, Fl Fl only-matching
+Prints only the matching part of the lines.
+.It Fl p
+If
+.Fl R
+is specified, no symbolic links are followed.
+This is the default.
+.It Fl q , Fl Fl quiet , Fl Fl silent
+Quiet mode:
+suppress normal output.
+.Nm grep
+will only search a file until a match has been found,
+making searches potentially less expensive.
+.It Fl R , Fl r , Fl Fl recursive
+Recursively search subdirectories listed.
+.It Fl S
+If
+.Fl R
+is specified, all symbolic links are followed.
+The default is not to follow symbolic links.
+.It Fl s , Fl Fl no-messages
+Silent mode.
+Nonexistent and unreadable files are ignored
+(i.e. their error messages are suppressed).
+.It Fl U , Fl Fl binary
+Search binary files, but do not attempt to print them.
+.It Fl V , Fl Fl version
+Display version information and exit.
+.It Fl v , Fl Fl invert-match
+Selected lines are those
+.Em not
+matching any of the specified patterns.
+.It Fl w , Fl Fl word-regexp
+The expression is searched for as a word (as if surrounded by
+.Sq [[:<:]]
+and
+.Sq [[:>:]] ;
+see
+.Xr re_format 7 ) .
+.It Fl x , Fl Fl line-regexp
+Only input lines selected against an entire fixed string or regular
+expression are considered to be matching lines.
+.It Fl y
+Equivalent to
+.Fl i .
+Obsoleted.
+.It Fl Z , Fl z , Fl Fl decompress
+Force
+.Nm grep
+to behave as
+.Nm zgrep .
+.It Fl Fl binary-files Ns = Ns Ar value
+Controls searching and printing of binary files.
+Options are
+.Ar binary ,
+the default: search binary files but do not print them;
+.Ar without-match :
+do not search binary files;
+and
+.Ar text :
+treat all files as text.
+.Sm off
+.It Fl Fl context Op = Ar num
+.Sm on
+Print
+.Ar num
+lines of leading and trailing context.
+The default is 2.
+.It Fl Fl line-buffered
+Force output to be line buffered.
+By default, output is line buffered when standard output is a terminal
+and block buffered otherwise.
+.Pp
+.El
+If no file arguments are specified, the standard input is used.
+.Sh RETURN VALUES
+The
+.Nm grep
+utility exits with one of the following values:
+.Pp
+.Bl -tag -width flag -compact
+.It Li 0
+One or more lines were selected.
+.It Li 1
+No lines were selected.
+.It Li \*(Gt1
+An error occurred.
+.El
+.Sh EXAMPLES
+To find all occurrences of the word
+.Sq patricia
+in a file:
+.Pp
+.Dl $ grep 'patricia' myfile
+.Pp
+To find all occurrences of the pattern
+.Ql .Pp
+at the beginning of a line:
+.Pp
+.Dl $ grep '^\e.Pp' myfile
+.Pp
+The apostrophes ensure the entire expression is evaluated by
+.Nm grep
+instead of by the user's shell.
+The caret
+.Ql ^
+matches the null string at the beginning of a line,
+and the
+.Ql \e
+escapes the
+.Ql \&. ,
+which would otherwise match any character.
+.Pp
+To find all lines in a file which do not contain the words
+.Sq foo
+or
+.Sq bar :
+.Pp
+.Dl $ grep -v -e 'foo' -e 'bar' myfile
+.Pp
+A simple example of an extended regular expression:
+.Pp
+.Dl $ egrep '19|20|25' calendar
+.Pp
+Peruses the file
+.Sq calendar
+looking for either 19, 20, or 25.
+.Sh SEE ALSO
+.Xr ed 1 ,
+.Xr ex 1 ,
+.Xr gzip 1 ,
+.Xr sed 1 ,
+.Xr re_format 7
+.Sh STANDARDS
+The
+.Nm
+utility is compliant with the
+.St -p1003.1-2008
+specification.
+.Pp
+The flags
+.Op Fl AaBbCDdGHhIJLmoPRSUVwZ
+are extensions to that specification, and the behaviour of the
+.Fl f
+flag when used with an empty pattern file is left undefined.
+.Pp
+All long options are provided for compatibility with
+GNU versions of this utility.
+.Pp
+Historic versions of the
+.Nm grep
+utility also supported the flags
+.Op Fl ruy .
+This implementation supports those options;
+however, their use is strongly discouraged.
+.Sh HISTORY
+The
+.Nm grep
+command first appeared in
+.At v6 .