freebsd-nq/tools/build/options/WITH_GNU_GREP_COMPAT

.\" $FreeBSD$
Set this option to include GNU extensions in
.Xr bsdgrep 1
by linking against libgnuregex.
bsdgrep: disable GNU_GREP_COMPAT by default The GNU extension bits in the base system are old, no longer faithful to upstream, and surprising in some regards. Switch to documenting WITH_GNU_GREP_COMPAT and default GNU_GREP_COMPAT to OFF in the name of good behavior. According to http://www.regular-expressions.info, GNU extensions: - Add missing quantifiers to BREs: \?, \+ - Add branching to BREs: \\| - Add backreferences (\1 through \9) to EREs - Add \w, \W, \s, and \S corresponding to :alnum:, [^[:alnum:]], :space:, and [^[:space:]] respectively - Add word boundaries and anchors: \b: word boundary \B: not word boundary \<: Strt of word \>: End of word \`: Start of subject string \': End of subject string These extensions are still available in /usr/bin/grep by default today, as it is still GNU grep. As part of the bsdgrep migration plan these extensions may be added to bsdgrep's regex support if necessary. Submitted by: Kyle Evans <kevans91 at ksu.edu> Reviewed by: cem Differential Revision: https://reviews.freebsd.org/D10114 2017-04-21 14:50:29 +00:00			`.\" $FreeBSD$`
			`Set this option to include GNU extensions in`
			`.Xr bsdgrep 1`
			`by linking against libgnuregex.`